View Full Version : Metering with filters, tips?

24-Aug-2014, 10:29
I've seemed to have a bit of trouble recently using my filters for some landscapes. I like darkening the skies with my deep red filters, one is a B+W 52 091 8x MRC. I think that's brand,thread size, I don't know what 091 is...maybe the shade, 8x means three stops of light held back I think? And I think MRC is a coating. I also have a 67mm size of the same filter. As well, I have a Y2 (Yellow) #8 filter that says filter factor 2 or 1 stop.

I have an analog spotmeter and I'm not sure the best way to meter with these filters. I think I've been trying to meter with the filter in front of my spotmeter because I don't always feel that I get exactly 3 stops difference or 1.5 for the two yellow filters I have.

Should I just meter like normal and add a filter factor or does it work to meter through a filter?

I'm really asking this because I seem to have gotten some thin negatives/underexposed when I meter through the negatives. I usually get good negatives shooting my ilford fp4+ at box ISO of 125 and I didn't know if this means I should overexpose some more.


24-Aug-2014, 13:43
Should I just meter like normal and add a filter factor ...


091 is another nomenclature for "deep red".

24-Aug-2014, 13:46
take out the guesswork and read some of these results:

24-Aug-2014, 14:00
Should I just meter like normal, and add a filter factor, or does it work to meter through a filter?

Field notes (w/ my Pentax digital spot meter) have helped me w/ personal filter factors.

If b/w filters, try shooting the manufacturer's recommendation – then "bracket" a second shot if metering through the filter suggests a different exposure. Back home, compare your shots & consult your notes. With enough experience and testing, you'll know which filter needs how much compensation (if any) for a particular shot. Eventually, you'll integrate this knowledge into a broader visualization process. It becomes second nature.

Steve Simmons in "Using the View Camera" meters b/w shots through the filter, then adds to this an additional "Hutchings Factor" (after Gordon Hutchings) when it's important to protect shadow detail typically illuminated by bluish light. If you have this book, see his index for this little discussed filter factor. I think a few threads address this matter.

For my Marumi polarizer filter, I add two stops of compensation (4x) no matter what strength of polarization I've chosen – this is for b/w or color shots. Hope these quick thoughts will help.

24-Aug-2014, 15:04
The Zone VI modified meters were modified for just this reason. Normal manufacturing standards apparently do not work to very tight tolerances with individual colors of the filters and therefore transmit false brightness readings from the filters themselves. The modifications were made to accommodate those individual colors and to be able to exactly measure the corrected brightness transmitter through each filter.

Doesn't Richard Ritter still do those modifications?

24-Aug-2014, 15:52
It is good to know that B&W contrast filters work with the color of the scene. If the sky is grey, and you are trying to make a dramatic or realistic sky, then there is almost no color to differentiate with no blue in the sky. Nothing happens.

Also, red filters compress tonal renderings on film so that some unhappy outcome occur.

24-Aug-2014, 16:35
I am also a big fan of dramatic skies. For that reason, I often combine a deep red with a Polarizer which, depending on the angle to the sun, can create a near black sky. That, against white clouds, is incredibly dramatic. I don't usually meter through the filters, so I just use the filter factors combined to get the results I want. As with any use of the Zone system, I measure carefully with my spot meter, compensate for the filter factors, over expose when shadow detail is important (and underdelvelop), then print for the highlights.

24-Aug-2014, 20:24
I'll probably just meter as normal and then apply the factor. I thought it might be more accurate to meter given that the color of the filter might influence how much light comes through and then I'll how how it'll actually look on the negative or in print ultimately. I do realize that the red would tend to darken green stuff as well as blue stuff though. Some of the scenes I've photographed that have went wrong include some storm clouds over a wetland. I metered something that I wanted dark but with detail on the ground and then under developed some. The sky looks great but there is barely any detail on the negative in the ground area so it seemed to be overall underexposed.

24-Aug-2014, 20:36
Hang on, You under developed, but did not say whether you over exposed to get the detail in the dark areas recorded on the film? If not, you just drastically effected an already underexposed area by then under developing as well, reducing any detail much, much more.

