Mansurvos has an excellent review on the D7000. I think it will help many of those new to the D7000, especially if they're considering moving to the D800 with 2x the resolution. The full review can be read
HERE.
"I know that some of the Nikon D7000 owners have complained about autofocus accuracy and reported having back/front focus issues. I also know that many of the visitors that read this review will focus on this part of the review more than any other, mostly due to the number of complaints they have seen on various online forums. Let me start off by saying that the
Nikon D7000 does NOT have a backfocus problem. Before some of the readers who were directly impacted by a D7000 backfocus problem start throwing tomatoes my way, let me first explain this in more detail. There are many variables that affect autofocus accuracy and a number of reasons why images from the D7000 might appear softer compared to older generation cameras. Many photographers who just got the D7000 as their first DSLR or moved from an entry-level DSLR like D40 to a D7000 simply do not have a solid understanding of how to use different focusing modes to obtain accurate focus. Without doing much reading and learning how to use the different AF modes on the camera, they just take pictures hand-held, expecting the D7000 to produce tack-sharp images. There are tons of photographs of blurry dogs and cats on the Internet photographed in Single Servo (AF-S) mode while they are in motion, with photographers blaming the equipment for out of focus images. In other cases, you hear some photographers say stuff like “my Nikon D40 was much sharper and I never had focus problems with any of my lenses on it”. Wait a second. Before, they were viewing a 6 MP image at 100% on their computer screens and now they are viewing a 16 MP image at 100% and are expecting both to look equally sharp? Of course they are! But they do not seem to understand the following:
- High resolution sensors need better lenses that can resolve more detail. Do not expect your old crappy DX kit lens to give you super sharp images on the D7000.
- Camera shake is more noticeable on high resolution sensors when images are viewed at 100%.
- Even slight autofocus errors are quite visible on high resolution sensors.
So, going back to viewing a 6 MP image versus a 16 MP image at 100%, if those photographers resized the 16 MP image to 6 MP in Photoshop, they would not see much difference in sharpness between the two 6 MP images.Take a look at the following examples:
The first image is a 100% crop from a 6 MP image, while the second one is a 100% crop from a 12 MP image. Looking at the 6 MP image, I can say that it looks acceptably sharp to me and if I add a little bit of sharpening in Photoshop, I will get a very usable image. Now take a look at the second image – this one looks soft/blurry in comparison. Both are taken from the same image and one is simply resized to smaller resolution. That’s why if your lens is not very sharp or if it slightly front/back focuses, you would not normally notice any problems when it is mounted on a low-resolution camera. Many photographers did not even know about front/back focus issues until they tried out the D7000 or saw hundreds of messages on online forums. Simply put, Nikon opened a can of worms with a high resolution sensor and people all of a sudden started discovering focus problems with their lenses.
Front/back focus issues are mostly related to lenses, not camera bodies. Again, as I have pointed out above, a slight focusing problem of a lens might not be noticeable on a low resolution sensor, but will certainly show up at high resolutions. Add camera shake and motion blur at slow shutter speeds and the situation is worsened even more. Not all lenses are perfectly calibrated when they leave Nikon factories, as can be seen from some of my
Nikon lens reviews, so you should not be surprised if your lenses are not 100% accurate. If you did not notice a focus problem with your lens before, it does not mean that it did not exist.
Now this all does not mean that a DSLR body cannot have any issues. I’m sure a number of Nikon D7000 camera bodies actually had some focusing problems – a normal problem that occurs when a product is manufactured. Some experienced photographers have clearly demonstrated DSLR autofocus problems and I am not going to argue with them. However, the number of people who truly had an autofocus problem with a D7000 body is extremely small. Inside the DSLR body, AF problems could be caused by badly aligned internal components and other calibration issues that are easy to fix by the manufacturer. If all of your lenses have focus issues which are not present on a different DSLR body, then you might have one of those defective DSLRs that need to be repaired/recalibrated by Nikon. Don’t try to repair or recalibrate the camera yourself. There are some people who advise to use a hex wrench inside the camera chamber to fix the focus problem, but it is not a good idea for two reasons – you might damage your camera and you might make AF accuracy even worse. Nikon uses specialized computer equipment to calibrate cameras and lenses and you should let them handle that instead.
Another reason why we hear so much about backfocus issues on the D7000 is because Nikon gave the ability to use AF Fine Tune on the D7000 (Nikon D90 and entry-level DSLRs do not have this feature). Many photographers, especially newbies, experiment with AF Fine Tune too much and they end up with even worse results. Tweaking AF Fine Tune values requires careful testing using special charts for accurate results, so I would not just use any arbitrary number and hope it will work. Obviously, using other people’s AF Fine Tune values is no good either… Lastly, autofocus problems on DSLRs and lenses have been known for many years now, pretty much since the day autofocus was invented. If you search for “backfocus test” in Google, you will find articles from 10+ years ago. So it is NOT a new problem on the D7000 – there were back focus issues even back in the film days.
