Leica CL Filter Thread

[Matlock]

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I am sure this topic has been covered before but, if so, I have missed it. Does anyone know why Leica chose the 39mm x 0.75 filter mount for the CL lenses instead of the normal 39mm x 0.5? I have just obtained a Heliopan 39mm x 0.75 filter but they are not very common.

[lct]

Leica did not make threaded filters for CL lenses, only Series 5.5 filters. 39 x 0.75 threads were made for the rubber hoods of 40/2 and 90/4 "C" lenses. This way M users could not use these rubber hoods on their 39 x 0.5 M lenses, at least theoritically. In practice i've been using them on M lenses like 50/2.8 and 90/4 since the last century and i sill use them today.

[Matlock]

Leica did not make threaded filters for CL lenses, only Series 5.5 filters. 39 x 0.75 threads were made for the rubber hoods of 40/2 and 90/4 "C" lenses. This way M users could not use these rubber hoods on their 39 x 0.5 M lenses, at least theoritically. In practice i've been using them on M lenses like 50/2.8 and 90/4 since the last century and i sill use them today.

 

I was asking WHY Leica chose the 39 x 0.75 option. I have the rubber hoods and 5.5 filters but find them cumbersome. To change the pitch of the lens/filter thread for the CL range seems rather strange when the 0.5 (E39) pitch could have been used..

[lct]

I was asking WHY Leica chose the 39 x 0.75 option. I have the rubber hoods and 5.5 filters but find them cumbersome. To change the pitch of the lens/filter thread for the CL range seems rather strange when the 0.5 (E39) pitch could have been used..

 

You were asking « why Leica chose the 39mm x 0.75 filter mount » and i tried to explain that Leica did not choose such filter mount since they did not make 39 x 0.75 filters then, and they still don't make them IINW. As for the 0.75 pitch, it's been used for M lenses like 28/2.8, 35/1.4, 50/1, 50/1.4, 90/2, 135/2.8 and 200/4 if memory serves. So there was no change of filter pitch for CL lenses, just the choice of a 0.75 lens hood pitch for the reason i tried to suggest (tongue in cheak) above.

[Matlock]

You where asking « why Leica chose the 39mm x 0.75 filter mount » and i tried to explain that Leica did not choose such filter mount since they did not make 39 x 0.75 filters then, and they still don't make them IINW. As for the 0.75 pitch, it's been used for M lenses like 28/2.8, 35/1.4, 50/1, 50/1.4, 90/2, 135/2.8 and 200/4 if memory serves. So there was no change of filter pitch for CL lenses, just the choice of a 0.75 lens hood pitch for the reason i tried to suggest (tongue in cheak) above.

 

The filter pitch on all E39 Leica lenses is 0.5 and only the CL lenses are 0.75. So I ask, once again, why the change for CL lenses?  I know that Leica do not make 39 x 0.75 mount filters but, luckily, Heliopan do. It is interesting that you state that Leica do not make such filters and then go on to say that the 0.75 pitch is used for 28/2.8, and so on, lenses. 

[lct]

I can just repeat with my poor English that there is no filter pitch on CL lenses the thread of which being made for hoods, not filters, and confirm that the 0.75 pitch has been used for several M lenses, which does not mean that it is still used at present.

[Matlock]

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I can just repeat with my poor English that there is no filter pitch on CL lenses the thread of which being made for hoods, not filters, and confirm that the 0.75 picth has been used for several M lenses, which does not mean that it is still used at present.

 

Your English is very good.

All 39mm Leica filters are 0.5 pitch. You can screw a 0.50 filter part way into a C lens but there is the danger of serious damage if you screw it in too far (likewise 0.75 into a regular Leica lens). Again I would point out that E39 lenses/filters are 0.5 pitch, not 0.75. 

[lct]

There is indeed no doubt about this. Hope i've helped you to answer your question.

[Matlock]

I would still like to know why Leica chose the 0.75 pitch for the CL lenses.

[lct]

M users were dissuaded to use the CL's rubber hoods on their M lenses, as i suggested above, but there are perhaps another reasons.

[Schrödinger's cat]

M users were dissuaded to use the CL's rubber hoods on their M lenses

 

Any thoughts on why that might be ?

[TomB_tx]

The Summicron is somewhat flare prone, and the CL was intended to pull in new Leica users, so the lenses were made so hoods would be used full-time, especially with the non-multi coated filters of that era. Making the lens so you had to use a hood to mount filters made some sense.

Note the original Leicaflex lenses also took series filters with special retainer threads.

[lct]

The feeling we had then is we were dissuaded to use CL stuff on the M system generally. Look at the efforts made by Leica to explain that CL lenses could not be focussed accurately on M bodies (see the 120/50 leaflet attached herewith). Been doing this for 30+ years w/o an issue but you will still find this explanation in not so old threads of the LUF.

 

120-50_list_en.pdf

[lct]

The Summicron is somewhat flare prone, and the CL was intended to pull in new Leica users, so the lenses were made so hoods would be used full-time, especially with the non-multi coated filters of that era. Making the lens so you had to use a hood to mount filters made some sense. [...]

 

Perhaps but C 40/2 and 90/4 lenses are not more flare prone than M 35/2 v4 or "thin" Tele-Elmarit 90/2.8 actually and the latter was sold with a rubber hood as well. I've not used the Elmar-C 90/4 for many years but i suspect that the T-E 90/2.8 is even worse from this viewpoint.

[Leicanerd]

Primarily Leica chose insert filters for the CL Summicron to avoid any vignetting. Screw-in filters would protrude more.

 

Retaining rings for insert filters (aka series filters) traditionally have a pitch of 0.75mm. The rubber hood, which is used in place of the retaining ring to hold the filter, of course, has the same thread pitch of 0.75mm.

[lct]

Primarily Leica chose insert filters for the CL Summicron to avoid any vignetting. Screw-in filters would protrude more [...]

 

I don't recall having got the least vignetting when using E39 filters on C lenses but it was in the last century so my memory may be failing.

[Matlock]

I don't recall having got the least vignetting when using E39 filters on C lenses but it was in the last century so my memory may be failing.

 

I have not experienced any vignetting with the Heliopan filter (although this is slimmer than Leica filters). As I said it is not advisable to use E39 filters on C lenses owing to the risk of thread damage or, worse still, locking of the filter to the lens. 0.5 and 0.75 don't mix,

[tobey bilek]

Why ?  To keep M users from buying the less expensive CL lenses.

[Matlock]

Why ?  To keep M users from buying the less expensive CL lenses.

 

Well that didn't work did it.

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Hallo,

Look here: Leica M