Steve S writes
I just wanted to compliment you on an awesome Making Sharp Images publication!! I think I found my new favorite photography source!
In any case, I am needing to calibrate my Pentax lenses for an upcoming trip. You know, I really love the overall quality (both build and image) of the Pentax K-4 and the DA* and Limited lens series. It seems extremely high-quality and precision-made. However, being a sharpness fanatic, I bought the Spyder LensCalc device, and want to get the maximum sharpness and resolution I can from this equipment.
Since it's my first camera with an AF Adjustment function, I find that I'm having difficulty achieving consistent sharpness from each of my four lenses. I just need more time to experiment with settings. Thanks again, sir!
DIGLLOYD: As I show unequivocally for both the Nikon and Canon pro bodies, autofocus accuracy is inherently error prone, and the best that can be achieved by calibration is to center the average focus on the correct point, thus reducing the average error. Most people think autofocus is accurate because they haven’t actually made an objective test and/or they are shooting 2-4 stops stopped-down, thus masking the error. When working with f/1.4 or f/2 lenses, this is a disaster. Use Live View for pinpoint focus when the subject matter allows for it.