Aperture setting does not show up on Leica T screen

[Tanndoktorn]

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Hi!

 

I'm new in this forum and new to leica cameras.

 

I just bought a Leica T and two Leica lenses (the 35mm summilux 1.4 ASPH FLE & the 75mm APO Summicron-M 2 ASPH) with an M adapter.

 

Problem:

The Leica T does not show what aperture I chose on the lens when shooting.

Neither does Lightroom.

 

The readout on the screen says: F0.0 regardless of which aperture I choose.

 

The lenses are 6 bit coded.

Is it supposed to be like this?

 

I guess it's ok while shooting, but it would be nice if the EXIF contained what aperture I have used.

 

B :-)

[Tanndoktorn]

Guess I found the answer here: http://www.l-camera-forum.com/topic/239785-leica-m-lens-adapter-question/

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[bencoyote]

It is actually really interesting how the M estimates the len's aperture. If go to http://www.berndmargotte.com/technical/objektivcodierung_en.html and scroll down to the section entitled "How is the aperture value transferred from the lens to the camera?" it is an interesting description.

 

Makes you think about all the challenges that lens designers had to go through back in the day when they had to either communicate mechanically or look for useful side effects. Now everything is just communicated electronically. 

 

One thing that I've never quite figured out was why there are 10 pins in the T's lens mount. If I were designing a new camera mount, I'd probably make the lens a really weird USB device and the lens mount a very oddly shaped USB plug. All the commands to the lens and data back from the lens would be just protocol over USB -- probably a dialect of HID. Anyway, I didn't design the T. Completely useless for the purpose of this discussion is this http://preamp.org/revenge/four-thirds-communication-protocol which kind of gives you an idea of what is going on between a lens and a camera. Who knows what Leica did though. I got digging into this because I thought that it might be cool if Leica added a cam to the M mount adapter to communicate focal distance. This way they could make an electronically controlled coupled rangefinder camera. The crazy idea that I had was push the T up to full frame, then sell a M-mount adapter which included a cam and use that to couple with an EVF which blended the image from the lens with information from a 2nd focus specific camera - basically a slightly rotating smartphone camera with optics designed to be much more telephot rather than be a wide angle lens. (Yes - sometimes I have trouble sleeping and the brain just spins.)

 

Some day when I tire of taking pictures and my job eases up a bit and have more hacking time, I want to reverse engineer the Leica T app's protocol and take control over the camera that way.

[pop]

.... basically a slightly rotating smartphone camera with optics designed to be much more telephot rather than be a wide angle lens. .

It does not even have to rotate. You can just move the image of the auxiliary camera when mixing it into the display.

[bencoyote]

It does not even have to rotate. You can just move the image of the auxiliary camera when mixing it into the display.

in my crazy idea, the smatphone like camera would have a FOV the size of focus patch in the rangefinder which meant telephoto optics and rotating camera assembly but yeah point taken. If the FOV is wider you could just select where the image overlapped. The thing that I didn't like about the idea was that the baseline of the rangefinder would be just the distance between the lens and the auxilary camera. To fix that you would have to move the lens left or the aux camera right. Moving the aux right would put it under your fingers holding the camera. Moving the lens left would make the camera ugly like those things that Samsung is putting out.

[pop]

You could install two aux cameras and place them where the M has the RF windows.