I have an oldish ( 12 years or so) 40d. I recently purchased a warrantied 100-400 EF zoom, but on trying it last weekend I notice that as I focus in, the image seems to drop once AF locked on and then return to normal on full shutter depression. This is resulting in blurred, poorly positioned subjects. Ive tried resetting the camera, that work for 1 or two shots, but then back to how it was before. Any other ideas, please.? Also, I am trying to find a way of checking my shutter count. Ive tried uploading a pic to myshuttercount, but no shutter data on the picture! Again, any ideas?
What do you mean by the image seems to drop? The camera doesn't capture the image till you fully depress the shutter, and you need to hold the shutter half pressed to keep the focus locked. How many focus points are you using? Are you using servo, if you are you may have motion being picked up that is shifting the focus slightly before full shutter press. I'm not sure how much experience you have or if the lens or camera have focus issues, which could be possible, but you also may want to look at the focus modes. And here is another question but how fast of shutter speed are you using... You need to have a shutter fast enough not only to freeze action in the shot but also camera shake. If your using a long lens you need to adjust accordingly, a very simple rule is to shoot faster than the length of the lens this rule has been around for decades and has been minimized by image stabilization but even that has its limits. So with no IS, I would be using at least 1/500 shutter. With IS you should be able to go a few stops slower and select maybe 1/125. Again with minimal info here I am exploring a variety of options since I am not sure how big of a beginner you are. Shutter count, well Ia quick search online says freeshuttercount works for the 40. Likely this is not a big issue as these can be picked up rather in expensively if it were to die.
