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Digital R - Review of possibilities


Angora

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So, I was catching up on 3D printers, amazed by the latest developments, and stumbled upon this article on a T-S lens adapter.

 

This prompted me to make a little search here on this forum to see if you guys had been discussing 3D printing applied to Leica hardware.

I found this three year old post from Bo Lorentzen, where he half-jokingly talked about putting an M9 sensor board on a self-printed DMR back.

 

Thus, I wonder: how far are we from a Franken kaMeRa?

M8s can now be had for 1500€ and 3D printers kits can be as cheap as 450€ (or one can just send the blueprints to a printing company). In other words, there’s potential for some experimentations. Maybe there’s something to be done about a digital R?

 

For reference:

• Mark Norton’s excellent Anatomy of a Leica M8.

R-to-M mount operation (Leitax)

 

My technical comprehension of internal mechanics is fairly limited, apologies for the reasoning mistakes.

 

 

Currently, there are three ways to use an R lens on a digital body (save for the DMR and the Visoflex): use an M body, a Canon/Nikon DSLR body, or a mirrorless body.

Their main limitations are the following: must focus via lens distance scale because there’s no rangefinder focus coupling; or must use working aperture because there’s no auto-aperture linkage; or must use focus peaking because there’s no stigmometer.

So the two main concerns in finding an appropriate digital solution are: (1) focus coupling with the viewfinder (for a rangefinder) or (2) auto-aperture linkage with the body (for a DSLR).

Taking these assumptions into account, options would be to:

 

Couple R lenses with the rangefinder of an M camera

Pro: could be engineered within an R-to-M adapter, which would basically transmit the position of the lens cam to the body’s focusing lever.

Pro: auto-aperture wouldn’t be a concern.

Con: some lenses could obstruct the viewfinder by quite a margin (but maybe we can raise it somehow… or would that ruin its alignment?); lenses still affected by close focusing limitations. Not a reflex experience.

 

Integrate a mechanical device within a R-to-F adapter ring

Pro: high-end Nikons natively support, through hardware and software, mechanical auto-linkage (AFAIK).

Con: probably no space to integrate that in such a small ring.

 

Integrate an electromechanical device within a R-to-EOS adapter ring

Pro: would enable auto-aperture

Pro: relatively independent from body upgrades

Con: no space; also unfeasible unless done by Canon or Sigma/Tamron who’re experienced in micromechanics and have retroengineered the mount’s electrical contacts.

 

Fit an M sensor & related electronics in a self-made DMR

Probably the most natural solution but « a bit of soldering and a firmware hack », as Bo puts it, would be very complicated.

 

Fit an M sensor & related electronics in an off-the-shelf 3rd party body

That would probably be even less practical…

 

Fit an M sensor & related electronics in a self-made body

Pro: no more internal & external space restrictions, can be shaped exactly as needed/wanted.

Pro: would use all digital components of the M, coupled with the mirror box of an R body. No need to hack the firmware, which also means no issues with firmware updates. No need to solder stuff (save for the top circuit board apparently) or manage the components’ different voltages. Basically just transplant the M’s components and controls over a different body.

Pro: possibility to somehow have auto-aperture, since the R cam mechanics could be preserved… but then that’d require an electromechanical device and some firmware hack at some point.

Con: no exposure indication in the viewfinder (not sure if possible to integrate the exposure LEDs), also how to properly fit the light & flash metering cells?

 

Fit a Nikon sensor & related electronics in a self-made body

If the Nikon adapter ring mentionned earlier doesn’t work due to lack of space.

Would have most pros & cons of the above; the big difference being that there shouldn’t be any need to mess with the firmware since the mechanical auto-aperture is natively supported. And it’d be easier to hack the firmware if needed, since some Nikon users have been doing it for some time.

 

All in all, it seems that the first (enhanced R-to-M adapter) and the last (fit the internals of a Nikon in a custom body) options are the most feasible. That doesn’t mean it would be easy, but that’d probably have the biggest success rate.

Successful 3D-printed proofs of concept could then pave the way for metal versions.

 

What do you think? Would either of these proposed options work? :confused:

 

 

P.-S.: I know this has been discussed to death yet please spare me the « R is dead, get over it » or « M240 & EVF is the ultimate solution – Leica told us so » comments. I’m interested in the technical feasibility, commercial desirability is of no concern.

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Couple R lenses with the rangefinder of an M camera

Pro: could be engineered within an R-to-M adapter, which would basically transmit the position of the lens cam to the body’s focusing lever.

