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Panasonic 7-14mm vs Samyang 7.5mm de-fished?

Discussion in 'Native Lenses' started by sootyvrs, Jun 21, 2015.

  1. sootyvrs

    sootyvrs Mu-43 Regular

    80
    Mar 6, 2015
    David
    Loving the use of my GM1 with 12-32mm as my take every where camera but my fave lens on M43 (panny 7-14mm) is a little large for this (tiny) concept so considering replacing it with the Samyang Fisheye as it's quite a bit smaller and lighter.

    I've read it's easy enought to assign a Canon 15mm fisheye profile to the lens in Lightroom to de-fish the images and could probably crop some edges (if required) if they are smeared with the correction?

    Question is whether the de-fished images are comparable in quality to the Panny 7-14 images which I use 7mm 95% of the time when I use it.

    I have taken a look at the showcase and have been impressed with the de-fished images but not sure how much post processing (excluding de-fish) is required to make them look that good!
     
  2. wjiang

    wjiang Mu-43 Hall of Famer

    I defish almost everything (using Hugin). The live preview is very useful, you can see the defish effect and level the horizon, adjust tilt etc just by dragging on the preview. Hugin is a great application but has a pretty crap workflow IMO.

    I tend to go to projections other than rectilinear (that smears things too much for my liking). Unfortunately for true architecture with loads of converging, horizontal and vertical straight lines you kind of have to go rectilinear...

    What kind of resolution are you after? Depending on the projection you go to, I'd say the resulting output ends up at the equivalent of something like 10MP. More if you reduce the defish effect, less if you make it more rectilinear.
     
  3. pdk42

    pdk42 One of the "Eh?" team

    Jan 11, 2013
    Leamington Spa, UK
  4. sootyvrs

    sootyvrs Mu-43 Regular

    80
    Mar 6, 2015
    David
    Thanks for that info. Do you really lose over 1/3rd of the resolution from defishing?
     
  5. pdk42

    pdk42 One of the "Eh?" team

    Jan 11, 2013
    Leamington Spa, UK
    Well, it depends how much you crop. Clearly, as the cropped FOV gets wider, you crop less. At 9mm effective FL, you'll be cropping a lot - easily a 1/3 I'd say. At 7mm, less so - maybe only 20%, but still quite a lot.
     
  6. pellicle

    pellicle Mu-43 All-Pro

    Feb 10, 2010
    Southport, OzTrailEYa
    pellicle
    Thats physics folks

    If you think about it imagine its printed onto a sheet of rubber and by stretching and squeezing it you make the shape you want.

    But keep in mind that you may not see that numerical loss

    It may not have had more resolution effectively anyway.
     
  7. SojiOkita

    SojiOkita Mu-43 Top Veteran

    614
    Feb 23, 2014
    France
    I think replacing an ultra wide angle lens by a fisheye lens is a bad idea.

    Don't forget that on the LCD you won't be able to see the defished image. So it's very hard to handle perspective.
    Also, on the examples, the photo is cropped to 9 mm, not to 7 mm. The extreme corners are quite poor when defished.

    Don't get me wrong, the result of a defished Samyang 7.5 mm image are impressive for a defished image.
    It can help out when you have no ultra wide angle lens, but if you really like taking pictures at 7 mm, keep your 7-14.

    I love the Samyang 7.5, it's a wonderful lens... for taking fisheye pictures (or stereographic images - I love stereographic projection - with a little correction)
     
  8. sootyvrs

    sootyvrs Mu-43 Regular

    80
    Mar 6, 2015
    David
    Thanks all.. I'm going to buy the fisheye anyhow and try it out and do some testing... I may even keep the 7-14mm... Shame there is no compact ultra-wide 7mm rectilinear prime lens available
     
  9. SojiOkita

    SojiOkita Mu-43 Top Veteran

    614
    Feb 23, 2014
    France
    yes, a 7 mm rectilinear prime would be great...
     
    • Like Like x 1
  10. pdk42

    pdk42 One of the "Eh?" team

    Jan 11, 2013
    Leamington Spa, UK
    The Kowa 8.5 gets close.
     