The drill is:

A Determine the area to be metered and decide if it is shadow and needs more exposure, or highlight that needs less exposure.

B: Decide what Zone (gray scale) you want that area to match.

C: Determine whether you need to underexpose for highlight, or over expose for shadow areas to preserve the details you want.

D: Make the appropriate exposure based on that decision as well as any filter factors.

E: Under, or over develop the film based on which type of compensation you made in exposure.

There is always an exposure adjustment to be made when you have to compensate for either highlight or shadow. Making the development changes without making the exposure compensation will either lose the shadows or block the highlights due to under or over development.

24-Aug-2014, 20:44
I can't remember very much of it right now and I don't know if I made a recording of my exposure, but I metered a portion in some shadow using the filter over the light meter and then I underexposed that by two stops. The sky was considerably brighter but had some nice clouds from a couple storms that were going through along with some dots of clear sky. I usually develop this film for 15 minutes in Rodinal 1:100 I think it was, and I decided to try it out at 12 minutes. I didn't want to have to do a ton of burning for the sky so that's why I underdeveloped. I think I did the other sheet for about 9 or 10 minutes.

"You under developed, but did not say whether you over exposed to get the detail in the dark areas recorded on the film?"
I've never read anything about having to compensate to keep shadows higher when developing as such. I was under the impression that those will generally stay the same or nearly the same as long as you don't drastically reduce development.

24-Aug-2014, 21:00
If you wrote this down correctly "under" exposed by two stops means that you wiped out the shadow detail as you gave it four times less exposure than your meter called for (since exposure is based on the square root thing). You should have over exposed by one or two stops to gather more light and therefore more detail.

By under exposing that much and not recording the detail at all, there was no way to recover. No amount of added development will show up detail that did not get recorded in the first place.

Exposing for the shadows means making sure that you get enough light on the film to record the shadow detail the way you will want to see it on the print. Slightly under developing is then used to control the possible blocking (loss of detail) in the highlights if the exposure range from shadow to highlight would place the highlight near pure white on the zone scale.

If you can get a copy of Adam's "The Negative" and bone up on his Zone System techniques, it would help you understand much more.

24-Aug-2014, 23:00
Perhaps I did type it incorrectly, but I'm basically saying that my meter wanted something dark to be medium gray, or zone 5, so I turned down my light meter two stops somitmwasnt too bright. I was metering through the filter so I didn't apply a filter factor. Basically, I was trying to put the shadows in zone 3 by under exposing what my meter told me by 2 stops.

Anyways, I'm still just going to meter with no filter and apply an exposure compensation to deal with the filter. Everything else that I shoot seems to turn out fine and it's fairly easy to print.

25-Aug-2014, 08:33
Understood, and that makes much more sense and is a definite Zone System application.

Drew Wiley
25-Aug-2014, 10:21
I'd never trust a meter reading thru a dark filter. Start with the published filter factor for your particular combination of film and filter, and then take some test shots
against a reference, like a gray card to evaluate the negative afterwards. The deep red filter you mention might be a 3 EV correction with some pan films, 4 with
certain others, and just too red for an orthopan film like ACROS. I leave it at the basics rather than complicate it with Zone System technique per se.

Ken Lee
25-Aug-2014, 12:56
If you only use a small number of filters, you can likely remember the required filter factors.

If you can't remember, you can write them somewhere convenient, like on the item in which you carry them.

25-Aug-2014, 16:34
If you only use a small number of filters, you can likely remember the required filter factors.

If you can't remember, you can write them somewhere convenient, like on the item in which you carry them.

Filter factors are usually engraved on the filter rim.

25-Aug-2014, 21:23
Place your favorite digital camera in to manual mode, set same iso as your film, zoom to match your view camera lens, put filter on.
By trial an error pickup exposure that matches your artistic taste. You may use histogram to fine tune your exposure. Transfer #'s to your lf lens shutter. Take pic.

Later on have beer with your friends and discuss zone system etc:)