V
Vivek
Guest
The A36 clamp on filter used for the likes of Elmar 3.5cm, Hektor 135 (early) and the likes have some restricted use mainly because the modern UV/IR cut filter version is absent. No wonder since that was from the 1930s. 
Filter adapters were also made by Leica, like the SOOGZ (A36 clamp on to 39mm filter). These are pretty expensive when found (in any condition).
I will show here, a few alternate possibilities that I use.
Untitled by Vivek Iyer, on Flickr
In the front row, there is an A36 clamp on filter without any glass (bought like this and it was cheap because of that), Leica push on filter FILTU (A36, the front filter glass is removable and can be exchanged with a filter from a 27mm filter), a clamp on filter from old movie camera use (this one has 36mm filter thread in the front), a Kodak push on filter (A36 to Serie VI, again the front is capable of taking appropriately sized glass).
I find the Leitz A36 clamp on filter most useful.
Untitled by Vivek Iyer, on Flickr
A 39mm to 40.5mm step up ring (ebay: "Heavystar") can be pushed on to the front. This is a tight fit. Best way is to cool down the brass Leitz filter in a freezer and warm up the filter adapter in a water bath before pushing them together.
Also, a 33.5mm to 52mm (or 49mm, these are the two readily available step up rings) can be screwed into the front of the A36 clamp on filter. Use a little epoxy if you want to make it permanent.
Untitled by Vivek Iyer, on Flickr
Lastly, there are also nylon push on caps of A36 size which make a very snug fit on an Elmar.
Untitled by Vivek Iyer, on Flickr
One can use them as lens caps or modify them easily to a filter adapter.
As it turns out, the W-Nikkor-C 2.5cm lens, though it has a proper 34.5mm filter thread, also would take the A36 clamp on filter (hence it is in the first photo).
Filter adapters were also made by Leica, like the SOOGZ (A36 clamp on to 39mm filter). These are pretty expensive when found (in any condition).
I will show here, a few alternate possibilities that I use.
Untitled by Vivek Iyer, on Flickr
In the front row, there is an A36 clamp on filter without any glass (bought like this and it was cheap because of that), Leica push on filter FILTU (A36, the front filter glass is removable and can be exchanged with a filter from a 27mm filter), a clamp on filter from old movie camera use (this one has 36mm filter thread in the front), a Kodak push on filter (A36 to Serie VI, again the front is capable of taking appropriately sized glass).
I find the Leitz A36 clamp on filter most useful.
Untitled by Vivek Iyer, on Flickr
A 39mm to 40.5mm step up ring (ebay: "Heavystar") can be pushed on to the front. This is a tight fit. Best way is to cool down the brass Leitz filter in a freezer and warm up the filter adapter in a water bath before pushing them together.
Also, a 33.5mm to 52mm (or 49mm, these are the two readily available step up rings) can be screwed into the front of the A36 clamp on filter. Use a little epoxy if you want to make it permanent.
Untitled by Vivek Iyer, on Flickr
Lastly, there are also nylon push on caps of A36 size which make a very snug fit on an Elmar.
Untitled by Vivek Iyer, on Flickr
One can use them as lens caps or modify them easily to a filter adapter.
As it turns out, the W-Nikkor-C 2.5cm lens, though it has a proper 34.5mm filter thread, also would take the A36 clamp on filter (hence it is in the first photo).
