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-   -   Are primes brighter and sharper than wide open zooms (http://www.photobanter.com/showthread.php?t=49519)

no_name September 29th 05 02:01 PM

Dr. Joel M. Hoffman wrote:

Given two lenses, one a prime (say 28mm) and the other a zoom (say
28-75mm) and both with an aperture of f2.8 -
- Will the prime be brighter than the zoom because it has fewer lens
elements?



No. f/2.8 tells you exactly how bright the lens is. (It's almost
like the old question about a pound of lead and a pound of feathers -
they do both weigh the same.)


However, a pound of gold and a pound of feathers do not.



W.E. O'Neil September 29th 05 02:46 PM


"Randall Ainsworth" wrote in message
...

An f/2.8 lens is going to allow a specific amount of light to go
through regardless of what kind of glass it's made of.


Strictly speaking you are on the wrong track. I think you may be confusing
transmission with focal ratio. F2.8 simply speaks to the focal
ratio.......slower materials would result in less light being transmitted.




Peter September 29th 05 02:50 PM


Randall Ainsworth wrote:
In article , Brion K. Lienhart
wrote:

Nope. F:2.8 is solely based on the size of the lens. Obsidian is glass,
you can grind it into a lens shape, but if you use it as an element in a
lens, you're going to get some reallllllly slow shutter speeds. Of
course that's an extreme case, the difference between plain old glass
glass, and exotic flouro-silicates is only a few fractions of a percent.


An f/2.8 lens is going to allow a specific amount of light to go
through regardless of what kind of glass it's made of.


Actually no, but in most cases the difference is unimportant.

One case where the difference generally is important is with
a mirror lens. A mirror lens is generally only about 60%
efficient compared with around 90%+ efficiency for a glass
lens with ten multicoated air-glass surfaces.

A 500mm f/6.3 mirror lens may let in about the same light
as a 500mm f/8 coated glass lens. This can be a significant
factor when deciding what lens to buy. A mirror lens does
not gather quite as much light as you would expect from
the aperture.

Peter.
--



Scott Schuckert September 29th 05 03:03 PM

In article , Randall
Ainsworth wrote:

An f/2.8 lens is going to allow a specific amount of light to go
through regardless of what kind of glass it's made of.


Ahem. Notice the previous 50+ responses in this thread? If not, read
some - you're dead wrong. What you're thinking of is a T-stop. Lenses
of the same mathematical aperture (f/stop) can and do wary widely in
transmission. Period.

Peter September 29th 05 03:17 PM


Brion K. Lienhart wrote:
Peter wrote:

You know, sometimes words have two meanings.

Most of us can live with slang terminology and standard technical
terminology without getting particularly confused. Slang terminology
can be very handy: I'm not going to stop saying "Hypo" when I know
that fixer is actually thiosulphate. It isn't very likely that someone


Not to be pedantic, but I think you mean "Jargon" not "Slang".



Actually you are being pedantic, saying "not to be pedantic"
in front of a sentence doesn't make it so.

I looked up "slang" and "jargon" in several dictionaries,
and at least some of the meanings are nearly interchangable.
I chose "slang" because I wanted to emphasize the non-standard
nature of the vocabulary rather than any lack of intelligibility
to outsiders.

Peter.
--



David Littlewood September 29th 05 05:09 PM

In article , Tony Polson
writes
Eugene wrote:

Perhaps my comments were a bit harsh. I just took offense to the
suggestion that it was ignorant to use the widely accepted and
understood term "prime lens".



But "prime lens" is NOT a "widely accepted and understood term".

Because of the history of its use, it is essentially ambiguous. It
has only been used as a descriptor for all fixed focal length lenses
in recent times, and only by people who are unaware of its prior
usage, which was as a descriptor for a "high quality" subset of fixed
focal length lenses. You might be too young to recall this.

There was no accepted definition of which fixed focal length lenses
were "prime" and which were not. It was merely an attempt by
marketing people to promote some lenses as being "better" than others,
the implication being that one brand was "better" than another because
of the "high quality" of their "prime" lenses.

The terms "high quality", "better" and "prime" are all essentially
meaningless unless backed up with something more objective, repeatable
and reliable. As we all (should) know, comparisons between lenses are
qualitative at best.

The most commonly used "objective" comparator - MTF - was never
intended for making such comparisons. It was intended as an aid to
lens designers and nothing more. As a result it misleads far more
than it ever informs, and those who claim it is of any real value when
comparing photographic lenses are suffering from delusions.


I agree with the first part of the above. The only point in which my
understanding differs is that the traditional use of the term "prime"
was in the sense of "primary" as opposed to secondary or auxiliary
optical components such as tele-converters, wide angle attachments,
close up lenses and the like. Thus prime as in the Latin "primus", first
or primary.

This is the interpretation given in the more rigorous works on
photography I consulted on this issue when the point was debated here
(ad nauseam) several years ago. (Anyone remember Neil Harrington?)

David
--
David Littlewood

David Littlewood September 29th 05 05:12 PM

In article , no_name
writes
Tony Polson wrote:

Eugene wrote:

Perhaps my comments were a bit harsh. I just took offense to the
suggestion that it was ignorant to use the widely accepted and
understood term "prime lens".

But "prime lens" is NOT a "widely accepted and understood term".


Who here does not understand what is meant when the term "prime lens"
is used?

A show of hands please?


As it is an ambiguous usage, i.e. one which is in conflict with the
traditional meaning of the word, then I personally avoid using the word
altogether. I agree that when others use the word it is usually apparent
from the context what they mean, but IMO it is mildly rude to one's
readers to deliberately choose to make them work out meaning from the
context.

David
--
David Littlewood

Jeremy September 29th 05 05:32 PM

"Randall Ainsworth" wrote in message
...

