I’ve had my D7000 for almost a year now and have taken over 5000 pictures with it to date. For about 6 months I have struggled with it focusing behind the subject. I’m not a pro photographer so I wasn’t sure what was causing the issue.
I made several communications with Nikon USA service about the issue. I sent in sample photos with different lenses and settings. It happened the most with action shots with the children, but not always.
The only troubleshooting they could help me with, without having the camera in their possession, was increasing the ISO to 400 and to use the 3d focusing mode when shooting these action shots. Unfortunately this did not fix the problem, in fact even in still shots I was still having the issue of back focusing. I noticed the trouble with my older 18-200mm VR lens more than with my 50mm f/1.8D lens.
Finally after going back and forth with tech support I resolved to send the camera in for service.
After checking the camera out for a couple of weeks they sent it back to me reporting that the camera was functioning properly and that it was possibly a lens causing the issue. Needless to say I was not happy or impressed knowing that the camera was having the trouble with back focusing with multiple lenses on it.
Accepting that maybe it was my older 18-200mm VR lens that was causing the problem, I ordered a nikkor 35mm f/1.8D lens to try on the D7000. I conceded that it could be the older lens after all I have taken almost 20,000 photographs with it. In the mean time I borrowed a friends 55-300 VR lens to see if I had the focusing issue with his lens on my camera body.
I proceeded to take pictures with the 3 lenses I had in my possession the 50mm prime lens my old 18-200mm and the borrowed 55-300VR lens. Once again focusing with the camera was inconsistent. Sometimes it was incredibly sharp and others it was focusing behind the subjects I was photographing.
In researching this problem I stumbled across a website Mansurovs.com. Nasim Mansurov had some insightful information on the increased resolution of the D7000 over my older D80 and the reasons why it was more prone to show camera shake and poor technique. He also taught me a few things on how to take action shots and which focusing modes to use. Actually it was because of his blog that I started mine:) He has a step by step guide on setting up a blog that is superb.
When my new 35mm f/1.8D arrived I anxiously mounted it on my D7000 and headed out to photograph the kids playing in the yard. As they ran around playing football and soccer I snapped away. I played with increasing the shutter speed to over 1/500 of a second to help with clarity and set the camera to the AF-C setting and the mode to 9d and 21d. With this set up you get a continuous focusing setting over a 9 or 21 sensor range in the center of the viewfinder.
Focusing with this set up was pretty quick and spot on for the most part taking into operator error. I continued to shoot shots cycling through the different modes. As soon as I switched to the 3d focusing mode the camera started to back focus something terrible. I was sick to my stomach at the results at first. Once I got over my initial irritation and anger I started closely paying attention to the lit up sensor in the viewfinder as it focused. What I found to my surprise was that the sensor would lock on the the child in the center of the viewfinder, but as the child moved the sensor consistantly moved off of the subject to a point behind them. So in a mode that was suppose to recognize the subject and track their movement automatically it was lagging behind the subject and as a result focusing on the background. I then played around with this mode with the kids holding still and it still on occasion would pick a focusing sensor off of the subject resulting in a focus behind them.
This was a big ah ha moment for me. I realized this is why my D7000 was focusing behind the subject. The autofocus system was accurate it was just picking an incorrect sensor to focus with on this 3d setting. I went back into the 39d, 21d and 9d modes to recheck my assessment and sure enough in these modes the camera focused sucessfully.
I’m not sure if others out there that are having trouble with their D7000’s focusing behind the subject could be having the same issue with the auto and 3d settings. I think it is a real possibility. If you read this and are having the focusing issue with your camera I would love some feedback on trying this experiment.