DR Summicron (my first images)

[a.noctilux]

Not exactly 51.8 mm but 51.9 mm

Not a myth, Raid you can check the real measured focal length of your DR.
Just unscrew the optical cell, then check if the serial number is the same of one in front of the lens.
Somewhere on the optical barrel, the "19" "1,9" or "51,9" can be seen.
That's the measured focal length in 1/10 mm.
All DR mount is calibrated for that 51.9 mm exactly.

That said, Rigid can also have that same 51.9mm focal length and one can see that on the mount near infinity mark.

Regards,

Arnaud

 

[a.noctilux]

Interesting article here:
http://www.rfsg.asia/leica-m8-50mm-f-2-summicron-dr/

 

[raid]

Not exactly 51.8 mm but 51.9 mm

Not a myth, Raid you can check the real measured focal length of your DR.
Just unscrew the optical cell, then check if the serial number is the same of one in front of the lens.
Somewhere on the optical barrel, the "19" "1,9" or "51,9" can be seen.
That's the measured focal length in 1/10 mm.
All DR mount is calibrated for that 51.9 mm exactly.

That said, Rigid can also have that same 51.9mm focal length and one can see that on the mount near infinity mark.

Regards,

Arnaud

Using Live View of a M 4/3 camera removes differences between Rigid and DR Summicron lenses. I can see how exact measurements may assist in RF focusing. Maybe.

 

[raid]

Interesting article here:
http://www.rfsg.asia/leica-m8-50mm-f-2-summicron-dr/

Thank you for the link.

 

[raid]

Thank you Helen. Yes, the OOF looks smooth.

 

[Rob-F]

Not exactly 51.8 mm but 51.9 mm

Not a myth, Raid you can check the real measured focal length of your DR.
Just unscrew the optical cell, then check if the serial number is the same of one in front of the lens.
Somewhere on the optical barrel, the "19" "1,9" or "51,9" can be seen.
That's the measured focal length in 1/10 mm.
All DR mount is calibrated for that 51.9 mm exactly.

That said, Rigid can also have that same 51.9mm focal length and one can see that on the mount near infinity mark.

Regards,

Arnaud

Ah, yes, 51.9 it is, for the DRS. I should have unscrewed the barrel and looked. That's what I get for trusting to memory.

 

[Ronald M]

51.9 is the design "target" focal length. Some of the 51.9 or perfect optical cells were made into DR.

My rigid is marked 19, but others that were not perfect were mated with adjusted focusing mounts.

Conclusion is all DR are 51.9, but not all 51.9 are DR.