An f/2.8 lens is going to allow a specific amount of light to go
through regardless of what kind of glass it's made of.


I believe that you are incorrect. the F-stops are geometric measurements of
the aperture opening. If a lens has a large number of elements, like a zoom
lens, less light may ultimately reach the film plane (or the chip) than
would be the case if a lens with a lesser number of elements were
substituted, even if both lenses were set to the same aperture opening.

My SMC Takumar 50mm f/1.4 is an interesting example. As is well known, the
rear element on those lenses had Thorium mixed into the optical glass
formula, and the decaying atomic particles have yellowed the lens over the
decades. That lens, set at f/1.4, probably transmits only an amount of
light equivalent to another (non-yellowed) lens at f/1.8.

I admit, however, that most lenses, at any given f-stop, probably transmit
about the same amount of light to the film or chip. But it is not
absolutely guaranteed. And these days, with TTL metering, the exposure
values can be adjusted to compensate.



Dave Martindale September 29th 05 09:52 PM

no_name writes:

(It's almost
like the old question about a pound of lead and a pound of feathers -
they do both weigh the same.)


However, a pound of gold and a pound of feathers do not.


Due to the archaic system of weights&measures that uses a different unit
with the same name for measuring precious metals.

But a gram of gold and a gram of feathers *are* the same mass, and have
the same weight in the same gravity.

Dave

Pete D September 30th 05 04:38 AM


"no_name" wrote in message
om...
John A. Stovall wrote:

On 28 Sep 2005 07:33:55 -0700, "Siddhartha Jain"
wrote:


Hi,

Given two lenses, one a prime (say 28mm) and the other a zoom (say
28-75mm) and both with an aperture of f2.8 -
- Will the prime be brighter than the zoom because it has fewer lens
elements?
- Will the prime be sharper wide open than the zoom at 28mm?

Ofcourse, a lot will depend on the particular makes and models being
compared but is there a rule of thumb?



Rule of Thumb: A prime at any focal length and wide open is better
than a zoom at any focal length wide open.


Except when it's not ... like a really well made fast zoom lens being
compared to a really poorly made slow prime lens.


So a Ferrari is faster than a Goggomobile, who'd of thought it??



no_name September 30th 05 04:41 AM

Dave Martindale wrote:

no_name writes:


(It's almost
like the old question about a pound of lead and a pound of feathers -
they do both weigh the same.)



However, a pound of gold and a pound of feathers do not.



Due to the archaic system of weights&measures that uses a different unit
with the same name for measuring precious metals.

But a gram of gold and a gram of feathers *are* the same mass, and have
the same weight in the same gravity.

Dave


OTOH, "the old question" was weight not mass.

Pete D September 30th 05 04:43 AM


"Chris Brown" wrote in message
...
In article ,
Tony Polson wrote:

Since there is no accepted definition of a "prime" lens we should just
drop the term, as it serves only to confuse.


Feel free to go ahead. The rest of the world will carry on using it.
You're
tilting at windmills.


IAWCB, I vote to not care what they call non zooms and non fixed lenses! ;-)



Paul J Gans September 30th 05 05:44 AM

In rec.photo.digital.slr-systems Tony Polson wrote:
Eugene wrote:

I don't think it has anything to do with the internet really. They've
been called prime lenses for as long as I can remember, and yes I do
pre-date the Internet ;-)



If only it was as simple as referring to all fixed focal length lenses
as "prime" lenses. Most subscribers to this newsgroup probably aren't
old enough to recall that some manufacturers used the term "prime" to
refer to a high quality subset of their fixed focal length lenses.


What made a particular fixed focal length lens design a "prime" lens
was not clear. Why other fixed focal length lenses were not described
as "prime" lenses was even less clear. But what is clear is that
assuming all fixed focal length lenses were referred to as "prime"
lenses is wrong. It was marketing, pure and simple.


Since there is no accepted definition of a "prime" lens we should just
drop the term, as it serves only to confuse.


I like the idea of FFL and VFL, especially as so many VFL optics are
not true zooms because they do not hold focus when zoomed. They are
often termed vari-focal lenses (also "VFL"), which term could be
extended to include the true zooms.


FFL and VFL has my vote.


;-)


I dimly recall the term "prime lens" as being the
lens whose focal length was equal (at least roughly)
to the diagonal of the film frame. That made a 50mm
(or 45mm) lens "prime" for 35mm film.

A 135mm lens was then a "telephoto" and a 35mm lens
was a "wideangle".

Zoom hadn't been invented yet.

By the way I find acronyms very hard to remember (VHR).
I much prefer a pronoucible name. Most acronym
users seem to as well, since they often make the
acronym pronouncible.

---- Paul J. Gans


Peter September 30th 05 05:57 AM


Paul J Gans wrote:

I dimly recall the term "prime lens" as being the
lens whose focal length was equal (at least roughly)
to the diagonal of the film frame. That made a 50mm
(or 45mm) lens "prime" for 35mm film.


The usual term for this is "normal lens"


A 135mm lens was then a "telephoto" and a 35mm lens
was a "wideangle".


A telephoto lens, properly speaking, is one in which
the lens (when set to infinity focus) is closer to
the film/sensor than the focal length of the lens.

It is quite possible to have a wide angle lens
which is of telephoto constuction. Olympus compacts
have had such lenses for years. On an Olympus XA,
the point 35mm in front of the film is actually
just in front of the front element of the lens.

A lens which is significantly longer than a normal
is called a long-focus lens if it is not of telephoto
design.

Wide angle lenses for SLRs are generally of an
inverted telephoto type in which a point one
focal length in front of the film may be somewhat
behind the rear element of the lens.

Peter.
--



Eugene September 30th 05 06:26 AM

Isn't that what's refered to as a "standard" lens?


