July, 2011

For anyone doing important photographic work, whether it be as a professional or serious amateur, accurate autofocus is crucial. Perfect autofocus is dependent on the calibration of both the lens and camera. Unfortunately, both lens and camera manufacturers have an acceptable tolerance range for calibration. So that new lens or camera you just bought might not be perfectly calibrated. This could mean that your new lens will back focus on every camera you attach it to because it's calibration is slightly off, but still falls within the manufacturer's acceptable range. Likewise, a perfectly calibrated lens may front focus on one camera, but back focus on another because the cameras are calibrated differently, but again, fall within the manufacturer's acceptable tolerance range. In the past you could correct this by sending all your gear to the manufacturer so everything could be calibrated together. Or you could keep trying different lenses until you found a copy that equalized the calibration with your camera body, so perfect focus was attained. But as soon as you bought a new camera the calibration match would be off again. Recently, some camera manufacturers have added a Micro-AF Adjustment feature to correct this problem, usually on their higher end cameras. Nikon calls this feature AF Fine Tune.

The Lens Align MkII is a tool designed to measure the focusing accuracy of your lens/camera combo. By using LensAlign you can determine just how much Micro-AF Adjustment your lens/camera combo needs to attain perfect focus. The Lens Align system was developed by Michael Tapes. The original version, the now discontinued LensAlign Pro, came assembled and included a steel ruler. The new version MkII, is designed to be taken apart and comes with a rigid Poly Styrene ruler. The advantage of taking it apart is that it's easier to carry if you're traveling. The LensAlign system provides accurate focus testing by using a parallel plane of focus along with a measuring scale where the focus point is as close to the center of the image as possible.

In order to achieve perfect centering it's best to mount the LensAlign tool on a tripod. The base of the unit has a standard 1/4-20 tripod socket built into it. A cheap $15 tripod will suffice. You can also put the unit on a table instead of using a tripod, but doing so will make it harder to line it up with the camera. The camera should be mounted on a good, sturdy tripod. All of the instructions on how to set up and use the LensAlign MkII can be found on the manufacturer's website. There's extensive written documentation as well as videos. I would have preferred that written instructions were included with the unit, or better yet, an instructional DVD.

Assembling the LensAlign MkII is fairly easy. Taking it apart is a different story. I have yet to do so. Any time I tried to remove the ruler I was worried I would bend or break something beyond repair. On their website the manufacturer claims to have taken a unit apart 50 times without affecting it's performance, but recommends that you leave the unit assembled unless you need to travel with it in it's flat state. Lining up the LensAlign MkII with your camera is fairly easy, but not a simple as shown in the video on the website. As of this writing the demonstration video on the website uses the discontinued LensAlign Pro. The video should be updated using the new MkII version.

Overall, the LensAlign MkII works as advertised. But it's probably not for everyone, especially since it's a bit pricey. For the pro photographer and serious amateur the MkII is a valuable, necessary tool. For the casual photographer though that may not be the case. I suggest you visit the LensAlign site here, read the Support documentation, and determine if LensAlign is right for you.