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Quick Lightroom De-fishing Tip for Samyang / Rokinon 7.5mm Fisheye Users

Discussion in 'Micro 4/3 News and Rumors' started by Amin Sabet, Aug 15, 2012.

  1. Amin Sabet

    Amin Sabet Administrator

    Apr 10, 2009
    Boston, MA (USA)
    I've been playing with my new Rokinon 7.5mm f/3.5 fisheye lens and noticed that the Lightroom lens profile for the Sigma 8mm f/3.5 fisheye is perfect for defishing the Rokinon.

    I haven't had time to shoot anything good yet, but here are a couple snaps to illustrate the before/after. Mouseover/rollover to see the defished version:

    https://farm9.staticflickr.com/8303/7784608422_054ac3e7a7_b.jpg" rsrc="https://farm9.staticflickr.com/8306/7784610720_231242ac17_b.jpg">

    [img]https://farm9.staticflickr.com/8308/7785209874_df2775f873_b.jpg" rsrc="https://farm9.staticflickr.com/8447/7785211392_dccc0db55c_b.jpg">

    Without defishing, the detail/resolution is impressive all the way to the corners, even wide open (assuming subject is within the DOF). Defishing will stretch the edges/corners considerably, so you don't get the kind of sharpness you'd get from a good rectilinear lens like the Pana 7-14mm. Still, there's plenty of resolution here for many applications.

    Depending on the subject, you may want to only partially correct the distortion in order to preserve resolution and angle of view at the expense of perfectly straight lines. Some of the other lens profiles such as the Nikon and Canon fisheye profiles work well for this.

    Here are the before and after de-fish full-res links (outdoor set was f/8, second f/3.5):





    PS - Thanks, Steven, for putting me onto a [URL="https://www.mu-43.com/f89/rokinon-7-5mm-fisheye-239usd-31012/"]great deal[/URL] for this lens in our Deals forum. I never would have considered buying a fisheye, but at this price it seemed like a good buy even for infrequent use.
    • Like Like x 9
  2. blue

    blue Mu-43 Veteran

    Jun 1, 2010
    Interesting, though oddly in the pic of the kids on the computers the fish-eye version somehow seems to be a more "natural" perspective.
  3. strang

    strang Mu-43 Veteran

    May 7, 2012
    • Like Like x 1
  4. strang

    strang Mu-43 Veteran

    May 7, 2012
    People are really bad subjects to be defished especially if they're near the edges.
  5. kwalsh

    kwalsh Mu-43 Top Veteran Subscribing Member

    Mar 3, 2012
    Baltimore, MD
    • Like Like x 7
  6. Amin Sabet

    Amin Sabet Administrator

    Apr 10, 2009
    Boston, MA (USA)
    As far as I can tell with my with my own RAW files in Lightroom, the Canon EF 15 profile only partially corrects the barrel distortion with this lens. The Sigma 8mm profile fully corrects the distortion.
    • Like Like x 2
  7. JJJPhoto

    JJJPhoto Mu-43 Veteran

    Jul 8, 2011
    Cincinnati, OH
    Jerry Jackson Jr
    Great shots and de-fishing examples, Amin.

    It has been a few years since I've used any fisheye lenses (I sold all of them after deciding that my Oly 9-18mm was wide enough for my extreme wide angle needs). That said, back when I was using fisheye lenses and de-fishing my shots I absolutely fell in love with the "Fisheye-Hemi" software from Image Trends:

    Image Trends - Fisheye-Hemi Plug-In - Corrects Fisheye Lens Distortion and retains Image Content Details

    I felt like this Photoshop plugin didn't give me as much distortion as the other de-fishing methods I was using at the time.

    I took this shot with a Pentax K10D and Sigma 8mm fisheye back in 2008 and used that Fishey-Hemi software to de-fish it. This shot probably has the worst possible combination of distortion isses for a fisheye image; man-made lines and natural lines (the trees) at varying distances along with the converging lines created by the fact I was tilting the camera up to take this shot. My de-fish attempts with other software turned out worse.

