Originally Posted by Michael R 1974
EI 80 isn't going to render a practical difference. EI 50 is an entire stop, and that will be noticeable in the shadow (film speed) department.
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Thanks everyone. I'm not developing my own film yet because I dont have the equipment. Was expecting my tank and reel to arrive this weekend but now find that it will be delayed almost 2 months.
I send my film to a lab that will let me specify D79, D96, HC110, DDX, XTOL, and TMAX developers. So far I've only tried D76.
How is a third stop change going to affect a film that has such a known wide latitude? I don't see how a "contrasty lens" can play into it?
With transparency film, 0.3 stop either way will be noticeable, 0.6 either way will either make or break the image, but with B&W film, you need to go 2 or 3 stops to get any benefit.
I have exposed ACROS at 400 and 80 in a pinhole camera (diffuse light) with no change to development at the lab.
Shooting at half box speed is a full stop not 1/3-1/2. With some B&W films and developers over exposing can give more grain.
Originally Posted by newtorf
Some people shoot at 80 because some testing indicated to them that this is closer to the "true speed". But as mentioned in most circumstances it should not make any significant difference. Some people are very precise in their approach and it does matter to them and they like to talk about it too.
Only time I will purposefully "overexpose" is when I have fairly contrasty conditions. Then I'll shoot Acros at 50 or HP5 at 200 or 250. I will also then pull development time back by 10-20% as well. This can do wonders for getting better shadow detail while also preserve highlight details too. And is also better for scanning in my experience.
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Actually, not just some, for any given film/developer combo it is my understanding that all normal B&W films get grainier as exposure increases. That has certainly been my experience.
Originally Posted by rich815
Chromogenics though, like XP2 and BW400CN, get reduced grain with increased exposure.
Mark Barendt, Beaverton, OR
"We do not see things the way they are. We see things the way we are." Anaïs Nin
OK, I'm still a bit confused. How to get a shot like this and make it look better? It was VERY dark and I boosted the shadows in post after scanning. I think it is easily understood that the bright sky made the camera expose the foreground dark. In such a situation, I am not sure when I should add +EV to make sure the foreground is the stand out part of the image. Should I point the camera at the sky and take a meter reading, then meter the ground and compare the two readings to the "mixed" reading? If the differences are extreme, then determine if +EV is needed?
Is this better than shooting at a different ISO rating?
Assuming even light, if possible, you want to take your meter reading off of a middle grey - the pavement looks like a good choice here.
In most cases that will determine your exposure.
You certainly want to avoid having the sky determine your exposure, unless the sky is what you are most interested in.
In rare cases you need to go further. Sometimes there are subjects of interest in the frame that are relatively much lighter or much darker than average, where a normal and otherwise correct exposure won't result in those subjects appearing the way you want them. In those unusual circumstances you may make the decision to change the exposure in order to favour those subjects, at the expense of the rest of the frame. An example would be strongly backlit subjects, where the foreground is emphasized at the expense of the blown out background.
Generally speaking you don't adjust your EI with circumstances - you determine your EI when you calibrate your system, and stay with that EI. Subsequently you may make decisions to deliberately under-expose or over-expose certain subjects, based primarily on issues of contrast.
Last edited by MattKing; 08-31-2012 at 06:30 PM. Click to view previous post history.
“Photography is a complex and fluid medium, and its many factors are not applied in simple sequence. Rather, the process may be likened to the art of the juggler in keeping many balls in the air at one time!”
Ansel Adams, from the introduction to The Negative - The New Ansel Adams Photography Series / Book 2
This is correct, although again, we're talking trivial differences when it comes to fractions of a stop. This can also end up being offset by the decreased graininess associated with decreased development - which is often the approach when giving extra exposure to support shadow densities.
Originally Posted by markbarendt
Good advice. Standardize your working EI, use your meter set at that EI, and make decisions on whether to give more or less exposure.
Originally Posted by MattKing