ASA/DOF/stereocameras

["The Photo-3D List" <photo-3d@xxxxxxxxxxxxxxx>]

A)  My first roll of Provia 100 through the Kodak is now being processed for
pick up tomorrow.  While using the Kodak, on several occasions the wind on
seemed to go on too long, but i thought perhaps there was some obscure
winding sequence required.  When i opened the camera there were some
sprocket holes ripped out of the film lying in the bottom.  (well-the film
surrounding the holes was lying there--the holes really can't be lying
anywhere, can they ;^} ) I hope they occurred at the beginning of the roll. 
DO Kodaks have problems with wind tension or sprocket hole damage?  In 37+
years of photography (i'm 47) I have only had cameras rip sprocket holes
two or three times--usually my fault. 

B)  I said:
 >> (Provia 100) really called for slower
 >>speeds, confirming my impression that the Kodak is basically a 'hand held
 >in bright light'kinda camera. 

Wolfgang said:
" Remember that these camera were designed for ASA 25 film,
try this and many of your speed problems will be solved. I use Fuji 50 and
it seems to work great, not as contrasty as the Kodak. "
Wolfgang SEll

Me again:  I like Fujichrome 50, use it a lot, and plan to use it in the
Kodak. I may try some Kodachrome 25 if i find the lenses are sharp enough
to deserve it (unlikely). 

But i am not sure how to apply the advice that my problems will go away
with the use of ASA 25 or 50 film.  I needed speeds BELOW 1/25 in shade
using ASA 100 film at f16, so slower film will require even slower shutter
speeds, although not so slow as to require bulb.  This leaves me with the
same problem--no easy way to shoot between, say 2 seconds and 1/25 second. 
I can time bulb exposures of 5 sec or longer. 

Perhaps you mean that the real solution may be (as Dr. T also advised me, 
in email) that the depth of field at f8 or f11
with these stereocamera ~35mm focal length lenses is quite sufficient for
stereo shots including infinity but not including near field material less
than 8 feet.  I am used to using f16 or f22 with my view cameras and
medium format cameras, and f11 or f16 with my 35mm cameras in flat
photography. 

If there are enough new users on the list it might be an 
interesting thread for the experienced to advise us about the differences 
in technique (and individual preferences) between sophisticated flat 
photography and equally sophisticated 3-d photography.  Not just how to 
avoid eye strain, but useful and appropriate subject distances/ranges and 
combinations thereof. I think traditional near/far may not work out so 
well for me as it has in flat photography (Dr. T. touched on this as well)
I don't recall much discussion of this recently, or even in the archives.

Thanks for the advice, Eric, about the Kodak DOF tables.  I knew enough 
to drop down 1 stop from the indicated ranges, but i didn't realize i 
needed 2 stops of insurance.  I wonder whether the f/1000 formula is 
applicable here.  It works for 50 mm lenses in 35mm full frame (.05 is 
one of the older cc specs, i think) but that was done assuming about 8x 
final enlargement. What is the apparent enlargement in a Red Dot or 
Kodaslide viewer?  Maybe Kodak is allowing twice as large a cc, assuming 
less final mag.  I find standard DOF ranges on flat cameras barely 
acceptable anyway, and usually use the engravings for 1 stop wider.

I had been told that the Revere used Cooke triplets, but i didn't realize 
all those other cameras did too.  Are there any other lens designs in 
use in stereo cameras, and how much does it matter, given the production 
tolerances of the day.

And why do these lenses vignette at small aperatures, whereas i get a 
LARGER image circle with my view camera lenses at small aperatures.

and why is the sky blue. (sorry--i'll shut up now)

best wishes and thanks to all for their good advice,

ted gosfield
gosfield@xxxxxxxxxxxxxxxxx 



------------------------------