Efke 25 Red/Yellow Filters

[dietcookie]

After scouring through a ton a links and old discussions, for some reason I can't figure out the solution. I am going to the Sierras this weekend for four days to shoot photos, I 50 sheets of Efke 25, 4x5 to go through. From what I can gather, it being a Orthopanchromatic film, it has a reduced red sensitivity compared to a "panchromatic" film such as TMX. So what i'm getting at is, how do I add contrast to a plain ol blue sky? Should I only use a Yellow 15 filter? From what I understand, the compensation for a Red 25 is 8 stops, and will this have any effect with this film? I will be using a polarizer, what filter should give me the darkest skies with nice cloud contrast? I pretty much learned that this is not the film to use for dramatic skies, but i'll make do.

 

[TheFlyingCamera]

A red 25 is not 8 stops. It's about 2 1/2 - 3. A Red 29 is four. A red 25 plus a polarizer is about 4 - 4 1/2. You're mistaking filter factor for f-stops. An 8x filter factor is approximately 3 stops, because it requires 8x more exposure - or 2x2x2. Remember that each additional fstop is 2x more exposure, and that it is exponential, not linear. To shift the exposure of the sky with an ortho-pan film like Efke, what you need to do is get a filter that will negate the blue sensitivity. A minus-blue filter would probably be best, especially at the altitudes you're at anyway, where the color temperature of the light is already shifted into the blue end of the range.

 

[dietcookie]

I was under the impression with this film, since it's red response is not as much as standard films, that the exposure compensation with the red filter you will need more light than normal as in shooting a red filter with TMX?

So using my Yellow 15 will be my best bet to darken the sky?

 

[reellis67]

Here is a chart that shows the filter factor in relation to the change in exposure needed

http://www.kodak.com/country/US/en/motion/support/h1/exposureP.shtml#filfactor

I agree with F.C. on this one, a #15 should get you where you want to go, but only by testing can you be certain to get the results that you want.

- Randy

 

[jim appleyard]

Take all of the above filters with you, bracket and see what does best for your tastes. They don't weigh much when compared to the rest of you LF gear.

If you're are going to the trouble of shooting LF, what's a few seconds more to change filters and exposures?

 

[dietcookie]

The conclusion is, if I were to use a red 25 filter it would act only as a ND filter, no effect what so ever except for a real long exposure. Yellow 15 is where it's at, unless someone else has something else to add?

 

[wildbill]

I've shot efke 25 for the last couple years and i don't recommend using a red filter. Orange an yellow, yes. I also don't use it for bright sunny days where contrast is often too high for this film.

 

[Vaughn]

Buy more film...

I suggest you buy more film -- a 25 sheet box of Ilford FP 4 or a box of T-max100. Use the ortho (orthopan?) film for scenes that do not have sky or long distance views, and the other film for skys.

Unless you after the 1800's Timmy Sullivan look in your landscapes, ortho just does not seem to be the right film to be experimenting with. But that is just my suggestion -- you might have good reasons to use this film that I do not understand (my capacity for mis-understanding is quite high, I'm afraid!) I like to experiment closer to home, and save the tried and true for the more expensive (and more rare now that I have kids!) road trips.

That said, I have made some of my nicest images using Kodak copy film (8x10) on in the landscape (tho without sky). Pleasant journeys!

Vaughn

 

[P C Headland]

I've found that Efke 25 tends to give nice looking skies on its own, without filters. A light green filter can help when you've got loads of foliage in the shot.

What you may find better though is to use a polarising filter (yes they do work well in B+W).

In any event, shoot and develop a couple of sheets before you go

 

[fschifano]

Unless you after the 1800's Timmy Sullivan look in your landscapes, ortho just does not seem to be the right film to be experimenting with...

Bingo! No amount of minus blue filtration is going to help very much with a film that has limited red sensitivity. Minus blue filtration includes red, yellow, and orange filters. Expect more than the usual speed loss for more common panchromatic films if you use these filters.

 

[magic823]

Here is what a red 23 filter will do to Efke 25. I did use a mask to burn in the sky even darker. Dead Link Removed

 

[srs5694]

In any event, shoot and develop a couple of sheets before you go

This was my thought -- if you're in doubt about how your film will respond to filters, odd lighting, or whatever, shoot some test shots before you go on a trip and take photos you can't easily re-shoot. Test your candidate filters and bracket your exposures to figure out what gives you the results you want.

AFAIK, the Efke films of a given speed have the same spectral characteristics in different formats, so I'd imagine you could do your tests on one or two rolls of 35mm or 120 film rather than use several sheets of LF film. Just be sure to test using the speed of film you intend to use. Or am I mistaken or overlooking something?

 

[Vaughn]

magic...

magic823,

Nice sky...judging from your results, Ekfe 25 may not actually a true ortho film...but perhaps as the original poster suggested it is actually an "orthopanchromatic" film. I thought he had mis-typed (I had not heard of the term before). Is it somewhere between an ortho and pan film, then...that is, sensitive to all colors, but not as sensitive to red relative to a panchromatic film (but more sensitive to red than an true ortho film)?

Generally speaking, for my rare images that include a bit of sky, I do not go for a dramatic sky. T-Max 100 with a yellow filter is usually too much...without a filter is usually about right (or Ilford FP4 with a yellow or none).

But it is a personal thing...but you used it well in the photo you showed us as an example.

Vaughn

 

[TheFlyingCamera]

Here is an example of Fomapan 200, shot with a Red 29, printed on Palladium. The Fomapan 200 is also a more-blue/less-red sensitive film. I don't know if its' spectral response is better or worse than Efke, or comparable. But nonetheless, it's an example of what you can do with the combination.

(there was a url link here which no longer exists)

 

[Thomas Bertilsson]

If you're looking to shoot AA dark skies, then any reduced red sensitivity film, like the Efke 25 is probably not going to get you there. I would echo the advice to bring a box or two of panchromatic film for that type of shot. It just eliminates a lot of unknowns.
The efke films are great, but they are somewhat limited by their sensitivity. Of course, you can choose to use that to your advantage as well.
I found that an orange filter works pretty well with the Efke 25 and 50. I have some prints that are too large for the scanner, but that combination produced decently dark skies. I still prefer a true panchromatic film for that type of shot, however.

- Thom

 

[Zathras]

If you're looking to shoot AA dark skies, then any reduced red sensitivity film, like the Efke 25 is probably not going to get you there. I would echo the advice to bring a box or two of panchromatic film for that type of shot. It just eliminates a lot of unknowns.
The efke films are great, but they are somewhat limited by their sensitivity. Of course, you can choose to use that to your advantage as well.
I found that an orange filter works pretty well with the Efke 25 and 50. I have some prints that are too large for the scanner, but that combination produced decently dark skies. I still prefer a true panchromatic film for that type of shot, however.

- Thom

What about the spectral sensitivity of Efke 100? Is it closer to a true panchromatic film?

 

[Thomas Bertilsson]

Yes it is closer to true panchromatic range. Totally different.

- Thom