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Zoom vs. Fixed-Focal-Length

 
 
JPS@no.komm
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      10-19-2004
In message <(E-Mail Removed)>,
"Roger N. Clark (change username to rnclark)" <(E-Mail Removed)>
wrote:

>I picked up my 100-400 and took the cover caps off,
>put it up to my cheek and zoomed.
>I was quite surprised how much air it was moving!
>I learned about this in this newsgroup.


Why would you be surprised? It is, after all, changing volume by a
large amount.

The question is, though, exactly where does the air blow out? If the
body cavity is airtight, very little air will flow out of the lens and
into the cavity even if air did escape that way, and I doubt that it
does. It gets dust inside the lens itself, which could sacrifice a
little contrast, but in practice it hasn't been a problem.
--

<>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<>
John P Sheehy <(E-Mail Removed)>
><<> <>>< <>>< ><<> <>>< ><<> ><<> <>><

 
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JPS@no.komm
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      10-19-2004
In message <(E-Mail Removed)>,
http://www.velocityreviews.com/forums/(E-Mail Removed) (EHHackney) wrote:

>I may be wrong, but it seems that single focal length lenses are faster, in
>general, than zooms. I remember a number of single F.L. lenses that went to
>F/1.4 or even F/1.2.


.... and you generally only see that in the 24 - 85mm range of fixed
focal lengths.
--

<>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<>
John P Sheehy <(E-Mail Removed)>
><<> <>>< <>>< ><<> <>>< ><<> ><<> <>><

 
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GT40
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      10-19-2004
On Tue, 19 Oct 2004 01:00:49 GMT, (E-Mail Removed) wrote:

>In message <(E-Mail Removed)>,
>"Roger N. Clark (change username to rnclark)" <(E-Mail Removed)>
>wrote:
>
>>I just tested the 100-400 L IS and it is
>>amazing how much air it pumps. I'll never put it
>>on a DSLR again!

>
>I haven't had any increase in sensor dust since I started using the
>100-400 regularly.


That lens needs to be fixed if its pumping air

 
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Roger N. Clark (change username to rnclark)
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      10-19-2004
Check this out:

http://www.webster-dictionary.org/de...on/zoom%20lens

"A zoom lens is a mechanical assembly of
lenses whose focal length can be changed,
as opposed to a prime lens, which has a
fixed focal length."

Case closed.

 
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Roger N. Clark (change username to rnclark)
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      10-19-2004
Ken Tough wrote:

> BWL <(E-Mail Removed)> wrote:
>
>
>>Just wondering which way I should go on this. I'll be getting a Canon 20D,
>>probably between new year's and spring. I have a G1 now, but this will be my
>>first DSLR. I've been reading up on lenses, and it seems apparent that fixed-
>>focal-length lenses have much better optics and photo quality. I was initially
>>thinking of getting a 28mm (or thereabouts), and a nice long 300 or 400mm for
>>wildlife photography.
>>
>>My question is: is the quality of fixed-focal-length lenses great enough to
>>offset the convenience of zoom lenses? I mean, if the difference in photo
>>quality is negligible, a zoom would be much preferable.

>
>
> I'm in about the same boat, thinking the same. [Not sure if Nikon
> or Canon yet]. Have you considered the "1.6x crop" of the dSRL
> (making a 28mm actually give the field of view of a '45 mm' on a
> 35mm film cam).
>
> Seems to me that a shorter Fixed Focal Length lens (say up to 50 mm)
> is more useful than a long FFL telephoto, since you can 'zoom with
> your feet' more easily on the wide end. With a telephoto you may
> need to walk a long way to zoom out if necessary. (I can imagine
> shooting wildlife, then have something show up 5m away and only be
> able to catch its eyebrows).


"zooming out, simply switch lenses." But really, "zooming
with your feet" is usually not an option in my wildlife
photography experience. Usually, the longer the better.
And if you start moving, you're likely to spook the animals.

Examples:
http://www.clarkvision.com/galleries...998.b-700.html
http://www.clarkvision.com/galleries...612.b-700.html
It might have been dangerous to be moving around with
these big bears nearby. Page through the gallery and you
will see 4 focal lengths used: 500mm, 700mm, 1000mm, 1400mm
from 1 lens (500mm f/4) and 2 TCs: 1.4x and 2x.

Often you can't move around due to physical restrictions
or things block the view. So a zoom would be best in all
situations. Too bad the image quality in the long
focal lengths is not there. So a couple of fixed lenses plus
telextenders takes the place and keeps the quality
high.

