Samyang/Rokinon 7.5mm Fisheye owners: corner sharnpess question!

Discussion in 'Native Lenses' started by phrenic, Jan 11, 2012.

  1. phrenic

    phrenic Mu-43 All-Pro

    Sep 13, 2010
    Hi folks, got my FE lens 2 days ago and I was checking out the new toy (super well-built by the way).

    However, upon looking at my pics full-sized I've noticed there's softness in the corners, particularly the botton left one (more so than the others). This is apparent at 3.5..looks like a bit less at 5.6. Not so noticable at web-size but it is when zoomed in. This is my first FE lens, so I'm not sure if they typically have mediocre-poor corners.

    Looking at other shots posted on the forums, I haven't seen that sort of softness, but at the same time the small web-sized shots don't show it very well, so if anyone else could check out their full-sized pics (or post them!) it would be much appreciated.

    I'm hoping I don't have a dud considering I want to take this lens on my trip to India in 2 and a half weeks. :frown:

    I'll post up some sample pics when I get home from work.
  2. ~tc~

    ~tc~ Mu-43 Hall of Famer

    Oct 22, 2010
    Houston, TX

  3. phrenic

    phrenic Mu-43 All-Pro

    Sep 13, 2010
    Is that typical for fisheyes? I'm curious given the rave reviews the lens has gotten for its optical qualities.
  4. thomash2

    thomash2 Mu-43 Rookie

    Nov 6, 2011
    I use this on a Sony nex and get a circular image. The edges are very soft, the sharpest aperture overall for me is f11. any smaller and the center gets softer. Any larger and the edges get too soft.

    On a mft its not such a big problem, but the 4/3 to nex adapter pushes the lens half a mm out to far, making it less Sharp on the nex.

  5. meyerweb

    meyerweb Mu-43 Hall of Famer

    Sep 5, 2011
    Given the extreme FOV of a fisheye I don't think you can expect corner or edge sharpness to match the center. But I think you should expect all corners / edges to be similar. If one corner is much worse than others, I think that's a decentering issue. But if it's only noticeable at 100% pixel peeping, I don't think I personally would worry about. But only you can decide how big an issue it is for you.
  6. Ray Sachs

    Ray Sachs Super Moderator

    Apr 17, 2010
    Near Philadephila
    This is my first fisheye too, so I don't have any comparisons, but I think its very good - better than I expected. Its obviously heavily distorted but a lot of those distorted lines look pretty sharp even in the corners. Here are a couple of examples - do they match what you're seeing?

    <a href="" title="Fisheye by ramboorider1, on Flickr">[​IMG]"1024" height="683" alt="Fisheye"></a>

    <a href="" title="P1012739 by ramboorider1, on Flickr">[​IMG]"1024" height="683" alt="P1012739"></a>
    • Like Like x 1
  7. fredlong

    fredlong Just this guy...

    Apr 18, 2011
    Massachusetts USA
    Real Name:
    Samyang lenses have a good reputation for making some interesting niche lenses with very good performance at a good price. The weakness is usually at the corners and edges. Similar lenses from the camera makers usually perform better at a much higher cost.

    The Panasonic 8mm and Olympus 4/3 8mm both perform better in the corners at more than twice the cost. I'd be happy to live with some corner softness for the price.

  8. phrenic

    phrenic Mu-43 All-Pro

    Sep 13, 2010
    Thanks for the perspectives guys..perhaps my expectations were too high.

    Ray: I can't see any significant softness in the corners of your shots at the flickr size..not too noticeable on my shots at that size either I think. I'll still try posting some up for a second opinion hah.

    But yeah I was just zooming in a abit and noticed the corner softness particularly when there's some textures or lines along the bottom half of the frame and these details get a lot softer when I hit the bottom left corner. I guess it sounds like decentering.
  9. phrenic

    phrenic Mu-43 All-Pro

    Sep 13, 2010
    Sorry for the delay but here's some shots to give an idea of the performance..not as much as a concern as when I first tried it out I suppose. :)

    <a href="" title="flickr-1050194 by one.mic, on Flickr">[​IMG]"497" height="640" alt="flickr-1050194"></a>

    And for those who are curious as to what I was worried about here are some corner crops (@5.6 fyi):
    bottom left
    <a href="" title="flickr-1050193-2 by one.mic, on Flickr">[​IMG]"640" height="626" alt="flickr-1050193-2"></a>

    bottom right
    <a href="" title="flickr-1050193-3 by one.mic, on Flickr">[​IMG]"640" height="480" alt="flickr-1050193-3"></a>

    Neither are great, but in the bad corner I swear more detail is..I don't know, obliterated? :smile:
  10. Ray Sachs

    Ray Sachs Super Moderator

    Apr 17, 2010
    Near Philadephila
    You can click through and see these full size on Flickr if interested. It's as sharp as I'd expect from a fisheye, but I'm a notorious non-pixel peeper, so they may not be great on closer inspection.

  11. -Swo0p

    -Swo0p Mu-43 Rookie

    Jan 16, 2012
    nice pics with this lens guys.... gonna pull the trigger on this one soon.. loooove fisheyes
  12. Art

    Art Mu-43 All-Pro

    Mar 13, 2011
    San Francisco, CA
    It is surprisingly my most used lens after Panny 14
  13. yottavirus

    yottavirus Mu-43 Regular

    Aug 13, 2011
    Looks like decentering. Just luck I suppose.
  14. phrenic

    phrenic Mu-43 All-Pro

    Sep 13, 2010
    Hmm is decentering considered a defect? Covered by warranties? Or would this fall within an acceptable sample variation?
  15. pxpaulx

    pxpaulx Mu-43 All-Pro

    Jan 19, 2010
    Real Name:
    I would say so, that is a fairly significant difference in overall quality.
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  16. phrenic

    phrenic Mu-43 All-Pro

    Sep 13, 2010
    Yeah I'll have to look at the warranty card. I bought it from b&h but it looks like the RMA would be a hassle. It's rather galling that I would be on the hook for the insured shipping cost to return the would leave me out probably 30-50$, after I paid a bunch just to get it shipped here to Canada. :rolleyes:

    It's one of those things where the soft corner doesn't drive me crazy, but I guess it's worth asking if Rokinon considers it a defect.
  17. pxpaulx

    pxpaulx Mu-43 All-Pro

    Jan 19, 2010
    Real Name:
    Fisheyes do tend to be soft at the edges, is it any better stopped down? If so I would probably live with it given the cost of returning.