Wisner and IR

[Jay W]

Back in about 2001, I bought 100 sheets of Kodak HIS (B&W infra-red). I shot a couple of sheets and found out the Wisner leather bellows is horribly IR leaky. So the film sat in the freezer until I found a Wisner IR bellows on Ebay this spring.

I just spent a couple days to shooting a few sheets, oh maybe 8 sheets, on the North Shore of MN. I found the Wisner IR bellows:

-Was cracked (thanks ebay guy, fixed it with some wood glue)
-Needs a little sanding to improve the fit
-Cannot be folded up with the camera like an original leather bellows...it's too fat (just a little heads-up if anyone else picks up an IR bellows.) So the camera has to be set up and then the bellows installed.

The question I have is about focusing the lenses. I tried focusing on something in front of the main subject to increase the lens to film distance a bit and cranking the lens down to F22 to 32. Does anyone have a feel for how much (if any) you have to extend the focus? I have Rodenstock 150 and 210 Sironars, and a Schneider 110.

Jay

[Renato Tonelli]

I read (can't remember which book) and made a note about focusing a 4x5 for infrared: "adjust by advancing the lens/camera bed approximately 1/70th of its focal lenght; mark it on the vew camera bed."

This seemed so cumbersome to me that I never even tried it. But it didn't matter. My Wisner never produced one single exposure on HIE out of a whole box. I couldn't change the bellows, so I covered the camera with a large changing bag but nothing doing. I gave up when I used the last sheet of film I had.
You may opt for sharp images via depth-of-field.
Now I have a box of Rollei Infrared that I am planning to try as soon as I get up enough nerve, this time with a Linhof.

[RichardRitter]

IR bellows can be made that fit the camera and the camera can close up with it on. In the long run anyone with a leather bellows will start having problems with the bellows leaking. Leather breaks down fast. I have seem Wisner bellows that look perfect and leak light like a sieve.

[Rob_5419]

Just a bit bewildered by this thread.

Do you mean your bellows are not light proof?

After repairing the bellows, how else can IR film be fogged if your bellows are light proof, since IR is light.

My Wisner never produced one single exposure on HIE out of a whole box.

The Wisner..... or the photographer?

I'm just perplexed as to how a specific camera brand with the same light-tight principles as any other LF camera might be prone to mishandling IR film. Just never realised that 'IR bellows' existed. Any light proof bellows will block light of all wavelengths.

Am I missing something?

[Marko]

Any light proof bellows will block light of all wavelengths.

Am I missing something?

Absorbtion/transmission/reflectance properties of any material depend very much on the wavelength and they are specific to the material/substance in question. This is the essence of spectral analysis.

In other words, the very same material or substance can reflect and transmit light in one wavelength and absorb it in the other. Water, for example, transmits and reflects light in visible wavelengths, but it absorbs (near) infrared very aggressively.

Another common example would be the atmosphere - it reflects blue pretty well but transmits red almost entirely, hence the blue sky and red sun at sunrise/sunset.

[RichardRitter]

Leather does not block IR only visible light. Even some off the older man made materials will not block IR. Look at film holder they have to have the proper number of bumps on slide handle to indicate they are IR safe.

[Steve Clark]

Leather does not block IR only visible light. Even some off the older man made materials will not block IR. Look at film holder they have to have the proper number of bumps on slide handle to indicate they are IR safe.

What is the proper number of bumps? I`ve only used IR roll films.
Thanks, Steve

[RichardRitter]

Five Bumps as per ANSI Standards.

[Rob_5419]

Leather does not block IR only visible light. Even some off the older man made materials will not block IR. Look at film holder they have to have the proper number of bumps on slide handle to indicate they are IR safe.

Maybe the bellows I have used for Sinar/Wista cameras are all faux leather then?

A Leica focal plane cloth shutter has no problem keeping out IR wavelength light from Kodak HIE, and it's much thinner than leather. While I'm scratching my head, I've never seen models sitting on IR glowing leather sofas with HIE either..

[Brian Ellis]

I used quite a bit of 4x5 HIE a few years ago and I never bothered to make any focus adjustment, I just focused normally and things worked fine. The adjustment is so miniscule there's no way you'll be able to do it perfectly. And even if you could do it perfectly, it isn't IMHO necessary anyhow given the small aperture you mention and the fact that IR is inherently soft.