Schneider 165/8 SA rear filtering?

[BennehBoy]

I regularly shoot 8x10 Tungsten film using a P2 & Schneider 165/8 SA lens wide open (environmental portraiture).

To correct the Tungsten film to daylight I use a 100mm 85b filter in a Lee filter hood attached with a 105mm adapter ring to the front of the lens.

I've noticed that in any circumstance where I need to use movements, typically rise/fall, that there's noticeable vignette on the slides - it's not very easy to pick up whilst shooting as I'm usually somewhere cramped and without great lighting.

Is there any simple way to mount this filter to the rear lens element which has no filter thread? I'd consider even just taping it on...

I'm looking for an inexpensive option. Tiffen 105mm 85b's are ~$350, and a Cokin X-Pro filter and holder is not far behind.

Has anyone had any luck taping gels to the rear element? I've got about 3 square metres of 85b here.

[Jac@stafford.net]

Is there any simple way to mount this filter to the rear lens element which has no filter thread? I'd consider even just taping it on...

If there is no filter mount for the rear element, it could be because the manufacturer thinks it is a bad idea.
Placing a filter there tends to make it become part of the optics. Among other things, it could cause focus
shift when you stop down. (Note that many long lenses for smaller format that that have filter slots in
the rear of the lens require a clear filter when no others are used.)

But you can try it! There are filter holders intended to be placed in front of
enlarging lenses (which we usually focus at working ƒ stop).

[BennehBoy]

I'd better get saving some beans for the X-Pro then.

[Bob Salomon]

If there is no filter mount for the rear element, it could be because the manufacturer thinks it is a bad idea.
Placing a filter there tends to make it become part of the optics. Among other things, it could cause focus
shift when you stop down. (Note that many long lenses for smaller format that that have filter slots in
the rear of the lens require a clear filter when no others are used.)

But you can try it! There are filter holders intended to be placed in front of
enlarging lenses (which we usually focus at working ƒ stop).

Placing a filter behind a lens that was not designed for a rear filter will create a focus shift of about ⅓rd the thickness of the filter, at every aperature. It will also effect the optical quality of the image as any defects, finger prints, smudges, etc will degrade the final results.

[Jac@stafford.net]

I'd better get saving some beans for the X-Pro then.

Been there. It is pain. Best of luck to you!

[Mick Fagan]

Just for a quick look and try, you could use Blu-Tack (spelling) which is what I've done with colour correction filtration when really stumped.

As you have heaps of filter material, cut some big enough so that you can place it in the folds of your bellows about midway between the lens and film. Tiny pieces of Blu-Tack on the bottom of the bellows to hold it, worked for me.

Worked better than I expected, but as Bob Salomon mentions, there are side effects.

Mick.

[Maris Rusis]

I've successfully used gels with Blu-Tac on the back of a Schneider Super Angulon 121 f8 mounted on my Tachihara 8x10 camera.
Focus shift is not a problem if I focus after putting the gel on the lens. The ground glass does not lie.
A clean gel won't hurt the image and because the gel is in the dark behind the lens it is not vulnerable to environmental stray light scatter as it would be in front of the lens.
A thick filter behind the lens introduces detectable spherical aberration but the effect of a thin gel is so small that it is lost among the much bigger errors that bedevil large format work: missed focus, film sag, subject movement, etc...

[mdarnton]

At one point Calumet even made filter trays to fasten on the back of lensboards.
https://www.bhphotovideo.com/c/product/801236465-USE/calumet_cambo_xenophon_100mm_4x4_rear.html

[B.S.Kumar]

I have this holder, which might be possible to be modified for rear-mounting:
https://s25.postimg.org/r0b9v9mvz/Adjustable_Filter_Holder75mm.jpg (https://postimg.org/image/mr6jt3jmj/)

Kumar

[Neal Chaves]

There are several versions of this lens, but they all look like the rear element is somewhat smaller than the front, which I take it is 105mm on your lens. What I have done in a similar situation is to adapt a step-up ring to fit on the unthreaded rear element. Determine the I.D. of the rear and find a step-up ring that is close and takes your 100mm filter, and glue it in place with silicone. You may have to file down the male threads of the step-up to get it to fit.

[Jason Greenberg Motamedi]

I have used the Lee Filters Gel Snap on rear elements before. It is pretty similar to the one that Kumar has, but held on with a rubber band. I am not sure it is big enough for your lens, but for $10 it is certainly worth checking out.

[BennehBoy]

Some good ideas everyone. I'll probably try the gel in bellows option first then keep my eyes open for cheap used x-pro stuff on the bay of fleas.

I've less than 50 sheets of E64T left to shoot, but this stuff comes up very cheaply quite often so I dare say I'll end up with more.

Next job is to get my 300/5.6 in Prontor Pro CLA'd - I checked the apertures last night (measured looking through from the front), F/5.6 indicated was actually more like f/9, & f/45 was ~ f/100.

The adjustment screws on the rear of the shutter look like it would be straightforward to get this closer to true but the wider end might engage on the final raised land of the aperture cam too soon - making it a bit notchy.

If anyone has a service/repair manual or just info on prontor pro shutters I'd be appreciative.

[Ari]

Here's another idea: get one of the 150mm universal filter holders from Haida (~US$100), or another manufacturer.
Cut a piece of your 85b filter to 150mm x 150mm and mount it to cardboard stock.
Done.

[tgtaylor]

This might not work for your P2 but recently I bought a Compendium Hood for my Toyo MII https://www.keh.com/shop/large-format-toyo-pro-compendium-hood-all-but-45a-cx-23g-8060-709727.html so that I could mount a 3-stop ND Gel when using the 14" Wollensack Veritar SF lens. I got the hood from KEH in what appears to me to be in mint/mint- condition for $59US and a Rosco Gel sheet for $9 locally. Simply cut a 2-ply board to fit the hood's filter slot and tape/glue the gel to it. I don't know if the Toyo hood will work with the P2 but maybe there is a Sinar hood.

Thomas

[BennehBoy]

More great suggestions, thanks.