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Samyang 12mm settings?

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  • Samyang 12mm settings?

    Does anyone know the proper R1 rail settings for a Samyang 12mm f/2.8 fisheye on a Nikon D750? Also, what’s the correct orientation and number of shots necessary to shoot a single row 360x180 panorama? Do I need to roll the camera or will portrait be sufficient? Thanks.

  • #2
    Do you already have a Samyang 12mm and R1 or are you considering purchasing one or both of these?

    I use a D800 (FX body same as D750) with a Samyang 8mm on an R1 with the rail set at 22 at +7.5°.
    4 shots round is sufficient, and possibly even just 3, but if there is movement such as people, animals or leaves blowing in the wind I take 6 round as 4 round leaves a gap in the center of each image with no overlap, but 6 gives full overlap for using PTGui's Mask option.
    Both 4 and 6 shots round give plenty of overlap for Control Point generation and +7.5° closes the zenith nicely.
    This arrangement gives me an Equirectangular of 13000+ x 6500+ (84.5Mp).

    For the the Samyang 12mm lens the geometry is similar to using the Samyang 8mm on an APS-C body where I use an NN3 with 8 shots round at -10° (or -15°) and 4 shots round at +45° to close the zenith.

    For both arrangements I use a handheld nadir shot and Viewpoint Correction in PTGui.

    I would have to experiment to see how I can use the Sigma 8mm with APS-C body on the R1, but I would suggest an NN3 for using a Sigma 12mm or a Sigma 8mm for use with the R1 unless anyone has a better suggestion.

    Note that if you change the tilt on the R1 that the setting on the rail will need to be changed as the camera/lens rotates about a point below the camera and lens as described in http://www.hugh360.co.uk/panoramas/t...rrallax-point/

    I hope this is of some help, Hugh.

    I have just been looking at the Nodal Ninja "Shot Calculator" on https://shop.nodalninja.com/shot-calculator/ which suggests that for a 12mm Fisheye lens with an FX body shooting in Portrait orientation that 4 shots round will give 25% overlap and 6 shots round will give 50% overlap with a Vertical Field of View of some 194° so suggest shooting 6 shots round at +7.5° to close the zenith, but with the hole at the nadir still within the head.
    You can use 4 shots round if you do not need to "Mask" anything.
    Fill the nadir using a handheld shot at approximately where the camera was on the R1 using PTGui's Viewpoint Correction:
    https://www.ptgui.com/examples/vptutorial.html

    As for the setting on the rail, ignore the numbers and set the lens so that the NPP (No Parallax Point) is on the Vertical Axis of Rotation.
    You can determine the NPP using methods described in:
    http://www.johnhpanos.com/epcalib.htm
    http://www.hugh360.co.uk/measurement...int-of-a-lens/
    Last edited by Hugh; 09-30-2018, 05:42 AM. Reason: Additional information

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    • #3
      Thanks. I already purchased an R1 with appropriate lens ring for my 12mm Samyang. I rolled the camera to 33 degrees and tilted up 5 degrees. I took 6 shots around. The zenith is perfectly closed but sometimes I’m getting stitching errors.

      I measured 97mm from the focal plane mark on the camera to the entrance pupil of the lens and set it there (based on the entrance pupil database).

      You say say you have a setting of 22. These Nofal Ninja components don’t come with instructions. I don’t even know how to read mine. I’ve attached a pic. I think I have mine set to 29? Is that right?

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      • #4
        I suspect (quite sure) that the distance from the focal plane to the NPP (Entrance Pupil) is different for the Samyang 12mm to the Samyang 8mm so 29 could well be right if this agrees with the 97mm from the table.
        Note that if you change the tilt on the R1 that the setting on the rail will need to be changed as the camera/lens rotates about a point below the camera and lens as described in http://www.hugh360.co.uk/panoramas/t...rrallax-point/ so if 29 was right for the lens horizontal (0°) then this would change a little for +5° tilt.

        According to the information from the Nodal Ninja "Shot Calculator" on https://shop.nodalninja.com/shot-calculator/ the Vertical FoV for a 12mm fisheye in Portrait orientation is 194° so you should still be able to close the zenith well with your +5° tilt, but with the camera in Portrait mode which may help with the stitching.
        I hope I am not giving you bad information as the geometry of the Samyang lenses is a little different to other fisheye lenses and http://www.northlight-images.co.uk/s...e-lens-review/ states "The Samyang 12mm lens - 180 degrees from corner to corner on a full frame (35mm) sensor", but the table at the bottom of the page states the Angle of View for 35mm + 180°.
        Perhaps you could post a single image for your Samyang 12mm on your D750 so I can solve this confusion in my own mind please?

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