| Fisheye lenses provide an alternate way of looking at the world in wideangle. Regular, "rectilinear", lenses are "corrected" to keep straight lines straight much in the same way as seen in Mercator projection maps of the world. Straight lines are straight but at the cost of severe distortion of the sizes of objects nearing the corners. In a map, this leads people to believe that Greenland is as large as Africa. The relative merits of various map projections is a bit of a political hot potato so I will drop that subject with this mention. Unfortunately it will be more difficult to remain neutral on the question of ultrawide images. In rectilinear wide angle photography, round objects tend to become ovals pointing toward the corners. The "problem" exists at all focal lengths but only becomes an issue in the realm of the wide angle. It becomes more extreme as the proportion between focal length and sensor size decreases. This essay only addresses use of Canon 1.6x crop factor DSLR's where the question arises as we go below 24mm focal length and becomes important below 17mm. Which system is better? That is a question each photographer must address for each use and will appear again and again as this essay continues.
 I have two fisheye lenses: The 8mm f/3.5 Peleng and the 16mm f/2.8 Zenitar. Both are by far the lowest cost lenses of their respective types. Opinions about the fisheye way of seeing presented here might apply to other brands (Sigma makes an 8mm and a 15mm; Canon makes a 15mm) but I have no experience with these lenses and can not offer a valid opinion on whether they are worth the considerable extra cost required over my two choices. This page discusses the Peleng 8mm and will explain the reason for the 11.2mm image above. |
8mm f/3.5 Peleng
| The MC Peleng 8mm f/3.5 is made in Belarus and sold primarily by mail either from eBay or other Internet sources. Usually it is priced between $250 and $300 US. My lens came packaged with an M42 (Pentax screw) mount on the lens and a manual Nikon F mount (requiring a screwdriver to install) in the box. It also came with a Japanese M42/EOS adapter which was added by the seller. The diaphragm on the lens is sometimes called "manual" but it is actually what used to be termed "Pre-set". One ring allows setting the desired aperture while a second requires turning from "Unlock" to "Lock" to actually stop the lens down to the preset setting. This makes it considerably easier to open up the lens for focus and stopping down to working aperture without removing the camera from the eye. The mount is metal and has a solid feel some might term more "clunky" than "refined". I consider it well built compared to consumer grade Canon lenses but it is no 'L'. Infinity is on the right end of the scale making the lens match Canon and Sigma lenses and run opposite Nikon and Pentax. The opposite end of the scale bears an M (macro?) which is just slightly closer than the last marking of .22 meters. "MC" in the name denotes multicoating. |  |
| The package (often, and correctly, demeaned in reviews as crude) also contains an imitation leather case and a set of colored filters which can be used in place of the clear one mounted on the rear of the lens for Black and White film photography. With digital camera (all I use these days), these are unnecessary so mine remain wrapped as received. One or the other of the rear mount filters must be used at all times or the lens will lose the ability to focus to infinity. The lens comes with a metal lenscap to protect the protruding front element. This is held in place (in theory) by friction and a way too thin ring of cloth that guarantees the cap will fall off regularly. I replaced this worthless material with a strip of black gaffer's tape and the cap fits perfectly. Your answer may differ but you will need to do something about that lens cap or it will be lost before you learn to spell "Peleng". While I'm sure I could drone on and on about other details, I'll skip ahead to the pictures and use examples to illustrate other points that seem worth mentioning. Examples here were taken with either my old Canon Digital Rebel (300D) or my new (newer to me than the Peleng) Canon 30D. I have no experience with the lens on other cameras (film, Nikon or otherwise) so don't ask. Rumors say the rear of the lens (or more exactly: the filter) strikes the mirror on some Nikon products. I once heard that someone had a problem with this lack of clearance on a Canon 5D but others reported no problem. I do not know the answer here but would warn all that the required (as part of the lens design!) filter must be completely screwed into place or it might stick back into the camera far enough to touch the mirror. There is no problem with the two cameras I have tried and I have heard nothing about any problems with other Canon models. |
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Part of me thinks I should show direct from camera images and there will be at least one somewhere down below but my experience with the Peleng suggests that I need to postprocess and crop to make images that look good enough that I am willing to show them to you. Cropping is needed to remove the ugly (my opinion) black corners and ragged edges of the image circle as seen on 1.6x crop cameras. The lens produces an almost circular image on a film camera or a no crop factor digital. The circle is clipped slightly at top an bottom (why they did not make it a 7mm, I can not say). On a 1.6x camera, the four corners are cut rather like you get using a telephoto lens hood on a wide angle lens. Making a rectangular image, therefore, requires cropping to the center section or expanding the corners by use of a defishing program. I will cover my experiences with PTLens in this regard later but it will suffice to say that there are several ways of correcting this situation and each of them has its plusses and minuses. My sandbox photo shows distorted trees that were not cropped out but my grandson (centrally located) looks pretty normal except for the enlargement of his legs which were slightly closer than the rest. The sandbox was round so it takes will with a lens that likes round things. At the top we see a small tree almost knocked down by a larger tree during Hurricane Isabel. It, and some other background trees, are bent in an unnatural way but trees are not always perfectly straight so you might have trouble telling which distortions belong to nature and which to the lens. This was taken from about three feet (just outside the sandbox) and was cropped to straighten and eliminate excess woods. Focus was done by a combination of eye and scale guessing. There is a lot of depth of field with this lens so subjects beyond this distance are pretty much considered at infinity unless you are shooting wide open (this is f/8). |
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| Another way to fill out the corners is to at least partially remove the fisheye distortion and stretch the image into those black spaces. My self portrait above demonstrates this. There is still some curve to the window frame and some other straight lines but I prefer to accept this instead of suffering other distortions introduced by the defishing process. I use (and recommend) PTLens as a plug in to Photoshop Elements. There are other brands which you are perfectly free to explore. This image was taken with the camera tethered to the computer. On the screen you see the image previous to this one since there is no live preview on a DSLR. |
