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01-01-2016, 10:02 PM - 2 Likes   #1
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Rokinon (Bower/Samyang) 8mm Fisheye, DA 10-17 Fisheye, and Sigma 10-20 comparison

I have had a Sigma 10-20 f4.5-5.6 for a while which I've used for ultrawide angle shots. I've mainly used it for interiors, exteriors in close quarters, and some landscapes. (For landscapes, it works best where there are 'big' features like mountains or beautiful cloud-filled skies.) More for fun than anything, I later picked up a Rokinon 8mm Fisheye. (One version of the Bower, Samyang, Vivitar one.) It actually has proven to be quite useful in addition to being fun. Both of them can deliver some excellent quality photos. I will note that my Rokinon 8mm FE is remarkably sharp.


The primary critiques I've had of the Sigma and Rokinon are that they are both rather large lenses, and my Sigma tends to be a bit soft at the 10mm end. So, especially for travelling, I started looking around for something smaller and that was in my price range. (As far under $300 as possible!) I looked at quite a few options: the DA 15 certainly looks desirable as does the DA 12-24 and Sigma 8-16. They each have their benefits, but they also didn't quite fit my needs being not wide enough, too big, or too expensive. I ended up focusing on the DA 10-17 FE, but I was wondering if this would do what I want, particularly as regards distortion. As is noted in the reviews, it's always possible to defish, and the lens is not particularly fishy from 13-17mm. I looked at these comparisons:
I found a used-but-like-new DA 10-17 FE at a good price, and I've been testing it in comparison with the Rokinon 8mm FE and the Sigma 10-20 f4.5-5.6. In the comparisons that follow, I am only looking at perspective and field of view. For now, I was mainly interested in seeing if the DA 10-17 FE can be used to render satisfactory rectilinear views. I'll compare color, contrast, sharpness, etc. later.

All shots at f5.6. Indoor shots were w/ tripod, timed shutter (except for stairway shot); outdoors all handheld

Uncorrected indoor shots:

Rokinon 8, DA10-17 FE @10mm, Sigma @10mm - This comparison highlights a few things that are consistent. The DA10-17 has the most chromatic aberration. The Sigma is softest and has some moustache distortion at 10mm. (note the ceiling line)


Vertical framing: Sigma 10-20 @10mm; DA 10-17 FE @10mm; Rokinon 8 FE
(my fault that the Sigma shot angle was off a bit)
This one shows how a horizontal line in the middle of the frame (the vertical steps in this pic) can be rather straight with both fisheyes and especially the Rokinon


Outdoor shot: Sigma 10-20 @10mm; DA 10-17FE @10mm; Rokinon 8 FE
This one also shows how things look pretty normal in the center of the frame, but you can really see where and how the distortion occurs on the left/right and top/bottom edges. You can also see that the somewhat stereographic fisheye of the Rokinon actually looks a bit more natural than the DA 10-17 FE.


One more outside: Sigma 10-20 @10mm; DA 10-17FE @10mm; Rokinon 8 FE
With this type of shot, you would almost not know that you were shooting with a fisheye except for the buildings on the extreme right and left edges. Again, the Rokinon is a somewhat more pleasing fisheye.


That gives some idea of perspectives. Again, don't bother about colors, sharpness, etc. In the next post, I'll show some examples of defishing the DA 10-17 FE and the Rokinon 8 FE to see how they compare with the rectilinear Sigma 10-20.


Last edited by mgvh; 01-02-2016 at 10:33 AM.
01-01-2016, 10:22 PM   #2
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Overall sharpness, contrast and color rendition is what I'm interested in. Which lens has it all?

In other words which one comes closest to the FA 31
01-01-2016, 10:59 PM   #3
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QuoteOriginally posted by Driline Quote
Overall sharpness, contrast and color rendition is what I'm interested in. Which lens has it all?

In other words which one comes closest to the FA 31
With some minor adjustments in Photoshop and Lightroom, I'm sure I can make any of them look like a FA 31 shot!
01-02-2016, 12:18 AM - 1 Like   #4
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Using a fisheye lens, the main thing to assume is that you'll get a fisheye shot! Part of the fun is playing even more with perspective by angling the shot (not shooting horizontally or vertically level) or by placing some object in the foreground which can be exaggerated. As I noted in my initial post, however, I'm trying to determine if I can use the DA 10-17 FE as a wider, smaller (and hopefully better) lens to obtain rectilinear views and replace the Sigma 10-20 f4.5-5.6 I have been carrying around. I.e., I need to defish the shots.

