I just got a few rolls back taken with a nice 28mm f2.8 AIS Nikkor that I was given as part of a deal to sell a bunch of stuff for a friend. The color and sharpness are top notch, but I noticed an unpleasant edge distortion on many pictures. It's not that straight lines are noticeably bent, but more that the corners seem to stretch things out much more than the RF wides do. Is this a retro focus limitation? That 28 Nikkor is a highly touted lens, but at this point I feel like selling it and putting the money towards a RF 28 like the new Voigtlander.

-- Andrew Schank (aschank@flash.net), August 20, 2001

Answers

Andrew, I have the impression that this is pretty much a consequence of the way perspective is rendered by wide angle lenses. The 38mm Biogon on my SWC does the same thing. Shapes near the corners seem to get drawn or sucked toward the corner. I haven't noticed it with my 28mm Elmarit, but then I haven't done much architectural work with it yet. Now that you've raised the point, I'll be keeping my eyes open for it.

-- Bob Fleischman (RFXMAIL@prodigy.net), August 21, 2001.

The 28 2.8 AIS Nikkor is possibly one of the THE best SLR 28s ever made (and one of the best Nikkors). According to Photodo.coms MTF charts it is right up there with the Contax G/Leica/Konica 28s.

But MTF and distortion are two different animals. I never noticed much distortion when I was using the Nikkor, especially compared to the old 24 from the 60's, which made everything near the edges look as wavy as Poirot's mustache.

If you are going to keep some Nikon stuff around, this is one of the real keepers in their line, but in theory the RF lenses should have less distortion.

But bear in mind that the current Leica and Voigtlander 28 designs are actually slightly retrofocus designs, to provide clearance for the metering systems of the M5/CL/M6. So they may actually show some distortion compared to the '60s era 28's and the Zeiss G-Biogon, which is a virtually symmetrical design. The Konica Hexanon-M is also very close to symmetrical, but I've never tried one.

So test before dumping the Nikkor!!

As an aside, has anyone tried the Konica Hexanon-M 28mm? Comments, image samples? The Photodo charts make it look slightly better than either the Zeiss G or Leica M lenses!!(?) I just shot camera-counter comparisons between the 28 'cron and the latest 28 Elmarit today - will swap my impressions for Konica impressions as soon as I get home and process the film.

-- Andy Piper (apidens@denver.infi.net), August 21, 2001.

Here's a shot (no artistic merit) with the 28 Elmarit. Note how the guy's shirt is much wider towards the corner (makes him look really heavy!), and how the picture frame at top right is not square. This is the normal perspective effect of a wide angle lens, but NOT distortion as defined optically.

Optical distortion is precisely defined as a part of the image being further or closer to the center than you would expect from an "ideal" lens (the "bent lines" idea - or what you see with a fisheye lens). What you may be seeing (and what this picture shows) is the exaggerated perspective from a wide-angle, which is common to any WA from RF to SLR to view camera (Look up Bruce Davidson's book "East 100th Street", mostly shot with a superwide on a 4x5).

Now let's see if my link worked....

-- Andy Piper (apidens@denver.infi.net), August 21, 2001.

Andrew,

I've experienced that phenomenon with extremely well corrected wide angles on rangefinders as well as on SLRs.

I'm therefore also quite convinced that this type of "elongation" on sides and corners is strictly a perspective issue, and not a distortion/correction issue. It does not appear at all distances with all subjects: you will notice it more often in close-ups, while shooting 3 dimensional subjects.

The way you hold the camera (strictly parallel to subject plane or not) also influences the phenomenon. Very noticeable with people (crowd shoots), and more visible the closer and the wider you go.

Try shooting a patterned flat subject(newspaper), with your film plane parallel to subject plane, and I'm quite sure you will NOT see that "stretching" of straight lines towards the corners. You will notice that you have a very well corrected almost distortion free lens.

Alan

-- Alan ball (alan.ball@yucom.be), August 21, 2001.

Oooops - don't know what happened to my image.

