I almost gave it all up. I just bought my first digital DSLR about two weeks ago. Coming over from film took quite a bit of mustard on my part. I shot with it for 35 years. I bought the Canon 7D, and 24-105mm f/4L to go with it. I traded in my two older non-L lenses on the new L glass. Later that day I went and took around 75 pictures. A few come out OK, not great, but most were short of the mark. I was in all honesty pretty disappointed. I thought I had a lot to learn about the camera, so I read the forum and the manuals, and Canon site everyday. I took 100-200 pictures everyday but my pictures were not improving, and 5 days in my camera gave me the infamous Error 20. Back to the camera store, none in stock, could be a month or two wait. 5 days later low and behold a brand new one from Canon shows up, even has the 1.2.4 firmware. Back into the field I go. Ducks, Turkey Buzzards, family, after 500 shots and 3 days later, I had but one thing to say, If my pictures are indicative of the results I can expect from digital photography, you can keep it. 95% percent of my pictures were not only soft, but when I blew them up 100% some of the birds looked like a fuzz ball. Colors were horrible. I thought the technology has a long way to go, I'm not Ansel Adams but I'm not that bad either. I got to thinking maybe I got a bad lens or a bad camera again. Maybe some testing is in order on the outside chance something is wrong. I go outside and set five bottles with writing on them, 6 inches apart at around 20 feet. I place the lens at 105mm @ f/4, turn the IS off and place the camera on a tripod. I place the focus on spot focus and get a good focus lock on the middle bottle. Perfect. I take the camera in and look at the picture at 100%. None of the bottles are in focus. The one I focused on is best and I can read the text, but it's very apparent it is much more distorted than it should be. I give the lens a -5, +5, +10 and +15 Micro adjust and repeat the same test at each micro adjust setting. Can't get the text in perfect focus although the lens was pretty good at +7. However at 35mm it's out of focus. That's the problem with Micro Adjust on zoom lenses, it usually only works at one focal length. In this case 105mm. Funny thing was the lens didn't really appear out of focus, it seemed like all the colors just weren't converging correctly.
Anyway I call the store and tell them now I have a bad lens. I get the you better talk to our Canon specialist. You must be doing something wrong speech. He is off today but will be in on Wednesday. So today I go to the store. He puts the lens on a 60D and goes around the store taking photo's at 1 to three feet. I keep telling him the problem is 10 feet and beyond but he doesn't seem to hear me. He keeps putting the photo's on the computer behind the counter and telling me look there sharp and nothings wrong with them. After 45 minutes of this I go get my camera out of the car, I show him a sign on the wall with a lot of writing on it. Probably 25 feet away. I take a shot and blow it up in the camera. I set the micro adjust to +10 and take the exact same photo. He then gets a 70-200 f/4 lens and takes the same photo. My problem solved he sees the problem with the lens.
I bought the 70-200mm f/4 L lens on the spot. I can honestly say I think I'm going to be much happier now. Below is from the first few pictures I shot with the new lens.
I've never been so happy to find out I had a bad lens.