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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)?

Thanks
Alex


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.


PostPosted: Tue May 07, 2019 6:13 am    Post subject: Reply with quote

Hi Alex,

I see that original post is over 6 months old, but hey, maybe someone will read it in the future Smile so I've decided to put my 2 cents.

I haven't shot neither on slide films nor B&W (which Mr Adams was writing about), but had some experience with negatives and simple answer to your question is: colour negatives store plenty of dynamic range when exposed properly. I was very amazed how much detail I was able to get in the highlights (however significantly less in shadows). When shooting general landscapes I was using average metering and 9/10 it turned out great and while shooting portraits (back-lit or any other) I was using spot metering on my OM2SP and OM4's and exposing for the face (Caucasian skin) and let background light fall anywhere it needs which presented great results as well mainly because of great overexposure latitude of the negatives.
In short: in comparison to shooting digital I was less careful about the highlights, because they usually behaved a lot better on negatives and can be bring down after scanning.

Another type of answer, however not very elegant, is to just try different films and note how they behave in over/under exposure conditions and so on. I usually took one roll of unknown film and exposed it from -3EV to +3EV with some average landscape scenery. After that I shoot some high contrast scenes with -1EV to +1EV bracketing to see how much I could restore from shadows and highlights + some portraits exposed properly and over/under to see how skin tones are behaving and that's it. Some negatives behave better than other even withing the same price range.

However...
For me it's also important, if not the most important, is what are you going to do with developed negatives. I will probably never enlarge them in non-digital lab and now I'm not scanning at lab either as I was getting very vivid and contrasty looking scans, but sacrifice a lot of dynamic range and even detail (here I've developed kind of comparison between lab scan and home scan: http://forum.mflenses.com/short-scaners-test-noritsu-vs-plustek-vs-frontier-t72784.html ). Because of that I could happily exposed my negatives in a way that my scanner likes them and scans them best.
I scan my negatives on cheap (and slow Razz) Plustek 7600i and found it the most reliable solution to the day. What I found, however, is that different negatives behave differently when under/over exposed while scanning.
For example:
Fuji Superia 200 - scans great and looks very airy when overexposed about 1 stop
Fuji Superia X-TRA 400 - scans best when exposed in point or slightly underexposed, while overexposed scans show some colour casts
Agfa Vista Plus 200 - scans terribly when overexposed, it's usually better to underexposed this negative by 0,3-1 stop for me as far as scanning goes (I had a lot of problems bringing proper skin tones when overexposed)
Kodak Portra 160 - in my environment doesn't like to be overexposed more than 2EV as it needs then a bit more processing after scanning
Kodak Portra 400 - almost the same as Portra 160

Which is not surprising one could restore plenty more information from professional grade negatives than from consumer ones. They tend to show a lot less contrast (which is obviously not a problem to alter in post). I've shot a few portraits on Portra 400 overexposed by +3EV with spot measuring on face and they turned out great.

I forgot to answer your question about Mr Adams zone system for B&W negatives in relation to colour negatives. I was amazed by his book (which I read just after I've started with negatives), but... well in my opinion in times when scanning negatives and altering them digitally is not a problem I think that such critically careful metering is not that important anymore. Just go in the summer on the beach and try shooting very high contrast scene with bracketing withing 3EV and you'll know what I mean. Even on cheap negative you could easily make shots from -2EV to +2EV look almost identical after scanning. Honestly - I've shot such scene with Kodak Gold 200 and after scanning I thought that I've forgotten to do bracketing and only looking at negatives I saw that indeed they look different.
But in the other hand I'm not good enough to be carrying Mr Adams tripod Wink so well... maybe I shouldn't be giving any advices.


PostPosted: Tue May 07, 2019 9:01 pm    Post subject: Reply with quote

Hi Alex, still asking those questions huh! Colour film has absolutely shiploads of latitude. Thats how Kodak Instamatics worked with their 80 ASA film and 1/60th at f11