    Subscribe to see EXIF info for this image (if available)
    • Like Like x 1
  8. strang

    strang Mu-43 Veteran

    May 7, 2012
    I'm interested to see the results from the profiles kwalsh created as well.
  9. Amin Sabet

    Amin Sabet Administrator

    Apr 10, 2009
    Boston, MA (USA)
    There are samples on the page Ken linked above. I'd love to see more examples as well.
  10. Mercurio

    Mercurio Mu-43 Veteran

    Jul 17, 2012
    Bogotá, Colombia
    I am using Apple's APERTURE software, is there a way to "defish" with it?
    I just bought the Samyang lens, I will post my experience when I get it.
  11. b_rubenstein

    b_rubenstein Mu-43 All-Pro

    Mar 20, 2012
    Melbourne, FL
  12. alessandro

    alessandro Mu-43 Regular

    Jan 29, 2010
    Among other solutions, I'd try PTGUI if I had that lens. Yes, it's a panorama stitching SW, but it looks like a very capable... defisher.
    It has nothing to do with PTLENS, whose tryout licence has expired for me, and that is another one to try.
    kwalsh's profiles seem also to work very well.
  13. alessandro

    alessandro Mu-43 Regular

    Jan 29, 2010
  14. Amin Sabet

    Amin Sabet Administrator

    Apr 10, 2009
    Boston, MA (USA)
    Interesting! Is that partially correcting the distortion or what?
  15. strang

    strang Mu-43 Veteran

    May 7, 2012
    Aperture doesn't have any lens distortion correction features based on profiles. I haven't looked into how it would be done manually in the app. However I am aware of other solutions:

    PTLens is a good payware for this ($25). Hugin is a good freeware alternative ($0). But with both of these you'd be doing it all manually. Both also double as panorama stitchers if you need something like that.

    I've always contemplated switching to Aperture seeing how I'm on a Mac and live in an Apple household. But I've been lazy and didn't want to port my current library over. It's huge with years and years of photos (current year on internal SSD, older on external HDD). Ok stopping here I'm going off topic.
  16. dwrk

    dwrk Mu-43 Regular

    Aug 10, 2012
    Hugin is a great free tool, has many defish projections, and allows fine-tuning too.

    I most prefer the Panini projection which looks most natural when people are in the frame.
  17. D MATIC

    D MATIC Mu-43 Regular

    Jul 18, 2012
    That looks great. Is that only avail with cs6? not cs5?
  18. strang

    strang Mu-43 Veteran

    May 7, 2012
    Looks like a new feature for CS6. That's too bad. I guess for ultimate results Photoshop is truly unbeatable.
  19. micksh

    micksh New to Mu-43

    Apr 18, 2012
    San Jose, CA, US
    Lightroom can't properly defish fisheye image because it can't change image size. Fully defished (to rectilinear level) fisheye image becomes much wider than 4:3 aspect ratio. You lose too much information if you crop it to 4:3 as Lightroom does.

    I use Paint Shop Pro X4 build-in defishing if I want rectilinear projection. 3.4K x 4.6K E-M5 image becomes larger - about 5K x 8K and its aspect ratio will be slightly wider that 16:9. This way resolution in center is not increased, it stays the same, but corner resolution is decreased more.
    However, since image is larger you can apply some filters on large image so when it's scaled down to 16MP or less it is perceived sharper.

    That's for rectilinear, but I often shoot people, and, as mentioned, Panini projection is better for people. Hugin will most likely work, but I use Fisheye-Hemi plugin for that because it's simpler. I run plugin in Paint Shop Pro as well, I don't have Photoshop.
    A good thing about this plugin is that you can apply it in cropped mode, that's designed to correct full frame fisheye on APS-C sensor. This won't fully straighten vertical lines but it will distort people's heads less. Sometimes it's useful tradeoff when people are close to the edge of the frame - they would be distorted too much otherwise. Don't know if you can do this in Hugin.
  20. Amin Sabet

    Amin Sabet Administrator

    Apr 10, 2009
    Boston, MA (USA)
    True, but all the part that gets cropped off the sides is super blurry/stretched and distorted looking, right? Seems to me that Lightroom gives me the usable part of the defished image.
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