Doubt with the F/

[Xavi]

Advertisement (gone after registration)

Hi,

I'm new to the M world and there are still things I don't understand. One of them is regarding lenses. 

I use an M11 and a summicron 35 which is 6-bit. When I set a focal length for example f/11 when looking at the exif most of the time it shows f/13. It doesn't make much sense that if it is able to tell the camera that it is a 35mm f/2 then it is not able to tell it that I am shooting with an f/2.

Can someone tell me why this happens?

[Jean-Michel]

Dozens of threads on this subject. Simple answer: the camera knows what lens you have mounted if the the lens is coded. There is no connection between the camera and lens, there is no way  in the for the cameras to know what f stop you selected. The wild guess it records (using the info from the small round window on the front of the camera and exposure data) is what you see in the EXIF. It is essentially useless information in any case.

[evikne]

Here is one of the most recent threads:

 

[Xavi]

Thank you, 

I searched and couldn't find the post... I guess my English didn't let me put the right words in the search.
Thank you very much.

[theseahawk]

This tripped me up too when I first used the M cameras. The info passed to the camera is rudimentary by modern standards but would add bulk, complexity, and cost to implement including capture of aperture values. 
By the way, you are setting the aperture, not the focal length. 

[jaeger]

It has the Leica patented "AGU" - (Aperture Guesstromonitor Unit) that has an accuracy of +-70%  Don't take it too seriously but I hope this answer can make you rest better...