What is the differance in the M adaptors?

[Skinny McGee]

Hello,

What is the differance in the LTM to M adaptors? Like the 28-50 compared to the 90mm one? I am looking for a 90mm, but I don't understand because you can mount the 90mm lens to my 111A without anything. It has to be the same threads? or is it the deepth. Just curious I know the has to be a resonable answer. probably the cam?

Thanks
Skinny

 

[Lear]

Hello,

What is the differance in the LTM to M adaptors? Like the 28-50 compared to the 90mm one? I am looking for a 90mm, but I don't understand because you can mount the 90mm lens to my 111A without anything. It has to be the same threads? or is it the deepth. Just curious I know the has to be a resonable answer. probably the cam?

Thanks
Skinny

Every M adaptor has a ridge, depending on focal lenght it will be shorter or longer. This ridge pushes a little lever on the camera mount (located in the opposit side of the release botton) So the 90mm has the longest ridge to activate the 28-90 frames, middle size for 50-75 and shortest for 35-135.

So you choose the adaptor for M bodies, that will give you the correct framing for your lens. To use the lens on LTM body no adapter is necesary.