There are a number of ways I found to defish a fisheye shot. (If someone has found a great and easy way to work with the DA 10-17 FE, please let me know.)
  • In Lightroom, there is a profile for the DA 10-17 FE. Enabling the lens profile does a fair job. I could still fix things a bit more by then using the manual correction to adjust distortion and make other tweaks.
  • In Photoshop, the image can be edited using Transform > Warp. It takes a little longer, but I could probably get better results this way.
  • Following links in my initial post, I found suggestions for using PTLens (a standalone program or Photoshop plugin), Hugin (standalone program also used for panoramas), and Image-Trendís Fisheye-Hemi (Photoshop Plugin). (This person does some especially nice work using Fisheye Hemi with the Rokinon 8mm FE.) Hugin is free, but I couldn't get it to work properly. PTLens and Fisheye Hemi are available for reasonable costs, but it doesn't appear they really support the DA 10-17 FE. (Someone correct me if I'm wrong.) One of these may simplify and speed up the process of defishing, but they didn't help me much in my quick trials with them.
So, below are some examples of defishing using Lightroom and/or Photoshop. (As noted before, at this point I'm still just working with perspective. The other qualities that make a good photo--color, contrast, resolution, etc.--will come later. I also apologize for not being more consistent in the order in which pics appear in the comparison. Be sure to check each heading to see what each one is.)


Rokinon 8mm with LR lens profile correction > DA 10-17 @10mm with lens profile correction > Sigma 10-20 at 10mm
As was evident in the initial post, and as you may well expect, the Rokinon 8mm FE was wider than the DA 10-17 FE at 10mm which was wider than the Sigma 10-20 at 10mm. We can expect, however, that some of the frame will be cropped with defishing. Using the lens profile correction is the quick way to get things straightened out, and this shows you how they match up. The book on the chair on the left is a square book, and the Rokinon 8mm does the best job with the sizing of it and the lamp. It's only as you move further to the edges that the Sigma 10-20 looks more natural. The dropleaf table is round to help you assess. (I should have applied the lens profile correction to the Sigma which would have gotten rid of some of that moustache distortion evident on the ceiling line.)


Original DA 10-17FE at 10mm > enabling lens profile correction in LR > manual adjustments in Photoshop using Transform / Warp
You can see that the profile correction does a pretty good job of straightening things out, but it does so at the expense of stretching the left/right edges quite a bit. Manually warping actually yields a pretty good perspective, but it comes at the cost of needing to crop off a bunch at the top and bottom.


Original DA 10-17FE at 13mm > after adjustments and cropping > Sigma 10-20 at 10mm original
This was my first attempt, and after cropping, it looks like closer to 12mm on the DA 10-17FE will match the field of view of the Sigma 10-20 at 10mm. You can see how nicely the cabinet in the middle straightens out. You can also see the kind of stretching the Sigma at 10mm has to do to render a rectilinear image. Again, the book on the chair on the left is a square book.


DA 10-17 @ 13mm with LR lens profile correction > DA 10-17 @ 13mm with PS warp adjustments > Sigma 10-20 @ 10mm
At 13mm, I don't need to crop off so much on the top/bottom when adjust warp. That book on the chair is square, so the warping did a pretty good job. Note the perspective/distortion shifts, however. Compare the wideness of the cabinet in the middle with the wideness of the chair and table. Again, the dropleaf table is round, so it appears to me that a better rendering would be somewhere between the view of the warped shot and the Sigma at 10mm.


Sigma 10-20 at 10mm > DA 10-17 @ 11mm with LR lens profile correction
This outdoor shot didn't look very fishy to start with, and just using the lens profile correction really tidied up the pic with only a minor loss of frame on the right and left.


DA 10-17 @ 11mm with PS warp adjustments > Sigma 10-20 @ 10mm
These two look quite similar. You may notice that the center section of the house with the DA is slightly thinner than that section on the Sigma. The objects on the sides of the DA, however, are slightly wider.


BOTTOM LINE: In terms of field of view and perspective only, I am satisfied that the DA 10-17 FE will be able to deliver satisfactory rectilinear renderings that can match the wideness of the Sigma 10-20. It will take a bit of extra work, however, and I will need to assess the effect on the quality of the picture. My initial impressions are that the DA 10-17 FE does quite well even after distortion correction. Also note that I've mainly been looking at the widest end of the DA 10-17 FE. Fishiness is much less pronounce from 14-17mm and takes much less effort to correct.


Last edited by mgvh; 01-02-2016 at 10:40 AM.
01-02-2016, 05:51 AM   #5
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QuoteOriginally posted by mgvh Quote
There are a number of ways I found to defish a fisheye shot. (If someone has found a great and easy way to work with the DA 10-17 FE, please let me know.)
DXO Optics Pro does a great job. It will defish automatically, or you can defish manually to control how much correction is done.

By the way, I'm not seeing any photos in your posts. Don't know if it's on your end, my end, or the nefarious workings of the interwebs.

---------- Post added 01-02-16 at 07:58 AM ----------

QuoteOriginally posted by mgvh Quote
BOTTOM LINE: In terms of field of view and perspective only, I am satisfied that the DA 10-17 FE will be able to deliver satisfactory rectilinear renderings that can match the wideness of the Sigma 10-20. It will take a bit of extra work, however, and I will need to assess the effect on the quality of the picture. My initial impressions are that the DA 10-17 FE does quite well even after distortion correction. Also note that I've mainly been looking at the widest end of the DA 10-17 FE. Fishiness is much less pronounce from 14-17mm and takes much less effort to correct.
I have a Tamron 10-24 and recently acquired the DA 10-17. Even after defishing, the DA 10-17 is noticeably wider at 10mm than the Tamron 10-24. I defish using DXO Optics Pro which gives great results.

I haven't had a chance to do a lot of "real world" shooting (especially outdoors) yet, but I can see the DA 10-17 may very well become my favorite lens.
01-02-2016, 07:34 AM - 1 Like   #6
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how does the rokinon compare to the pentax with IQ? i have the rokinon and have wondered about how u feel it matches up with the pentax bc i like the way it renders color but im not entirely sold on the IQ of the rokinon. this may be that im asking too much of it or user error. i might try to trade up for AF alone. if Rokinon's infinity/focus scale was calibrated i wouldnt mind as much but its annoying. the close focus difference is an aspect too bc i wanna get super close to accentuate the fishiness. i want my cat to look ridiculous.

also i feel like im the only person who doesnt want to defish and actually i want to fish as much as possible. is the pentax more fishy in your experience?

Last edited by elementdtlop; 01-02-2016 at 07:41 AM.
01-02-2016, 07:59 AM   #7
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i find the rokinon gives best iq at 5.6 and changes very little beyond that.
01-02-2016, 08:56 AM - 1 Like   #8
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QuoteOriginally posted by elementdtlop Quote

also i feel like im the only person who doesnt want to defish and actually i want to fish as much as possible. is the pentax more fishy in your experience?
you aren't - I have the DA 10-17 and revel in its 'aberrations and distortions'..... I did not buy it to defish it....

01-02-2016, 09:37 AM   #9
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QuoteOriginally posted by MPrince Quote
By the way, I'm not seeing any photos in your posts. Don't know if it's on your end, my end, or the nefarious workings of the interwebs.
Arrgghh.... I just checked and the pics show up in Firefox and Chrome. They do not appear in Internet Explorer or the new Microsoft Edge.
I'm taking the pics from my Dropbox account.
Anyone know how to make them show up?