No go. R lenses don't have a rangefinder cam. Adding one would basically involve making an all-new mount - and require a degree of precision that's far beyond what current "maker" 3D printers can achieve.

Integrate a mechanical device within a R-to-F adapter ring
Look at the Leitax R to F converter: there is no space whatever for a mechanical aperture control - especially since the R and F stopdown levers move in opposite directions!
Integrate an electromechanical device within a R-to-EOS adapter ring

As you say, no space.
Fit an M sensor & related electronics in a self-made DMR

Could possibly be done with the M8 sensor, but the film gate on the body isn't big enough to take the full-frame M9 sensor.
Fit an M sensor & related electronics in an off-the-shelf 3rd party body
This seems pointless because there's no third party body that gives auto-aperture with R lenses; might as well use Leitax+Nikon or converter+Canon.
Fit an M sensor & related electronics in a self-made body

Fit a Nikon sensor & related electronics in a self-made body

This is pretty much what Leica decided was unaffordable when they cancelled the digital R. Good luck!
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No go. R lenses don't have a rangefinder cam. Adding one would basically involve making an all-new mount - and require a degree of precision that's far beyond what current "maker" 3D printers can achieve.

I’ve searched for proper pictures for quite a bit, but couldn’t locate the rangefinder cam on M lenses and bodies. Where are they?

 

Could possibly be done with the M8 sensor, but the film gate on the body isn't big enough to take the full-frame M9 sensor.

Wouldn’t bumping the back, like on the DMR, suffice to fix that limitation?

 

This is pretty much what Leica decided was unaffordable when they cancelled the digital R. Good luck!

 

It’s actually quite exciting of a project. The only real issue is the design of a coupling mechanism from the R lens to the Nikon hardware.

I realise that using an M sensor would have maybe bigger drawbacks, since the light metering would be messed up. In addition to the rangefinder cam thingy.

 

I really wish I knew how to use CAD softwares, because it’s definitely an interesting project.

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Isn't this conversation rather pointless given that Leica have announced the new M as an 'R solution' ? Am I missing something or are you missing something?

 

I think you are missing the last sentence of my first post :)

 

P.-S.: I know this has been discussed to death yet please spare me the « R is dead, get over it » or « M240 & EVF is the ultimate solution – Leica told us so » comments. I’m interested in the technical feasibility, commercial desirability is of no concern.

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Ha! Seems like some Nikon users are quite inspired too.

DIY: Nikon Nikkormat with Sony NEX-5N digital guts | Nikon Rumors

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I’ve searched for proper pictures for quite a bit, but couldn’t locate the rangefinder cam on M lenses and bodies. Where are they?

They're visible in the photos at Leica M mount - Wikipedia, the free encyclopedia. The cam on the lens is the brass ring, which rotates with the focusing ring and moves backwards and forwards by the amount needed to focus a 50mm lens to whatever distance. The cut-out portion of the lens mount proper shows the range of movement between infinity and closest focus.

Wouldn’t bumping the back, like on the DMR, suffice to fix that limitation?
To get the thing to focus right, the digital sensor has to be in exactly the same position that the film would have been. But (a) the sensor proper is behind one or more layers of glass (IR-cut filter, AA filter on most sensors) so when the sensor is in the right place the front of the "sensor pack" is well in front of the "film plane". And (B) if the sensor is "full-frame" - 36x24mm - the need to support the filter pack and seal the assembly means that the sensor package is at least a couple of millimetres larger in each dimension. Result: the sensor needs to protrude into the film gate but is too big. That's one reason the DMR didn't have a full-frame sensor.
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They're visible in the photos at Leica M mount - Wikipedia, the free encyclopedia. The cam on the lens is the brass ring, which rotates with the focusing ring and moves backwards and forwards by the amount needed to focus a 50mm lens to whatever distance. The cut-out portion of the lens mount proper shows the range of movement between infinity and closest focus.

 

To get the thing to focus right, the digital sensor has to be in exactly the same position that the film would have been. But (a) the sensor proper is behind one or more layers of glass (IR-cut filter, AA filter on most sensors) so when the sensor is in the right place the front of the "sensor pack" is well in front of the "film plane". And (B) if the sensor is "full-frame" - 36x24mm - the need to support the filter pack and seal the assembly means that the sensor package is at least a couple of millimetres larger in each dimension. Result: the sensor needs to protrude into the film gate but is too big. That's one reason the DMR didn't have a full-frame sensor.

 

I see, not an easy task indeed. Thank you for your detailed explanation :)

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