Nikon fisheye lens differences

[johnny01101]

Hey guys,

Im in the market for a new Nikon mount fisheye lens but I need a little clarification..... I have never used them and Im wondering what are the differences in the fisheye lenses that make the picture look like it's all rounded off and curved, and what are the fisheye lenses that just keep everything strait and flat but give you a very, very wide angle, and what are they called? I have heard the term "circular fisheye" thrown around but have no idea what people are talking about.... Im guessing they mean the rounded, curved picture look? Can someone explane the differences in these lenses and the names for each? I am looking for a "flatened" fisheye with a good wide angle, (12mm or lower) without spending over $400-$500 (maybe Im dreaming?) Im just not sure what to look for. Thanks guys !!

Johnny T.

 

[f8lee]

Johnny, you are actually asking about two different kinds of wide angle lenses - a fisheye and a so-called "rectilinear" wide angle.
There is a property called barrel distortion that can appear in lenses, particularly wide angle lenses. This is where truly straight lines in your subject area are rendered as concave curves when they are viewed through the lens - mostly near the edges of the viewing area. Normally this is something for which lens manufacturers make corrections, so that the image rendered on film (or CCD) still has straight lines.
Rectilinear wide angle lenses, like the 14mm Nikkor or Sigma, have extremely wide angles of view but are corrected so that if there is, say, a building on the left edge of the scene it will appear more "normal", i.e. - not curved inward towards the center of the scene. These lenses are typically rather costly, though the Sigma 12-24mm wide angle zoom seems pretty good and is about $650 at B&H and other reputable stores.
Meanwhile, true "fisheye" lenses are those where the manufacturer not only does not try to prevent this curving effect, but lets them go full throttle. A "true" fisheye has a 180 degree angle of view, which means that it also places a circular image on the film (that's the only way to get a true 180 degree view on a flat surface). You are more likely referring to the so-called "ful-frame fisheye" type of lens - here the full 24x36mm film area is covered but the 180 degrees of view angle is only accurate when measured across the diagonal. That is, from the left to the right edge of the frame the lens is displaying somewhat less than 180 degrees.
With full frame fisheyes, the curvature becomes more apparent the further from the centerline a given straight line appears. That is, say you're taking a photo of a scene with a flagpole using a FF Fisheye. If the pole is dead center in the viewfinder, it looks straight (as in,normal). As you pan your camera to the left or right, however, you will immediately see the pole curving - bowing out in either direction.
As for costs, I don't know if you'll find anything new for under $400-500; except for a brand of Russian-made fisheyes that are rather inexpensive (I forget the name but they're often found on eBay nowadays)
Hope that helps.
Bob

 

[johnny01101]

Bob,

Superb!! Just what I was looking for.

Much thanks !
Johnny T.