"David J. Littleboy" <(E-Mail Removed)> wrote in message news:(E-Mail Removed) ...
> "Chris Malcolm" <(E-Mail Removed)> wrote:
>> David J. Littleboy <(E-Mail Removed)> wrote:
>>> Sure, the Nikon 14-24 is real nice (flipping amazing, even wide open), but in real life, one shoots way stopped down for wide
>>> things, since more
>>> foreground comes into view the wider you go. So the Stigma 12-24 (with its superb geometric correction) at f/11 and f/16 (on a
>>> sturdy tripod) produces superb images with the 5DII. Unfortunately, while my copy of the Stigma 12-24 is excellent out to the
>>> corners at all focal lengths at f/11 and f/16 _for interiors_, it is good out to the corners only at 14 and 15mm at infinity
>>> focus; Sigh.
>> Is that because it has a curved plane of focus which is closer at the
>> edges? If so, that's rather handy for interiors. Is it impossible at
>> any aperture to focus distant edges?
> In my testing, I wasn't able to get sharp corners at infinity whatever I did (at 12mm or 17mm or longer). It looked to be more a
> matter of the lens not resolving (smearing the image) than a focus problem. The DoF formulas tell you that you should see a lot of
> DoF at 15mm (the f/16 hyperfocal distance is a tad under 1 meter), but with such an extreme retrofocus zoom, life seems a bit more
> complex than the DoF formulas predict. (It's only recently that I did the tests to figure out how to get sharp corners at
> infinity, and I haven't done much outside with the lens since then (and I haven't determined how far I can defocus from infinity
> at 15mm and f/11 and f/16 and still get sharp images across the frame at infinity). There is the point, of course, that if the
> plane of focus is actually a plane, then the "distance" from the lens to the stuff at the lower corners with an extreme wide angle
> lens is actually very very short (a point which was implicit in your question).)
>
> For interior work, even at 12mm at f/16, getting both the far wall of a large room and the carpet close at hand in focus requires
> care. (For a CoC of 0.018 mm, the hyperfocal distance should be 1.7 feet, so just leaving focus set to 1 meter should cover all
> interior sins, but it doesn't.)
>
> Lots of people seem happy with the 12-24 and don't seem to (or say that they) have the difficulties I do. Even with the
> difficulties, though, it's great for interiors and is still the cheapest 15mm lens around for landscapey things.
>
> (I just shot the interiors of a couple of 1843 Beacon Hill (Boston, the one in the US<g>) row houses, and used 12mm for just about
> everything. I haven't had time to process the images, and I'm a bit afraid that all that 12mm stuff is going to get real old real
> quick when I show them to people.)
>
> --
> David J. Littleboy
> Tokyo, Japan
This little lens has been surprisingly good: the tiny 12mm f5.6
Voightlander (made for Bessa rangefinder or Nikon reflex
bodies). Its performance peaks around f8, but it is similar at
all other stops - and its sharpness into the corners is remarkable
(although overall it is not the equal of the 14-24mm f2.8 Nikkor).
There is no reflex viewing with it, but the optical finder supplied
with it is accurate for framing (but that does have rather extreme
barrel distortion, although the lens has essentially no distortion).
There is also a useful side-view leveling bubble. The main failing
of this lens is illumination roll-off toward the corners, but that
often doesn't show in images, and can be at least partially
removed if it does. For a photo of it, and one made with it, go
here:
http://www.donferrario.com/ruether/fs-misc-photo.htm.
--David Ruether
www.donferrario.com/ruether
(E-Mail Removed)