Metering ambient light

Scarecrow

Scarecrow

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Derek
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I have a vague memory from my days of shooting film that it was possible to buy a filter that you placed on your lens that allowed you to use your camera to meter the ambient light in a scene, rather than measure the light reflected form your subject.

I was just wondering if such a thing is still available, or if anyone else knows what I am talking about?
 
Yes a diffuser to measure the incident light falling on the scene. I wonder why this is needed nowadays with spot metering and histograms. You can also meter off an 18% grey card for the same effect but I'm intrigued as to why.

John
 
If you want to play around with the idea, you could try white tissue or tracing paper secured with an elastic band over the lens to get an incident light reading.
 
Surely with this all you are doing is measuring the light falling on the lens. An incident lightmeter with a diffuser is held at subject position and pointed towards the camera or split between camera and key light such as the sun. This metering does not not take in to account the reflected values within the scene and is particularly favoured by cinema DOP's to maintain skin tone consistency between the various shots in a sequence.


pete
 
Scarecrow said:
I have a vague memory from my days of shooting film that it was possible to buy a filter that you placed on your lens that allowed you to use your camera to meter the ambient light in a scene, rather than measure the light reflected form your subject.

I was just wondering if such a thing is still available, or if anyone else knows what I am talking about?
Click to expand...

Hi, This is an attempt at helping with the little I know thus far - are you certain that you are not getting confused with a filter to reduce ambient glare(s)?

What I do is take several reading (diffused) and add them to the memory and the meter works out the general ambient light before you tackle the subject itself. Would that be something of what your after?

Alistair
 
Scarecrow said:
I was just wondering if such a thing is still available, or if anyone else knows what I am talking about?
Click to expand...

You are thinking of the Expodisc. It is now sold for getting accurate white balance but originally it was designed for incident light metering on an SLR.

I used to use one occasionally with my OM-1, when shooting slide film in difficult conditions such as backlighting or water with lots of reflections - it worked brilliantly. However once I moved to an OM-4 which had spot metering I got just as good results, with less effort, by using the spot meter and the zone system.

Now that most cameras have spot-metering and we don't need to worry about the cost of bracketing, I don't think it is worth getting an expodisc. I still have mine along with the OMs but I doubt if I'll be using any of them again....
 
Try facing your own outstretched palm towards the light source(es), from your subject position, or anywhere you like if the lighting is distant and/or even (no falloff factor to consider), and then spot meter your palm at (in my case) + 1 1/3 stops. That will place skin tones in a good position on the tonal scale. Most other things should be well positioned too, and you should hold highlight details other than specular reflections and light sources.
 
Thanks for the responses guys. It wasn't necessarily something I wanted to use, I was just checking that my memory wasn't playing tricks on me.

If I ever feel like experimenting, I'll try sticking my hand out as suggested by Tim. ;)
 
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