Whether or not a zoom is adequate for a photographer
depends on that person's standards and/or desires. If you
wish to get top photos of wildlife, use a tripod (this
will make the most difference), then select the best fixed
lenses you can afford. I chose the cheap zoom route 15
years ago. In the long run it cost me a lot more money
than if I would have understood the quality differences.
There is a reason pros use certain lenses, and it is
definitely not because they are expensive.

If the price seems high, buy used. I heard a Canon 500mm
f/4 L IS went for about $1,500 this morning on ebay--that
is less than 1/3 the mail-order new price!

Roger

So I'd personally plan on a zoom tele
> and a fast 50mm for people & 'walking around'. Due to the dirt-on-
> the-sensor issue and wanting to travel light, I'm also thinking the
> 17-85mm IS lens is nice because it has a decent zoom range, and the
> IS effectively opens its aperature a couple of stops at the tele end.
> (The Nikon 18-70 feels a little short for my liking, and its relatively
> smaller aperature isn't countered by any IS).
>


 
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David J. Littleboy
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      10-19-2004

"Roger N. Clark (change username to rnclark)"

> Check this out:
>
> http://www.webster-dictionary.org/de...on/zoom%20lens
>
> "A zoom lens is a mechanical assembly of
> lenses whose focal length can be changed,
> as opposed to a prime lens, which has a
> fixed focal length."


There are enough googits* giving that meaning to make it clear that that is
the _current_ meaning.

> Case closed.


Not yet<g>. The Focal Encyclopedia of Photography gives only the "lens to
which a converter is attached" meaning. From that I take it that the "fixed
focal length" meaning seems to be a more recent usage, as suggested by
others in this thread.

*: Googits: "Google hits", term used by Japanese->English translators, who
often find themselves desperate for reliable information on current English
usage, especially those of us who have been out of the US for extended
periods...

David J. Littleboy
Tokyo, Japan



 
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Jeremy Nixon
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      10-19-2004
David J. Littleboy <(E-Mail Removed)> wrote:

>> http://www.webster-dictionary.org/de...on/zoom%20lens
>>
>> "A zoom lens is a mechanical assembly of
>> lenses whose focal length can be changed,
>> as opposed to a prime lens, which has a
>> fixed focal length."

>
> There are enough googits* giving that meaning to make it clear that that is
> the _current_ meaning.


Oxford lists "prime lens" as "(Photography) a lens of fixed focal length."
No notes as to other meanings or pointing out any incorrectness of the
usage.

Oxford is also descriptive in its approach, but if that doesn't "close the
case" as to the *current* meaning at least, I don't know what does.

--
Jeremy | (E-Mail Removed)
 
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Nostrobino
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      10-20-2004

"Tetractys" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> Nostrobino wrote:
>
>> There is NO dictionary definition for
>> "prime" that means "fixed (or single) focal length," or "fixed" or
>> "single"
>> anything else for that matter.

>
> Except for the three I included in my
> post, right,


Remind me, where exactly did you provide a definition for "prime"? I can't
find that anywhere in your post.


> or the six dozen others
> that come up when you Google "prime"
> and "lens?"


I do note your references for "prime lens," and I'm sure there are plenty of
others. As I said, this misusage has spread like a weed, and unfortunately
has found its way into supposedly "authoritative" texts too.

Again:

There are in fact a number of variable prime lenses (prime lenses of
variable focal length), catalogued just that way, "variable primes," by
Zeiss, Schneider and other lens makers. I am not aware of any camera maker
who catalogues FFL lenses as "prime." I know that Minolta does not, and
never has, and no lens literature I have from Nikon or Canon misuses the
term in that way either.

"Prime lens" uses "prime" in the sense of primary, original, chief,
etc.--all standard dictionary definitions for "prime," today just as much as
in the past.

There is NO dictionary definition for "prime" that means "fixed (or single)
focal length," or "fixed" or "single" anything else for that matter.

This is a misusage which evidently started when someone misunderstood the
term "prime lens," used the term incorrectly himself and the misusage was
picked up by others--and today, through the wonder of the Internet, the
misusage has spread like a weed. It has become popular jargon, which of
course makes it hard to kill. Some people love to use jargon because they
think it makes them sound knowledgeable.

It is, in short, an ignorant term, and should be avoided unless one
particularly wants to display his ignorance.

