Samyang (Rokinon) 8 mm 3.5 Fisheye Focus and Stitching Issues

[DCastoral]

Hi folks, I need a little direction on this, I've googled everything on this lens for focus and stitching. My results are poor at best.I have sent the first lens back and now this new one seems better in the focus dept, though not perfect.

I have tried numerous settings between camera | Lens | PTGui, I cannot find a starting point of repeatable results so i could "tweak" settings. I have just taken another set to try a fresh view but am hitting the same wall with the stitching 

Equipment:

1.   Canon EOS Rebel T5 EF-S 18-55mm IS II Digital SLR 

2.   Samyang (Rokinon) 8 mm 3.5 Fisheye

3.   Nodal Ninja 3 MKII Full Spherical Multirow Panoramic QTVR Tripod Head

I am shooting in Manual Mode Shutter Speed 1/500  FStop 3.5 ISO 1600

I have the photos shared here https://drive.google.com/folderview?id=0B6ad7vOgO2bgSFQ2bUFkSER1cDg&usp=sharing         and also making a video of my process there too, I have no idea what settings I am making wrong 

Please If Anyone can Advise I Greatly appreciate it!

[Willy Kaemena GM]

well  I have got a good stitch. Your main error is in your lens settings. That lens is a “FULLFRAME FISHEYE”

Try it with this settings again.

Willy

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[DCastoral]

I cannot see the settings Willy and thanks for that fast reply!

[John Houghton]

On Monday, April 4, 2016 at 1:09:01 AM UTC+1, DCastoral wrote:

I cannot see the settings Willy and thanks for that fast reply!

The settings can be seen by switching into Advanced mode via the button on the Project Assistant tab, and then selecting the Lens Details tab. 

It was obviously a windy day, judging from the evident movement of the tree branches.  This inevitably causes alignment difficulties there and also in the sky with the scudding clouds.  I optimized the images excluding the zenith and then aligned the zenith with the other images.  For the panorama generation, I used the alternative blender Smartblend (for Windows), which gave a nice sky automatically.  PTGui's default blending does a poor job there, but it should be possible to get a good result with some masking.  My project file is at https://www.sendspace.com/file/vufk9k .

John

[PTGui Support]

Also the images are quite unsharp, which also causes PTGui trouble
finding control points. Have you tried adjusting the focus at f/3.5
using Live view on your camera (at 10x magnification)? Once it's
focused, set the lens to f/8 to get a greater depth of field.

The 50mm you see in the EXIF window is actually a Canon camera bug, it
will record 50mm as focal length when a manual lens is attached.

Joost

[DCastoral]

There is definitely a focus issue here, and it was a very windy day for sure. I have changed the settings in Advanced Mode and find the settings won't stay, I have made a screencast of me trying to change these settings in the same file as the test photos if you could take a look. Why do the settings not stay? If it's a cannon bug then I cannot select 8mm or Fullframe Fisheye? each time I return, the settings have defaulted back. I will try the smartblend  and the focus suggestion. Though not quite sure how to add the zenith later, i can never find the control points for the 4/5 photos (nadir and zenith)  

[John Houghton]

On Monday, April 4, 2016 at 10:40:00 AM UTC+1, DCastoral wrote:

There is definitely a focus issue here, and it was a very windy day for sure. I have changed the settings in Advanced Mode and find the settings won't stay, I have made a screencast of me trying to change these settings in the same file as the test photos if you could take a look. Why do the settings not stay? If it's a cannon bug then I cannot select 8mm or Fullframe Fisheye? each time I return, the settings have defaulted back. I will try the smartblend  and the focus suggestion. Though not quite sure how to add the zenith later, i can never find the control points for the 4/5 photos (nadir and zenith) 

When you go to the Lens Details tab, simply select the lens type from the pull down list in that field.  Likewise, type in the focal length (9mm is a better starting point than 8mm).  The lens information is not available in the exif data as the camera is not electrically connected to the lens as happens with Canon lenses.  You can store the current lens details in the Lens Database (preferably after evaluating all the lens parameters with the optimizer).  Or you can use File->Make Default to store all the current settings for PTGui to use as the default  for new projects.  Or you can store the settings as a template with File->Save as Template and apply to similar projects with File->Apply Template.

You can add images at any time by button at the bottom of the Source Images tab.

John

[Erik Krause]

Am 04.04.2016 um 00:00 schrieb DCastoral:
> I am shooting in Manual Mode Shutter Speed 1/500 FStop 3.5 ISO 1600

Since you shoot from a tripod anyway, you don't need such short exposure
times. Hence you can turn down ISO to 100 which would reduce noise and
set fstop to at least 8, which would make your images sharper.

