I didn't want to start more controversy with a moderator but I felt I had some useful information to share. Take this information as you wish, I'm simply trying to inform a few out there...
I did a lens test last night. I have used a Canon 28-105 f3.5-f4.5 USM lens for over 10 years as my general purpose walk around lens. I have been disappointed at times with the quality I got from the lens when I made large blowups 20" or larger. However, I recently started to notice this lenses faults even with small 5x7 prints. So, I was in the market for a new general purpose lens. I looked around and found a 17-40 F4 L lens that used goes for about $500. Not too expensive but not cheap. The 28-105 f3.5-4.5 goes for about $150-200. So what did I find were the differences between the two lenses? For those of you with the "kit" lens that came with your slr you may be surprised at the results...
This is the Canon 28-105 F3.5-4.5:
And here is the Canon 17-40 F4 L
These photos were 100% crops with both lenses set at about 40mm. There was no post processing done to these photos at all. Exposure and all other factors were the same. While the sharpness of the 17-40 astounded me, I wanted to point out a couple other attributes of the nicer lens. Contrast. Look at how much better the contrast is with the 17-40mm lens. I would imagine that is another reason why the test photo looks so much sharper with this lens. The other positive attribute that isn't too evident in this test photo is also the colors. The green came out more natural. No doubt if I had some test shots of more colorful subjects those photos would bear that out. Now I'm not saying you need to go out and buy a $500 lens... I'm saying that I was rather astounded at the noticeable difference in image quality between a $200 lens and a $500 lens. I also think this is another positive for going with a slr type camera over a fixed lens camera. You have the variability to take off one lens and put another lens on if you aren't satisfied with the speed, range, and quality of the lens you currently have. Hopefully this is informative to those of you with lenses like my 28-105 that I own.
