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Nodal Ninja Quick Reference Guides

R1/R10

Lens Ring for Canon EF 8-15mm f/4 L USM


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


Preparing 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 can use live view to set a focus distance where the distant and near objects are both in focus.
Alternatively, they are recommended to reproduce the scale near the red ring on the lens. Follow the guide in the next page for the procedure. With the labels affixed, focus distances can be easily read by the manner described below.
Firstly, make sure the reference mark is between the maximum and minimum focus distances. Secondly, rotate to align the reference mark to the long line at minimum focus distance. Thirdly, reverse the rotation to align the reference mark to the long line at maximum focus distance. Fourthly, reverse the rotation again to align the reference mark to the desired focus distance value.
Remember to align the reference mark to both extremes first and not to go outside the extremes during the steps.
For best sharpness, do tests to find the optimal focus distance and aperture settings for different situations.


Installing the Lens Ring to the Lens


Click to enlargeLens Ring
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 of the inner ring to AF/MF switch on lens. Stretch the ring to pass over the zoom limit switch. Position it evenly between the focus ring and zoom ring. Use the cross section of slit for alignment. Keep even spacing between the slit and AF/MF switch. Place a piece of paper to cover the AF/MF switch to protect it from glue of tape.

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. Cut any tape that goes beyond the chamfered area on either side of the slit. Test that focus ring and zoom ring rotate smoothly. If not, nudge the inner ring slightly away from the hindered focus ring or zoom ring and test again.

Installing 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 it so that it snaps to the inner ring and rotates smoothly. Rotate the zoom ring to align a nearest ridge on the rubber ring to the reference line. Align the 90° notch to the reference line with the help of rubber ridge. Tighten the knob fully.

Lens Mounted to the Camera
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. To set a different roll angle, redo the last step and align the reference mark to other notches (at 30° interval) for accurate roll angle alignment.

Reproducing the Focus Distance Scale Using Pre-made Image


Focus Distances and Reference Mark
Print the label image above on a high quality label sheet and cut in pieces. Open the page as image in PDF compatible image editor and move them to the proper positions when printing on a die cut label.

Click to enlargeFocus Distances and Reference Mark
Place the reference mark label on the focus ring as shown. This is the new reference mark. Place label for maximum focus distance to cover the text “FISHEYE ZOOM” as shown. Rotate the focus ring to the left until the focus scale stops moving. This is the maximum focus distance. Continue to rotate the ring to the left till the reference mark aligns with the long line in the label. Then reverse the rotation and carefully feel a sudden increase in friction. Stop immediately when friction rises! Place label for minimum focus distance at position indicated. Make sure the long line aligns with the reference mark. Rotate the ring between these 2 lines. Friction should rise sharply when reaching these lines. Shift the position of one label (if needed) to fine tune the accuracy. With the maximum and minimum positions set, the scale is ready.

Reproducing the Focus Distance Scale From Scratch


Focus Distances and Reference Mark
The lens uses USM motor for auto focus. The focus ring is not rigidly linked to the focus mechanism. That means the ring can still be rotated after reaching the limits of the focus distances. This presents a challenge in reproducing the scale. One workaround is to reproduce the whole range including the maximum and the minimum and turn the focus ring in a special manner described below.
First of all, turn AF/MF switch to MF! The area near the red ring is best place for the new scale. Place a small label on the focus ring as indicated, put a line there. This is the new reference mark. Place a label of about 4mm x 30mm on the ring above to cover the text “FISHEYE ZOOM” as indicated. This ring has some taper angle. Label will be curved if it is too long. Rotate the focus ring to the left till the maximum focus distance is reached. A sudden increase of friction in the ring can be felt. Continue to rotate until the new reference mark is near the left edge of the label as indicated. Add a mark to denote the maximum focus distance. Then reverse the rotation to the minimum focus distance. Carefully feel the increase in friction. Stop immediately when friction rises! Denote this minimum focus distance. Rotate the ring between these 2 extremes. Friction should rise sharply when reaching their markings. Shift the position of one label (if needed) to fine tune the accuracy of these extreme positions. With the extreme positions set, the other distances can be added easily by the manner described below.
Firstly, make sure the reference mark is between the extreme positions. Secondly, rotate to just touch one of the extreme marks. Thirdly, reverse the rotation to just touch the other extreme mark. Fourthly, reverse the rotation again to the distance values of interests (e.g. 1m and infinity) and add the markings. To mark distances not available on the original scale, place a target with known distance to camera sensor, manually focus to achieve sharp target image, mark the label with known distance value. Remember to touch both extremes first and not to go outside the extreme limits during the steps.

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