Comments on: Jeffrey’s Autofocus Test Chart

By: mbrobich

mbrobich — Sun, 27 Nov 2011 20:41:37 +0000

Thank you. I have just tuned my 5 lenses using D7000 !!

By: Claence Butts

Claence Butts — Sun, 18 Sep 2011 14:43:29 +0000

Thanks Jeffrey for your effort on this project.

I would highly recommend shooting test shoots tethered into Capture One Pro. There is an “In Focus” indicator in Capture One which allows you to watch the focus point move backward or forward as you change the setting using AF Microadjustment in Custom Fuction on 5DMII.

By: Mike

Mike — Fri, 09 Sep 2011 20:07:56 +0000

Update on the post just above: I found a post describing how to find the adjustment screws for the A55 here: http://forums.dpreview.com/forums/read.asp?forum=1037&message=36869148 and, with Jeffrey’s chart, adjusted over 3 different lenses and going side to side (left focus point, right focus point) until I got a good overall compromise. The difference can only be described as OOOO MMMM GGGG. It’s like a totally different camera now. Sharp, sharp, sharp! (Both on the test chart and real subjects.)

I ended up adjusting one side of the AF sensor unit up and the other down, each by about 1/2 turn of the screw. In the end a final check using the center sensor showed that it was also right on.

Thank you, Jeffrey! Now I don’t have to argue with the Sony people who seem, unfortunately, utterly clueless in large part — in addition to taking 3 weeks to turn around a service.

(BTW I’m in Palo Alto, CA)

By: Mike

Mike — Fri, 09 Sep 2011 17:42:47 +0000

This chart really is great, thank you Jeffrey!

I have one question: what is the rationale behind the vertical spacing between the digits? It appears to be about 0.21 inches, or 0.55 cm, not round numbers by any means. And what is the meaning of the rectangles along the sides? I am trying to figure out if there is a simple way to communicate the extent of a focus issue in terms of actual distance.

Also I wonder if commenter Steve of 6/22/11 is listening. I also have an a55 and have what I believe is very severe back focus issues. I sent it in to Sony and they said it’s OK. But I really went to work with these charts and found that (I think) the three groups of sensors (left, center, right) have very different issues. The group on the right has near-perfect focus; the group on the left is way way back focused (by many multiples of DOF),, and the center group is about in between. That leads me to believe the AF sensor unit is crooked. I also have some issues with inconsistency of results but not to the extent Steve did. I did find that the center focus point (at least) has a very wide horizontal region where it locks on, extending maybe 3x the size of the focus point’s square in the viewfinder on either side of the sensor. I have a call in to Sony to complain but this time will be armed with lots of data.

There’s nothing manifest in the spacing… the numbers just give you something to refer to. The rectangles — a repeating regular shape — give you a concrete way to compare focus, or lack thereof. Depending on the situation, sometimes the squares are more useful, and sometimes it’s the solid thick lines. Perhaps it depends on the person. —Jeffrey

By: Jeff

Jeff — Thu, 01 Sep 2011 22:10:54 +0000

Thank you very much. I calibrated several L lenses and most were only slightly out. My 75-200II was spot on. But, I found my 1.4x II teleconverter when added to my lenses needed far more adjustment. Fortunately my 5dII allows individual adjusts for various lenses and converter combinations. Great help, thank you.

By: Don McVee

Don McVee — Sun, 28 Aug 2011 23:12:23 +0000

Thank you for doing this. I was able to improve the focus with my 80-400 on my new D7000 noticeably.

By: Andres

Andres — Sat, 02 Jul 2011 06:54:21 +0000

Hi Jeffrey, thanks for the advices. I am experimenting some Af problems with my d7000. I am using a tamron 17-50 2.8 VC.
I had to fine tune the camera at the maximum value -20. I verified with other lens the backfocus problem. So i tested with this method. Now the situation its like that. I am not using any fine tune, but even so i have some differences. Horizontally i experiment a little front focus, and vertically a little backfocus!
With liveview the results are similar but less detectable but is acceptable, at least with this 50mm lens.
I am tacking the pics at 2.8 and 50mm. 40 cm from the target and with objects of 1cm of difference.

By: Steve

Steve — Wed, 22 Jun 2011 11:48:32 +0000

I tried a variety of lenses and a variety of focal lengths for each of my zoom lenses. I'm getting VERY variable results ranging from pretty severe front focus to very severe back focus (on a 50mm macro lens). Is this common ? What is the likely cause ? Camera is a Sony A55 SLT. The macro lens was the one that caused me to do the test, the difference I noticed between a flower using AF and same flower using MF was shocking to me, with MF delivering a fantastic super sharp photo. On other lenses I've just noticed the occasional softening in faces where the ear for instance might appear in better focus. Guess I'll start by opening a support call with Sony ! My first impression hearing about the wild fluctuation is results is that it's probably user error (that the camera is not focusing exactly where you think it is), or some kind of freaky firmware problem. I'm not familiar with Sony cameras and their autofocus, but you might try testing with LensAlign, which is perhaps easier to be sure you're using properly. —Jeffrey

By: Ravi Peter

Ravi Peter — Thu, 16 Jun 2011 11:30:19 +0000

Thank you Jeffrey for a very useful website! It helped me a lot to calibrate my Nikon D7K.
Thank You!

By: Felix

Felix — Thu, 05 May 2011 10:26:19 +0000

Thanks for the quick reply Jeffrey, I have another question if you don’t mind… If I have back focus problem where should I add the value? is it on positive (Upper) or negative (Lower)?

Thanks!

I have no idea… check your manual, or just give it a try. —Jeffrey