Long time lurker, first time poster. I am in a bit of a quandry what to do and thought I would solicit advice.
I received my Mark III Kit from Adorama last week and finally had time to put it thru it's paces this weekend. Love the camera, but will take quite a while to get up to speed on all the functions- coming from a t2i, it's quite a bit more complicated. I am, however, disappointed in the image quality using the kit lens as compared to several other lenses I own which I also tried on the new body. Don't own any EF lenses below 70 mm, so my comparisons on the Mark III are at the upper focal range end of the kit lens. Compared to my Sigma 70 Macro, Canon 100 2.8L Macro and my Canon 70-300 L lens shows the kit to not be sharp at all in the outer half of the frame, not just the very edges and corners. I would have suspected it to be less sharp than the two macro lenses, but am amazed at the huge difference between it and the 70-300 L. I did tripod based, self timer, multiple focus method tests (including Live view and manual focus) , at multiple apertures, and the 70-300L is razor sharp on the new 5D Mark III all the way to the edge, whereas the 24-105 is almost as sharp in the center, but rapidly drops sharpness about a 1/3rd of the way from the center towards the edge and is poor at the edges. Stopping down to f 11 or 16 improves things a little, but still nowhere near the sharpness I would expect from an L lens. I did remember to turn IS off when on the tripod, as the first tests I did I had left it on, then remembered that might be the culprit, but alas, no improvement. These tests were at two target distances, one my backyard fence at 15-20' and then distant rock outcrops, focused at near infinity. I also put the 24-105 lens on my t2i and compared it to my EF-S 15-85, and it doesn't seem as sharp as that lens either when compared at the same focal lengths, but more apparent at the upper end of the range. All of these comparisons don't jump out at normal magnification but at 100% the difference is obvious.
Also - I am aware of is the issue with DPP high res mode, so these comparisons were done in both fast mode, and also in LR 4.01 RC, which does accept the Mark III raw files.
If anyone else has both the 24-105 and the 70-300L, I would appreciate your thoughts on how yours compare.
I have been lucky thus far in my previous lens purchases, which includes EF-S 10-22, EF-S 60 Macro, Sigma 150 Macro (non-IS), all of which met or exceeded my expectations for sharpness. I've read of people having issues getting a bad lens and strugging with Canon to get it right or getting a new one. I bought this 5D Mark III kit during the fortunate window Adorama had where for the same price I received a SD card, backpack, and a Red Giant software bundle. My question is - what would be the normal process to follow - return the entire kit (ie lens and body), or just the lens, and is Adorama responsible for the lens or do I deal with Canon? I'm at work, so can't attached images showing the problem, but if I get a chance this evening will try to figure out how to post examples, so you can see if the lack of sharpness is normal for this len.
Thanks in advance for your advice.