spot meter

Jim Nelson · June 15, 2009

I know that a spot meter is a reflective meter but gives you a meter reading from 1 to 5 degrees and that it gives you a reading equivalent to an 18% middle grey.

So how do you do to get the f-stop that you want on different areas using a spot meter? What I mean is that I don't want an 18% middle grey, I want a higher or lower exposure than the middle grey on different areas.

David Rakoczy · June 16, 2009

Sam,

This book will help you tremendously.

FILM LIGHTING

Ron Sharp · June 16, 2009

A spot meter is a great tool, with the experience to understand the info it confirms for you. A image is made up of a range of light's(highlight's) and dark's(shadows), a spot meter confirms this range of highlight's and shadows. The dynamic range of the medium your using will determine the clipping point of the highlights and shadows for a image. Read about the "zone system" it will help a lot.

SLR cameras now use a matrix metering system for exposure, this is just a number of spot meter readings in the camera with a algorithm to determine the exposure for you(Program mode). but it is still just used in the same way.

Ron

Chris Keth · June 16, 2009

With a spotmeter, you really have to know the film you are working with. Obviously you don't want everything to be a middle grey.

So say you're metering something that you indeed do not want to be middle grey.

First question is "what tone do you want it to be?" This is a beautiful question because it implies that you have a choice (and you do, of course) of how to light that area and how to expose it.

Second question is "how much under- or overexposure do I need to give that area to make it record on film the way I want it to?" Here is where you need to know your film. Lets say you metered an area you want to record as white with full detail. For one extreme, on reversal film this might mean that you should overexpose that area by 2 stops. If you're shooting a modern negative film, that will mean you have to overexpose that area by more like 3-4 stops. These numbers all depend on what film you are shooting, how you are processing it,, and how you are printing it.

The book David linked-to is a really good start. I bought it my first year in school and read it three times. Another classic work that explains the fine points of exposing film is Ansel Adam's The Negative. It is specifically written for shooting black and white sheet film (using the zone system which he and a few others developed as a scientific way to expose film), but the principles still stand for what we do to a very large extent. I recommend it highly.

Chris Millar · June 16, 2009

I've often wondered how many times people have taken a heavily side biased or back lit scene and spot metered a reading off a grey card parallel to the focal plane.

The card being flat will get only the general diffuse spill reflection of the surrounding area and none of the direct light from the sources.

Solution ... well, there isn't one exactly, a prescribed one at least - you just have to get your head around the limitations of a meter so you're not stuck with just the general cases - once you do understand the limitations they actually become useful ...

Yes, books are good - zone system, good, but don't get bogged down in it too much to begin with.

Chris Keth · June 16, 2009

I've often wondered how many times people have taken a heavily side biased or back lit scene and spot metered a reading off a grey card parallel to the focal plane.

The card being flat will get only the general diffuse spill reflection of the surrounding area and none of the direct light from the sources.

Solution ... well, there isn't one exactly, a prescribed one at least - you just have to get your head around the limitations of a meter so you're not stuck with just the general cases - once you do understand the limitations they actually become useful ...

Yes, books are good - zone system, good, but don't get bogged down in it too much to begin with.

I spot meter a lot and have never once used a greycard. There are other much more useful ways to use that type of meter.

Chris Millar · June 16, 2009

I spot meter a lot and have never once used a greycard. There are other much more useful ways to use that type of meter.

yup, actually - I must admit lately I've given up on the card and now just bounce off the skin directly to check things are as expected - if its important stuff I note the range from dark to light is also of interest as I soup the negs for pt/pd (pyro PMK) ...

Ha, wonder how many other large format people there are on here ? You and I often turn up in these spot meter threads :P

David Mullen ASC · June 16, 2009

Sam, the spot meter assumes everything is 18% grey -- it's simply up to you to decide how much over or under 18% grey you want to expose the object. You point the spot meter at the lit side of the face and it gives you a reading... but you know that caucasian skin tone is lighter than 18% grey so you decide that in this case, you want it to be one-stop lighter than 18% grey so you open up one stop from what the meter read. Or whatever you want. The reading requires that you make a creative decision.

David Rakoczy · June 16, 2009

I've never used a gray card for spot metering either... I'll use a Ambient Meter for that type of reading... I use my Spot to read what is 'actually' being seen through the lens... wait... I do use a gray card when checking the calibration of my Spot :lol: