Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
05-27-2012, 12:03 PM   #16
Veteran Member
madbrain's Avatar

Join Date: May 2008
Location: San Jose, CA
Posts: 790
Original Poster
QuoteOriginally posted by Louicio Quote
Embrace the distortion =) It's not a lens you use for architecture it is supposed to distort the perspective (or retain the true perspective however you look at it) and the samyang fisheye is pretty good choice for a low price.

And as a side note on distortion, a fisheye actually retains the perspective of the image better than a rectilinear and does not attempt to flatten the image as in the bar photo. But don't replace an ultra wide with a fisheye and try to flatten it, too much effort for an average reward esp if you already have a sigma 10-20. =)
The point is not to replace the sigma, I'm keeping it anyway for sure. It is more of a question of weight and volume in the camera bag. I don't think I would ever want to carry both. And so, if I occasionally have the samyang 8 in my bag and not the sigma, could I still obtain a decent rectilinear ultra wide shot with some pp?

This is especially important if I also happen to carry the canon body that day instead of the pentax, as I couldn't use the sigma on it due to lack of aperture ring.

05-27-2012, 01:59 PM   #17
Veteran Member
RioRico's Avatar

Join Date: Jun 2008
Location: Limbo, California
Posts: 11,264
QuoteOriginally posted by madbrain Quote
I will say however that I'm not fond at all of the cheap adapters. I tried some before for wide angle with the da 18 55, and there was terrible vignetting. When I did some PP to remove vignetting, the FOV was almost the same as without the adapter. It was basically useless. That was a big reason why I got the sigma 10 20 in the first place.
I suggested the 0.25x FE adapter as a cheap way to find whether full-circle or frame-filling FE suits you more (or at all). Full-circle FE does more than merely 'vignette' -- it's a full image circle surrounded by black space! Such images should be cropped square, maybe mounted in a circular matte. Frame-filling ~180-degree FE (like the Samyang 8, or DA10-17 @10mm, on APS-C) doesn't vignette, but it's also not really suitable for flattening-out by defishing. Even the Sigma 15 or Zenitar 16, or the DA10-17 @17mm, don't do well with full defishing.

IMHO defishing is rarely worth the effort. If you want rectilinear pictures, stick with your 10-20 UWA. If you want rectilinear images wider than its ~100-degree maximum view, stitch-up some panoramas. There's no magic bullet here. Fisheyes give bendy distortion, and rectilinear UWAs give stretchy distortion, and that's reality. To avoid distortion, shoot a series with a 28mm lens in portrait (vertical) aspect and stitch them together. That is the *only* distortion-free option AFAIK.

QuoteQuote:
The DA 10 17 is not in my price range, and also lacks an aperture ring, therefore I would not consider it.
Price range, I understand. It's not cheap. It's the lens that drove me to Pentax because there was nothing comparable at anywhere near the price -- and there still isn't. But do *any* of these fishies have aperture rings? I haven't checked. The old Vemar-Sigma 12/8 has an aperture ring, if you don't mind f/8-11-16 Waterhouse stops. It merely lacks a focus ring!

My argument against FE primes: They're one-trick ponies. And that trick can get tired pretty quick.
05-27-2012, 03:03 PM   #18
Pentaxian




Join Date: Jan 2010
Location: Vancouver, BC
Posts: 1,421
QuoteOriginally posted by RioRico Quote
My argument against FE primes: They're one-trick ponies. And that trick can get tired pretty quick.
if you think about it, any prime lens is a one-trick pony. But these one-track ponies are almost always sharper and faster than zoom lenses. If your argument is that one can get quickly tired of exaggerated curves of FE shots, I'd disagree. Any well executed shot, whether it be an FE image or an extreme telephoto image, is pleasing to the eye. But I wouldn't want to look at 100 FE shots or 100 telephoto shots in one sitting, however well they are executed.
05-27-2012, 07:05 PM   #19
Veteran Member
Louicio's Avatar

Join Date: Mar 2012
Location: Melbourne
Posts: 432
Well thats the thing, it is a specialty lens you use for a certain look and as such wouldn't see as much use as a more conventional lens but it is definately worth having in the bag. It's also fairly small and light. Maybe hire one and see if you like? You mentioned a canon body, if you can't find a dealer who hires pentax fisheyes then hire a canon see how you like and then make a decision?