I dimly recall the term "prime lens" as being the
lens whose focal length was equal (at least roughly)
to the diagonal of the film frame. That made a 50mm
(or 45mm) lens "prime" for 35mm film.

A 135mm lens was then a "telephoto" and a 35mm lens
was a "wideangle".

Zoom hadn't been invented yet.

By the way I find acronyms very hard to remember (VHR).
I much prefer a pronoucible name. Most acronym
users seem to as well, since they often make the
acronym pronouncible.

---- Paul J. Gans


Tony Polson September 30th 05 11:07 AM

"Peter" wrote:


Paul J Gans wrote:

I dimly recall the term "prime lens" as being the
lens whose focal length was equal (at least roughly)
to the diagonal of the film frame. That made a 50mm
(or 45mm) lens "prime" for 35mm film.


The usual term for this is "normal lens"




.... or "standard lens", which is common usage in the UK.



Chris Brown September 30th 05 11:57 AM

In article ,
Nostrobino wrote:

Well, not necessarily, though of course the more people who misuse the term,
the harder it will be to correct it.

Most people do not want to use wrong terminology since it makes them look
ignorant. In the case of "prime" being used to mean FFL, this has only
spread because readers who have not seen the term before, and then see it
used by people they assume are knowledgeable, naturally adopt it themselves.


I know this may give you apoplexy, but my nice shiny EOS 5D which I bought
yesterday includes, in the box, an accessories catalogue from Canon, which
amongst other things features a complete list of their current EF lens
range. They split it up into the following categories (from memory):

Zoom
Macro
Tilt and Shift
and, yes, Prime, which lists all of their fixed-focal length lenses (apart
from the Macros and T&S).

So at least one manufacturer is using the term to mean fixed-focal length.

Peter September 30th 05 02:28 PM


Chris Brown wrote:

I know this may give you apoplexy, but my nice shiny EOS 5D which I bought
yesterday includes, in the box, an accessories catalogue from Canon, which
amongst other things features a complete list of their current EF lens
range. They split it up into the following categories (from memory):

Zoom
Macro
Tilt and Shift
and, yes, Prime, which lists all of their fixed-focal length lenses (apart
from the Macros and T&S).

So at least one manufacturer is using the term to mean fixed-focal length.


I am willing to bet that some (possibly all) of the "macro" lenses
in the brochure are not really macro lenses intended primarily for
1:1 and greater magnification.

I would not be even slightly surprised if the word "telephoto" were
used more than once in the brochure to describe something that is
not actually a telephoto lens.

If you get your terminology from advertising literature, you are
probably going to get it wrong.

Peter.
--



Chris Brown September 30th 05 02:43 PM

In article .com,
Peter wrote:

Chris Brown wrote:


Macro
Tilt and Shift
and, yes, Prime, which lists all of their fixed-focal length lenses (apart
from the Macros and T&S).

So at least one manufacturer is using the term to mean fixed-focal length.


I am willing to bet that some (possibly all) of the "macro" lenses
in the brochure are not really macro lenses intended primarily for
1:1 and greater magnification.


Actally they are. Canon have lots of lenses with so-called "Macro" zones on
their focus ring, which aren't actually 1:1, but AFAIK all the lenses in the
"Macro" category are true 1:1 or greater lenses.

I would not be even slightly surprised if the word "telephoto" were
used more than once in the brochure to describe something that is
not actually a telephoto lens.


If you're going to object to the "misuse" of telephoto, you're fighting a
cause which is even more lost than the "prime" caus. I rather suspect that
the vast majority of non-LF photographers don't actually even understand
that it ever had a different meanning to its current one. What woul dyou
have people call what the whole world and their granny now calls "telephoto"
lenses? Narrow-angle, perhaps?

If you get your terminology from advertising literature, you are
probably going to get it wrong.


If you want to be prescriptive about language, then you're off to a really
bad start by chosing English to fight your battle in. Perhaps you'd have
better luck with Latin?

Peter September 30th 05 03:41 PM

Chris Brown wrote:
In article .com,
Peter wrote:


I am willing to bet that some (possibly all) of the "macro" lenses
in the brochure are not really macro lenses intended primarily for
1:1 and greater magnification.


Actally they are. Canon have lots of lenses with so-called "Macro" zones on
their focus ring, which aren't actually 1:1, but AFAIK all the lenses in the
"Macro" category are true 1:1 or greater lenses.


I think you misunderstand me. A _real_ macro lens is not one
which has a focus ring which goes up to 1:1, but a lens which
is primarily intended for 1:1 or greater magnification.

Real macro lenses have names on them like:
Leica (or Leitz) Photar
Leitz Micro-Summar (old)
Carl Zeiss Luminar
Carl Zeiss Jena Mikrotar
B&L Micro-Tessar (old)
Nikon (or Nippon Kogaku) Macro-Nikkor

They usually have no focusing ring and very often have the
same thread mount as microscope objectives. The old Leitz
Micro-Summars and B&L Micro-Tessars can often be had
quite cheaply, the modern ones tend to be very expensive.

Nikon is unusual in that they reserve the word "macro" for their
true macro lenses. Nikon uses "Micro-Nikkor" for their lenses
designed for normal close-up work.


I would not be even slightly surprised if the word "telephoto" were
used more than once in the brochure to describe something that is
not actually a telephoto lens.


If you're going to object to the "misuse" of telephoto, you're fighting a
cause which is even more lost than the "prime" caus. I rather suspect that
the vast majority of non-LF photographers don't actually even understand
that it ever had a different meanning to its current one. What woul dyou
have people call what the whole world and their granny now calls "telephoto"
lenses? Narrow-angle, perhaps?


Narrow-angle it could be, and I have seen it used, but the normal
expression is "long-focus lens." As I posted in another part of
this thread, Olympus has made compact 35mm cameras for years which
have 35mm telephoto lenses on them which are thus both wide-angle
and telephoto. I know the lens on the Olympus XA was like this and
I believe it is also true for the Stylus Epic.

