15mm Super-Wide Heliar: Good or not?
I have shot about thirty rolls of Tri-X with this little gem. My results are not always great, probably because my technique is a bit spotty. I shoot very quickly on the street and try to pre-focus and preset my f/stop before I raise the camera to my eye. I never meter with the camera up to my eye...to slow for my taste. The exposures are generally right on and sharp, but here's the problem: when I slightly tilt the lens up or down, I see the perspective distortion in the final print. I also shoot panoramics with the Horizont and the Noblex, and these have even more perspective distortion. Is there any way to minimize this? Is this common with all ultra-wides? Is the Zeiss Hologon that much better at ten times the price? If I scan the negatives (heaven forbid!) could PhotoShop CS2 fix it easily?
Perspective distortion is a fact of life - or rather the laws of nature. All ultra-wides will show it to some extent, depending on the image angle (not focal length). Even pinholes will give exactly the same "distortion".
-- Ole Tjugen, Luddite Elitist
To use these lenses, without perspective distortion, the camera must be absolutely level. Voightlander (sp?) sells a flash shoe "splitter" with slips into the flashshoe of the camera and provides two new shoes, one for the finder and one for their level.
The hologon would not be better in this regard.
I would live with the distortion caused by tilting the camera, this often provides interesting perspective. If I needed straight lines, I'd use a view camera.
You can control some minor distortion in the darkroom by raising and lowering the proper edge of the easel. You may need to stop down a bit to cover DOF, and use longer exposures. The tilted easel does work, additional cropping is usually necessary. The idea is to tilt the easel exactly as you would a standard on the view camera. Line up a vertical wall in the easel the print. Yes, you can use PS to clean up camera tilt!
I usually place a film box or something similar under the raised edge to keep the easel from moving about!
OK lens? No. Stunning!
Not just an OK lens. It is stunning. Kinda difficult maybe but stunning.
If you want verticals to be vertical you need a level. I glued the tiniest one available (12mm diameter) to the finder so that a vertical shot is vertical.
The center portion of the frame is practically free of distortion. At least it is very manageable. The outer parts are stretched a lot. Naturally, because without barrel distortion you get Mercatorian (?) distortion. Like in stretched maps of the world.
And there is vignetting. Not necessarily a bad thing, you can use it. It is gone by f5,6 or f8.
Did I mention sharp? Well, very.
The method of restricting photo attachments is very unclear. It has taken me three edits to get it right. This takes away the joy of posting on APUG.
cheers and goodbye. May light and wisdom be with you all.
Last edited by laptoprob; 03-15-2006 at 04:38 PM. Click to view previous post history.
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You know that you can get a level that sits beside the auxiliary viewfinder and has its own little optical system to show you the bubble when the finder is at eye level. There's a double shoe adapter made to take the finder and the level at just the right separation.
On all technical specs and serious reviews it's one of the best C.V. lenses.
The Zeiss Hologon and the new 15mm Distagon 2,8/15mm are over 10X more expensive and I am afraid it's difficult, even for me, to compare the 4,5/15mm C.V. results with the new Distagon 2,8/15mm on the M7.
Yes, there is always distortion and the C.V. lens is sensitive for situations with direct reflective light.
Originally Posted by Karl K
actually you see converging lines, no distortion. Distortion are bended lines at the edges (Barrel or pincushion). Different from SLR lenses this lens is almost distortion free.
On a RF camera you cant get any wide lens under perfect control without a level, I use the Voigtländer level mounted on a double shoe.
A la recherche du temps perdu: www. bersac.de
Yes the 15 mm Heliar is deadly sharp and for the price I got mine an optical wonder!
The only way to avoid this kind of distortion is to keep the lens absolutely level. You can use a bubble level for that and, preferably, a tripod. But the distortion can also be used for artistic purposes. Try to experiment with the distortion and see how it can be used to the shot's benefit.