Why didn't 1st generation SLR cameras use L39 lens mounts ?

It would seem to make sense....make the latest technology backward compatible with an existing stock of lenses.

So why don't we have any SLR bodies that use L39 screw mount lenses ?

We DO(!) have early Zeniths with 39mm SLR screw mount, which has same flange distance as M42.

The advantage of LTM & RFs is LESS(!) flange distance + no need to keep a mirror box clear. And oops, the Jupiter 12 doesn't fit in front of metal shutters...

I believe the Brits built a bastard camera with less than a full sizenreflex finder, just some center spot to SLR-focus on. Dunno which lenses that one took.

The Periflex uses 39mm lenses.

Periflex - Camera-wiki.org - The free camera encyclopedia

Indeed, no room for the mirror box.

The Soviet Zenit SLR did use a 39mm thread mount, but with a flange-film distance similar to other SLR mounts, so rangefinder lenses could only be used for macro work.

Adapters were made for using the Soviet M39 SLR lenses on the Kiev 10/15 SLRs and KMZ Start. There were also interchangeable mounts in M39 for the Soviet "A"-type lenses (Jupiter-37A, Mir-10A, etc.) though they are hard to find. I have a couple of them.

These M39 SLR lenses can also be used on M42 SLRs with an adapter ring or to Pentax K bodies with a M42 adapter (both have same flange distance).

L39 screw mount lenses typically have a short flange to film distance, which precludes the insertion of a mirror box and mechanism. At least that's my explanation.

It seems to me that if you make the mirror go down, instead of up, that it might fit.

Some M39 lenses still pretty far in, and especially the collapsible ones. Don't use those.

Reminds me that the usual bedroom dressing mirror goes almost to the floor,

but only needs to go about halfway down to see your feet. The mirror doesn't

need to be near the size of the image, close to half.

There are soviet M39 lenses for SLRs, but as already hinted, the lens flange distance is different from the LTM. In ordering the FED (LTM) or Zenit (M39 long...) lenses you have to be sure which are which.

The Perfex lens mount (M38) was NOT compatible with the Leica.

There are soviet M39 lenses for SLRs, but as already hinted, the lens flange distance is different from the LTM. In ordering the FED (LTM) or Zenit (M39 long...) lenses you have to be sure which are which.

 

The Perfex lens mount (M38) was NOT compatible with the Leica.

Which begs the question... what, if any lens might be compatible to the Perfex TM ? If it is call 39mm..what is the difference to the Leica mount? Flange difference? Or it may be the pitch of the threads ? Enquiring minds want to know :)

Umm I see now we are talking about the UK PerifLex not the US model Perfex... never mind.

L39 screw mount lenses typically have a short flange to film distance, which precludes the insertion of a mirror box and mechanism. At least that's my explanation.

Not just typically, it's one of the features that DEFINES L39. The L denoting Leica and indicating a rangefinder mount with 28mm flange distance.

There have also been other M39 rangefinder lenses with slightly shorter flange distances but these were never really popular. Mine was relatively easy to modify so they can be used on L39 bodies/adapters.

There are SLR cameras that use the same M39 thread, but with greater flange distance (sometimes called Z39 for Zenit m39), using L39 lenses on these limits you to close-up shooting as the lens will be about 20mm further from the film than it was designed for. One possible partial exception are the retractable 50mm lenses like the Industar 10 - I think these when not extended are close to Zenit m39. Of course when retracted the rear of the lens will foul on any SLR's mirror so they could only be used with extreme care using mirror lock up.

Then there have been enlarger lenses using m39 threads too - these have no fixed flange distance.

Range finder lenses are not made in focal lengths greater than 135mm, with one of these mounted on a Zenit m39 body the maximum focus distance is about 1.6m, any shorter focal length will focus closer still.

Range finder lenses are not made in focal lengths greater than 135mm,

Huh?

Just to name one, the Olympia Sonnar 180mm for the Contax, 1936 (Zeiss Contax RF Olympic 180/2.8)

Not just typically, it's one of the features that DEFINES L39. The L denoting Leica and indicating a rangefinder mount with 28mm flange distance.

