Sharper Photos (Part 2)
In a recent article “Tips for Sharper Photos” we discussed how to get sharper looking pictures by using various techniques from tripods, bracing, remote triggers, etc. Today we’ll discuss another important aspect to getting sharp pictures and that is your camera gear itself. While we would all like to think that camera manufacturers such as Canon, Nikon, Sony, Pentax and others would deliver a product that is 100% with no defects we don’t live in utopia.
Allowed tolerances in camera and lens manufacturing by these companies can creep up and bite you. Let’s use the following tolerances for manufacturing. Let’s say when a camera body leaving the factory is allowed a + or – 2% tolerance in the focal plane of the sensor (the point where the image is actually captured by the sensor). Let’s also say that a +2% tolerance results in a back focusing issue (where the camera is actually focusing behind the actual point you are asking it to focus on) and a -2% results in a front focusing issue (in front the point you are focusing on). Yes, that’s right you ask the camera to focus on a subject and the true result is an accurate focus either ahead of or behind the subject you have spotted.
That’s only 1/2 of the problem though. Now let’s throw a lens into the equation and have the same + and – 2% tolerances for focusing. Add the two together and you could have a + or – 4% tolerance in accurate focus (now outside the manufacturers own tolerances). If you are lucky and you have a body that is -2% and a lens that is +2% then everything is equal and voila no problems, but if you want to take that gamble I suggest a winning trip to Vegas is not in your future.
So what is the solution to this problem? Michael Tapes Design to the rescue.
Michael has designed a product called “LensAlign” which is basically a target with guide ruler beside it. Setup your camera and Lens Align on tripods following the instructions Michael has provided here. Most of the recent new cameras by the manufactures provide for an “Auto-Focus Micro-Adjustment by lens”.
Following Michael’s instructions you should see the zero in the middle of the ruler in sharp focus after you have made any necessary AF Micro-Adjustments. If you have the 8 in front of the zero in focus then you have a front focusing issue and you have to instruct your camera to apply some back focus whenever it uses that particular lens. That’s right, using micro-focus adjustments by lens your camera will make the necessary adjustments whenever you switch lenses.
I highly recommend purchasing the LensAlign kit and accurately adjusting all your lenses and body combinations and you will be on your way to getting sharper pictures from your camera if you also follow the previous guidelines in “Tips for Sharper Photos”.
Another source for LensAlign instruction is over at Luminous Landscape. Michael Riechmann has an article for additional sources.