|Nikon D4, Sigma 120-300mm ƒ/2.8 DG OS HSM S, ISO 12800, ƒ/4, 1/2000|
Yearly exams become important in the late thirties when changes in vision and focus along with eye diseases are more likely to develop.
Now your camera lenses are probably less likely to change in focus just from aging alone, but heavy use will affect the lenses.
|[cropped version of the above photo] Nikon D4, Sigma 120-300mm ƒ/2.8 DG OS HSM S, ISO 12800, ƒ/4, 1/2000|
Just to remind you when you focus on an object like this book, anything in from or behind the book should be slightly out of focus. However, if the points in front or slightly behind are sharper than the book cover this is when you need to make adjustments either to the lens or the camera fine tune focus adjustments.
The Sigma 120-300mm ƒ/2.8 DG OS HSM S can be fine tuned calibrated for 16 different focus points using the USB dock and software that you put on your computer.
I then check all the cameras again with the camera.
Just like you need to see an eye doctor to adjust your prescription take the time and check out your camera and fine tune focus the lenses as well. You will be surprised as to how sharp your lenses really can be.