Adding Filter Factors- B&W

[timbo10ca]

I've read on a number of occasions that additional exposure should be added on top of a filter factor, originally suggested by Gordon Hutchings- 1 extra stop for an orange #16 and 2 extra stops for a red #25. I've never done this when shooting 35mm, spot metering TTL and filter, and have had no obvious problems. I have also not applied additional exposure when using infrared film (HIE, EIR or SFX).

Since moving to LF I haven't added filters to the equation until recently. When I did however, I found that when I metered as usual (through the red filter) and did not apply additional exposure, the neg was quite dark. I'm thinking I should have added that extra 2 stops of exposure.

Do many people apply that extra exposure? To all formats, or just LF? Why would I notice an effect in LF and not in 35 mm?

Thanks,
Tim

[Scott Kathe]

I usually shoot the yellow I have at +1 stop, my orange at +2 and my red at +3. But there are different yellows, oranges and reds as far as the amount of color, ie a light yellow may only require +1 while a dark yellow would require more. I have no idea why you didn't observe this with 35mm.

Scott

[timbo10ca]

I usually shoot the yellow I have at +1 stop, my orange at +2 and my red at +3. But there are different yellows, oranges and reds as far as the amount of color, ie a light yellow may only require +1 while a dark yellow would require more. I have no idea why you didn't observe this with 35mm.

Scott

Are you refering to their filter factors, or what you give in addition to the FF's, according to Hutching's reccomendation?

[thetooth]

I usually shoot the yellow I have at +1 stop, my orange at +2 and my red at +3. But there are different yellows, oranges and reds as far as the amount of color, ie a light yellow may only require +1 while a dark yellow would require more. I have no idea why you didn't observe this with 35mm.

Scott

with the 35mm you are metering through the lens and the filter , so there is no factor the meter has already compensated for the filter . with large format most use a hand held meter and the filter factor would come into effect .

that's the way i understood it . i have never factored when using 35mm i just trust the meter .

[timbo10ca]

with the 35mm you are metering through the lens and the filter , so there is no factor the meter has already compensated for the filter . with large format most use a hand held meter and the filter factor would come into effect .

that's the way i understood it . i have never factored when using 35mm i just trust the meter .

I meter through the filter when using my handheld meter for LF, so essentially the same effect as when I do 35mm.

[thetooth]

I meter through the filter when using my handheld meter for LF, so essentially the same effect as when I do 35mm.

yes . but what type of meter . if you screw the filter directly on to the spot meter that may work . but if you are just holding it in front of the incandescent or reflected meter that's probably no good . i imagine you would get a lot of stray light in the reading , then i would factor .

it also depends on how you meter . i find the point in the scene that i want 18% grey and base my exposure off of that . at that point i would factor in filters depending on the scene .

thanks

tim

[timbo10ca]

yes . but what type of meter . if you screw the filter directly on to the spot meter that may work . but if you are just holding it in front of the incandescent or reflected meter that's probably no good . i imagine you would get a lot of stray light in the reading , then i would factor .

it also depends on how you meter . i find the point in the scene that i want 18% grey and base my exposure off of that . at that point i would factor in filters depending on the scene .

thanks

tim

Yes, I see what you mean... I'm using a Soligor spot meter and holding a square filter in front of it. I thought I was doing it with good contact....
Thanks.

[Scott Kathe]

To do this the correct way you need to do a film speed test with no filter and then another speed test with the filter on the lens and use the meter with no filter in front of it. That will give you the correct filter factor for each of your filters. I've never bothered with that. You can take a meter reading through your filter but depending on your subject it may be off. I had a yellow filter on my Nikon FM2n with a 50mm lens last year and was taking pictures of plants on the dunes by the ocean and everything came out way overexposed.

Scott

[GaryT]

Have you added in a bellows factor?

FWIW, you are correct in thinking that if you meter through the filter you've already included the filter factor...all things being equal. Reflected reading from a gray card?

[thetooth]

To do this the correct way you need to do a film speed test with no filter and then another speed test with the filter on the lens and use the meter with no filter in front of it. That will give you the correct filter factor for each of your filters. I've never bothered with that. You can take a meter reading through your filter but depending on your subject it may be off. I had a yellow filter on my Nikon FM2n with a 50mm lens last year and was taking pictures of plants on the dunes by the ocean and everything came out way overexposed.

Scott

but did you factor for the sand ? which would throw off the meter by a stop or 2 ( reflected light )