focus adjustment 2

this may seem a silly question but at what distance from chart do you test. have seen varying methods from use min focus then back off a few inches to 50x focal length of lens so that would put 300mm lens 15 m from target,don,t have that amount of room.also what size should the chart be. as i have never done this before would be grateful for replies, want to check a couple of lenses / camera. DA*16-50,DA40, K5

I usaully move in as close as possible, to minimise depth of field, which I find gives the best results. A standard A4 printout is fine.

Points to note
Set the aperture to wide open.
Use natural light
Make sure the camera is secure on a tripod and set very accurately at 45 degrees to the chart.
Use a remote delayed shutter release.

With the zoom you should check at several focal lenghts, it is not unusual for variation across the range.


Regards - Steve

thanks steve . i thought 50x focal was a bit far.