jason_b. Posted October 24, 2006 Share Posted October 24, 2006 So, it has been a while since I've posted. I have been trying to get the vibe of the 50/1.4 ASPH and my 28'cron. Pretty amazing lenses. I've been wanting to try a 21mm again, but hate the stretched feling that some 21mm lenses give. I DON'T mean the geometric wide angle distortion by which lines converge etc, but rather the way an object seems to smear as it nears the corners. Supposedly the 21/3.4 is great at controlling this, and the subsequent Leica lenses haven't come as close. How does the ZM measure up in this regard, and for that matter the 21G? Aside from distortion, the only other quality I care about is resistance to flare. Sharpness and contrast are less important to me these days - I've already got lenses that do that! Link to comment Share on other sites More sharing options...
shambrick007 Posted October 24, 2006 Share Posted October 24, 2006 " but rather the way an object seems to smear as it nears the corners. Supposedly the 21/3.4 is great at controlling this,"<p>Is this not a factor of the FOV/focal lenght of lens, not the brand? Link to comment Share on other sites More sharing options...
Rob F. Posted October 24, 2006 Share Posted October 24, 2006 That's pretty much my understanding, Sheldon. My 38mm Biogon/SWC does the same thing. Objects near the edges and corners get stretched out, elongated. I think it's a necessary consequence of the wide angle of view. If you bring your eye in close to the print, until the eye subtends the same angle of arc as the camera lens did when taking the shot, the stretching disappears. Link to comment Share on other sites More sharing options...
al_kaplan1 Posted October 24, 2006 Share Posted October 24, 2006 I've read that the Super Angulon gives straighter lines than most other ultra wides but I agree with Sheldon that the "smearing" elongation effect in the corners is just a result of the perspective. The 21/3.4 is a pretty amazing lens if you consider that it's a design that's past its 40th birthday. I love mine. If you shoot with a 15mm for awhile the 21mm shots start looking perfectly fine...LOL Link to comment Share on other sites More sharing options...
peterblaise Posted October 25, 2006 Share Posted October 25, 2006 . ... ahhh, the endless defining of terms. Jason, you're not noticing "optical" distortion as the term is most often used technically and regarding photographic lens and flat image mapping. See Paul van Walree's excellent exploration at http://www.vanwalree.com/optics.html and especially http://www.vanwalree.com/optics/distortion.html for your specific terms. ... and as mentioned - STAND BACK! ;-) -- Click! Peter Blaise, wide angle lover, closeup even! Link to comment Share on other sites More sharing options...
ronald_moravec1 Posted October 25, 2006 Share Posted October 25, 2006 The wider the lens, the more objects will stretch toward the corners. Circles in the corners will go into eliptical shape. 21 3.4 does it as do all 21`s. No rectilinar lens can eliminate the problem and it will be there until film can be fastened to the inside of a sphere, or maybe spherical sensors. Link to comment Share on other sites More sharing options...
billc1 Posted October 25, 2006 Share Posted October 25, 2006 You could wait for next spring for Zeiss to release their new ZM 21 4.5 lens, they say it is distortion free. Link to comment Share on other sites More sharing options...
joseph_wisniewski Posted October 25, 2006 Share Posted October 25, 2006 As several others pointed out, being "smeared" or "stretched" into corners is a characteristic of a good rectilinear wide angle lenses. It's just simple perspective. Oddly enough, lenses with barrel distortion have less of this smear, so it's a case of a real distortion countering a perceived perspective. My favorite way around it, scan the film (or shoot digital, g'day M8) and then use a program called Panorama Tools to remap the image from rectilinear perspective to cylindrical. If the distorted "object" in the corner is, well, human, the cylindrical perspective really helps. Link to comment Share on other sites More sharing options...
andrew1 Posted October 25, 2006 Share Posted October 25, 2006 Jason- you should check out a good 24mm lens. The smear effect is not lens distortion, but a result of the angle of view, as others have pointed out here. The 24mm length suffers a good deal less from this than 21mm. For a long time 24mm was the only wide I used, and if someone would make a good, compact 24 f2.8 with a good finder, I'd happily go back to it, and stop carrying a 28mm and a 21mm altogether. Link to comment Share on other sites More sharing options...
jason_b. Posted October 25, 2006 Author Share Posted October 25, 2006 Did the 24mm thing for a while. Lots of fun, but I was better off with the 28 in the end. I KNOW all wides distort, but as has been documented on nemeng.com etc. there is a difference between certain lenses (just try a nikon 21 vs a leica - the total coverage is the same, but everything is in a different place within the frame). From my recollection, the 21/3.4 was more pleasing in the corners than the 21/2.8 pre asph. So, same focal length, different optical output. Once again, does anyone have experience with how the two existing zeiss lenses perform relative to the two Leica ones I just mentioned? Link to comment Share on other sites More sharing options...
jason_b. Posted October 25, 2006 Author Share Posted October 25, 2006 This discussion touches on what i mean about things being in different places: http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=002hc3 Link to comment Share on other sites More sharing options...
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