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| Some people prefer rectilinear images to the point that they would software correct every shot. I disagree. Above we see the same photo with and without PTLens correction. On the left we see the out-of-camera fisheye result complete with rounded window frames. On the right is the same image corrected in PTLens so the window frames look better but the child's head is now stretched into the corner. This result is very much like what we would get with a 10mm rectilinear lens from the same position. Opinions vary; I'll take the fisheye version. |
| Update: I became aware of another option for correction of fisheye images that deserves mention. RectFish improves the mapping of Peleng and Zenitar images (I have not tried it on other originals) using a routine somewhat different from PTLens. It does a wonderful job straightening things out without adding the horrible flying corners of standard rectilinear adjustment (which the program offers as a bonus option as well). It crops a minimal amount of the image information in the process. My limited experience with the program suggests that the results are good and I can recommend it to anyone willing to pay the price for defishing. RectFish appears to be a work in progress (notably the promise for improved fine tuning and rotational controls) so I hope it will continue to develop into something really great with future updates. Its author appears to be on the right path toward a great tool for those of us who work with fisheyes. |  The above example was corrected with RectFish, otherwise uncropped or manipulated. Recent updates now allow adjustment of the degree of correction for those times when you wish to retain more of the fisheye effect. RectFish does a fine job of filling in those black corners without requiring excessive cropping or stretching. |
| The Peleng diaphragm has nine blades producing an interesting 18 pointed star if a strong light source is included in the frame. Nine blades on an 8mm focal length means that each blade is extremely small. It would require extremely tight tolerances to produce a mechanism so small that would give absolutely even results. This was lacking in the Peleng. Add to this the fact that there will be distortion if the light source is anywhere but dead center in the image and the star effect can be shaped a bit oddly. Flare from the sun in the image was only moderate and not as serious as some results when the sun was just outside the scene. There is no provision for a lenshood on the lens but I have considered trying to fabricate something appropriate considering the image reduction that comes with the 1.6x crop camera format. So wide an angle of view makes for a challenge to keep the sun out of the frame if it is anywhere except directly at your back. In that case, the problem becomes keeping your shadow out of the picture. Flash photos with the fisheye are possible as long as you use bounce and can find a bounce surface that is not in the scene. That can be troublesome as well. I have done some images with flash fill using the bubble bag or other diffusers discussed on my flash diffusers page but care must be taken that no part of the light from the flash goes forward an strikes the glass. The usual answer is to rotate the flash head and tilt it slightly backwards. The churchyard image (St. Peter's Episcopal Church, Lewes, Delaware) was partially corrected in PTLens to straighten out some curves so the round sun became elliptical. Some healing brush work was required to remove small flare spots. The odd look on the lawn is due to it not actually being grass but a succulent ground cover. I have found that many Peleng images require more attention in postprocessing than "normal" photos. It is not a toy for those purists who believe that postprocessing is a sin. I doubt that this is greatly different with any 8mm lens so it should not be considered a fault unique to Peleng. |
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| As promised I will provide an uncropped and unstretched shot (above left) and, just to fill space, will show (right) a 100% crop of a portion of that same image. Most obvious is the set of four black corners. At the top is a bright blue rim of flare on the light side of the image while the bottom shows a wider (but less obvious) band of lowered contrast flare. The severity and placement of these faults varies with the image but one or the other appears in most images. The blue rim is less a problem since it is narrow enough that it crops out easily. The low contrast band is a bit harder to crop sometimes but can be locally enhanced with careful use of selection and contrast controls. This is not my sharpest Peleng shot but will serve to illustrate that the lens is somewhat short of 'L' glass quality. I believe it is in the general area of the kit lens image quality (possibly a bit better). Certainly it makes fine 4x6 inch prints and 12x18's are good as long as you view them from a respectful distance for a print that size. Remember that a 100% crop of an image this size simulates a 32x48 inch print (assuming 72 dpi on the monitor) so fair viewing of a crop requires standing across the room. For the record, this image shows a blue stain on the boy's face and hand. This is not a photographic fault but comes from rubbing an inked hand stamp (for being a good boy at pre-school) across your mouth. |
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I really dislike the black corners and the flare edges. They make it difficult to crop an image and maintain the proportions desired without cutting out something significant. I tried using a 1.4x Tamron converter (the cheap model) producing an 11.2mm f/5 full image fisheye which lacked the black corners and the flare. Framing in the finder certainly is easier when you do not have to allow for the uncertain flares. Is 11.2mm wide enough? Usually! Sharpness, unfortunately, is reduced by more than lost by cropping to the same degree and there is no avoiding the one stop loss of light. I have a comparison image that might talk you out of trying the idea. Using this extender requires taping of extender pins as shown at bottom to avoid ERR01. The extender removes the offending parts of the image (black corners and flare edges) while still giving a much wider view than the Zenitar 16mm. Taping the extender is not necessary if you use a Focus Confirmation M42/EOS adapter (eBay!) which fools the camera into thinking there is a real lens attached. Below is an example of this combination. |
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| In summary, the Peleng 8mm Fisheye is far from perfect but can provide a fun experience and decent image quality with a little effort (and stopping down a couple stops). Certainly I would prefer a better lens with autofocus and, especially, auto diaphragm but my needs for this specialized type of lens barely justifies the price of the Peleng let alone the lens of my dreams. I recommend its purchase to anyone in a similar situation. |