Classic light metering questions

[ruben]

Yesterday I bought an Euro Master light meter, and since I feel quite tense until I get this legendary instrument, why not killing time by asking some basic questions about classic light metering, after a few words for those unfamiliar with the Weston Master breed.

I have bought it for the easy provision to quickly compensate the average reading, not found (the provision) in either of my two digital sekonics, nor in my older and cumbersome Gossen Sixtar. (And, if I am not wrong, the Master is half the size of my Sekonic L-308, and a third of the spot L-408 !!!!)

The Euro Master, like other Westons has a triangle marking the average reading, and four stops leftwards the fixed triangle an "U". Three stops rightwards the triangle, there is an "O'. Correct me if I am wrong, I understand that this 7 stops scale comes to represent the latitude of classic B&W film, like Tri-X, Ilford HP and others.

Now suppose the meter is in my hand and I go outdoors, in a sun brightly illuminated day. If my memory doesn't fail me, the difference between a brightly illuminated white, under these conditions, and a shadowed black, may reach perhaps an 11 stops gap.

Therefore, according to what I want in my final film image, I have to choose. Either go for the detailed shadowed black and meter it following the "U" (under) readings of the Master, or I pursue a detailed bright subject metering it and aplying the readings of the "O" (over). At each case I will be benefiting my choice at the expense of the other extreme. No councious choice via incident (white dome) reading and I will be harming both extremes. Correct ?

But now I enter my kitchen, poorly illuminated by a fluorescent light and I find that the difference between shadowed blacks and illuminated whites is no more than 4 stops. How do I deal with it having a film of 7 stops latitude ?

And what can I do through exposure choice in order to widen the contrast at the final film image ?

The question becomes more accute, if I recall a few weeks ago making a pic of a young lady seating a meter from me at night , in a poorly illuminated restaurant, with less latitude than at my kitchen !!!

Lastly I want to ask about the 18% average black, which is what any light meter is supposed to indicate, before photographer compensation. Why 18% black and not 50%, why 18% ???

Cheers,
Ruben

 

[ClaremontPhoto]

The real world is typically 18% black so the light meters are set up that way too.

 

[ruben]

The real world is typically 18% black so the light meters are set up that way too.

Would you be so kind as to detail for less telegraphic minded humans?

 

[markinlondon]

When Kodak did their tests around Rochester, they actually found that the world was, on average 12% grey. I think 18% was an approximation based on the the sensitivity curve of the films of the day.

Westons are pretty wide patterned so I wouldn't advise using them for ZS-type shadow index readings, metering a midtone is probably your best bet. I find my very battered Euromaster startlingly accurate. I don't think it would have helped with the lady in the restaurant. That's a kind of "hope for the best" situation IME.

To control excessive contrast your best bet is overexposure and underdevelopment. I'd give at least an extra stop and pull development time by about 20%. For a 35mm roll this may mean thin negs elsewhere, but that's what paper grades are for.

Mark

 

[ruben]

Hi Mark,
Thank you for your answer. How do you meter and compensate low contrast situations?

What is "ZS-type shadow index readings"

And kill me if I understand what is 'the world is 18% grey.'

Cheers,
Ruben

PS: Is your avatar a self portrait ? Mine not.

 

[markinlondon]

Hey, Ruben somehow I guessed that about your avatar. I'm sorry to say that mine is me, what you see, etc. It's not a self-portrait, my partner took it (with my camera, I developed and printed the film).

Have a Google on the Zone System for more then you could possibly want to know about sensitometry (?sp). But contrast control is really down to exposure and development, not metering. I owe a debt to the late Barry Thornton and the living Mike Johnston who summarised thus:

Low subject contrast: Expose and develop at manufacturer's recommended EI and time (adjusting to your own setup/water/tastes of course) So that's HP5 @ EI400 7mins in ID-11/D76 1:0 (say).

Nice day, reasonable shadows: Shoot at 1 stop over and develop for ~20% less time. So HP5 @EI200, 5.5mins in ID-11 1:0

Very bright day (such as you probably see a lot of in your part of the world): Reduce film speed further (another half stop maybe). Develop for 33% less that maufacturer's recommended time. So HP5 at EI125-160, 5 mins in ID-11 1:0.

I can say this works and gives about 75% of what the ZS does without the
hassle of testing for your "personal EI". Any inconsistencies are made up at the printing (or PS) stage, but what we're looking for here are negatives that print without excessive burning and dodging. I don't understand why ZS acolytes spend half their life testing for perfect exposure in the camera and then need 15 different exposures on the same print.

If you're not doing your own processing this won't help. If you're using C41 you can use the speed offsets and they'll print fine. If you're shooting chromes I've just completely wasted my time and yours, so I hope this is useful.

Mark

 

[ruben]

Hey, Ruben somehow I guessed that about your avatar. I'm sorry to say that mine is me, what you see, etc. It's not a self-portrait, my partner took it (with my camera, I developed and printed the film).

WYSIWYG...

Thank you Mark for the detailed info

 

[pshinkaw]

I bought this book.

The Hand Exposure Meter Book (Paperback)
by Gerald Hisrchfeld, Bob Shell, Martin S. Silverman, Jim Zuckerman

I think I paid about $22 for it directly from Bob SHell (autographed) for some reason it's on Amazon.com for $125. I have seen it at some photo supply stores for about $30.00. I thank that's the real world price.

I highly recommend it.

-Paul