QuoteOriginally posted by madbrain Quote
The point is not to replace the sigma, I'm keeping it anyway for sure. It is more of a question of weight and volume in the camera bag. I don't think I would ever want to carry both. And so, if I occasionally have the samyang 8 in my bag and not the sigma, could I still obtain a decent rectilinear ultra wide shot with some pp?

This is especially important if I also happen to carry the canon body that day instead of the pentax, as I couldn't use the sigma on it due to lack of aperture ring.


05-27-2012, 07:06 PM   #20
Pentaxian




Join Date: Nov 2011
Photos: Gallery | Albums
Posts: 3,655
QuoteOriginally posted by RioRico Quote
I've seen other lenses under different badges but otherwise identical labeled as . . . f/1.8- . . . -2.0 (MUCH greater difference).
Pentax even used the same badge to label a lens both as f/1.8 and f/2:
SMC/S-M-C/Super-/Auto-/Takumar 55mm F1.8 Reviews - M42 Screwmount Normal Primes - Pentax Lens Reviews & Lens Database
SMC/Super-/Auto-Takumar 55mm F2 Reviews - M42 Screwmount Normal Primes - Pentax Lens Reviews & Lens Database
05-27-2012, 07:28 PM   #21
Veteran Member
RioRico's Avatar

Join Date: Jun 2008
Location: Limbo, California
Posts: 11,264
That's a great case, because they have the same exact optics, but the f/2 has an internal pin to keep the aperture from opening to f/1.8. The Asahi Pentax attempt at a budget kit lens, eh? Too bad they didn't do the same with the M50/1.7 and f/2. Then my M50/2s might be worth something... What's astounding is that the f/1.8 will sell for upwards of US$50-60 whilst the f/2 WON'T sell when listed at US$15. Ay yi yi.
05-28-2012, 05:55 AM   #22
Pentaxian
Lowell Goudge's Avatar

Join Date: Jan 2007
Location: Toronto
Photos: Gallery | Albums
Posts: 15,344
I have botht he sigma 10-20 F4-5.6 and the samyang (AKA ProOptic in my case) 8mm fisheye

I use the fisheye principally for what it is, a fisheye, but have on occasion, used it and de-fished it with an image editor

My experience is that when de-fished, there are some amplifications of lateral CA that also need to be corrected, especially if you defish, and also perform perspective correction. o extreme angle shots. I did this simply because i was taking a picture of a mural with only 4 feet of alley way to back up and the 10mm sigma was not wide enough. the results are definitely accepthable after defishing to crop square and print on 81/2 x 11 paper but that is about the limit
05-28-2012, 06:45 AM   #23
Veteran Member
RioRico's Avatar

Join Date: Jun 2008
Location: Limbo, California
Posts: 11,264
QuoteOriginally posted by Lowell Goudge Quote
...i was taking a picture of a mural with only 4 feet of alley way to back up and the 10mm sigma was not wide enough. the results are definitely accepthable after defishing to crop square and print on 81/2 x 11 paper but that is about the limit
That's a situation where I would stitch. One of my stitchers drives this: PhotoStitch (3.1) that Canon distributed with printers and copiers some time back. It allows stitching scanned sections of large sheets (like maps), and stitching parallel shots. Thus: Mount camera on tripod. Shoot one end of a horizontal scene. Move over a few feet, shoot again. Move and shoot again, to the other end. Run PhotoStitch; select Parallel Camera Movement in Merge Settings. With enough parallel shots, the output will have little distortion. Beware: PhotoStitch has little tolerance for parallax error, so keep distances constant.

