How much can you change shutter speed for filters?

[wrs1145]

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. What are they?

Many thanks,
Bill

 

[Deleted member 65559]

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. What are they?

Many thanks,
Bill

The same....a stop difference for filters can be achieved by opening the aperture or lowering the shutter speed.

 

[seany65]

I think it's 2 stops for green, 1 and a 1/2 stops for Yellow-Green.

Keeping the same shutter speed (say, 1/250th), you open 1 stop for Yellow (say, going from f11 to f8), so for shutter speeds, if you wish to keep the same f number (say keeping at f11) you'd use 1 speed slower, (say going from 1/250th to 1/125th).

 

[SilverShutter]

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.

 

[Coldkennels]

I think it's 2 stops for green, 1 and a 1/2 stops for Yellow-Green.

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!



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



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!

 

[shawn]

You can also measure it with a light meter in the light you are in. Just take a reading, then take another with the filter in front and either use the difference as a mental correction or adjust the ISO on the meter to get the second reading back to the first. Then shoot like that with the filter in place. The Gossen Luna Pro Digital, and probably others, has a filter measuring correction function built into it. This would be for typical panchromatic films.

 

[Mos6502]

I also find it interesting that UV filters supposedly necessitate a 1-stop change in exposure on some films!

Many of those old orthochromatic films were sensitive into the UV spectrum, which would explain this. Plenachrome, despite what its name seems to imply, was an orthochromatic film.

 

[Coldkennels]

Many of those old orthochromatic films were sensitive into the UV spectrum, which would explain this. Plenachrome, despite what its name seems to imply, was an orthochromatic film.

Is this also true of modern Ortho films like Ilford's Ortho Plus? What about duplicating films like Eastman 5302?

I might have to be a bit more careful about which lenses I use with ortho films if that's the case... my Summicron and 28mm Color Skopar have UV filters effectively permanently fixed on them to keep them safe.

 

[Godfrey]

As the saying goes: "When in doubt, bracket."

By and large, for most of what I shoot with film and the filters I have, Yellow is 1 stop loss, Green is 2 stops, Orange is 2.5 stops. I only rarely use Red or Blue filters. But rather than tweaking the numbers mentally, when I fit a filter I adjust the ISO by the number of stops and just meter normally with the adjusted ISO.

Of course, that only works if I'm using a hand held meter and not an in-camera TTL meter ... then you have to learn the in-camera meter's response curve and see how different filters affect its accuracy.

Again: "When in doubt, bracket." 😉

G

 

[Mos6502]

Is this also true of modern Ortho films like Ilford's Ortho Plus? What about duplicating films like Eastman 5302?

I might have to be a bit more careful about which lenses I use with ortho films if that's the case... my Summicron and 28mm Color Skopar have UV filters effectively permanently fixed on them to keep them safe.

I've never used it, so I didn't know off the top of my head, but checking Ilford's datasheet, yes, their Ortho film is sensitive to ultraviolet light. I think it'd be an interesting thing to check, if removing a UV filter actually results in another stop of exposure with this film.

 

[shawn]

I've never used it, so I didn't know off the top of my head, but checking Ilford's datasheet, yes, their Ortho film is sensitive to ultraviolet light. I think it'd be an interesting thing to check, if removing a UV filter actually results in another stop of exposure with this film.

I would doubt it for most any modern lens as the coating block a bunch of uv anyway. Those that shoot uv photography seek out lenses that transmit uv better and they are typically uncoated with fewer elements.

 

[wrs1145]

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

 

[Mos6502]

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

You've already been told.
One shutter speed is equal to one stop. So if you have a filter factor of 2, which is one f/stop, you could either open the aperture by one f/stop, or drop the shutter one speed.

Just for example, let's say you have your camera set to 1/100 of a second, and the lens set at f/16. You put on a yellow filter, which requires one stop of extra exposure. You could leave the shutter at 1/100, and set the lens to f/11. Or you could set the shutter to 1/50 and leave the lens at f/16. Either way, you've added one stop of exposure.

This is really one of the most elementary aspects of setting exposure. As they say, google is your friend.

As for the specific number of stops, you're going to need to reference whatever the manufacturer specifies. There are light yellow filters, medium yellow filters, and deep yellow filters. Each has a different filter factor. These days, the medium yellow is the most common, and needs an increase of one stop in exposure. But that doesn't mean all yellow filters need the same. If you want a really good explanation of filters/exposure, the best I've seen in print is given in the old book The Amateur Photographer's Handbook. You should be able to find a copy for next to nothing.

 

[Deleted member 65559]

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

Bill, often the filter factor is on the filter rim. As written in some of the responses.... it's not always exact...it depends..the specific filter,.the lighting, the film etc.....
Bill...filter factors in a google search will give you lots of information....

Redirect Notice

 

[Bill Jones]

Bill the number of stops depends on the filter density and the film you are using. Filters come in different densities. Yellow filters can vary from .5X to 3x depending on the density which gives an experienced photographer a choice in pectoral effects. Typically a filter is marked on the outside ring with some number that is that filter factor (eg 1X). You multiply the shutter speed as marked (eg 2X for 125 becomes 250) by this number. For keeping the shutter speed the same increase the f-stop by 1 stop (eg f5.6 to f8). as shown above. For a more definite answer show a clear picture of the text on the od of each filter.

Bill

 

[Deleted member 65559]

Bill the number of stops depends on the filter density and the film you are using. Filters come in different densities. Yellow filters can vary from .5X to 3x depending on the density which gives an experienced photographer a choice in pectoral effects. Typically a filter is marked on the outside ring with some number that is that filter factor (eg 1X). You multiply the shutter speed as marked (eg 2X for 125 becomes 250) by this number. For keeping the shutter speed the same increase the f-stop by 1 stop (eg f5.6 to f8). as shown above. For a more definite answer show a clear picture of the text on the od of each filter.

Bill

Actually the other way.... the factor is how much more exposure..... the aperture gets bigger f8 ....f5.6. or the shutter speed gets longer 1/250 becomes 1/125....

 

[Bill Jones]

Actually the other way.... the factor is how much more exposure..... the aperture gets bigger f8 ....f5.6. or the shutter speed gets longer 1/250 becomes 1/125....

Thank you for the correction. Of course your right.

Bill

 

[shawn]

One other thing to point out, if your camera has TTL metering (or a light sensor inside the filter ring) you likely don't need to compensate manually. The meter is measuring the filtered light.

 

[Cascadilla]

One other thing to point out, if your camera has TTL metering (or a light sensor inside the filter ring) you likely don't need to compensate manually. The meter is measuring the filtered light.

Not necessarily--meter sensitivity doesn't always match film response. My otherwise excellent Soligor 1 degree spot meter was modified by Zone VI with filters over the silicon blue cell so that it matched common B&W films in spectral sensitivity. It definitely made a difference for me in accuracy of exposure.

 

[shawn]

Not necessarily--meter sensitivity doesn't always match film response. My otherwise excellent Soligor 1 degree spot meter was modified by Zone VI with filters over the silicon blue cell so that it matched common B&W films in spectral sensitivity. It definitely made a difference for me in accuracy of exposure.

True, but you will see the effects of that more on a spot meter than you would elsewhere. The spot is seeing a smaller amount of reflected light with a narrower spectral range compared to other types of metering. Either way you would not apply the full filter correction to a meter that is metering through the filter.