If you get your terminology from advertising literature, you are
probably going to get it wrong.


If you want to be prescriptive about language, then you're off to a really
bad start by chosing English to fight your battle in. Perhaps you'd have
better luck with Latin?


Some battles in camera language have been won by the purists.
It used to be really common in the first half of the twentieth
century to use "Depth of Focus" incorrectly for the depth on the
object side of the lens. The purists won, and practically everyone
gets the "depth of field" vs. "depth of focus" distinction correct
nowadays. If you doubt me on this, look in a Leica Manual from
1935 to 1947 where the writers get the terminology wrong. In the
1951 and later editions, as well as almost any modern photography
book, the terms are used correctly.

Peter.
--



Nostrobino September 30th 05 04:06 PM


"Eugene" wrote in message
...
You make it sound like it's some kind of disease.


It is. And highly contagious, as we have seen.


In the grand scheme of things, does it really matter?


Yes. Words mean things. The meanings should not change willy-nilly, and
certainly not because some ignorant misusage becomes commonplace.


Languages are dynamic, and the meanings of words are constantly changing.


That argument has been used for as long as I can remember to justify
misusages of language.


The original meaning of "prime" in the photographic sense is just an
invention anyway.


No, it is not. "Prime" is used in the sense of "primary," "main," "chief,"
"original," etc. All are dictionary definitions (though not every dictionary
carries every one of those) and plainly that is the way the word was and is
properly used.


Referring to the dictionary I find no mention of lenses as related to the
meaning of the word "prime".


Look under "blue" and you'll probably find no mention of shirts, either. Do
you take that to mean that "blue shirt" can be taken to mean a red shirt, or
any other meaning unrelated to the usual meaning of "blue"?

What do the terms "primary lens," "chief lens," or "original lens" have for
you? Fixed focal length? I don't think so.

There is NO dictionary definition for "prime" that means fixed focal length
or fixed anything else.


Who is therefore to decide which usage is correct? You apparently!


That "decision" was made before I got involved in photography, which was
over 50 years ago. Since zoom lenses then were unheard of for 35mm cameras
(at least I don't recall any then), obviously there was no need for a term
to distinguish non-zooms from zooms.



The first listing that I found at dictionary.com is...

"First in excellence, quality, or value"

I think therefore it's perfectly reasonable to refer to a high quality FFL
lens in this way.


That is one of several meanings for "prime," but it isn't how the term is
being misused. If it were, that would at least reduce the objection to it,
but would still leave a good deal of confusion. Who is to decide (as you put
it) which lenses are "high quality" and which are not? You?



Perhaps you should just "chill out" a little and stop preaching about who
or who isn't ignorant.


I've been saying the misusage is ignorant. It is. I haven't said that the
people misusing the term are ignorant. On the contrary, I presume that most
of them are folks of at least ordinary intelligence who have innocently
picked the misusage up from Usenet and elsewhere. To be ignorant of some
particular state of affairs before one has the facts is hardly a shameful
thing. To try to DEFEND that ignorance after being apprised of the facts,
however, is stupid. Please note that I am making a careful distinction
between ignorance and stupidity. The former is often only temporary; the
latter tends to be lasting.

N.



Nostrobino September 30th 05 04:21 PM


"Brion K. Lienhart" wrote in message
...
Eugene wrote:
You make it sound like it's some kind of disease. In the grand scheme of
things, does it really matter? Languages are dynamic, and the meanings of
words are constantly changing. The original meaning of "prime" in the
photographic sense is just an invention anyway. Referring to the
dictionary I find no mention of lenses as related to the meaning of the
word "prime". Who is therefore to decide which usage is correct? You
apparently!


It's pretty much established jargon in the photo industry. I've seen it
used in this sense since the mid-70s (when I started paying attention to
photo stuff).


I doubt that very much. I suspect that's a false memory, to which people are
very prone. I don't doubt that you saw "prime lens" used that long ago; I've
seen it used since the 1950s, when of course there was no need for a term to
distinguish FFL lenses from zooms. But I've been reading about photo stuff
extensively since I first got into it in 1951, and it wasn't until the early
1990s that I ever saw the term misused in this way. Obviously the misusage
started with someone's misunderstanding the term, and it's possible that you
did that long ago, though it seems somewhat unlikely.

People often "remember" things that never were. In another argument on this
same subject, a user claimed her father remembered using "prime lens" to
mean FFL lens back in the 1930s. Now why on earth would anyone use a term
meant to distinguish non-zoom lenses when there were no zooms?


I hardly think it can be blamed solely on the internet.


You're right there. I first saw it misused in this way on the old Fidonet,
some time before I had access to the Internet per se. That was back in my
386 days, so probably 1991 or so.

N.



Nostrobino September 30th 05 04:48 PM


"Eugene" wrote in message
...
I don't think it has anything to do with the internet really. They've been
called prime lenses for as long as I can remember, and yes I do pre-date
the Internet ;-)

I certainly don't think it's some kind of fad. I suspect it would have
originated about the same time as zoom lenses.


Much later than that, I think. I was fairly heavily into photography before
I saw my first zoom lens, the Voigtlander Zoomar. That was around 1960. I
bought my first zoom in the late 1960s, and I'm dead certain no one used
"prime" to mean FFL at that time or for many years after. FFL lenses were
still the common kind of lens to have, in any focal-length range, and so
there was no need for a special term to distinguish them. Zooms were just
not highly trusted. Throughout the 1970s and well into the 1980s, most of my
lenses were FFL. There simply wasn't any need to use a term for something
that was assumed anyway. It was the *zoom* that was the exception and needed
a special designation. Now it's the other way around.