---------- Post added 01-02-16 at 11:46 AM ----------

QuoteOriginally posted by elementdtlop Quote
how does the rokinon compare to the pentax with IQ? i have the rokinon and have wondered about how u feel it matches up with the pentax bc i like the way it renders color but im not entirely sold on the IQ of the rokinon. this may be that im asking too much of it or user error. i might try to trade up for AF alone. if Rokinon's infinity/focus scale was calibrated i wouldnt mind as much but its annoying. the close focus difference is an aspect too bc i wanna get super close to accentuate the fishiness. i want my cat to look ridiculous.

also i feel like im the only person who doesnt want to defish and actually i want to fish as much as possible. is the pentax more fishy in your experience?
I'm going to do more comparison, but my initial impressions are that the Rokinon is very good. Colors and contrast are excellent, and sharpness is outstanding too. Perhaps it is due in part to the way it handles the fisheye projection. I also have a good copy of the Rokinon in terms of it scale. I measured things out, and it's pretty close. I use manual focus (because I can't always get focus lock using AF), set it to f5.6 or 8, and set the distance to the closest thing I want in focus.

As for fishiness, yes, I do also enjoy a good fisheye. Someone somewhere used the word "whimsical" for the kind of pics a fisheye can do, and both the Rokinon 8 and the DA 10-17 can do that. I will certainly use my DA 10-17 for fisheyes, but I also need to do more 'documenting' types of pics. That's why I'm playing with making things rectilinear so that I can use the DA 10-17 for both as a single lens solution when I'm hiking or traveling.

---------- Post added 01-02-16 at 11:54 AM ----------

QuoteOriginally posted by elementdtlop Quote
Is the pentax [DA 10-17] more fishy [than the Rokinon 8mm] in your experience?
If I can get the pics to work in my initial post, you'll see that the fishiness of the two lenses is different. The Rokinon 8m is wider, so it does give a more fishy view that way, but it's projection tends to minimize it a bit. There are articles linked via links in my initial post where people are doing the mathematical explanations, but the analogies are something like trying to overlay an image on a bowl as compared to a plate or to a horizontal band on a barrel.
01-02-2016, 10:16 AM   #10
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QuoteOriginally posted by mgvh Quote
Arrgghh.... I just checked and the pics show up in Firefox and Chrome. They do not appear in Internet Explorer or the new Microsoft Edge.
I'm taking the pics from my Dropbox account.
Anyone know how to make them show up?
I use Explorer on my tablet and also have Chrome on the tablet. I use Firefox on my desktop. I'm not seeing photos regardless of which computer or browser I'm using.

QuoteQuote:
---------- Post added 01-02-16 at 11:46 AM ----------

[/COLOR]

As for fishiness, yes, I do also enjoy a good fisheye. Someone somewhere used the word "whimsical" for the kind of pics a fisheye can do, and both the Rokinon 8 and the DA 10-17 can do that. I will certainly use my DA 10-17 for fisheyes, but I also need to do more 'documenting' types of pics. That's why I'm playing with making things rectilinear so that I can use the DA 10-17 for both as a single lens solution when I'm hiking or traveling.[COLOR="Silver"]
I let the photo decide whether it wants to be fishy or defished. Some photos cry out for straight lines, others don't. Either way, the 10-17 is a stellar performer and I wish I had bought it years ago.
01-02-2016, 11:30 AM   #11
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QuoteOriginally posted by MPrince Quote
DXO Optics Pro does a great job. It will defish automatically, or you can defish manually to control how much correction is done.
I just went to the DXO site, but I'm not sure what I would use. Is the DXO Optics Pro the package I would want? Or the ViewPoint? Or do you need both?

I see that they support the DA 10-17 FE and the Sigma 10-20, but they don't have a lens profile for the Rokinon/Bower/Samyang 8mm FE on a Pentax.
01-02-2016, 11:47 AM   #12
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I'll speak only to the Rokinon because I have it (and did extensive testing on it), but you'll find that nearly all UWA and fisheyes have similar characteristics regarding sharpness - needing to go to f/11 or greater to get maximum sharpness into the corners.

The Rokinon is sharpest in the center at f/5.6. Near the edge, f/8 is best. In the corners, f/11 is best. So, if you have a subject somewhere near the center it requires a more-open setting than for landscapes.

