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color film, metering, number of stops
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PostPosted: Sun Aug 05, 2018 7:59 pm    Post subject: color film, metering, number of stops Reply with quote

Hi all,
I am shooting some color film and I am about to do my first experiments with a notebook (keeping notes for each frame)

I still wonder what is the latitude exposure I can expect from color film and how color film might relate to adams zone system for black and white film.

More specifically, I can use my cameras meter but also an external meter. How many stops a color film can support. This is a relevant question for beach shots where the sun and the shadws can be 5-6 stops easily. I can use reflectors to reduce differences but how many stops there should be from example from the strongest highlight to the middle tones to be registered approriately from the film? Is it something like -2 for near black to +2 to close to white (where 0 is the middle grey)?


PostPosted: Mon Aug 06, 2018 5:51 am    Post subject: Reply with quote

For negative:- https://petapixel.com/2015/08/10/how-much-can-you-overexpose-negative-film-have-a-look/
While neg film doesn't really like too much under exposure, positive (slide) film is reverse in that it is better to underexpose slightly if in doubt after taking an exposure reading...but have never tested slide film for exposure latitude as it's too expensive to waste.

PostPosted: Mon Aug 06, 2018 4:32 pm    Post subject: Reply with quote

Just to add to Excalibur's comments, I've shot LOTS of slide film over the some 35 years or so that I've been a photographer, plus I have a collection of Kodachromes that my dad shot while he was in Korea between 1952 to 1954.

As for what sort of underexposure a slide will handle, it is really quite remarkable just how much information you can pull out of the shadows in a slide and still have good color and detail. I found this to be especially true with Kodachrome.

To show you what I mean -- here is a dupe of a Kodachrome slide that my dad took in Korea. Sorry about the size, but this is the only digital copy of this scene that I have that I can get to quickly. I duped the slide using my Sony NEX 7 and a slide copier I assembled with a 55mm f/2.8 AIs Micro Nikkor as the taking lens. It was a Christmas pageant at an orphanage that was close to the base where he was stationed. Unfortunately, he miscalculated his exposure, or he didn't use a flash when he should have. But the result was a slide where almost nothing was visible except that white sheet or curtain or whatever it is in the left part of the frame. I did some post processing work on the image, and you can see for yourself just how much detail I was able to extract from the shadows. I was able to lighten the image even more than this, but I decided on this example because to me it looked to be most natural.

Here's another example. This is a pic I took of m girlfriend (now my wife) at the Griffith Park Observatory in Los Angeles at sunset one winter day. Terribly underexposed. But it was a Kodachrome.

And after a fair amount of massaging, I came up with this:

And after a bit more, this:

I like the first rendition better than the second. The colors are more saturated for one thing. In order to pull this sort of detail out of a slide, I used my duplication setup and produced a series of six or seven exposures of the slide, from way underexposed to way overexposed, then put them through an HDR process to bring out the detail at close to a normal exposure level. I think it worked out pretty well, considering what I had to start with.

So, to sum things up, I've found that I can often overexpose color print film by as much as 1 stop, but I prefer 2/3 stop. I tend to get better contrast and color at that amount. But I would say that's for non-professional box film. When I'm shooting Kodak Portra, for example, I prefer to shoot it at box speed because it is a professional film, and the way I see it, Kodak has already figured in this "fudge factor" when they determined the ISO.

But I never, never underexpose print film, at least intentionally. Underexposed print film is just a muddy mess. The only exception to that would be intentional push processing, in which case results can be acceptable.

And to continue with the summing up -- slide film has a much narrower latitude than print film. So precise exposure is more important. This makes things trickier to use, but when you've shot slides as much as I have, you pick up certain things -- like using fill flash to open up shadows, so the subject remains within the film's exposure latitude. The worst thing you can do to slide film is to overexpose it. Because wherever you have burn-through to white, you've lost all image data.