TRY CLICKING HERE

Alan is also right on, as I hope you'll see.

Andy

-- Andy Piper (apidens@denver.infi.net), August 21, 2001.

I use the same 28mm lenses (latest Elmarit 2.8 and Nikkor 2.8 Ais that focuses to 20cm). Both are very nice lenses. I get the same feel as you do that when I shoot off centre HEADS ( or 3 dimentional round objects), at near distances, off centre, Nikkor produces slightly more distortion (stretch) than the Elmarit. This is just a feeling, I haven't actually done any tests.

-- sait (akkirman@clear.net.nz), August 21, 2001.

I met very unpleasant sort of aberration named the COMA, when was shooting with the Nikkor f2.8/28mm AI, and the Rollei 35S f2.8/40mm. Any round subject (for example, a face from 4-5 m) displaced near the edge looked like a pear, and it was impossible to improve with stopping down. Though, I didn’t pay attention to straight lines near the edges of the frame. Meanwhile the Nikkor f3.5/28 AI and the Summaron’s f5.6/28mm, are free from such a sort of aberrations.

-- Victor Randin (ved@enran.com.ua), August 21, 2001.

I just gave a good look at the images and I think it does really only show up most on closer subjects. I have taken so many images in the past few years with my 40 Rokkor and 50 Summicron, which of course do not have the corner perspective distortion of a wide like a 28mm, that may be why it seemed so noticeable. My 35 f2.8 Summaron doesn't seem to do this type of corner stretching either, nor does the 35 f2.8 on my Contax T3, but maybe its just because the 35mm is not as wide as a 28mm.

-- Andrew Schank (aschank@flash.net), August 21, 2001.

Andy Piper:

Nice photo! You should share some more with us!

-- Jack Flesher (jbflesher@msn.com), August 21, 2001.

Andrew

Welcome to the world of real wide-angles! This is one of the reasons why 28mm is about as wide as you can get really if you care about the look of groups of people (or rather if you are going to share photos with them). Once you get to 24 or 21mm you can imagine what happens to people at the edge of the frame! Photojournalists (who often seem to use them) don't care as the people involved don't talk back and sometimes the effect is good, but "real" w/a shots of family groups or groups of friends in which people appear on the edges will not make you Mr. Popular with those who unhappily chose to stand at the edge of the frame. You do not notice this effect with a 35mm.

-- Robin Smith (smith_robin@hotmail.com), August 21, 2001.

The effect is similar to that of stretching a globe to fit on a flat map. It is inherent in the physics of lenses and has nothing whatever to do with SLR v. RF.

-- Peter Hughes (ravenart@pacbell.net), August 21, 2001.

I understand this of course Peter, but it seems to me that like the elusive "bokeh", some wide angles have a more pleasing way that they bend a wide 3D world to fit in to that little 24 X 36mm flat rectangle.

-- Andrew Schank (aschank@flash.net), August 21, 2001.

Robin is quite right, and this phenomenon is the price you pay for the "sleathy" advantage of ultrawides in crowd shots. You do get the unaware nearby people in the frame, while they think you are photographing someone/something else.

But you are also at risk of inducing a "strangeness" in those people's features, especially if those at the edge of the frame are also those who are the nearest to the camera. That strangeness will or will not spoil the image depending on the informational nature of the shot: the viewer will gladly relate to the picture if this information is interesting, rather than be distracted by esthetic details. On the contrary, if the information content is low or banal, then the viewer's eye will be attracted by the esthetical "defects" (in this case unusual perspective phenomenae).

That is probably why the ultra-wide is a favourite with photojournalists covering crowd events (immense depth of field, view from within the action, etc) but not in most other circumstances involving people (except of course if you NEED such a "strangeness" to attract the viewer's attention to your picture).

Again, I cannot see why RF wide angles would be a protection against such perspective phenomenae. They do not in my experience (21mm Apo, 28mm Ricoh). But I am ready to be convinced I am wrong by any solid argument of course.

-- Alan ball (alan.ball@yucom.be), August 22, 2001.