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fire diver
09-26-2007, 22:44
Ok, I know I'm still living in the stone age with my 35mm camera. Until I can afford an entire digital setup, I use what I got.

Anyway, my UW camera has auto speed indexing, but only sets for ISO 100 or 400. I have had decent luck with 400 speed film at depth, but have been wondering about testing some things. If I load 800 film, the camera will index it as 400. I know that this is only one f-stop difference. But can I shoot 800 at 400 speed in the deep, dark water and get better results? Will doing this pull more light from my strobe? Or will I end up with way too much contrast and crappy pics?

Sorry, I've been out of photography class too long, and spoiled by my digital land camera.

FD

peteg
09-27-2007, 09:07
I must confess that I am a bit rusty. It will underexpose by a stop, unless you can make a manual adjustment to the exposure settings. If you are shooting negative, no worries...800 can be wonderfully flexible and pulling it down to 400 should yield nice results but again, you wont gain an extra stop so you are wasting $$ on the more expensive 800. If you are shooting slides, then you will probably have a problem. I am sure someone else can refine my answer. I just realized it's been a very very long time since I shot film.

PlatypusMan
09-27-2007, 09:26
It will underexpose by a stop, unless you can make a manual adjustment to the exposure settings.


Absolutely correct, right down to your observation concerning slides.

The only other way to do this is if you are processing your own negative film, or spending the $$$ at a custom lab and telling them in advance that the film requires special processing, and why.

If you don't mind burning the cash on a series of tests, try all your film options by taking a short (12-exposure) roll of all the same U/w objects under the same or similar conditions and do each suggestion above to see which gives you the best results. 12-shot rolls are cheaper for that kind of thing in the long run.

BobArnold8265
10-04-2007, 22:08
Shooting 800 speed film 1 stop overexposed isn't going to help you unless you are finding that your camera is already underexposing your 400 speed. Can you override your camera to correct for the 800 speed film (i.e. set the camera at ASA400 but adjust the exposure to underexpose by 1 stop).

You could also adjust your flash to compensate for the 1 stop. Bottom line is that the advantage to the 800 speed film is to either enable you to shoot with a little less light, close down the lens an extra stop for a little more depth of field or to double your shutter speed to capture the fast moving critters. By shooting 800 speed film at 400 speed exposure settings negates any of the advantages of the higher speed film.

fire diver
10-04-2007, 22:16
Thanks for the replies folks. I have given up on this idea. The MotorMarine2 camera has an auto-indexed film speed, and the fastest setting is 400. Increasing the depth of field is the only thing that might make this workable, but that would have to be for some very specific shots. I'll just stick with shooting 400, and hope I can get enough ambient light for distance shots.

FD

diver 85
07-09-2008, 23:57
Ok, I know I'm still living in the stone age with my 35mm camera. Until I can afford an entire digital setup, I use what I got.

Anyway, my UW camera has auto speed indexing, but only sets for ISO 100 or 400. I have had decent luck with 400 speed film at depth, but have been wondering about testing some things. If I load 800 film, the camera will index it as 400. I know that this is only one f-stop difference. But can I shoot 800 at 400 speed in the deep, dark water and get better results? Will doing this pull more light from my strobe? Or will I end up with way too much contrast and crappy pics?

Sorry, I've been out of photography class too long, and spoiled by my digital land camera.

FD

I always used 100 speed film in my SS MM II---that's what they recommended also......