I too went down that rabbit hole. I bought books. I did exposure tests. I honed my technique to get every tone rendered on the negative. I fretted that I ought to carry more than one camera so that I could shoot with extended or compressed tonal range to suit the scene. Sorry – to suit my interpretation of the scene.
Then I realised I was taking more test shots than pictures.
I did the magic developer too. The one that is supposed to capture every nuance of tonality but instead just looks muddy.
Spot meter? Got one. It can drive you to panic when you realise how wide a range of brightness there can be in a scene.
Actually, I think digital helped. There was no magic method for capturing twenty zones and no magic development for producing detailed shadows and ethereal highlights. You had a sensor. You crowded the exposure as far to the right of the histogram as it would go. You played a bit with the contrast afterwards. Nobody cared – they either liked the picture or did not and not one person congratulated me on my tonal rendition.
I’m sure this zone thing works, but it works best where the camera takes single shots and you can develop them singly. For roll film you’re kinda stuck with whatever you choose as the average.
Actually, no, there is a use for this zone thing, but it’s not to match the range of the film to the range of the scene. Where I do find it useful is to place the exposure of the important bit of the picture. The answer to my panic using a spot meter is that the exposure needs to be right for the important part of the scene. As long as the rest of the scene is not distracting, it’s fine. For portraits I might measure the highlight on the skin and place that correctly, letting the rest fall where it may. Better yet, and see below, I could measure the shadows and make sure I got enough light into them. For something like streetlights at night, I would probably expose for the light under them and let the shadows go empty. Really easy to do with digital as you can chimp it and have the zebra-flashes to show where things will fall off the scale. Not so easy with film as you obviously can’t see until later what you got. I do sometimes cheat though and use stand development. Good old Rodinal at 1:100 is pretty effective at getting at least something out of the shadows without turning the highlights stark white.
So where is this all going? The zone system was interesting, but a huge sink of time and effort and resulting in little that made a practical difference to the photography I was doing. Having some understanding of how exposure works is useful though. Digital cameras seem to work best by giving them all the exposure they can take short of blowing the highlights, then dialling it back in post-processing to get the lighting you thought you saw. People say that digital needs to be exposed like slide film, but I think it’s different. You need to protect the highlights with slide film but you know you can always put more light through the dark areas of the developed slide to see what was in it. Underexposing slides tended to give rich colours. Underexposing with digital tends to give noise. So you need to give digital loads of light like a negative film, but to stop short of the highlights going off the scale. With black and white negatives you can protect the highlights like digital or give it enough exposure to get texture in the shadows and then hold the highlights back with special development. Or you can if you go all Zone on it. For all practical purposes the S shaped response curve of film is your friend.
What this means is that negative film does not have a straight-line response to light: adding one stop’s worth of light doesn’t necessarily add one stop’s worth of density to the negative. At the shadow end of the scale it takes a bit of light before the film even starts to respond. But at the top end, the more light you add the less extra density the negative gains. It’s all quite technical and you can follow the hyperlinked article above. In practice it means that you can give a negative film a fair bit of overexposure without blowing-out the highlights. Indeed, there is a whole argument based on the right exposure being the biggest one.
Colour negative film is the same: this stuff seems to revel in exposure – the more you give it, the finer the grain and smoother the results. What it doesn’t seem to like is underexposure. The exception to this seems to be the cinema-derived film – this stuff seems to be genuinely miraculous at coping with whatever you throw at it.
So what does this all mean in practice? Don’t be afraid to give a negative film extra exposure. It took me a long time to realise that a thin negative was not a good negative. I think I read somewhere that it would be the sharpest negative, but who cares about sharpness if there is no detail in the picture? So I have started feasting my film on photons. I deliberately overexposed a roll of XP2 when I was diving. The negatives were dense but loaded with detail and were easy to scan.
The other thing that’s interesting with film is the bottom end of that response curve, where it takes an amount of light before the film even starts responding. There was a Zone System technique of flashing the film with a small amount of light before taking the main shot. This primed the film to start responding immediately and was supposed to give more detail in the shadows. Interestingly, it looks like this is what Adox has done with their HR-50 film. Their speed boost looks like they pre-flashed the film so that the dark bits got lighter and the overall contrast of the film was reduced.
What’s interesting to me in this is not the Zone adjustment, but what might happen if you flashed the shadows with different colours using black and white film. In open blue-sky landscapes the shadows are blue. Preflashing with blue light might have an even greater effect. Or perhaps preflashing with yellow might balance the light in the shadows better? Perhaps preflashing with blue light for a portrait might render the shadows as though they were shot on ortho film, with the highlights being shot on normal panchromatic film. Or perhaps shoot the portrait on ortho film and flash the shadows with red light?
Do I see a new rabbit hole before me? Quite possibly, but one of my cameras does easy double exposures, so it would be simple to pop on an appropriate filter, take an underexposed shot of something without detail, then take the main shot.
Anyway, I’m not shooting landscapes this year, so I will be trying this out with people shots. Watch this space for a future update.