People needed a handy term to distinguish their FFL lenses from the new
zooms. FFL may be easy and quick to write, but 'prime' is quicker to say.


So is "egg," and even quicker to write. If a term must be coined for FFL on
the basis of quickness and ease, I suggest "egg." It even has a vague
logical connection to the idea of single focal length, since the egg is sort
of a symbol for unity. But best of all, it has the overwhelming advantage of
not being incorrect. No one at present is using "egg lens" for anything
else, so the likelihood of confusion is practically nil.


Also if we're going to get pedantic about linguistics then why not take
offence to the term "zoom lens". Surely they should be called Variable
Focal Length Lenses, or VFL lenses. That's much better... Now we just have
to re-educate all the millions of poor ignorant fools using the incorrect
terminology ;-)


Well, you're partly right there, except that zoom lenses are not just
variable focal length lenses. A zoom lens, strictly speaking, is a variable
focal length lens that is parfocal (stays in focus throughout its
focal-length range).

Now it is certainly true that not all "zoom" lenses do this, and those that
don't are properly called varifocal lenses. For example, every "zoom" lens
I've ever seen on a projector has been a varifocal and not a true zoom. And
the "zoom" lenses on point-and-shoot cameras are for the most part really
varifocals.

So yes, sure, if you want to do that, then by all means let's get people
straightened out on that terminological inexactitude.

Right after we correct the "prime lens" snafu. First things first.

N.



Nostrobino September 30th 05 04:51 PM


"Tony Polson" wrote in message
...
Eugene wrote:

I don't think it has anything to do with the internet really. They've
been called prime lenses for as long as I can remember, and yes I do
pre-date the Internet ;-)



If only it was as simple as referring to all fixed focal length lenses
as "prime" lenses. Most subscribers to this newsgroup probably aren't
old enough to recall that some manufacturers used the term "prime" to
refer to a high quality subset of their fixed focal length lenses.

What made a particular fixed focal length lens design a "prime" lens
was not clear. Why other fixed focal length lenses were not described
as "prime" lenses was even less clear. But what is clear is that
assuming all fixed focal length lenses were referred to as "prime"
lenses is wrong. It was marketing, pure and simple.

Since there is no accepted definition of a "prime" lens we should just
drop the term, as it serves only to confuse.

I like the idea of FFL and VFL, especially as so many VFL optics are
not true zooms because they do not hold focus when zoomed. They are
often termed vari-focal lenses (also "VFL"), which term could be
extended to include the true zooms.


That is true. True zooms are essentially a subset of varifocals, I would
say.



FFL and VFL has my vote.

;-)


Mine too, but FFL first. To get rid of that pesky other thing. ;-)

N.



Nostrobino September 30th 05 05:03 PM


"Eugene" wrote in message
...
OK, I stand corrected. This does make sense. Actually now that I think
about it I don't tend to use the terms "prime" and "zoom" much anyway. I'd
nearly always just refer to the specific lens type. Like I'd just say 50mm
f1.4 rather than 50mm prime. Adding "prime" is kind of redundant. If only
one focal length lens is given then it's obvious I'm not talking about
variable focal length.


Exactly, and this is what makes my teeth hurt when I see someone mention
"28mm prime," for example. (As opposed to what, a 28mm zoom?)



Also I think there would be very few situations where lumping everything
into 2 distinct groups would make sense. For example "zoom" could equally
refer to an EF-S 18-55, as it could to an EF 70-200 f2.8 L. Aside from the
fact that both lenses can change focal lengths, they really have nothing
much else in common. They serve entirely different purposes and an
entirely different market. Likewise "prime" (meaning FFL) could equally
refer to a 7mm circular fisheye, or a 1200mm super-telephoto.

Grouping lenses by focal length ranges makes more sense, ultra-wide,
wide-angle, medium-telephoto, super-telephoto etc.


And in fact that is just how camera makers *do* group them, in my
experience. I have been for 25+ years mostly a Minolta man (until I got into
digital, anyway) and admittedly I'm less familiar with other manufacturers'
lens literature, but what I have seen has followed Minolta's practice of
grouping lenses as wide-angle, standard, telephoto, zoom, etc. I have never
seen any camera maker's literature use "prime" to mean FFL, and I sure hope
I never do. (It is almost unthinkable.)

N.



Peter September 30th 05 05:12 PM


Peter wrote:


I just looked it up and Canon does indeed make real macro lenses
with the inscription "Canon Macro Photo Lens." If those are
the lenses under "macro" in the catalogue then I apologize,
they are _real_ macro lenses.

Nikon is unusual in that they reserve the word "macro" for their
true macro lenses. Nikon uses "Micro-Nikkor" for their lenses
designed for normal close-up work.


Canon uses "macro" on both their real macro lenses and their
not-quite macro lenses. The words "macro photo lens" seem to
be reserved for their true macro lenses.

Peter.
--



Nostrobino September 30th 05 05:13 PM


"Chris Brown" wrote in message
...
In article ,
Tony Polson wrote:

Since there is no accepted definition of a "prime" lens we should just
drop the term, as it serves only to confuse.


Feel free to go ahead. The rest of the world will carry on using it.


"The rest of the world" is defined as the few dozen people who post in a
couple of newsgroups?

Camera manufacturers don't use "prime" to mean FFL. They never have. They're
not part of "the rest of the world," I guess?

Lens manufacturers do sometimes use "prime," and they use it to mean actual
prime lenses. Not FFL lenses, necessarily. Zeiss and Schneider, for example,
have catalogued variable prime lenses. Now can you guess what a variable
prime lens is? No? It's a prime lens of variable focal length. (Not a zoom,
because a true zoom has to be parfocal.)

I'll bet there are a lot more people (and a lot more knowledgeable) in Zeiss
and Schneider than there are in your "rest of the world" that thinks "prime"
means fixed focal length.

N.



