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08-04-2021, 08:45 AM   #1
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Filter Factor

I'm starting to experiment with B&W filters, but I'm reading a lot of mixed information.

Should I be adjusting my EV compensation dial for use with Yellow and Orange filters, or does the TTL metering handle that for me on an SLR?

08-04-2021, 08:55 AM   #2
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Well, you can experiment and verify your TTL works good enough with the filter on. Most yellow filters have a filter factor of 2 (1-stop reduction). So put the camera on a tripod without the filter and get a meter reading. Now Put the filter on and see if there is a one-stop reduction. Most BW films have a lot of latitude. Arguing over say 1/3-stop more or less exposure doesn't mean much.
08-04-2021, 09:04 AM   #3
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As long as it is in the optical path the meter will take it into account in any SLR within some tolerances. However, the creative part in us usually play a lot with exposure compensation for different effects.

Thanks,

Last edited by ismaelg; 08-04-2021 at 09:13 AM.
08-04-2021, 09:07 AM   #4
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QuoteOriginally posted by trixtroll Quote
I'm starting to experiment with B&W filters, but I'm reading a lot of mixed information.

Should I be adjusting my EV compensation dial for use with Yellow and Orange filters, or does the TTL metering handle that for me on an SLR?
Your camera's TTL light meter may or may not be sufficient. Some (most, IIRC) camera light meters are not especially colour blind, which can lead to erroneous readings.
The easiest way to check this is to take a reading off of a neutral coloured object (a gray card is ideal) with no filter, and then see if the filter causes the meter to deflect the same amount as the filter factor.
If it does, you are golden, if it doesn't, you will need to fudge the exposure, either by adjusting the ISO a bit or by compensating via the exposure compensation dial. The latter is the more accepted way as it doesn't interfere with the base ISO of the film that you have determined to be correct (something surprisingly few photographers bother doing).

08-04-2021, 09:15 AM   #5
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QuoteOriginally posted by trixtroll Quote
I'm starting to experiment with B&W filters, but I'm reading a lot of mixed information.

Should I be adjusting my EV compensation dial for use with Yellow and Orange filters, or does the TTL metering handle that for me on an SLR?
Your cameras built-in TTL meter will compensate for the filters light loss, the same as if you were using an extension tube. (Though sometimes it's going to be a bit off)

The filter factor on a coloured filter, is required if you are using a hand-held light meter instead of the cameras TTL one. My Gossen light meter has a filter factor dial where you preset the value, along with the film's ISO, so when you meter the FF is already compensated for. (That way you never forget to compensate)

Phil.
08-04-2021, 05:12 PM   #6
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Soooooooooooooooo..... It depends on your camera and its metering system. Most modern cameras have a metering system with a color response curve similar to the eye and their sensor (I would also say film but then they wouldn't be "modern" exactly). These will work with most any colored filter and make exposure adjustments that agree with the filter factor pretty well, and will produce properly exposed shots without taking any manual action.

Older cameras can have a color bias in their metering systems and if they do, the amount of compensation accuracy will depend on the color of the filter. As mentioned, it's a very easy check using a gray card. You most likely won't have to do this with any digital ("modern") camera.

Last edited by Bob 256; 08-04-2021 at 05:18 PM.
08-05-2021, 06:19 AM   #7
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Thanks all for the feedback!

Comparing my metering results, against a grey card, was so simple that it hadn't even occurred to me.


My results were as follows:

My PK showed exactly 1 stop difference with the filter mounted, but I can't see any point in using a colored filter on this camera.
My ZX-M also showed exactly 1 stop difference, so the metering was accurate and I like that I won't have to think. The plastic fantastic is my favorite body right now, so that was pleasing. Hopefully this one doesn't decided to destroy itself.
My P30-T only showed a 1/2 stop difference, so that was interesting.....I love the viewfinder on this body, but it's so frustrating that I can't manually set the ISO or dial in EV compensation.

08-05-2021, 09:37 AM   #8
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QuoteOriginally posted by trixtroll Quote

Comparing my metering results, against a grey card, was so simple that it hadn't even occurred to me.

Good deal. It's nice not having to remember to dial in an EV fudge factor.

Using a grey card sounds like a controlled experiment but you won't be taking pictures of a grey card. The filter factor difference needs to also show up on your typical outdoor shot too. My 2 worth says also try the test outside.
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