Canon 50D Back focus

[OneCosmos (Chris)]

Anyone know what this measurement is?

[bojan]

You mean this?

http://improvephotography.com/4552/b...tton-focusing/

[OneCosmos (Chris)]

Originally Posted by bojan

You mean this?

http://improvephotography.com/4552/b...tton-focusing/

Maybe related but I'm talking about matching the camera with the field flattener. The field flattener has a back focus of between 71.4 and 81mm according to the specs (seems a lot of latitude) so obviously need to subtract whatever the 50D is from that to figure out the length of spacers required.

Chris

[bojan]

Aha.. then you will find the answer here:
http://en.wikipedia.org/wiki/Flange_focal_distance

[adman (Adam)]

Canons EF mounts are all the same - 44mm

[OneCosmos (Chris)]

Perfect - thank you gentlemen.