Adjusting for backfocus on D7000 with 18-105?

I've done initial testing of my autofocus using the chart created by Jeffrey Friedl. The pictures show that I have a backfocus issue. My question is; do the numbers on the chart correspond directly with making adjustments in the camera? Ex. If the number 10 of the backfocus section on the chart appears the sharpest, do I set the camera to a minus 10? Thanks.

Camera Fun said:

I've done initial testing of my autofocus using the chart created by Jeffrey Friedl. The pictures show that I have a backfocus issue. My question is; do the numbers on the chart correspond directly with making adjustments in the camera? Ex. If the number 10 of the backfocus section on the chart appears the sharpest, do I set the camera to a minus 10? Thanks.

Click to expand...

No. Those are only relative numbers... based on too many variables... Move the values in your camera to the minus 10, (the max is 20)... and re-do the test... you should see a difference between the first test and the second test... continue making adjustments and tests until the focus point moves to where you want it...

I set everything up and don't move anything, only removing the memory card between test shots...

I have heard it said that the following procedure works for correcting backfocus on the D7000. I have no idea if it will work for you or not, but I'd say it's worth a shot.

Go into the Custom Settings menu and set everything back to the default value. Even if you haven't played around in here, go in and check that ALL the values are at their default. Then go into the Shooting Menu and set everything back to default as well, check every value and put it back to its factory default. Once that's done, do a two-button reset of the camera by pressing and holding the two green buttons simultaneously. Restart your camera and see if that helped. More than one person has reported this has corrected the issue for them.



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I've tuned both a D7000 and a D800 and in both cases it was a back and forth ordeal that took several hours to get it right. I would start by moving from zero to +/- 5 and repeat until I got it within +/- 1 and repeat. With each new change I would take a minimum of 3 shots before I concluded I whether or not it was better or worse. It's also important to force the lens to re-obtain focus with each shutter release otherwise the results seem to be misleading. Having the camera tethered to my computer (via Nikon Camera Control, or LR) made it infinitely easier than doing it piecemeal. But while it's a giant pain in the arse to tune all your lenses, in the end it's so worth it when you start seeing those super sharp and crisp photos on your computer screen.

Ok. I'm going through the process more. I want to see how it works and not try the total reset process at this point. My next question is should I base my final decision on only one focal length or should I check focus throughout the range of the lens? I'm using 400 ISO, 1000 shutter speed, and largest aperture possible for a given focal length.

The focus point becomes a factor at the widest f-stop, so use that as your base... OTOH, if you have a lens that you use at a particular f-stop... use that as your base... If you read all that has been written on the subject, you'll find the answer to your question all over the map... Somewhere in the middle is the answer... I have adjusted mine to the largest f-stop (small number) because that reveals the shortest depth of field... and most of what I shoot is portrait so focusing on eyes is the sweet spot where I want to be...

Measure at the widest aperture possible. That will give you the best read on the lens itself as the focus will not aided by a smaller aperture.

Thanks again to everyone's comments. Right now I've got the setting at -7. I'll try that for a while and see how things go. The most time intensive part of the process for me was getting the chart and camera aligned correctly and also enough light.

Is there a thread that explains how to do this test with the chart?

Thanks

zmcgovern45 said:

Is there a thread that explains how to do this test with the chart?

Thanks

Click to expand...

Jeffrey Friedl's Blog » Jeffrey’s Autofocus Test Chart