Nostrobino September 30th 05 05:24 PM


"Paul J Gans" wrote in message
...
[ . . . ]

I dimly recall the term "prime lens" as being the
lens whose focal length was equal (at least roughly)
to the diagonal of the film frame. That made a 50mm
(or 45mm) lens "prime" for 35mm film.


I have never seen "prime" used in that way, but at least it's no more
incorrect than the way it's mostly being used in these newsgroups. ;-)

It used to be considered that the proper (or normal) focal length for a
camera was the diagonal of its negative. Similarly, the length + width of
the negative was considered a suitable focal length for portraits. I don't
think anyone has paid much attention to those rules of thumb since we've had
such a vast range of focal lengths available to us which were undreamt of a
few decades ago.

N.



Nostrobino September 30th 05 05:28 PM


"no_name" wrote in message
om...
Nostrobino wrote:

[ . . . ]

Just because "popular usage" may not appear in a particular dictionary
does not constitute "misuse".

If you speak of a prime lens to photographers, they know what you're
talking about.


The problem is, they may not. I do sometimes have occasion to mention "prime
lens" and I assure you I use it correctly. People who think it means fixed
focal length will, therefore, not understand what I am saying.

N.



Neil Ellwood September 30th 05 05:41 PM

On Fri, 30 Sep 2005 04:44:00 +0000, Paul J Gans wrote:


I dimly recall the term "prime lens" as being the
lens whose focal length was equal (at least roughly)
to the diagonal of the film frame. That made a 50mm
(or 45mm) lens "prime" for 35mm film.

In the UK in the sixties they were called normal lenses.

A 135mm lens was then a "telephoto" and a 35mm lens
was a "wideangle".

The 135mm was often called a long focus lens (which most at that time
were), the 35mm were often retro-focus lenses but I cannot ever remember
them being called that.
Zoom hadn't been invented yet.

Zooms were used on cine cameras quite a while before still.


--
Neil
Delete delete to reply by email

Nostrobino September 30th 05 05:44 PM


"Chris Brown" wrote in message
...
In article ,
Nostrobino wrote:

Well, not necessarily, though of course the more people who misuse the
term,
the harder it will be to correct it.

Most people do not want to use wrong terminology since it makes them look
ignorant. In the case of "prime" being used to mean FFL, this has only
spread because readers who have not seen the term before, and then see it
used by people they assume are knowledgeable, naturally adopt it
themselves.


I know this may give you apoplexy, but my nice shiny EOS 5D which I bought
yesterday includes, in the box, an accessories catalogue from Canon, which
amongst other things features a complete list of their current EF lens
range. They split it up into the following categories (from memory):

Zoom
Macro
Tilt and Shift
and, yes, Prime, which lists all of their fixed-focal length lenses (apart
from the Macros and T&S).

So at least one manufacturer is using the term to mean fixed-focal length.


That is *NOT* how Canon categorizes them on their web site:

http://consumer.usa.canon.com/ir/con...categoryid=111

There, as you can see, they separate EOS lenses into these categories:

Ultra-Wide Zoom
Standard Zoom
Telephoto Zoom
Wide-Angle
Standard & Medium Telephoto
Telephoto
Super Telephoto
Macro
Tilt-Shift

And no mention of "prime" in any way, shape, manner or form.

But there is no question that the misuse has crept into what *should* be
responsible and even authoritative areas. In the past couple of years I have
seen "prime" misused (maybe two or three times) by caption writers in Pop
Photo, though the mistake was not repeated in the actual editorial content.
There have been a few other examples too.

The cases so far have been few and relatively isolated. There's no reason
the disease cannot be eradicated. We stamped out smallpox, didn't we?

N.





Nostrobino September 30th 05 05:51 PM


"Eric Miller" wrote in message
. ..

"Nostrobino" wrote in message
...
Zoom lenses ARE prime lenses, notwithstanding the now-popular misusage of
"prime."

A prime lens is the camera lens as distinct from some other lens or
lenticular device (close-up lens, tele converter, etc.) used with it. It
has meant that since long before zoom lenses became commonplace, and
therefore no need to use another term to mean "non-zoom."

"Prime" is properly used in the sense of primary, main, chief or
original--all dictionary definitions for "prime."

There is NO dictionary definition for "prime" which means fixed focal
length or single focal length, or fixed or single anything else.

It would be nice if this nonsensical misusage, which obviously is based
on someone's misunderstanding of the term some years ago (and then spread
like cancer through the power of the Internet) could be stamped out.
Surely "FFL" is at least as easy to type as "prime" anyway, and there
never was any reason other than shortness to replace "fixed focal length"
with the incorrect term.

N.


Many now accepted meanings of words have been created through misusage.


Yes. The unfortunate thing is that some people think this is evolution, when
in fact it is deterioration. "Accepted meanings of words" now are sometimes
even the reverse of the actual meanings. For example, many people think "hoi
polloi" means the wealthy upper class.


Perhaps you would prefer a dead language to English?


No, English is great. If I didn't care for it so much I wouldn't be trying
to defend it.

N.



Nostrobino September 30th 05 06:14 PM


"Eugene" wrote in message
...
Just some links you may want to check out...

http://photonotes.org/cgi-bin/entry.pl?id=Primelens
http://en.wikipedia.org/wiki/Prime_lens
http://www.absoluteastronomy.com/enc...prime_lens.htm


Your sources are in error. Anyone can set up a web page which says anything,
and in this case you have pages repeating misinformation the authors
presumably obtained from other sources on the Internet, such as the
newsgroups where this misusage occurs. Doubtless there are web pages about
kidnappings by flying saucer which are about as reliable as the ones you
list.



Please stop spreading misinformation. The first usage of a term is not
necessarily the correct one. If you start referring to zooms as "prime"
you're just going to make yourself sound stupid. Whatever you think it
meant originally, is not what it means now.


