agustin.benencia Posted March 21, 2006 Share Posted March 21, 2006 Hi. I've recently owned a brand new Canon 17-40 L (my first L glass), and I just want to know if the distortion that appears in the corner of the image results acceptable for your judgement. Data: f4.5 / 1/40 TIA, AGUSTIN<div></div> Link to comment Share on other sites More sharing options...
agustin.benencia Posted March 21, 2006 Author Share Posted March 21, 2006 Here is the Crop<div></div> Link to comment Share on other sites More sharing options...
mendel_leisk Posted March 21, 2006 Share Posted March 21, 2006 Just curious, is the camera full frame or crop factor? Link to comment Share on other sites More sharing options...
bobatkins Posted March 22, 2006 Share Posted March 22, 2006 What distortion? Link to comment Share on other sites More sharing options...
peter_daalder Posted March 22, 2006 Share Posted March 22, 2006 From Augustin's other posts, I'm assuming that this was shot with his 20D. At f4.5 you have to put up with some <i>softness</i> in the corners. What you're showing above (100% crop) is quite acceptable, imo. Link to comment Share on other sites More sharing options...
shambrick007 Posted March 22, 2006 Share Posted March 22, 2006 That's not distortion, it's soft corners. Typical from this lens shot almost wide open at f4.5. Link to comment Share on other sites More sharing options...
dogbert Posted March 22, 2006 Share Posted March 22, 2006 It may be typical, I don't know becuase I don't have a 17-40 L. But then why do people rave so much about this lens? It doesn't seem overly impressive to me. Link to comment Share on other sites More sharing options...
shambrick007 Posted March 22, 2006 Share Posted March 22, 2006 because it's built well, focuses fast, and peforms well in real world conditions = stoped down, and making pix, not pixel-peeping. Link to comment Share on other sites More sharing options...
dogbert Posted March 22, 2006 Share Posted March 22, 2006 Fair enough but then there are plenty of lenses like that including most Canon prosumer, L and sigma EX lenses. Link to comment Share on other sites More sharing options...
affen_kot Posted March 22, 2006 Share Posted March 22, 2006 geoff, the 17-40 allows (along with the other budget L's) the <i>everyman</i> the ability to sport an L lens. brilliant marketing by canon. Link to comment Share on other sites More sharing options...
johan_prins Posted March 22, 2006 Share Posted March 22, 2006 Is it not more like vertical camera shake? Horizontal lines are double and vertical lines are sharp. Look fi. at the rail and bars in the centre. Link to comment Share on other sites More sharing options...
leon chang Posted March 22, 2006 Share Posted March 22, 2006 I used that lens in the past on my ex- 10D and must say I never noticed any severe distortion. The lens was a satisfactory overall peformer, though it was not as good as any of the canon fixed focal lenght lenses I've used. I guess it also depends on print size right? Link to comment Share on other sites More sharing options...
matt_sallis Posted March 22, 2006 Share Posted March 22, 2006 Johan has it right here: vetical camera shake is the problem for sure, just look at the railings. I wouldn't often jump to the defence of this lens, but with this example it's only fair that I do. It can produce sharper results than this in the corners of a crop camera. Full frame is another matter... Link to comment Share on other sites More sharing options...
alberto greco Posted March 22, 2006 Share Posted March 22, 2006 Agustin, I dont think the pic has a distortion problem (my copy of 17-40 has some distortion between the range 17-20, but no more in longer focal lenghts). I believe is a falling lines problem (the camera was not parallel to the building while shooting) which caused a crooked picture. Could someone (Bob?) confirm? cheers Alberto Link to comment Share on other sites More sharing options...
John Crowe Posted March 22, 2006 Share Posted March 22, 2006 Yes you are right. Not only is this image not taken straight up and down it is also taken on an angle sideways. To properly test for distortion you take a picture of a building like this, or any subject with lots of vertical and horizontal lines on one plane with the camera back parallel to that plane. Brick walls are the typical subject. Then there is also perspective distortion which you can just start to see in the person standing in the bottom right corner - the person is becoming elongated. Link to comment Share on other sites More sharing options...
agustin.benencia Posted March 22, 2006 Author Share Posted March 22, 2006 Many thanks for your comments. And yes, my mistake asking for distortion instead of softness. AGUSTIN Link to comment Share on other sites More sharing options...
ed_skibeki Posted March 22, 2006 Share Posted March 22, 2006 According to the EXIF file on your 100% crop you took the picture at 1/40th sec. Unless it was on a tripod that's pretty slow... Link to comment Share on other sites More sharing options...
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