How much can you change shutter speed for filters?

[Godfrey]

... This is why you must always test and calibrate when planning to use B&W filtration.. 😉

G

 

[Rob-F]

Thanks, but I'm at bit more confused than when started. What I'm asking for is The number of stops I need to reduce my speed for the following:

Yellow filter ____
Orange filter ____
Red filter ____-
Green filter ____

Thanks,
Bill

This post sounds like what the OP really wants to know (or how I'm understanding them) is how many stops it takes to darken the image when using a given filter. So maybe this is what they are looking for:

If a yellow or green filter has a 1 stop published factor, and you want to reduce density by 1 stop, then do nothing; leave the aperture and shutter speed the same as you would have them without the filter;

If an orange filter has a 2 stop factor, and you want a 1 stop density reduction, open up 1 stop;

If a red filter has a 3 stop factor and you want a 3 stop density reduction, do nothing; if you want a 1 stop reduction, open up 2 stops; etc.

wrs, is this what you needed; if not, let's try again.

 

[Rob-F]

I mean you normally would use colour filters for the creative effect of colour filtration rather than the loss of light. If you just want loss of light use NDs, or close down the aperture to bring down shutter speed since they are proportional. A same level of exposure can be obtained through a variety of speed and aperture combinations established by the light value you choose.

Correct... kinda.

Technically it depends on the film stock you're using and the time of day. Leitz New York published this table in the 1930s showing how filter factors can vary from film to film. All the "Filter No. 0, Filter No. 1" in the daylight sections are various grades of yellow filter; I also find it interesting that UV filters supposedly necessitate a 1-stop change in exposure on some films!

View attachment 4835717

And here's a chart from Wikipedia to help convert filter factors into "stops":

View attachment 4835718

Modern films are (mostly) a lot different to the film stocks being used back then with regards to colour sensitivity and the like - but it's still going to vary wildly from film to film, so it's worth testing with your most commonly-used films. I seem to remember the original Acros having an unusual response to certain colours compared to, for instance, HP5+.... and, of course, Ortho films are a totally different kettle of fish from the "regular" panchromatic stocks.

I had one particularly derpy moment where I tried to use an orange filter on Ortho film with a standard two-stop exposure adjustment, only to get a blank frame for my trouble. Felt like a right idiot when I realised what I'd done!

I'm fascinated by the Kodak entries. When I was just barely old enough to notice such things as film speed, I was aware of Kodak Panatomic-X; Plus-X; and double-X. My dad switched from Double-X to Tri-X when Tri-X came out. At age 8 I was shooting Verichrome. Here I see Kodak "Super Sensitive" and "Super X." I have no memory of these. I'm having no luck with Google; but I'm guessing "Super Sensitive" might be a forerunner of Plus-X, and "Super X" could be the early Double X? Does anyone know?

 

[Deleted member 65559]

This post sounds like what the OP really wants to know (or how I'm understanding them) is how many stops it takes to darken the image when using a given filter. So maybe this is what they are looking for:

If a yellow or green filter has a 1 stop published factor, and you want to reduce density by 1 stop, then do nothing; leave the aperture and shutter speed the same as you would have them without the filter;

If an orange filter has a 2 stop factor, and you want a 1 stop density reduction, open up 1 stop;

If a red filter has a 3 stop factor and you want a 3 stop density reduction, do nothing; if you want a 1 stop reduction, open up 2 stops; etc.

wrs, is this what you needed; if not, let's try again.

I'm not sure how you deduce that. Darkening the image = underexposure, non?
Typically we're trying to change the tonal relationships....

 

[Rob-F]

I'm not sure how you deduce that. Darkening the image = underexposure, non?
Typically we're trying to change the tonal relationships....

Yes, typically we are. But as I read the OP's last post, they asked to reduce their speed, which I took to mean sensitivity to exposure. Maybe they meant the shutter speed in order to increase their exposure owing to the density reduction of their filter, in which case I read them wrong. I believe then the answer they wanted would be to open up by an amount equal to the filter factors they already know and cited in post #1, for the filters mentioned. However, this point had already been answered before I responded, so I thought they must have meant something else. I'm sure now that I misunderstood.

The amount of correction also depends on whether the subject and the filter are the same color, or different. If they are the same color, little to no correction is appropriate. If color complements, e.g., a blue area photographed with a yellow filter, the blue area of the picture will record very much darker in the print. A yellow area in the same photo will likewise need no correction, in order to record with normal density. If that's what the photographer wanted, then once again no correction should be used. So for example a yellow sign against a blue sky, taken with a yellow filter, and the photographer wants the sign normally exposed and the sky darkened, no correction is needed. Such details are just as important as memorizing filter factors.

 

[Retro-Grouch]

If I may add my $0.02, think of it this way. You photograph an 18% gray card, and that gives you a density of X on your negative. If you again photograph that card with a colored filter, the filter factor is the additional exposure you would then need to still achieve that density of X. A filter factor of 2 would require you to open up by one stop, or use the next lower shutter speed. Thinking of it this way divorces exposure from the variances introduced by photographing specific colors. All that being said, some experimentation is still in order.

 

[Mos6502]

Yes, typically we are. But as I read the OP's last post, they asked to reduce their speed, which I took to mean sensitivity to exposure. Maybe they meant the shutter speed in order to increase their exposure owing to the density reduction of their filter, in which case I read them wrong.

I think the first post in the thread provided necessary context: "I gave seen the standard rules for filters: 1 stop for yellow; 2 stops for orange; 3 stops for red; 1 stop for green. But there are corresponding rules for shutter speed lowering for the same purpose."

 

[seany65]

Bill, Have you been confused by many of the responses?

I usually am when I ask a question in the internet, half of the answers seem to say "this", half of them seem to say" that" and half of them seem to say "the other", and you're bound to get an argument that nearly ends in a fight, lol.

Anyway, as for compensating (giving more expsosure to compensate for the density of the filter when using a hand held meter or "sunny 16"/"sunny 11") I usually follow the info that Hoya give:

Yellow: Filter Factor 2, Exposure Compensation 1 stop.

Green: FF 4, EC 2 stops.

Orange: FF 4, EC 2 stops.

Red: FF 8, EC 3 stops.

Curiously, now:

Yellow-Green: FF 1.2, EC 1/4 of a stop.

When Hoya answered an email some years ago, they told me:

Yellow-Green: FF 3, EC 1.5 stops.

So you have three options:

1) Keep the same shutter speed but use a wider aperture by opening by the correct number of f-stops.

2) Keep the same aperture and use a slower shutter speed by slowing the speed down by the correct number of shutter speed-stops.

3) Use a combination of wider aperture and slower shutter speed to a total of the correct number of stops.