There have also been other M39 rangefinder lenses with slightly shorter flange distances but these were never really popular. Mine was relatively easy to modify so they can be used on L39 bodies/adapters.

There are SLR cameras that use the same M39 thread, but with greater flange distance (sometimes called Z39 for Zenit m39), using L39 lenses on these limits you to close-up shooting as the lens will be about 20mm further from the film than it was designed for. One possible partial exception are the retractable 50mm lenses like the Industar 10 - I think these when not extended are close to Zenit m39. Of course when retracted the rear of the lens will foul on any SLR's mirror so they could only be used with extreme care using mirror lock up.

Then there have been enlarger lenses using m39 threads too - these have no fixed flange distance.

 

Range finder lenses are not made in focal lengths greater than 135mm, with one of these mounted on a Zenit m39 body the maximum focus distance is about 1.6m, any shorter focal length will focus closer still.

I have a 180 f/6.3 Tele Tessar K for my Contax RF cameras that was made in 1936--coupled to the rangefinder and accurate in focusing.

I have a few 39mm Zenits, and a couple of FEDs. Most of my lenses are for the Zenits, though I have a Jupiter 9 in FED fitting.

Anyhow, I looked up (here, on the Industar-22 page of a Zenit archive site) the flange-film distances and they are 28.8mm for the RF lens, and 45.2mm for the SLR one. The difference is 16.4mm. Now, I also have some extension tubes for the Zenit, and I find they are 13mm, *16.4mm* and 26mm long. Yippee! Mind, what this lets me do with the FED cameras is nothing great; I could now use my Zenit lenses on my FED bodies, but only with scale focus; and the shutter is more or less exactly the same on all the cameras, and the FED bodies (I have the 3 and 4) are if anything less ergonomic than the old Zenits.

On the other hand, I also have a Leica adapter for my EOS M50 (specially for that Jupiter 9). I could easily get a 39-42 step-up ring and an M42 mount adapter to use the Zenit lenses too, but it seems I can play with the Zenit lenses using the middle extension ring and the leica adapter. Being a daft old coot, I felt obliged to check this was true before posting it, and it works. Focusing from my skylight on chimney pots across the road, I find three out of four lenses I tried show a shorter range on the scale than is true; but not by enough to stop me using them (what is actually about 20 meters is reading as 6-10m). They're old lenses; I can't swear the scales are right when mounted on the Zenit. And anyway, this camera shows me the focus quite well in the VF; I won't be needing scale focus.

Our list of 39mm RF lenses at Camera-wiki (which doesn't claim to be complete; please help if you can) also has a rangefinder-coupled 250mm Meyer Tele-Megor, seen at a Westlicht auction. Petrochemist's statement is true if we relax it to 'rangefinder lenses longer than 135mm are quite rare'.

Huh?

 

Just to name one, the Olympia Sonnar 180mm for the Contax, 1936 (Zeiss Contax RF Olympic 180/2.8)

I've always heard that the longest focal length contax lenses required the Flektoskop, Flektometer or Panflex mounts which add a reflex viewer, effectively turning the rangefinder into a SLR.

As well as many printed sources over the years claiming rangefinders were limited to 135mm for focusing reasons (it would take me years to find them) this can be found at Contax rangefinder

If this is inaccurate perhaps the Contax, which is often acknowledged as the best rangefinder managed to stretch things somewhat, with really top grade hardware.

I've always heard that the longest focal length contax lenses required the Flektoskop, Flektometer or Panflex mounts which add a reflex viewer, effectively turning the rangefinder into a SLR.

As well as many printed sources over the years claiming rangefinders were limited to 135mm for focusing reasons (it would take me years to find them) this can be found at Contax rangefinder

 

If this is inaccurate perhaps the Contax, which is often acknowledged as the best rangefinder managed to stretch things somewhat, with really top grade hardware.

As we all know, not everything we read on the internet is totally accurate... The pre war Contax models did have the longest base length for their rangefinders which enabled accurate focusing with longer focal length lenses such as the 180. Even so, Zeiss eventually released the 180 f/2.8 Sonnar in a mount for the reflex housing since the Contax II/III rangefinders weren't accurate enough wide open with the rangefinder.