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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. |
"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. |
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. |
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. -- |
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 |
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 |
"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. |
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 |
"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?? |
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. |
"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! ;-) |
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 |
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. -- |
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 |
"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. |
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. |
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. -- |
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? |
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. -- |
"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. |
"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. |
"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. |
"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. |
"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 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. -- |
"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. |
"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. |
"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. |
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 |
"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. |
"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. |
"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. |
"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. |
"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. |
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 |
"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. |
"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) |
"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) |
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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