I’ve always had a sneaking suspicion, that my Canon 5D Mark II and my Canon EF-135mm 2.0 USM lens weren’t playing nicely together. Even in situations when the autofocus system should’ve had an easy time, I’ve always found myself with focus problems with this specific camera/lens combination. The focus seemed to be off by quite a bit; especially when shooting wide open. In close-up situations, for example, the tip of the nose would be in focus when I clearly focused on the eyes.

“Must be a problem with my camera” I kept telling myself for months, too lazy to actually look into the problem even though it always bothered me. Too lazy to do something, until I received an email from the folks at Datacolor, writing me about their latest product: SpyderLensCal.

According to Datacolor, almost all autofocus systems in DSLR cameras and lenses are manufactured within certain allowed tolerances. If lucky, your camera body and lens have the same tolerance data and work fine together. If not, the only professional solution is to send the camera body and lens to the manufacturer to have them calibrated together (which can be both time-consuming and costly). Datacolor’s SpyderLensCal instead attempts to provide a fast and reliable method to measure and adjust the focus performance of your camera and lens combinations.

Sounds almost to good to be true, right? Well, we got ourselves a unit and put it through a quick test for you.

The Spyder LensCal System

The SpyderLensCal is actually a very simple product. It’s not much more than a flat piece of plastic that folds up to be either mounted on a tripod or set up on a flat surface. Once set up, it basically looks like a black and white square with a diagonal ruler attached to the side. No cables, no processing power, no magic. So how is this system supposed to work?

The little quick start guide basically asks you to align your camera and lens to the center of the target area, set your lens to AutoFocus and take a picture in Aperture Priority mode with your lens wide open for a shallow depth of field. You then view the image on the camera LCD and zoom to maximum magnification, navigating to the intersection of the target and the ruler. If your camera/lens combination are calibrated correctly, the the line at “0″ should be in sharp focus. If it isn’t, you’re either suffering from front or back focusing issues and should adjust your camera’s lens calibration (more on that below).

Sound easy enough. But does it work?

SpyderLensCal Practice Test

To test the SpyderLensCal system I put it to the test with my Canon EF-135mm 2.0 USM, the same lens that has been giving me focus issues for months. So, how did the lens do? Shockingly bad, actually! As you can see in the picture below my lens had major focusing issues. The lines behind the “0″ mark were much more in focus than the ones in front. So I wasn’t imagining my focus problems after all!

Before Calibration (click image for high resolution)

After Calibration (click image for high resolution)

To correct the issue I entered the “AutoFocus/Drive AF Microadjustment” menu on my Canon 5D Mark II and selected the “adjust by lens” sub-menu. Since the numbers on the Spyder LensCal ruler and the AutoFocus adjustment numbers in Canon’s menu don’t correlate, I was conservative with my adjustment, at first, and set it to “-5″. I then went ahead and took another picture. The focus was still off. Turns out, that in my specific case, I had to set the AutoFocus adjustment to “-20″ (which coincidentally is also the maximum amount of adjustment that Canon allows) to get fairly good results. If I could have set it at “-25″, I probably would have.

The Microadjustment Focus Menu on the Canon 5D Mark II	The default setting for the EF-135mm lens
Adjusting the Focus to -20	Adjusted Lens Setting

Either way, the SypderLensCal calibration system, not only confirmed my suspicion that I had focus issues, it also helped me correct them. As a matter of fact, I will contact Canon in the morning to request free service on my lens to offset this major focus problem. I will use the calibration pictures to make my case.

The other Canon lenses that I tested were either in perfect focus or off by just a few units. All together, I tested and corrected a total of 4 lenses in under 30 minutes. The SpyderLensCal may be simple in concept, but the results are powerful. Set your camera to aperture priority mode, open up up your lens, focus on the target, and shoot. Then zoom into the resulting image, check the ruler, and make corrections if necessary. It the picture isn’t sharp at “0″, your camera/lens combination is off! Simple as that. End of discussion!

SpyderLensCal Review Conclusion

If you’re experiencing focus problems with your camera/lens set-up I can strongly recommend the Datacolor SpyderLensCal system, even if it may be a bit pricey at $59 for basically a piece of plastic. It’s still cheaper, and definitely much quicker, than professional calibration service and may be all you need to get your camera/lens combination back in focus. I’ll be definitely using mine with each new lens I purchase for my 5D Mark II.

Keep in mind, however, that the SpyderLensCal can only visualize focus issues, not fix them. To actually fix the focus issue you’ll need a camera that has a “lens micro calibration” feature. Fortunately most professional DSLR cameras, such as my Canon 5D Mark II, do. Other camera’s that will work include: Canon 50D, 7D, 1D MkIII, 1D MkIV, 1Ds MKIII, 1DIV; Nikon D300, D300s, D700, D3, D3s, D3x; Sony A850, A900; Olympus E-30, E-620; Pentax K7, K20. If your camera isn’t on the list, check your manual before you purchase this system.

You can pre-order the SypderLensCal calibration system directly from Datacolor. Pre-orders will ship on September 30th. Let us know in the comments if you have any questions.