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Forum: Pentax SLR Lens Discussion 08-31-2013, 08:59 PM  
Beginner Fish Eye Lens reco?
Posted By stevebrot
Replies: 9
Views: 1,282
That is why it is good to use them judiciously. For some subjects a fisheye is the best solution. For others it makes the composition possible.

Thanks for suggesting the Sigma 15mm fisheye. Some of the best photos on the fisheye fever club thread have been taken with that lens. They are fairly expensive new ($609 MSRP), but may be much less used. KEH has one in LN condition for $600 :p ...better probably to look elsewhere!


Steve

P.S. I found a blog posting that suggests that the Sigma 15mm also suffers from focus calibration issues.
Forum: Pentax SLR Lens Discussion 08-31-2013, 11:28 AM  
Beginner Fish Eye Lens reco?
Posted By stevebrot
Replies: 9
Views: 1,282
...and if you find one, be sure that it comes with the rear "clear" filter attached. It is part of the optical system and the lens is hopelessly unsharp with out it.


Steve
Forum: Pentax SLR Lens Discussion 08-31-2013, 10:56 AM  
Beginner Fish Eye Lens reco?
Posted By stevebrot
Replies: 9
Views: 1,282
I own both the Samyang 8mm (a.k.a. Rokinon, Bower, Vivitar, ProOptic...) and the Russian Zenitar 16mm fisheyes. Although I have only owned the Samyang (in Rokinon clothing) for a couple of weeks, I have formed a firm opinion on the lens. Here are a few bullet points for each.

KMZ MC Zenitar 16/2.8 Fisheye
  • The Zenitar is a FF lens and is only moderately "fishy" on APS-C. Much depends on camera angle and the nature of the subject. I use my Zen for general landscape shots as well as for fishy stuff.

  • Decent (metal) build

  • Compact

  • Light

  • Approximately 120 degress FOV on APS-C and 180 degrees diagonal on 35mm FF

  • Excellent performance at apertures f/5.6 and narrower. Good performance at wider apertures.

  • Relatively easy to focus, though an aftermarket focus screen with split image is a big plus. Contrary to what you might read, ultra-wide does not mean infinite DOF. If you want foreground images to be sharp, you need to be sure they are in focus.

  • Sort of hard to purchase new from a reputable dealer. Most are sold as gray-market transactions (sent as "gift" from new Russian friend) due to VERY high import duty. I got mine and a Jupiter-9 from rugift.com and had mixed experiences on both purchases.

  • No "A" contacts, so you must use stop-down metering in M mode with your K-30

  • Proprietary lens cap...lose it and $$ to replace


Samyang 8/3.5 Fisheye CS
  • Provides a full 180 degrees diagonal FOV on APS-C cameras

  • Features a unique "stereographic" projection intended to minimize edge of field distortion

  • Big lens with HUGE front element

  • Very decent build (mostly metal)

  • Impressive optical performance at most apertures

  • Short focal length means everything is teeny in the final image (see below)

  • Hard to focus (see below)

  • Poor focus calibration from the factory (see below)

  • Has "A" contacts and will support all exposure modes for your K-30

  • Easy to buy...in stock with most of major online retailers

  • Proprietary lens cap...rumor is that is expensive to replace


Both
  • Currently (August 2013) selling at about the same price point on the U.S. market

  • Purple fringing is part of the experience with both lenses with much depending on subject

  • Flare resistance is much better than you would expect for both lenses

  • Fun factor is very high for both


I have to admit to being overly fond of the Zenitar. It has been a good photo buddy and party to many memorable images. Easy to use, well-balanced on the camera, usable on my film cameras, and capable of great results, what more could one want. The Samyang, on the other hand, has been a little harder to grow fond of.

What I was not prepared for was the effect of the short focal length. I won't go into great detail, but the short story is that it is hard to bring an object of moderate size to prominence with the Samyang. Even at closest focus (a little less than 1 foot), something the width of a 35mm camera body will only cover about 20% of the frame width. The same object with the Zenitar on a 35mm film camera (same diagonal FOV, same distance to subject) occupies 30% of the frame width. Both lens mated to their native formats will show the same elements of the composition in the frame, but the Samyang shows them smaller. Why the short focal length when 12mm would have been adequate? I believe that it has to do with the stereographic projection. For every improvement, there is a price to pay. In my opinion the Zenitar provides a more "natural" (???) fisheye view.

Which brings us to the matter of focus. Even with a viewfinder split image, the Samyang is difficult to focus. Everything is simply too small. I have read numerous reviews and the mantra is "set at 6' and f/8 and forget about it". Those settings will provide DOF from 13" to infinity. In fact, the hyperfocal is at 16" for f/8. My K10D is rather dated and it occurred to me that things might be easier with a camera that supports focus peaking in live view.

Still though, there are numerous complaints on the Web regarding "soft" results at other than close distance with the Samyang in Pentax and Nikon mount. This has been traced to poor factory focus calibration. I think Ken Rockwell (I hear boos in the background) determined that the copy provided for his test was calibrated with best infinity focus at the 1.5' mark on the focus dial. Not good. I was seeing similar softness and was able to determine (using the better viewfinder on my Pentax Program Plus) that the focus ring on mine was about 35-40 degrees off from where it should be for a subject at 1' distance. I was able to reposition the focus ring (probably voided my warranty) and now things are much better, though I still have to focus using the distance scale on the lens.

To be fair, the Russian Zenitar has the same reputation for poor factory infinity focus calibration. I had to do a similar adjustment on mine. Why Samyang has not fixed this is a mystery, though it might has something to do with the limitations of production focus calibration jigs for short focal lengths.

For further information, there are lens clubs for fisheyes and the Samyang 8mm and lens reviews for both the Zenitar and the Samyang.

Here are links to shots taken with both lenses:

Fotostevia: Zenitar Fisheye on Flickr

Fotostevia: Samyang Fisheye on Flickr


Steve
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