Difference between LTM and LSM?

[pattyadams]

I have seen an LTM adaptor (Leica Thread Mount ) and an LSM adaptor (Leica screw mount ) online. They appear to be quite different in size. One is marked 5 cm and one is marked 9cm.Its probably an obvious question but as a newbie, one I need to ask. If I am looking at an LSM lens for the M mount are there different adaptor sizes for the different lenses and I assume its the LSM adaptor I need.
Sorry for such a basic question.

 

[ZDP-189]

M39 is synonymous with LTM and LSM. the specification is:

• Thread: 29mm 26tpi Whitworth.
• FFL: 28.8mm
• Image circle: full frame

The reason why there are different adapters made is to trigger the different standard viewfinder frame-line combinations:

• 35mm and 135mm
• 28mm and 90mm
• 50mm and 75mm

As the Ricoh A12 Mount has no viewfinder with integral frame lines, it is not relevant to you. Any one will do.

The difference between a good and bad adapter is found in the machining:

• The lens should focus perfectly at infinity in the emulsion when the focus dial is set to the infinity mark
• The focus mark should line up a top dead centre
• The finish should be smooth with no burrs

 

[pattyadams]

Thanks that is really helpful. Sorry for not thanking you earlier but somehow I missed your reply.

 

[ZDP-189]

I'm glad to be of help.

 

[autochrome]

Hi

•35mm and 135mm its a ring that is ready for rangefinder Leica Type (for exemple M4,M8,M9 etc) with lens 35mm & 135mm Rangefinder COUPLED
•28mm and 90mm its a ring that is ready for rangefinder Leica Type (for exemple M4,M8,M9 etc) with lens 28mm & 90mm Rangefinder COUPLED
•50mm and 75mm its a ring that is ready for rangefinder Leica Type (for exemple M4,M8,M9 etc) with lens 50mm & 75mm Rangefinder COUPLED
and also, in the words ZDP-189,different adapters go to trigger the different viewfinder frame-line combinations


on the digital cameras "no rangefinder" for exemple GXR A12-M (no rangefinder):we have not optic finder,we have not frame-line,and
we have not rangefinder:and so, all 3 rings we can use !

Good Shoots