Re: [PanoToolsNG] Samyang 8mm
- View SourceMy 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:
>[Non-text portions of this message have been removed]
> 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
> 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
> 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
> "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
> I've played with have sliders to eliminate CA. Play with
> them until
> you can't see coloured fringes at full x1 screen
> Roger W.
> Business: www.adex-japan.com
> Pleasure: www.usefilm.com/member/roger
- View SourceI 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