N.


 
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Nostrobino
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      10-20-2004

"Ryadia" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> Nostrobino wrote:
>> "Tetractys" <(E-Mail Removed)> wrote in message
>> news:(E-Mail Removed)...
>>
>> <gibberish deleted>

>
>>
>> There is NO dictionary definition for "prime" that means "fixed (or
>> single) focal length," or "fixed" or "single" anything else for that
>> matter.
>>
>> This is a misusage which evidently started when someone misunderstood the
>> term "prime lens," used the term incorrectly himself and the misusage was
>> picked up by others--and today, through the wonder of the Internet, the
>> misusage has spread like a weed. It has become popular jargon, which of
>> course makes it hard to kill. Some people love to use jargon because they
>> think it makes them sound knowledgeable.
>>
>> It is, in short, an ignorant term, and should be avoided unless one
>> particularly wants to display his ignorance.
>>
>> N.

> Narrow minded people expect the rest of the population to conform to their
> own version of correctness. "Prime" is an term for primary.


Correct. So far, so good.


> Primary lenses are the first choice lenses for photographers weighing up
> variables and deciding on the appropriate set up for a given photograph. A
> Photographer may have several lenses referred to a "Prime" which become
> the primary lens for specific situations.


You're thinking of beef. You had it right the first time: "prime" is used in
the sense of "primary," i.e., the camera's primary lens as distinct from
some other optical attachment used with it. It is not used in the sense of a
USDA grade of beef.


>
> The only spread of weed like jargon on the Internet is through global
> acceptance of a term or usage of that term. Global refers to the
> population in general. In a democratic society, acceptance of an occurance
> by the society is creation of a precedent and therefore acceptance by
> society itself of the term.
>
> "Prime" when referring to a lens for a camera is quite acceptable.


It is perfectly acceptable when used properly, yes. The camera lens (as
distinct from some other optical device used with it) is indeed the prime
lens. This is true regardless of whether the lens is FFL or zoom.


> Society has deemed it so. Why are you not part of society, Nostrobino?


I am a part of the literate section of society. I have no desire to be part
of the illiterate section, no matter how widespread or popular their
illiteracy becomes.

The OP in this thread used the term "fixed focal length," which is correct
for what he was asking about. Now I understand that "fixed focal length" is
somewhat of a nuisance to type out, and "prime" is much easier. This is
undoubtedly the reason for its popularity over the correct term. Why not
"egg lens"? "Egg" is even easier to type than "prime," makes just as much
sense (which is to say, not much at all), and has the advantage of not being
confused with the CORRECT usage of "prime lens." I suggest therefore that
"prime" (incorrectly meaning fixed or single focal length) be abandoned in
favor of "egg." One could even make the point that since an egg is somewhat
symbolic of unity, it does have a vague connection with the idea of single
something, which "prime" does not.

N.


 
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Nostrobino
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      10-20-2004

"Terry Hollis" <(E-Mail Removed)> wrote in message
news:06Xcd.16$(E-Mail Removed)...
> Nostrobino wrote:
>> "Tony Lewis" <(E-Mail Removed)> wrote in message
>> news:(E-Mail Removed)...
>>> On Mon, 18 Oct 2004 02:51:26 GMT, "Nostrobino"
>>> <(E-Mail Removed)> wrote:
>>>
>>>> This is a multi-part message in MIME format.
>>>>
>>>> ------=_NextPart_000_0076_01C4B49B.D8BD1F20
>>>> Content-Type: text/plain;
>>>> charset="iso-8859-1"
>>>> Content-Transfer-Encoding: quoted-printable
>>>>
>>>
>>> I would like to read what you are saying but it is very difficult
>>> unless you post pure text and not html.
>>>
>>> Thanks.

>>
>> Tony, I'm sorry, but I was only replying to the post. I never set
>> HTML in my own posts; my news sending format is set to "plain text."
>> Evidently the post I was replying to has that HTML feature turned on
>> and if there's any way to turn it off in my reply, I don't know what
>> it is. I will experiment a bit and see if I can get rid of it..
>>
>> N.

>
> To change from HTML to Plain Text in OE when writing a message...
>
> select Format/Plain Text
>
> This will work for the current message without changing your default
> settings.


Thanks! Got it.

N.


>
> --
> Regards - Terry Hollis, Auckland, New Zealand
>
> replace "nospam" with "terry.hollis" to reply
>
>



 
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