You might want to explain that to lens manufacturers such as Schneider and
Zeiss, both of whom along with Arri and some others have catalogued variable
primes (i.e., prime lenses of variable focal length). They've been making
world-famous lenses for a hundred years or so, but perhaps aren't as
knowledgeable about proper terminology as you are.

Here's a current ad from Schneider Kreuznach,
http://www.schneideroptics.com/info/...res/pdf/vp.pdf

There are lots of others, but I recommend this one to you because it has
VARIABLE PRIME in nice, great big letters right at the top of the page.

N.



Zoom lenses ARE prime lenses, notwithstanding the now-popular misusage of
"prime."

A prime lens is the camera lens as distinct from some other lens or
lenticular device (close-up lens, tele converter, etc.) used with it. It
has meant that since long before zoom lenses became commonplace, and
therefore no need to use another term to mean "non-zoom."

"Prime" is properly used in the sense of primary, main, chief or
original--all dictionary definitions for "prime."

There is NO dictionary definition for "prime" which means fixed focal
length or single focal length, or fixed or single anything else.

It would be nice if this nonsensical misusage, which obviously is based
on someone's misunderstanding of the term some years ago (and then spread
like cancer through the power of the Internet) could be stamped out.
Surely "FFL" is at least as easy to type as "prime" anyway, and there
never was any reason other than shortness to replace "fixed focal length"
with the incorrect term.

N.




Nostrobino September 30th 05 06:59 PM


"Eugene" wrote in message
...


The use of "prime lens" for "fixed focal length lens" appears
to originate in cinema where the need for a handy term
for a non-zoom lens was felt long before such a term was
needed in still photography. As a handy bit of slang, it
has much to recommend it: it is easy to say and quickly
understood. As a technical term, it has two major difficulties:
the word "prime" has little connection to what is meant,
and there was a prior use of the term in which the word
"prime" actually made sense.


OK, fair enough. You make a valid point, but in the case of "prime lens",
given the definition of the word, I don't think it's nescessarily
incorrect or ambiguous. Shortening complex expressions is just how
language works.


Sure, but where's the "shortening complex expressions" in this misusage? No
amount of shortening (or even Crisco) will make "prime" out of "fixed focal
length."


Just a few other slang photographic terms I could think of would be
"film", or "sensor", or "flash", or even "lens". Everyone knows what these
terms mean, although none of them is strictly correct or complete.



If you start referring to zooms as "prime" you're just going
to make yourself sound stupid.



No, because you would always also be using an additional term
such as "supplementary lens" or "teleconverter" which would
supply the context which would make the meaning clear.


Perhaps my comments were a bit harsh. I just took offense to the
suggestion that it was ignorant to use the widely accepted and understood
term "prime lens".


It *is* ignorant to misuse a term which has a proper technical meaning. The
fact that the misusage is "widely accepted and understood" does not make it
less ignorant.

Examples abound. The news media commonly use "bullets" when they mean
cartridges. It's not an error that any literate shooter would make; you will
not see cartridges called "bullets" in any respectable shooting publication;
when such a publication says "bullets" it means bullets.

Likewise, "prime lens" has a specific meaning, i.e. the camera lens as
opposed to some other lens or lenticular device used with it. One does not
necessarily expect accuracy in terminology from the news media, which get a
lot of things wrong anyway. But shouldn't photographers who've been at it
for a while be reasonably literate when they talk about equipment?


It seemed clear that the Nostrobino was just being undully pedantic and
argumentative, and his comments added nothing to the thread.


Correcting a technical misusage is, I think, a useful thing to add to a
thread having to do with any sort of technology.





Whatever you think it meant originally, is not what it means now.



You know, sometimes words have two meanings.

Most of us can live with slang terminology and standard technical
terminology without getting particularly confused. Slang terminology
can be very handy: I'm not going to stop saying "Hypo" when I know
that fixer is actually thiosulphate. It isn't very likely that someone
will think I mean the actual chemical "sodium hyposulphite" AKA
"sodium hydrosulphite" which is AFAIK not used in photography.
But it is still good to distinguish between slang and proper technical
language. If I ordered "sodium hyposulphite" from a chemical supplier
who served dyers it is just possible I might get the wrong chemical.


As an Australian I certainly have no problem with slang ;-) Mind you when
I'm writing things for an international audience I'm careful to avoid
terms that will confuse people in other parts of the world. If I wrote the
way I would typically talk to other Aussies then a lot of people wouldn't
know what I was talking about. I hardly think though that "prime lens" is
one of those confusing obscure slang expressions. Everyone knows what it
means.


Well, everyone thinks they do, and some of us actually do. :-)

N.



Nostrobino September 30th 05 07:02 PM


"David Littlewood" wrote in message
...
In article , Tony Polson
writes
Eugene wrote:

Perhaps my comments were a bit harsh. I just took offense to the
suggestion that it was ignorant to use the widely accepted and
understood term "prime lens".



But "prime lens" is NOT a "widely accepted and understood term".

Because of the history of its use, it is essentially ambiguous. It
has only been used as a descriptor for all fixed focal length lenses
in recent times, and only by people who are unaware of its prior
usage, which was as a descriptor for a "high quality" subset of fixed
focal length lenses. You might be too young to recall this.

There was no accepted definition of which fixed focal length lenses
were "prime" and which were not. It was merely an attempt by
marketing people to promote some lenses as being "better" than others,
the implication being that one brand was "better" than another because
of the "high quality" of their "prime" lenses.

The terms "high quality", "better" and "prime" are all essentially
meaningless unless backed up with something more objective, repeatable
and reliable. As we all (should) know, comparisons between lenses are
qualitative at best.

