setting a lower film speed?

[hiorgos]

Hi!

Just a question. I have seen that some people recommends to set the film speed lower than the iso speed, for example with iso 400 film set the camera at 320.

Do you do that? All the time or ust when you feel like it? Are there any specific rules/situations for it?

Im going to use neopan 400 for a while, what I should expect if I change the speed setting to 320? (And i'm sending the film to a lab for developing)

I would like to hear your thinking about this, thanks!!

 

[ChrisN]

Some people find that the "box speed" of the film is not the true speed ie exposed at that speed it will not record the fullest possible range of tones and detail. This is especially true in high-contrast conditions eg bright sunny days. Many experts recommend that in these conditions you should over-expose by one stop (ie rate the film for a slower iso) and shorten the development time to avoid over-developing the highlights. The extra exposure ensures good detail in the shadows. (This is for B&W with traditional processing, not slide or colour neg or other C41-process film.)

Mike Johnson had a good article about this. He called it his "not much of a system system".

see http://theonlinephotographer.com/the_online_photographer/a_simple_system.html

 

[charjohncarter]

I FIND the speed of every film I use that I like for developer and post-processing. I do it even with C-41 and Transparency film. Everything is different: each cameras (even f-stops in each camera), processing, post processing, type of developer, I even use some films for inside or cloudy days, others for sunny days, some for special effects, bad lenses, good lens for each situation. It goes on and on, and it will drive you crazy. But as John Sexton said: I just use two films, one developer, one enlarger, one paper, one paper developer. Maybe that is over simplified (John Sexton), but you have to choose on your own. Use other peoples guesses for a given situation, but in the end do what you like.

 

[hiorgos]

Thanks for the info! So, roughly, i would get the same exposure setting iso to 320 or compensating it to -1, no?

Not yet into home development, but maybe soon.. 🙂

 

[Chriscrawfordphoto]

Setting a 400 film for 320 is a 1/3 stop overexposure, not a -1 exposure. -1 exposure would be EI 800. I test each film and developer combination I use. Some I expose at box speed, like Ilford FP-4 Plus in D76, and others I give less exposure. I expose Tri-X in D76 at 320 and Acros 100 in Rodinal at only 50!

 

[hiorgos]

ops, i get it now.. thanks!

 

[btgc]

When I used only P&S cameras, I rated +1 constantly with canister DX code override method. Better shadows, richer tones, and some rare occasional burnouts. It's more question from which end you start eating egg, I'd compare.