I can't call this a stupid newbie question, because I am not a newbie anymore. ;-)
Previously I have not shot much with wide angles. I used my Canon 17-40 in Yosemite and thought I noticed some trees leaning in slightly in some shots. But only slightly. I have noticed a lot of distortion using the 16-45 on the K100D. While sometimes I don't mind this, other times I have been annoyed because I wasn't taking it into account. I am also reassessing the lens. However, I realize I am not all that clear on the difference between barrel distortion and perspective distortion. I also realize that getting more in the frame than normal perspective would allow must mean something will happen. I am curious if there is a formula for when perspective distortion will not occur, or some focal length at which it will not occur? Would about 45mm be the cut off point -- it won't occur at 45mm? As for barrel distortion, it seems to be depend on the lens. It seems people use brick wall to test for barrel distortion. Is that true, some wide angles have barrel distortion and some do not? Or do they all to some degree? As you can tell, I am not quite sure how to phrase this question. Basically what I want to know is when I shoot with the 16-45 when I will get some distortion and when I am likely not to. So I can take it into account and plan for it. And use the 16mm end or zoom in a bit more to avoid it when I want to avoid it. And anyone who wants to expound more on the difference between barrel distortion and perspective distortion, too, feel free. I am pretty clueless on the whole topic. I think this is perspective distortion... (which I don't mind in this case, but this is not the strongest example, just one I have shown) http://members.aol.com/eactivist/PAWS/pages/temple2.htm I think this was may be barrel distortion. When I looked at it I found the lamp post leaning in, so I straighten the picture in Elements 5 with Transform/Skew. Hence the distortion isn't showing anymore, but it was there. http://members.aol.com/eactivist/PAWS/pages/bars.htm I can go back and look at exitf if needed, but I think the top was shot at 16mm and the lower one longer. TIA for anything you want to offer, Marnie aka Doe :-) --------------------------------------------- Warning: I am now filtering my email, so you may be censored. ************************************** See what's new at http://www.aol.com -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
