Is this tyical difference between zoom and prime?

"Carl" wrote in message
...
brian wrote:
"Owamanga" wrote in message

I admit, it is common use, but I don't think (and neither do the
manufacturers) that the fact alone makes it right.

--
Owamanga!


Rather than say it is a photography term, I should have said it was a
term
used by most Photographers to describe a fixed focal length lens, the
fact
that the manufacturers use this term in a different context is neither
here
nor there. For the purposes of this question a prime lens in a lens of
fixed
focal length, simple as that. In days gone by, before the introduction
of
zooms, a photographer would have a lens that he would use first and
foremost, his "prime" lens, basically his "preferred" lens.Just because
a
word means something in a dictionary, it doesn't mean it MUST always be
used
in that context, If you look up the word "train" in the dictionary,
it's
literal meaning is to betray, also if you want to go down that road,
its
not a "lens", its a series of lenses combined to create a device that
concentrates and focuses light, as a lens is a singular piece of glass,
so
should we be asking for a Canon 70-200mm lenses?, the context used by
the
manufacturers may be correct for them , but its not for photographers.
Neither use or definition is incorrect. It's all about context.

Brian...................



Actually "prime" is a photographic term and owes its antecedents to the
cinematographic industry, from which 35mm photography was derived.

Meanings of Prime form just ONE dictionary, I don't see even one definition
here that includes anything photographic :-

Main Entry: 1prime
Pronunciation: 'prIm
Function: noun
Etymology: Middle English, from Old English prIm, from Latin prima hora
first hour
1 a often capitalized : the second of the canonical hours b : the first hour
of the day usually considered either as 6 a.m. or the hour of sunrise
2 a : the earliest stage b : SPRING c : YOUTH
3 : the most active, thriving, or successful stage or period in the prime
of his life
4 : the chief or best individual or part : PICK prime of the flock, and
choicest of the stall -- Alexander Pope
5 : PRIME NUMBER
6 a : the first note or tone of a musical scale : TONIC b : the interval
between two notes on the same staff degree
7 : the symbol ´
8 : PRIME RATE

ALSO

Main Entry: 2prime
Function: adjective
Etymology: Middle English, from Middle French, feminine of prin first, from
Latin primus; akin to Latin prior
1 : first in time : ORIGINAL
2 a : of, relating to, or being a prime number -- compare RELATIVELY PRIME b
: having no polynomial factors other than itself and no monomial factors
other than 1 a prime polynomial c : expressed as a product of prime
factors (as prime numbers and prime polynomials) a prime factorization
3 a : first in rank, authority, or significance : PRINCIPAL b : having the
highest quality or value prime farmland c : of the highest grade regularly
marketed -- used of meat and especially beef
4 : not deriving from something else : PRIMARY

AND

Main Entry: 3prime
Function: verb
Inflected Form(s): primed; prim·ing
Etymology: probably from 1prime
transitive senses
1 : FILL, LOAD
2 a : to prepare for firing by supplying with priming b : to insert a primer
into (a cartridge case)
3 : to apply the first color, coating, or preparation to prime a wall
4 : to put into working order by filling or charging with something prime a
pump with water
5 : to instruct beforehand : COACH primed the witness
6 : STIMULATE
intransitive senses : to become prime
- prime the pump : to take steps to encourage the growth or functioning of
something

In message ,
Crownfield wrote:

wrote:

MTF alone does not determine the sharpness of the lens in the context of
its use. The size of the recording medium must be factored in, too. If
you were to look at the inverse of MTF, in terms of resolution at a
given contrast, you would have to halve the practical resolution for a
18*12mm sensor, compared to 35mm film.

does that presume full color pixels?

Only if you're looking at chromatic resolution. It has little effect on
the perception of sharpness.

You can take a very sharp color image which has been downsampled to
guarantee mostly-measured values for each channel of each pixel, and
view it at 100%, and blurring the hue a few pixels without blurring the
luminance is harldy noticeable.
--


John P Sheehy

In message ,
Colin D wrote:

I notice that almost every time somebody does a lens test they do not
say how they focused the lens. The worst possible thing to do - apart
from not focusing at all - is to rely on AF when testing a lens.

I always like to slant the test pattern or subject slightly, so that
some part of it has to be in focus if I am off, and I focus manually on
the center. The sharpest strip is where the lens is focused (unoless it
is at an edge).
--


John P Sheehy

Chris Stolpe wrote:

I am looking to move up from a Canon S45 to a SLR.
I was thinking of getting a 70mm-200mm f2.8 Zoom (probably a Sigma not a
Canon L) until I ran across this:
http://www.luminous-landscape.com/re...tten-400.shtml
If this is a typical difference between a zoom and a prime then I think I
might go for the prime.



Another point no one mentioned, do you plan on always using a large tripod?
If not, you'll NEVER see the difference posted here.
--

Stacey