Fixing Front and Back Focus
The Spyder LensCal is another lens alignment tool, designed by a company specializing in screen, color, and lens calibration products. While the markings aren't as intricate as those of the LensAlign, the LensCal is very easy to set up and put away.
The box contains only the LensCal unit itself, as well as an oversimplified quick start guide and a thank-you card. On the back of the box you will find, again, an oversimplified series of illustrations that try to explain how to set the unit up.
Start by removing the LensCal unit out of the box and folding it upwards so that the target is perpendicular to the base and the ruler is locked in place.
Next, as with the LensAlign, position the LensCal on a flat surface or put in on a tripod. As pictured above, you can use the bubble leveler to make sure the unit isn't tilted one way or another.
Mount your camera on a tripod, align it with the small target directly to the right of the ruler, and fire away. Refer to the previous page on more specifics on what you need to ensure prior to starting your tests.
The LensCal as seen by the camera being tested. (Lens: FA* 85mm at F1.4)
You can use the edges on the target to verify that your camera is aligned properly; just try to ensure that all the lines run perfectly up-and-down or left-and-right. Although this system isn't as precise as the LensAlign TPA, it will still get the job done.
Next we take a look at some results.
No Adjustment Needed
Below is a close-up of what the ruler will look like if your lens is good to go. The zero should per perfectly sharp and the markings going in both directions should get progressively blurrier. There is a shadow in our test photo; please disregard it.
In this photo, the lens exhibits front-focus, and you would need to apply a negative AF adjustment in your camera. Subtract one until the photo looks like the one above.
Here's what back-focus looks like on the LensCal. You would need to apply a positive AF adjustment in your camera to fix it.
The LensCal's ruler isn't quite as fancy, and there aren't as many targets, but as you can see from the photos above, it still gets the job done in detecting front- and back-focus!