James Fry wrote: I've been a 17-40 owner for about a year. The sample I have is pretty soft on my 20d (although not as bad as the samples in this test) and I always put it down to me being incompetant. However, I've recently been shooting with my 1v and it's actually quite good.
Given that my other lenses (28-135, 50mm 1.8 mkI/mkII, Sigma 70-200 2.8, and some borrowed lenses) all appear to work fine on my 20D, and unscientific testing of the 17-40/20D combo suggests the lens is focussing infront of where it should, could it be there is an incompatibility between the 17-40 and certain bodies? I think I need to do some proper testing to determine what exactly is wrong with which bits my gear, or if it's another case of PEBCAP (problem exists between camera and photographer!). ------------------------------------------------------------------------ ---- There have been instances where a lens will work perfectly on one camera body but not another. Sometimes it has to do with the camera, and in many instances the way to fix this would be to have the body recalibrated along with the lens. I am just finishing up an article on digital lenses and in my research I found this problem generally occurrs as a back focusing issue. Most of the time it occurs with fast lenses and may be due to the image sensor mounting as opposed to a problem with a lens. Sometimes a lens may work perfectly on one camera body but not on another. To check your camera's AF use a flat subject and take several shots of it with one or more lenses wide open. If you are experiencing a problem with focusing, the remedy may be to send the camera body in for recalibration. If it is happening only with a specific lens, then you may need to send that lens along with the camera body back to the manufacturer and ask them to recalibrate the camera body using that lens. This will generally correct this issue. Peter K * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
