Originally posted by ozzi-paul Is there any downloadable charts and guides that show you how to do this properly.
Also is there a guide for adjusting the ff/bf in camera to suit different lenses.
I have read that this can be done but don't know how.
I have a K20D with a Sigma 17-70, 2.8-4.5 lens, I think it has good focus but would
like to check just to be sure that its correct.
A chart many people like is at
focustestchart.com, but I don't like using it that much. Part of the problem is that I read in
this thread and elsewhere that you should use a distance of about 5 feet (1.5m) when testing focus, but using that chart with a wide angle lens at 5ft., it's impossible to be sure whether you've locked the sensor on the "focus here" line or one of the other lines on the chart which would render the results worthless.
To make changes to the focus adjustment in the K20D, go to the custom menu, and on option 35 change the setting to 'on', and you'll end up in the adjustment menu. Apply All changes the adjustment across the board for all lenses, while Apply One will remember that model of lens and apply the adjustment to that lens only. Personally I adjusted each lens using apply one, 'till I found that all of them needed around -7 on my camera, so I made -7 the default and then changed the "apply one" to 0 or +1 or -1 as necessary for each lens. That way when I get a new lens, it will be close to right out of the box because the -7 seems to relate to my camera.
- Higher adjustment numbers (+) move the focus closer to the camera
- Lower adjustment numbers (-) move the focus farther away.
So my camera front focus by default, so -7 moves the focus point further away about the right amount.