05-28-2012, 07:01 AM   #24
Pentaxian
Lowell Goudge's Avatar

Join Date: Jan 2007
Location: Toronto
Photos: Gallery | Albums
Posts: 15,344
QuoteOriginally posted by RioRico Quote
Beware: PhotoStitch has little tolerance for parallax error, so keep distances constant.
that's where i like to avoid stitching.

I would really love a stich program that could consider geometric rescaling and perspective correction as part of the process, so that I did not have to be careful.
05-28-2012, 09:04 AM   #25
Veteran Member
troyz's Avatar

Join Date: May 2008
Posts: 389
QuoteOriginally posted by Lowell Goudge Quote

I would really love a stich program that could consider geometric rescaling and perspective correction as part of the process, so that I did not have to be careful.
Hugin can do mosaic stitching with scale/yaw/pitch/roll correction

Hugin tutorial Stitching flat scanned images


(K20D, Pentax 12-24 @12mm, stitched from 4 exposures taken at different positions)
05-29-2012, 05:56 PM   #26
Veteran Member
madbrain's Avatar

Join Date: May 2008
Location: San Jose, CA
Posts: 790
Original Poster
QuoteOriginally posted by RioRico Quote
IMHO defishing is rarely worth the effort. If you want rectilinear pictures, stick with your 10-20 UWA.
That's what I would do if the 10-20 happens to be in my bag that day :-)

QuoteQuote:
If you want rectilinear images wider than its ~100-degree maximum view, stitch-up some panoramas.
Stitching up would require carrying a tripod. A good one is much heavier than an extra lens. At that point, purely based on weight and volume, I would just choose to carry both lenses, rather than carry a tripod. Though I may need a bigger bag.

QuoteQuote:
Price range, I understand. It's not cheap. It's the lens that drove me to Pentax because there was nothing comparable at anywhere near the price -- and there still isn't. But do *any* of these fishies have aperture rings? I haven't checked. The old Vemar-Sigma 12/8 has an aperture ring, if you don't mind f/8-11-16 Waterhouse stops. It merely lacks a focus ring!

My argument against FE primes: They're one-trick ponies. And that trick can get tired pretty quick.
Yes, the Samyang 8 has an aperture ring, which would make it usable on both my Pentax K-r and Canon T3i bodies. Further, it appears to have an "A" setting on said aperture ring, which would allow for auto-exposure on the Pentax body, thus making it an attractive choice.

From what I understand, the Samyang 8 can also be used on FF bodies, if you shave off the lens hood :-)

Shaved or original Samyang 8mm mounted on a full-frame Canon 5D or 1D - Spherical Panorama - Panoramafotography - 360

But yes, it vignettes at that point (circle). I don't have any FF body at this point anyway, but one can always dream.
05-29-2012, 06:00 PM   #27
Veteran Member
madbrain's Avatar

Join Date: May 2008
Location: San Jose, CA
Posts: 790
Original Poster
Hi Lowell,

QuoteOriginally posted by Lowell Goudge Quote
I have botht he sigma 10-20 F4-5.6 and the samyang (AKA ProOptic in my case) 8mm fisheye

I use the fisheye principally for what it is, a fisheye, but have on occasion, used it and de-fished it with an image editor

My experience is that when de-fished, there are some amplifications of lateral CA that also need to be corrected, especially if you defish, and also perform perspective correction. o extreme angle shots. I did this simply because i was taking a picture of a mural with only 4 feet of alley way to back up and the 10mm sigma was not wide enough. the results are definitely accepthable after defishing to crop square and print on 81/2 x 11 paper but that is about the limit

Do you have any examples of pics with the Samyang 8 that you have defished, along with the original ? I am not making large prints.
The most critical viewing conditions for my pictures are on my two 30" monitors which are each 2560x1600 (4MP resolution). I rarely make any prints at all.
05-29-2012, 06:02 PM   #28
Veteran Member
madbrain's Avatar

