zargahi Posted September 24, 2008 Share Posted September 24, 2008 What causes mostly the barrel effect, aperture or focusing distance? Many thanks, Masoud Link to comment Share on other sites More sharing options...
chrissyone Posted September 24, 2008 Share Posted September 24, 2008 That shape of the glass causes that, it has nothing to do with aperture. Link to comment Share on other sites More sharing options...
ronald_moravec1 Posted September 24, 2008 Share Posted September 24, 2008 Poor lens design criteria. It is a management decision to allow so much. Nikon does it too. Leica has very little except for a few older zooms. I will say zooms are very much harder to design distortion free. PtLens. com to straighten it out Link to comment Share on other sites More sharing options...
PuppyDigs Posted September 24, 2008 Share Posted September 24, 2008 Money and weight considerations mostly. If you throw enough money at it and size is of no importance, I'm sure Canon could make a wide zoom with little barrel distortion. But we want it affordable, light, small and a wide zoom range so compromises happen... Sometimes the light’s all shining on me. Other times I can barely see. - Robert Hunter Link to comment Share on other sites More sharing options...
ralph_jensen Posted September 24, 2008 Share Posted September 24, 2008 Sigma 12-24 has just about zero distortion, but it has other shortcomings (resolution, CA, doesn't hit stride until f11-16). And yes, focusing distance is a factor; most lenses with barrel distortion will show more distortion at closer focusing distances. Link to comment Share on other sites More sharing options...
doug_nelson3 Posted September 24, 2008 Share Posted September 24, 2008 A pet peeve of mine. To get a minimum of barrel distortion with a prime lens on a crop-sensor EOS (an easily portable package), it seems I'd have to use a Nikkor 20mm AIS 2.8, or a Zuiko OM 21 f2 or f3.5 with an adapter and forget autofocus, shooting manual or AV. With the crop factor, I'd end up with about a 32mm angle of coverage. Canon USED to make excellent wides with minimal distortion: the 24mm f2 FDn, 35mm f2 FDn, and the 28mm f2 SSC. Leica's wides are nearly free of distortion. Hopefully, the barrel distortion, if not combined with waveform, could be easily dealt with in an imaging program. If this is true, I may just go with a Pentax body and their 21mm f3.2 to carry around. Link to comment Share on other sites More sharing options...
alex_lofquist Posted September 24, 2008 Share Posted September 24, 2008 Barrel distortion is a common characteristic of reverse-telephoto (wide angle) designs. Conversely, pincushion distortion is usually a problem with true telephoto lenses. Optical correction can result in "mustache" distortion. There's no free lunch! Link to comment Share on other sites More sharing options...
zargahi Posted September 26, 2008 Author Share Posted September 26, 2008 Many thanks for comments. Regards, Masoud Link to comment Share on other sites More sharing options...
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