The most commonly used "objective" comparator - MTF - was never
intended for making such comparisons. It was intended as an aid to
lens designers and nothing more. As a result it misleads far more
than it ever informs, and those who claim it is of any real value when
comparing photographic lenses are suffering from delusions.


I agree with the first part of the above. The only point in which my
understanding differs is that the traditional use of the term "prime" was
in the sense of "primary" as opposed to secondary or auxiliary optical
components such as tele-converters, wide angle attachments, close up
lenses and the like. Thus prime as in the Latin "primus", first or
primary.

This is the interpretation given in the more rigorous works on photography
I consulted on this issue when the point was debated here (ad nauseam)
several years ago. (Anyone remember Neil Harrington?)


I do!

I see him every time I shave. :-)

N.



David Littlewood September 30th 05 07:34 PM

In article , Nostrobino
writes

"David Littlewood" wrote in message
...

I agree with the first part of the above. The only point in which my
understanding differs is that the traditional use of the term "prime" was
in the sense of "primary" as opposed to secondary or auxiliary optical
components such as tele-converters, wide angle attachments, close up
lenses and the like. Thus prime as in the Latin "primus", first or
primary.

This is the interpretation given in the more rigorous works on photography
I consulted on this issue when the point was debated here (ad nauseam)
several years ago. (Anyone remember Neil Harrington?)


I do!

I see him every time I shave. :-)

N.

Oh, Hi Neil!

David
--
David Littlewood

Nostrobino September 30th 05 07:41 PM


"Randall Ainsworth" wrote in message
...
In article , Brion K. Lienhart
wrote:


As others have already noted, Randall, you're just flat wrong about this.
And your earlier, more absolute statement,
"F/2.8 lets the same amount of light through regardless of the lens
design. F/2.8 is f/2.8"
is even more absolutely wrong.

An uncoated f/2.8 lens for example will not let through as much light as a
coated f/2.8, and a multicoated one will do even a bit better.

All "f/2.8" says is that the effective aperture is 1/2.8 the focal length.
It doesn't say anything about actual transmission. T-stops do that, but they
have rarely been used on still-camera lenses.

At one time I had Minolta 50mm lenses in f/1.2, f/1.4 and f/1.7. From the
f-numbers you would suppose the f/1.2 wide open was a full stop faster, and
the f/1.4 half a stop faster, than the f/1.7 lens. But that simply wasn't
so. For that matter, I have never seen an f/1.4 lens that was really a full
stop faster wide open than it was at f/2.

Someone else mentioned the disparity between mirror and refractor lenses,
too. I can attest to that! I once had a Minolta 500mm f/8 mirror lens that
seemed to lose about a full stop (maybe more) compared to what an
all-refracting lens would have done.

N.



Floyd Davidson September 30th 05 08:37 PM

"Nostrobino" wrote:

I've been saying the misusage is ignorant. It is. I haven't said that the
people misusing the term are ignorant. On the contrary, I presume that most
of them are folks of at least ordinary intelligence who have innocently
picked the misusage up from Usenet and elsewhere. To be ignorant of some
particular state of affairs before one has the facts is hardly a shameful
thing. To try to DEFEND that ignorance after being apprised of the facts,
however, is stupid. Please note that I am making a careful distinction
between ignorance and stupidity. The former is often only temporary; the
latter tends to be lasting.


Your entire diatribe about language and word usage is then,
according to the above, *stupid*.

Language *is* dynamic. Dictionaries are *not* an authoritative
source of *correct* word usage, and this abjectly silly
suggestion that any jargon not found in a dictionary is
therefore wrong is a demonstration that you are ignorant about
this topic. Dictionaries are a compilation of current usage,
and have very little to do with what is or is not "correct".

Whether it is jargon, which might well be restricted to a small
enough fraction of all speakers and therefore will never show up
in any general dictionary, is unimportant. All that counts is
whether the speaker does in fact convey the desired meaning to
the target audience.

The essence of all that has previously been explained in detail
by others, and continued efforts to "DEFEND that ignorance" is,
in your own words: stupid.

--
FloydL. Davidson http://www.apaflo.com/floyd_davidson
Ukpeagvik (Barrow, Alaska)

Floyd Davidson September 30th 05 08:40 PM

"Nostrobino" wrote:
I hardly think it can be blamed solely on the internet.


You're right there. I first saw it misused in this way on the old Fidonet,
some time before I had access to the Internet per se. That was back in my
386 days, so probably 1991 or so.


So, along with the correct meaning of words being fixed in time
by when you first understood them, the Internet didn't exist
until *you* discovered it too, eh?

Hmmmm...

--
FloydL. Davidson http://www.apaflo.com/floyd_davidson
Ukpeagvik (Barrow, Alaska)

Paul J Gans September 30th 05 08:51 PM

In rec.photo.digital.slr-systems Peter wrote:

Paul J Gans wrote:


I dimly recall the term "prime lens" as being the
lens whose focal length was equal (at least roughly)
to the diagonal of the film frame. That made a 50mm
(or 45mm) lens "prime" for 35mm film.


The usual term for this is "normal lens"



A 135mm lens was then a "telephoto" and a 35mm lens
was a "wideangle".


A telephoto lens, properly speaking, is one in which
the lens (when set to infinity focus) is closer to
the film/sensor than the focal length of the lens.


It is quite possible to have a wide angle lens
which is of telephoto constuction. Olympus compacts
have had such lenses for years. On an Olympus XA,
the point 35mm in front of the film is actually
just in front of the front element of the lens.


A lens which is significantly longer than a normal
is called a long-focus lens if it is not of telephoto
design.


Wide angle lenses for SLRs are generally of an
inverted telephoto type in which a point one
focal length in front of the film may be somewhat
behind the rear element of the lens.


Yes. I know you are correct. But I don't think
that was the popular usage back then.

The general public was not very sophisticated
in such matters. Still isn't.

---- Paul J. Gans


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