Join Date: May 2008
Location: San Jose, CA
Posts: 790
Original Poster
QuoteOriginally posted by RioRico Quote
That's a situation where I would stitch. One of my stitchers drives this: PhotoStitch (3.1) that Canon distributed with printers and copiers some time back. It allows stitching scanned sections of large sheets (like maps), and stitching parallel shots. Thus: Mount camera on tripod. Shoot one end of a horizontal scene. Move over a few feet, shoot again. Move and shoot again, to the other end. Run PhotoStitch; select Parallel Camera Movement in Merge Settings. With enough parallel shots, the output will have little distortion. Beware: PhotoStitch has little tolerance for parallax error, so keep distances constant.
Thanks. I do have the PhotoStich program. I just never tried it. Keeping the distance constant after moving the tripod would seem to be quite a challenge. I will certainly try to do stitching some day, but I don't think this will be a frequent activity for me.
05-29-2012, 06:19 PM   #29
Veteran Member
madbrain's Avatar

Join Date: May 2008
Location: San Jose, CA
Posts: 790
Original Poster
QuoteOriginally posted by troyz Quote
Hugin can do mosaic stitching with scale/yaw/pitch/roll correction

Hugin tutorial Stitching flat scanned images


(K20D, Pentax 12-24 @12mm, stitched from 4 exposures taken at different positions)
Thanks, this is very interesting, I will really have to look into it some day.
05-29-2012, 08:01 PM   #30
Veteran Member
madbrain's Avatar

Join Date: May 2008
Location: San Jose, CA
Posts: 790
Original Poster
QuoteOriginally posted by liukaitc Quote
fisheye is a very cool lens for portrait as well.
I am inspired by the video host by B&H
The Art of the Fisheye - YouTube
that guy's favourate wedding lens are 10mm fisheye and 15mm fisheye (he uses APS-C camera)
so honestly, I think pentax 10-17 fisheye is a lot versatile than samyang 8mm fisheye.
Interesting but quite lengthy video. I watched the first 10 minutes or so.

I don't do wedding photography and I am not a pro.I doubt that I would ever want to shoot with one camera in each hand as he does, without looking through either the viewfinder or LCD screen. When he takes all his shots, the angles can't be totally random. I don't have that kind of experience to be able to choose them the way he does. DSLRs are heavy and expensive also and I wouldn't use one without a neck strap personally. From what I gather in the very nice pictures in your photo album, you have quite a bit more strength in your arms than I do :-) I have suffered from tendinitis in my wrists since age 19, so that doesn't help also. I cannot use a mouse on a computer because of it, trackballs only for me, and on the left side, mouse means instant pain.

None of what this guy does would be possible without AF lenses also. A manual focus lens like the Samyang would be out of the question for that. Perhaps my Sigma 10-20 on 10mm would work that way. It would would have about the same angle of view as his Sigma 15 fisheye.

The AF does buy a lot of extra flexibility, but of course costs more. There is no single AF lens that would work in AF mode on 2 DSLR bodies from different brands I wish the new K-30 had an articulated screen, then perhaps I could end my affair with the Canon T3i DSLR and stick only with a Pentax body. Alas, there is still not a single model in the Pentax lineup that has one.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
10mm, 8mm, aperture, distortion, fisheye, k-mount, lens, pentax lens, ring, samyang, sigma, slr lens, software
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
For Sale - Sold: Sigma Zoom Super Wide Angle 10-20mm f/4-5.6 (US) jgredline Sold Items 3 10-19-2010 12:39 PM
For Sale - Sold: Sigma 10-20mm Super Wide Angle Lens TomInJax Sold Items 5 08-06-2008 04:47 AM
Sigma Super Wide Angle 10-20mm or Pentax Fisheye? azcavalier Pentax SLR Lens Discussion 11 10-13-2007 01:40 AM



All times are GMT -7. The time now is 10:48 AM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top