Over the past weekend I've tracked down an issue with my primary camera body, Canon EOS 5D, that has left me in a quandary. After working with this camera successfully for more than a year, it seems somewhere over the last few weeks that is has developed an auto-focus problem. Many of the photos that I was taking, in ambient light and with off-camera flash, were coming out really soft. Under more scrutiny I realized that the camera was focusing to some degree behind the subject, even though the auto-focus point had locked on the spot I intended it to. Much of my weekend was spent testing this problem to see if this was an issue with a particular lens or if it was the camera itself. After using a standard test involving a graduated scale photographed from various distances, using all of my lenses, I found across the board, more often than not, that the auto-focus mechanism was indeed locking substantially behind (back-focusing) the subject. You can look at this 100% crop photo below and see the degree of this problem.
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Canon EOS 5D with 100mm f/2.8 USM Macro lens displays back-focus problem. |
Here, the scale is setup on a 45 degree angle (where the left side is closest to the camera and with appropriate marks in centimeters to measure horizontal distance), photographed from a tripod mounted, remote shutter released camera 2.5 meters away, lens at maximum aperture, and the center auto-focus point locked on the single, vertical line between the four number ones. This shows that the actual focal point/plane is nearly off the scale on the far right, some 10-13 centimeters behind the target.
What this means in reality is that the camera will not capture in focus the details crucial to the shot. That is, when using a very shallow depth of field, it will be very unlikely or sporadic that the eyes of someone in a portrait will be in focus; rather, the hair on the back of their head, or the tree/wall/whatever background will be in focus while their eyes are blurred and soft.
Obviously you can see how frustrating this can be for a fledgling business. Getting ready for some major travel and events in the next few weeks has left me scrambling to find a replacement camera that will provide the same or better quality of imaging that I've come to expect out of this 5D. Where I am fortunate, however, is in the support and enthusiasm that my wife brings me. When I'm ready to collapse, she is there to hold me up and help keep me excited about the opportunities that are before us. So, I'll keep moving forward and look at this challenge with the eyes of one who is blessed beyond measure and is hopeful through the trials.
~Jeff