Re: autofocus (fwd)

[Yiing Lin <ylin@xxxxxxxxxxxxxx>]

---------- Forwarded message ----------
Date: Sun, 17 Dec 1995 20:25:10 -0500
From: Eric Goldstein <egoldste@xxxxxxxxxx>
To: photo-3d@xxxxxxxxxxxxxxx
Subject: Re: autofocus

At 2:00 PM 12/17/95, Alan Lewis wrote:
>I have no problem with matching focal lengths of fixed lenses
>on my Canon T-50 rig, are you talking about matching zooms?

Yes, exactly. Sorry to have been unclear about this, but that's just what I
was getting at.

>I also use my
>SLR rig for the serious shots, ones that have to be the best.  The SLR rig
>produces excellent exposure balance and contrast, and manual focus assures
>the right results.

Good points. Until P&S cameras allow for better manual control and improve
some more optically, the "best" rigs for quality will continue to be the
larger, more expensive cameras, though not necessarily SLRs. I'm sure that
twin M-6s or the new top end Contax rangefinders would make outstanding
twin rigs (anybody hit the lottery recently?:-)), except for...

>One other thing about SLR rigs that makes me go back to
>them from my "point and shoot" rig is the viewfinder.  I don't like the P&S
>viewfinders, not good image quality and too small  of an image.  SLR
>viewfinders are much more enjoyable to use, you get a real sense of
>composition and can see details in the composition better.

Well said. As good as the rangefinders on the top-end rangefinders are
(using relatively "normal" lenses), the through-the-lens view is tough to
beat. And you can optically preview DOF, which can be quite useful in our
work.

>I'm not sure what the obvious reasons are for zooms.

Probably unwise of me to be so dismissive on the matter of cheap zooms.
There is a good, thoughtful treatment of this subject at:

http://www-swiss.ai.mit.edu/philg/photo/point-and-shoot.html

the site which Stephen Kearney refers to in his post today. In a nutshell,
zooms (and particularly compact ones) have many more optical barriers which
must be overcome compared with primes, and thus are much more difficult to
design and manufacture. Attempting to do so with the short money most P&S
cameras go for necessitates manufacturers to make some dramatic compromises
in optical quality and performance. These short-comings are more pronounced
at wider apertures, and so are not quite as big an issue for us as for 2-D
photographers. The recent use of plastic aspherics in zooms such as the new
Minolta (about $200) are also improving this situation. But as a general
rule, the optical performance of a compact fixed focal length lens should
be visibly better than a compact zoom lens of even significantly higher
price.

>If you want to do slides you must set your
>limit of cheap at no less than $100 and maybe up to $250 each.

Another important point... what is the viewing criteria? I am a slide
shooter, and as you state that means I'm going to need higher levels of
performance than most print shooters (notice that weasel word "most"...
print shooters on the list, please be kind!) because of the shorter tonal
scale of that medium and the (generally) smaller viewing size/lower
magnifications. My entire thinking for developing a P&S twin-rig is geared
toward getting the best possible chromes for the shortest money with the
greatest ease of use. For prints, I know students who get some excellent
results with twinned fixed focus, 3 lens element $25 reloadables from
Vivitar and Fuji!

>From the reports that I have read the Nikon Lite Touch is optically in
>the same league as these (Yashica, Leica, Contax).

It has a 28mm lens, compared with the 35mm lenses on the others. I
personally find this less desireable, but others may have a different view
(angle of view? :-)).

>The ultimate is certainly , as you say, linked auto focus and exposure.

Easy for me to say, but I don't know that I have the skills to make it happen.

Now if I had the experience (and talents) of say, a Mike Watters...


Eric G.
egoldste@xxxxxx



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