I bought the FoCal software package but haven't tried it out yet. The user guides say to set up the target at 50X the focal length you are trying to calculate.
I'm having real problems with me 70-200 2.8L when shooting at 200mm and longer distance. I shoot mainly people/portraits and when I try to do a full body standing shot at 200mm I have to be backed up quite a ways. Lately every shot I've taken in that set up comes out a muddled, mushy mess. I have this lens for 3 years and now on my 3rd body (a 5D III) and this behavior has only recently started.
But to my question...when I print out the target and set up at 50X focal length at the working distance I'm trying to calibrate for, the target is pretty small in the view finder. Hardly even extends out of the spot meter circle.
I haven't tried running through the software yet because I can't find a good day of light outdoors and the light inside my house sucks. But I did a trial set up to see what it would look like at 32 feet distance - which is 50X 200mm and that target is awfully small.
Can I still calibrate with that target at that distance or do I need to get the target enlarged?
If you are having problems with target size, print a large one, 20 X 30 or something like that. Just measure the distance of the bar on the chart in mm, and put that number into FoCal, and it will then recognize the distance to target correctly.