Samyang lenses are reported to have a badly aligned focus ring
sometimes. To try set the camera exactly 1m away of something well
structured. Measure from the sensor plane, not from the lens. Then try
to focus in live view as Joost wrote. Look at the focus scale. If it
shows a larger value you won't be able to focus for infinity, in which
case I'd return the lens. If the value is lower, measure the offset on
the lens ring, mark it for infinity and use it such.

You can also try to calibrate it yourself, if you are brave enough.
There are some tutorials on the web, f.e. http://tinyurl.com/z4cz5zz

--
Erik Krause

[ErnestoP]

Hi DCastoral
I also have the same lens (sold here with label "Walimex Pro 8mm") and as Erik Krause says, the focus ring of my lens was far away from being correct. I was not able to get a right focus.
In internet I found instructions how to solve this problem myself. The screw that you need to open/close you find under the rubber of the focus ring (you can evert this rubber without damage). You need a very small screw driver to open the screw a little bit. Then you can adjust the ring and fix again the screw.
Now this is my preferred lens for 360° panoramas - works fine now.
Hope, this helps.
Ernst

[PTGui Support]

Hi Dennis,

The settings do stay. But if you press the EXIF button, PTGui will again
read the focal length from the exif data (which has not changed and
still contains the wrong value). You should only do this once though;
from there on PTGui will use the settings as set in the Lens Settings tab.

I can understand the confusion, I'll add a workaround for the Canon bug
in a future version of PTGui (so that the lens is recognized as an
unknown manual lens instead of 50mm).

Once you have proper settings, do File - Save As Template. You can then
apply the correct settings using File - Apply Template.

Kind regards,

New House Internet Services BV
Joost Nieuwenhuijse

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[DCastoral]

Thanks so much for this help everyone ........ first thing, I have measured 1 m (3 ft )to an object and the focus ring says 1.5 ( 5ft ). looks like i am resetting the focus, wish me luck! 

[DCastoral]

You Guys are Awesome! Lens is focused and I am able to stitch with much better results. Thank you all so much for the Spot On Support!

adding to the same folder the focused panos

On Sunday, April 3, 2016 at 6:00:37 PM UTC-4, DCastoral wrote:

[John Houghton]

That's much better, but it looks to me like the knob on the panohead is in much sharper focus than the distant features, which is not what I expect to see.  What aperture setting are you using?  Focus visually with live view on something 1 metre away and tape the focus ring so it cannot move.  (Measure from the focal plane symbol on the camera body - a small circle with a line through it). 

Further general observations:

1. You really don't want to have a large pan & tilt lever sticking out at the nadir.  If possible, remove the head altogether.

2. Do convert the raw images to tiff rather than jpg format and remove chromatic aberration and purple/red fringing in ACR if that's what you are using to convert the images.

3.  When shooting the nadir, stand behind the vertical rail to minimise your intrusion into the scene.  Take two shots spinning the head through 90 or 180 degrees between them.  The aim being to capture as much of the nadir as possible, unobstructed by yourself, hardware and shadows.  Mask away these intrusive items from all images.

4. Take a handheld shot of the nadir area with the tripod shifted away and stitch that in with viewpoint correction.

5. Consider shooting  the zenith at pitch +60 to 70 degrees rather than +90  so that the lower edge covers an area close to the horizon where there are more likely to be features for control points.  The zenith hole will still be covered.

John

[DCastoral]

So, a bit of a learning curve but i have found also that a new tripod has also helped tremedously. I have followed all the suggestions her and came up with this. I believe there are no errors here please tell me if i'm wrong and a very hearty Thanks for all the help  

On Sunday, April 3, 2016 at 6:00:37 PM UTC-4, DCastoral wrote:

[John Houghton]

On Wednesday, April 27, 2016 at 10:28:36 AM UTC+1, DCastoral wrote:

So, a bit of a learning curve but i have found also that a new tripod has also helped tremedously. I have followed all the suggestions her and came up with this. I believe there are no errors here please tell me if i'm wrong and a very hearty Thanks for all the help.

The focus at the nadir now looks fine and the general stitching is ok too, apart from some slight misalignments in the surface of the path at the edge of the nadir shot.  These might be eliminated by creating some control points in these areas.  If they don't go away, try switching on viewpoint correction for the nadir image (with control points only on the path surface).

John