  11. sootyvrs

    sootyvrs Mu-43 Regular

    80
    Mar 6, 2015
    David
    Shame that lens is rather big (especially with the hood) and heavy!
     
  12. sootyvrs

    sootyvrs Mu-43 Regular

    80
    Mar 6, 2015
    David
    After some more thought about replacing the Panny 7-14 with the Samyang, it occured to me that there is the Olympus 9-18mm which is only half the weight of the Panasonic and much smaller (when not extended)...

    Not sure why I never thought about this lens (perhaps as it's not as wide?) but will get this instead I think rather than defish and see if it will work for me... These are going really cheap with the Olympus cashback offers available in the UK
     
  13. wjiang

    wjiang Mu-43 Hall of Famer

    Try it on the 7-14, just be sure that 9mm is wide enough for you. When I look at the equivalent focal length comparisons here (http://imaging.nikon.com/lineup/lens/simulator/), the equivalent 14mm is quite a big jump from the equivalent 18mm.
     
  14. pdk42

    pdk42 One of the "Eh?" team

    Jan 11, 2013
    Leamington Spa, UK
    I have both the 9-18 and the Panny 7-14. The Panny has slightly better IQ (esp corner sharpness), but the 9-18 is very small and light and it takes filters. 9mm is wide, but nowhere near as wide as 7!! :)
     
  15. sootyvrs

    sootyvrs Mu-43 Regular

    80
    Mar 6, 2015
    David
    Yes thanks, I have zoomed to 9mm on my 7-14 to see the difference... I would prefer 7mm but I have found I'm leaving it behind when I have my GM1 with me.

    I don't think I can sell the 7-14 as I love that lens and most of my favorite images were taken with it so will more than likely keep it unless I get rid of M43 altogether which is unlikely.

    I have a Voigtlander 15mm prime which I use on my other camera Sony A7S so I will have a 3 ultra wides now which perhaps is excessive :)
     
    Last edited: Jun 25, 2015
  16. HarryS

    HarryS Mu-43 Top Veteran

    918
    Jun 23, 2012
    Midwest, USA
    Good choice on the 9-18mm as a small WA zoom. I use that along with the 7.5 fisheye.

    While the fisheye is a fun lens, it's not what I want to use as a substitute for a wide rectilinear lens. You have to compose the shot with a flat horizon if you don't want to do heavy edge cropping after defish.

    Here's an example with 9mm compared to the fisheye. I left the horizon round, not intending to defish, but defished it anyway in LR. I did not rotate or crop the defish, so you can see how the lens profile worked. I used a lens profile developed by DPR member "kenw".

    By the way, I was too chicken to get closer to the edge.
     

    Attached Files:

    • Like Like x 1
  17. Zobeid Zuma

    Zobeid Zuma Mu-43 Regular

    39
    May 13, 2013
    De-fishing the Samyang with PTLens has worked well for me, surprisingly so.

    A while back I did a sort of simple, un-scientific comparison with a Samyang 7.5mm fisheye on my E-M5, and a Samyang 10mm rectilinear lens on a Pentax K-01 (which has a slightly larger sensor, you know). What was most striking to me was... After de-fishing the 7.5mm images, they looked very, very similar to the output from the 10mm. It seems that rectifying those images optically or in software produces pretty much the same kind and amount of image degradation. The practical difference was that the 10mm lens was heavy and almost comically big, like a clown camera, while the 7.5mm lens was palm-able.

    And of course, the other advantage of the 7.5mm is that I can shoot actual fisheye photos with it. Which is sometimes cool. That's less space in my camera bag, less money spent, does the job of two lenses. Seems like a winner.
     
  18. Jermonic

    Jermonic Mu-43 Veteran

    228
    Jan 14, 2012
    Denmark
    Yup, a stellar 7-8 mm rect prime @ F3.5 sold at a sensible price point would be a winner for me. Most wide angles are just expensive, unfortunately.
     
  19. Turbofrog

    Turbofrog Mu-43 Hall of Famer

    Mar 21, 2014
    It looks like your 7.5mm/3.5 has some edge issues, even when it's not de-fished. The right side of the frame is really distorted...this isn't usually the case.

    Have you tried checking the rear element to see if it's screwed in properly?

    https://www.mu-43.com/threads/54212/
     
  20. EarthQuake

    EarthQuake Mu-43 Top Veteran

    830
    Sep 30, 2013
    Whoa, yeah something looks seriously wrong with that fisheye, mine is sharp across the frame.