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Nodal Ninja Quick Reference Guides


Lens Ring for Sigma 8mm Fisheye Canon Mount

The lens ring consists of a metal outer ring and a plastic inner ring that fits the lens snugly. The plastic ring allows reproducible mounting of lens and protects the lens from stress by providing maximum area of contact to the lens.

Preparing the Lens for Ring Mounting

Click to enlargePreparing the Lens for Ring Mounting
Manual focus is preferred for making stitched panos. Turn the AF/MF switch to MF. The focus distance scale will be hidden by the lens ring. Users are recommended to use tape to fix the focus ring at around 0.5-1m on the scale and use an aperture of f/8. For best sharpness, do tests to find the optimal focus distance and aperture settings for different situations. If not taped, the focus ring is still movable with the lens ring installed. Users can use live view to set a focus distance where the distant and near objects are both in focus.
Alternatively, the distance scale can be reproduced on visible area of the lens barrel with labels. Turn the focus ring to the desired distance. Place labels at the positions indicated. Put Mark 1 on the label on the focus ring. This is the new reference mark. Then put Mark 2 on the label above. To mark more distances, turn the focus ring to other distances of interest and add the marks. Mark 3 and Mark 4 are at focus distances of 1m and 0.5m respectively.
A reference mark for roll angle can also be added for accurate alignment.

Installing the Lens Ring to the Lens

Click to enlargeInstalling the Lens Ring to the Lens
Loosen the knob on the outer ring until its slit is about 6mm (1/4") wide. Squeeze to take out the inner ring. Check the label on the inner ring to confirm with the lens in use and the direction of mounting. The arrow should point to the front of lens.

Installing the Lens Ring to the Lens
Align the slit on the inner ring to AF/MF switch on lens. Insert the lens. Stretch the ring when necessary. Move it to a position where it fits snugly. Keep even spacing between the slit and AF/MF switch. Push it against the anchor point to ensure reproducible mounting and consistent NPP settings.

Click to enlargeInstalling the Lens Ring to the Lens
Fix the inner ring with a piece of tape about 40mm (1.5") long. Stretch the tape so that the ring will grasp the lens firmly. This prevents movement of inner ring when outer ring is rotated, thus protecting the paint of lens barrel. Cut any tape that goes beyond the trimmed area of the inner ring.

Click to enlargeInstalling the Lens Ring to the Lens
Align the outer ring to the slit of inner ring. Insert the outer ring (loosen its knob further if needed) from the back of the lens. Tighten its knob slightly. Rotate the outer ring so that it snaps to the inner ring and rotates smoothly. Align the notch below the lens ring plate to the AF/MF switch. Tighten the knob fully.

Installing the Lens Ring to the Lens
Mount the lens to the camera and it is now ready for use on any Arca Swiss compatible gear. The camera will be in portrait mode with handgrip pointing up. Loosen the knob on the ring to rotate to other angle. Use the notches (at 30° interval) at the back of ring to have accurate roll angle alignment. Use the center of AF/MF switch as the reference.

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