If you are de-fishing to a considerable extent, a true fisheye is very weak towards the edges because of the extreme stretching involved in the rectilinear distortion (yes, rectilinear is a form of distortion). Also, the Rokinon is not a classic fisheye; it is closest to stereographic projection (some call this proportional). For natural objects (not involving straight lines) it probably looks least distorted and usual requires less correction. As a projection, it is somewhere in the middle between classic fisheye (Pentax 10-17 at 10mm) and rectilinear. The Pentax projection would be somewhat comparable at around 12-13mm, but the extreme edges would be more compressed.
01-02-2016, 12:23 PM   #13
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QuoteOriginally posted by mgvh Quote
I just went to the DXO site, but I'm not sure what I would use. Is the DXO Optics Pro the package I would want? Or the ViewPoint? Or do you need both?
Defishing is done by Optics Pro. I have version 1.2 of Viewpoint, it does not defish. Viewpoint version 1.2 also does not process raw files.

I don't know if the current version of Viewpoint defishes.

You can download both programs for a 30 day trial.
01-02-2016, 03:31 PM - 1 Like   #14
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Thanks for the responses. ScooterMaxiJim's response is helpful.
MPrince: When I have a bit more time, I'll download the DXO programs to give them a try. (I see that the normal price on Amazon is the same as the 1/2 price sale at the DXO site.) I contacted their support, but I couldn't get an answer. It appears to me that DXO ViewPoint is what I would want to defish and it works with LR and PS.

---------- Post added 01-02-16 at 06:24 PM ----------

We had a nice sunny day today, so I was able to take a bunch of pics without having clouds and light complicate matters. I'm still using the Rokinon 8mm FE, the Pentax DA 10-17 FE, and the Sigma 10-20 f4.5-5.6. A question I'm trying to resolve is whether the DA 10-17 can serve for rectilinear photos and how it compares to the Sigma 10-20.

Here are some things I learned:
  • There are so many factors that come into play that it is very hard to make good comparisons. Focal length, f-stop, precise angle of shooting, lens variation, interaction of body and lens, metering... They all affect the quality of the picture.
  • I am more and more impressed with the Rokinon 8mm FE. It really can take a high quality photo with a pleasing fisheye effect. It's remarkably resistant to flare and has a nice starburst. Color, contrast, and resolution are excellent. It can be defished, but you would want to crop off about 1/5 of the frame on the left and right. (I.e., the wide plane) The top/bottom are pretty good even after being defished.
  • The DA 10-17 FE is also a very fine lens. I love its small size, the great Pentax colors and contrast it renders, the versatility of a zoom that moves from fisheye at 10mm to nearly rectilinear at 17mm. It is subject to both purple and green chromatic aberration, but that's quite easy to fix. It can be defished if desired, but you're going to want to crop off about 1/8 of the frame on all sides at the 10mm end. At 17mm, the image really does not need to be cropped after defishing. Shooting at about 12mm on this lens and defishing will give about the same field of view as the Sigma 10-20 at 10mm. It's kind of a tradeoff whether to shoot wider (10-11mm) on the DA 10-17 and defishing and cropping or going with 12-13mm and defishing without cropping.
  • I enjoy shooting with the Sigma 10-20, but it has its own set of compromises. Mine is a bit soft at 10mm and at wider f-stops, and it needs more attention with regard to sun and metering. It delivers rich colors and very good resolution, especially from 14-20mm on my lens.
  • What I'm discerning is that the Sigma 10-20 uses the lens optics to create the rectilinear view. Defishing the DA 10-17 accomplishes the same thing via the software. There are compromises to both, especially on the wide edges. Sometimes the defished DA 10-17 looks much better than the Sigma, and sometimes it's the opposite. Some parts of a picture are sharper on one than the other, and other parts of the picture it will be the opposite.
There are so many trade-offs on the qualities that make up a good picture that I would be hard-pressed to choose between the DA 10-17 FE and the Sigma 10-20 for rectilinear perspectives. For now, for me, that means the DA 10-17 FE is the lens I'm going to carry around because of its size and versatility.
01-02-2016, 04:29 PM - 3 Likes   #15
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QuoteOriginally posted by ScooterMaxi Jim Quote
The Pentax projection would be somewhat comparable at around 12-13mm, but the extreme edges would be more compressed.
DA10-17 at 17, 15, 14, 13, 12, 11 and 10 mm. The projection does not change much until you get to 11 or 10mm.



I find the Panini projection best for defishing.

https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/216203-do-y...ml#post2287582
https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/300933-fish...ml#post3330702

Last edited by kh1234567890; 01-02-2016 at 04:35 PM.
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