first day's impressions of 17-55

So I took over 500 test photos yesterday comparing the EF-S 17-55mm f/2.8 IS with the EF-S 18-55mm f/3.5-5.6 and EF 50mm f/1.4, as well as 200 "real world" photos at Mountain View Cemetery. I'm not posting them here or linking to them yet, because Flickr is still being worked on, and I don't want to waste time uploading them now. But I'll tell you what I think so far.

1. There is noticeable field curvature at 17mm.


2. Both the barrel distortion at the wide end and the pincushion at the long end are noticeable in landscapes.


3. The lens has a considerably reduced focal length range at close focussing distances. At the 55mm setting and 1.4m focus distance, it's wider than my 50mm prime. At the 17mm setting and 0.55m focus distance, it's about the same field of view as the 18-55. Thus, at portrait distances, it's roughly a 18-50mm lens.


4. This lens absolutely rocks in real world shots in artificial lighting indoors. Outdoors is a mixed bag. Will take more shots today.


5. There are some issues with AF accuracy at close distances, even in fairly good light, both on and off tripod. Will investigate further today.


6. Focuses fast, like 85mm f/1.8 - maybe even faster.


7. Nice implementation of IS - no jump on start like the 70-300mm f/4-5.6 IS, much quieter, and seems to be faster startup.


8. I'm not getting the full three stops of image stabilization. I don't know exactly what I am getting because of the focus problems mentioned.


9. Zoom and focus rings not too smooth, with variable resistance in the zoom ring, presumably as different lens groups engage/disengage.


10. I have yet to find a lighting situation it can't handle handheld, even when it's too dark for me to see clearly.


11. Lens flare is well controlled, generally only showing ghosting (but very little loss of contrast) when the sun is in the frame. There was one 70-300-like ghost when the lens was not pointed at the sun - I'll post it later on Flickr.


12. Purple (really, blue) fringing is pronounced at f/2.8 in backlighting. Not as bad as the 50mm f/1.4 or 85mm f/1.8 wide open, but, if I remember correctly, worse than either of those at f/2.8.


13. Lateral chromatic aberration is almost indetectable, even in the worst backlighting. Interestingly, it is still worse than the kit lens when the bright areas are not blown - but this may be because the kit lens is not sharp enough to resolve the subpixel width of the CA. The 50mm f/1.4 is much better than the 17-55, showing no detectable CA.


14. Vignetting is easily seen in blue sky shots at 17mm f/2.8, but otherwise negligible. While darker in the corners at f/2.8 than the kit lens at f/3.5, the falloff is very minor until you get past the far edges, unlike the kit lens, which has a almost linear dropoff straight from the center (i.e., only a small circle in the center of the kit lens has apparently full brightness, whereas most of the frame seems this way on the 17-55).

So far, it looks pretty good. Not a miracle worker, but the only serious problem so far is the AF accuracy. The jury is still out though.