Saturday, November 15, 2008

YSM35B Building the Vibrating Mount Part 3

This is the fourth in the series of instructions on how to build the YSM35B Vibrating 35mm DOF Adapter. In the last part we started to cut the base parts of the mount. Here we finish building the static part of the mount.

Finish the Mount as Static

Watch the video because its easier to explain that way.

We start by drilling holes on the two plastic base holders where previously marked. If you don't have a rotary tool and a press you can use a regular drill. Just set it to its lowest setting. Failing that you can find something sharp and round like a precision screw driver to poke a hole. Use a drill bit that has a sharp end so it doesn't catch on the plastic and try to spin it. Something slightly smaller than a 1/8" bit is good for these syringe plungers.

It wasn't shown in the video but between drilling the holes and mounting the plungers I cut out the opening on the bottom base. Use a metal straight edge and a sharp knife. It will take multiple cuts to break through. Work on top of cardboard or a stack on newspapers to avoid scratching your table or floor.

Now that the holes are done its time to put the base on stilts. Take your syringe plungers and cut off the push tabs with a knife. Fit the rubber plunger through the bottom base (plastic card). You might have to slip it in a slant then rotate it to get it all the way in. Repeat to get all three stilts on. Then slip the top base (pringles lid) on top. Don't worry if stilts appear slightly skewed. It will still work.

Mount the assembled mount on top of the F-mount then screw on ring #2. Measure about 50-60mm from the front of the F-mount and the end of the plungers. Cut off with scissors or cutter from pliers. The mount won't look as wonky after this.

Get ready to glue on the Ee-A focus screen. Before doing that, make sure to clean your fingers with isopropyl alcohol. Also identify which side is matte. You can hold it against the light and tilt it slightly to compare. One side will be more reflective. The Ee-A has a big tab. If this tab is upper left or lower right you have the matte side up. I like to have the tab located lower right. It doesn't matter which way you have it.

Adjust the base so its about 45mm from the flange (front edge) of the F-mount. When the focus screen is set it will be near the right distance for infinity. It won't be perfect yet but it will be close enough for now.

Rest the focus screen matte side up on the top base. Carefully align the edges and hope it doesn't fall off. If you cut off too much material for the window you might have to hold it while you glue the edges. Time to plug in the hot glue gun.

The glue gun needs about 3-5 minutes to heat up. When you glue, pull away from the focus screen. This ensures the left over glue threads don't land on the screen. The glue gun leaves strands of glue as you pull away, use your fingers to cut them.

Let it cool for about 5 minutes. Now it is safe to handle. You can screw the #3 and #1 macro tube rings on. See how much clearance the top mount has to the wall. It's okay if they touch on some points. It just makes it noisy. You can cut at the touch points to increase clearance.

At this point you have a static 35mm adapter!

Why did we do this?
The rubber on the plungers allows the top base to vibrate freely while limiting the vibration transmitted to the adapter body. Yes, the top base making contact with the inner wall of the macro tube will introduce some vibration. Shaving the contact points will reduce that. Syringe plungers were used because these are relatively easy to get. Any strong yet flexible material can be used as long as you can attach it to the Nikon F-mount.

What's next?
Setting the focal plane to correct distance prior to making it a vibrating unit.

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