Quote Originally Posted by bob williams
I thought this was the distance you need to be away from the target to get a full frame shot at the specified dimensions (47.25"x31.5")

That's correct, although it might be better to say 'frame-filling shot' instead of 'full frame shot' since the latter implies a sensor format (i.e. crop vs. FF; Bryan states where distances are for APS-C vs. FF on some EF lenses, and obviously EF-S lenses must be framing distances for a crop sensor).


The three numbers are the subject framing distances for the native lens (135mm), lens + 1.4x Extender (189mm) and lens + 2x Extender (270mm).