Metering

[Barney]

First of all a big thank you to those of you who recommended Ansell Adams books, I have been reading The Negative and its turned my understanding upside down, I particularly like how he ties the exposure, development and printing together into one concern.

It is leaving me full of questions to which I am sure that you guys and gals have all the answers. I have, when using manual cameras, been using incident metering by enlarge on MF and auto on the 35mm cameras apart from F2. How can an automatic setting get it right when it does not know the exposure latitude of the film, and come to think of it neither do I. What is it measuring to arrive at its conclusion ? Is it placing the average reading of the whole scene on 18% grey or comparing the brightest and darkest areas in some way.

 

[srichards]

If the camera has DX coding then it can know the exposure latitude as it's actually in the specification. Not sure how many cameras actually make use of it though.

There's some useful info in this: https://thedarkroom.com/light-meter-photography/

 

[Topsy]

The automatic metering on most film cameras was a form of centre weighted metering that would indeed average out the scene to give an approximate 18% reflectance of the scene. Most were "calibrated" for negative film which has a good deal of exposure latitude and biased towards saving shadow detail at the expense of highlights, which is why it was always more difficult to get slides right because they are entirely opposite. Re your incident metering I've always found it to be great for slides but I'll give it a bit extra for negs for the same reason as above (but in reeverse) if that makes sense.

 

[Barney]

If the camera has DX coding then it can know the exposure latitude as it's actually in the specification. Not sure how many cameras actually make use of it though.

There's some useful info in this: https://thedarkroom.com/light-meter-photography/

Thanks Suz, I did not know that.

Do manufacturers publish the latitude of their black and white film?

 

[srichards]

Thanks Suz, I did not know that.

Do manufacturers publish the latitude of their black and white film?

I’ve never really looked. I have seen tables with claims about latitude about various films from people but not manufacturers.

 

[Barney]

The automatic metering on most film cameras was a form of centre weighted metering that would indeed average out the scene to give an approximate 18% reflectance of the scene. Most were "calibrated" for negative film which has a good deal of exposure latitude and biased towards saving shadow detail at the expense of highlights, which is why it was always more difficult to get slides right because they are entirely opposite. Re your incident metering I've always found it to be great for slides but I'll give it a bit extra for negs for the same reason as above (but in reeverse) if that makes sense.

That makes perfect sense Paul, Interesting your comments regarding positive film.