Filter on Schneider lens

[Bryce Vader]

I am new to large format and in the process of buying equipment.
1. What is the best approach to mounting filters on a lens ... on the front thread or the back thread of the lens.
2. If using 3x3 or 4x4 filters , what is best to use ... gel , resin or glass ?
3. Are the threads the same pich on large format lenses as other lenses ?
I have a Schneider 300mm Symmar-S lens that has what appears to be a 77mm rear thread size but I can not start a 77mm filter on it.
No sign of damage ... just won't start ?
Appreciate your response.
Bryce.

[Emmanuel BIGLER]

Welcome to the large format gang !

3. Are the threads the same pich on large format lenses as other lenses ?
In principle, yes. But as far as rear threads are concerned, some of them are there only to hold the rear lens element. So there is no reason why they should feature the the same pitch as usual filter threads.
As far as front threads are concerned, I am not aware of any unusual diameters or pitches.
To the best of my knowledge, all filter threads of modern lenses and of course of European (and Japanese) lenses use metric threads.
Here is a short list of current metric diameters and pitches :
- up to a diameter of 40.5 mm, pitch is 0.5 mm
- from 43 to 82, pitch is 0.75 mm
I do not think that there is any rule for the clip-on diameter for a clip-on lens cap, I would say that adding one (or two ?) mm to the thread size correponds to the clip-on diameter.
- 82 and above e.g. 95 used for the 360 tele arton have a 1 mm pitch.
Again this is for the most current metric filter threads. There exist several other pitches, but they are non found easily. However, many are listed for example on the Heliopan catalogue.
Note that shutter mounting threads with one or two exceptions do not correspond to standard filter threads.

[erie patsellis]

Having two of the same lens, with the Calumet label on them, one has no rear threads and one with 77mm x .25 (or .5, hard to get the pitch gauge just right and see too) pitch threads, neither of which will accept threads, depending on which version you have (it think the difference is MC vs not) the rear slip on cover is either 75mm (Symmar-S) or 80mm(Symmar-S MC).


Welcome to the large format gang !
Note that shutter mounting threads with one or two exceptions do not correspond to standard filter threads.

True, but the Copal 3 Mounting thread is 62x.75, so a 67-62 step down ring and 2 mins with a small file will do in a pinch. (One of the exceptions you mentioned, I'd imagine)
erie