Hi everyone,


I've had suspicions for a while now that my kit isn't performing as well as it should. I see 100% crops on TDP from Bryan and from many of you, and I've always thought to myself, "wow, that's way sharper than my shots ever are." I always thought there that maybe my issues with sharpness were mostly due to my own inexperience (too long shutterspeed, not using tripod, etc.), but the times that I have done everything in my power to get a sharp shot (mirror-lockup, remote activator, tripod), I've still never really achieved the sharpness that I feel I'm supposed to be getting. The 17-55, by all accounts, is about the best lens you can get without the <span style="color: #ff0000;"]L <span style="color: #000000;"]designation. So at the end of it all, I<span style="color: #000000;"] finally decided to check out the focus on my 17-55 connected to my XSi.


I set up a measuring tape on the coffee table, the XSi is on my Manfrotto 190XB locked down well, the camera was positioned close to directly above the end edge of the table. The camera was about 8 inches above the plane of the table.


There are four shots here. I took 8 shots total using exactly the same settings, one after the other. The first seven all were taken on center-point AF, mirror-lockup, IS off, f/2.8, ISO800, either 1/40 or 1/50 sec exposure. The last one used all the same settings, except I used LiveView MF. I was shocked at the variance between all the AF shots. I have selected three of the AF shots that are the most different from each other, and the last one is the MF shot.


These are all nearly 100% crops, but not quite (maybe 90%? I don't know how to do an exact 100% crop, actually). [:P]


For all of them, the red light from the center point was aimed at the intersection of the horizontal and vertical lines right next to the number 4.


Number 1, the very first shot that I took


[img]/resized-image.ashx/__size/800x0/__key/CommunityServer-Components-UserFiles/00-00-00-24-73/DPP_5F00_0001.JPG[/img]





Number 2, the second shot I took (look how DIFFERENT the focus is!!!!)


[img]/resized-image.ashx/__size/800x0/__key/CommunityServer-Components-UserFiles/00-00-00-24-73/DPP_5F00_0002.JPG[/img]





Number 3, somewhat in between one and two


[img]/resized-image.ashx/__size/800x0/__key/CommunityServer-Components-UserFiles/00-00-00-24-73/DPP_5F00_0003.JPG[/img]





and this last one is the one in which I used MF using LiveView. I tried to focus right on the horizontal and vertical line intersection next to the 4.


[img]/resized-image.ashx/__size/800x0/__key/CommunityServer-Components-UserFiles/00-00-00-24-73/DPP_5F00_0004.JPG[/img]





This seems pretty bad to me. Unfortunately, as stated above, I have an XSi, so no AF microadjust. I only have one lens, so I guess I don't know if this problem is the lens or the camera, right?


So how bad is this, and what are my options?


As always, I really appreciate everyone's thoughts!


alex