Sometimes the difference between getting an awesome image and throwing another one in the electronic trash-heap is a matter of millimeters. When photographing people, birds, or critters, one of the most important criteria is making sure that the focus is dead-on. This usually means the eyes are sharp, and as many of us have found out the hard way that is not always an easy task. Fortunately, most modern cameras have the built-in ability to micro-adjust your auto focus to ensure that you are getting the best possible focus on every shot. Here I have illustrated the step-by-step process of using the Datacolor Spyder Lenscal a very handy and easy to use tool for micro-adjusting focus.
The Spyder Lenscal is a simple device that allows you to precisely focus on an exact spot and then utilize your camera’s internal software to make fine-tuning adjustments.
Having two tripods to set up makes it easy–if you don’t have a second tripod just place the Lenscal on a flat surface like a table or stool. Make sure there is good consistent light for your calibration.
Turn your auto focus on and your vibration reduction off. Place your auto focus sensor on the small squares next to the angled square. Activate the auto focus and take a picture.
With the image preview active zoom into the image as far as possible–zooming into the area near the zero on the angled scale. Access the sharpness of the calibrated lines–are they sharpest at the zero, or in front, or behind?
In your camera’s software find the “Autofocus AF Micro adjustment” (Nikon or other brand cameras this might be called something slightly different, but you get the idea.)
You can adjust all your lenses or select “Adjust by lens” (again this is the Canon menu, and I am not sure of the specifics on other brands.)
Make any necessary adjustments to fine-tune the autofocus settings. In this example, my Canon 70d with the 24-70 lens needed a slight adjustment to ‘push’ the focus back slightly in the telephoto range and ‘pull’ the focus forward slightly in the wide-angle range. Save your adjustments and take another image of the Lenscal to make sure your adjustments are correct.
This is a simple and easy process and only takes a few minutes–it can make the difference in a keeper or a throw-away. Now I have a few more lenses I need to go adjust!