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Re: [PanoToolsNG] Samyang 8mm

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  • A Kielcz
    Ricardo, Thank you for replying. I ll try it. Could you please post an image. A Kielcz Cincinnati, Ohio, U.S.A. ... From: Ricardo TVB
    Message 1 of 62 , Nov 1, 2010
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      Ricardo,
      Thank you for replying. I'll try it.
      Could you please post an image.

      A Kielcz

      Cincinnati, Ohio, U.S.A.

      --- On Mon, 11/1/10, Ricardo TVB <ricardo.araujo@...> wrote:

      From: Ricardo TVB <ricardo.araujo@...>
      Subject: Re: [PanoToolsNG] Samyang 8mm
      To: PanoToolsNG@yahoogroups.com
      Date: Monday, November 1, 2010, 12:09 PM







       









      My best results using Samyang with 5D MKII is at F/8 and

      focus set to 0.7m. This is the sharpest image for this combo

      (at least for my samples) from 30cm to infinity.



      Em 01/11/2010 13:03, Roger D. Williams escreveu:

      >

      > On Mon, 01 Nov 2010 22:00:36 +0900, A Kielcz

      > <roblee007@... <mailto:roblee007%40yahoo.com>> wrote:

      >

      > > Thank you Roger.

      > > It was shot in RAW at 5.6 and focus was set to 1.5m.. I

      > could not u/l

      > > original NEF, because it wouldn't accept it.

      > > Is it possible that CA wasn't even on both sides,

      > because it wasn't

      > > level?

      > > Tests are good, but I want be able to correct anything

      > anyway.

      >

      > You're welcome. Hmmm. Looks a bit soft for F/5.6. Try it

      > at F/8 and 11

      > and see if you get noticeable improvements. Also try 2.0m

      > or even 3.0m.

      > As I said, I had to focus further out than dictated by the

      > hyperfocal

      > rule in order to get the best sharpness from my Peleng.

      >

      > If CA is not the same on both sides the cause will be in

      > the internal

      > geometry of the lens, not any orientation of the camera. I

      > suggested

      > "decentering" which simply means that the optical axis of

      > the lens

      > isn't precisely aligned with the lens barrel. But the

      > effect is very

      > slight, so I wouldn't worry about it.

      >

      > You must have used a RAW file processor to get your JPEGs,

      > and it

      > can introduce softness in the resulting images. The RAW

      > processor is

      > where you should remove the CA. CA looks bad and seems

      > serious, and

      > if left uncorrected plays havoc with control point

      > location (think

      > about having fringes on the opposite sides of the same

      > feature when

      > it appears on the extreme left of one shot and the extreme

      > right of

      > the next, overlapping, shot! You don't want that. All RAW

      > processors

      > I've played with have sliders to eliminate CA. Play with

      > them until

      > you can't see coloured fringes at full x1 screen

      > magnification!

      >

      > Roger W.

      >

      > --

      > Business: www.adex-japan.com

      > Pleasure: www.usefilm.com/member/roger

      >

      >



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    • Michel Thoby
      ... Mark, thank you very much for sharing this link. I had found by myself the same way to mechanically set the focus scale ring at the correct position. I can
      Message 62 of 62 , Feb 10, 2014
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        Le 9 févr. 2014 à 23:22, <markdfink@...> <markdfink@...> a écrit :

        Absolutely don't trust the focus scales on any of their lenses! I found out the hard way with a 35mm that I rented, and see that both my 14mm and 8mm have the same issues. I used this link to find out how to fix it so that I can reliably use hyperfocal settings when shooting.


        Mark
        Mark, thank you very much for sharing this link. 
        I had found by myself the same way to mechanically set the focus scale ring at the correct position. I can confirm that it made me a happy user of the Samyang 14 mm for more than three years now. 
        I was inspired by Jeffrey R. Charles who had kindly taught us in 2009 how to solve the problem that similarly affects the Samyang 8 mm f3.5 fisheye lens. It is a simpler fix than for the rectilinear WA though:

        Best regards, 

        Michel Thoby
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