Ron R
I survived a lathey foreman
Brilliant + good explanation on how to achieve centering a razor .Square, Plumb and Level Your USB MicroscopeI played around a bit this afternoon with the "optical leveling" idea I had a few days ago. The cheapest and easiest mirror I could think of was an old cd. It's easier to cut with regular scissors than actual glass, and easier to drill too. I'm not suggesting anybody else needs to do this in order to take pictures, I really just wanted to check if it would work. It actually does! I did a pretty good job lining things up by eye, but skew has a larger impact on photo accuracy than megapixels, so I wanted a way to be sure that I don't have any skew. This is a pretty quick and easy way to check. Using the optical leveler to double check for skew only adds a few seconds to the normal 60-90 seconds it takes me to line up a shot. Enough preamble, here's how it works.
(New & Improved with Frickin Optics and Laser Beams)
Step 1: Making a Optical Leveler: This part is pretty straightforward. Find yourself an old blank CD-ROM or a Barry Manilow cd. Make it look like PacMan with a pair of scissors. It should look like this.
Step 2: Drill a hole in your Optical Leveler: You'll want to select the smallest drill bit you have for this. Larger drill bits will tend to crack or deform the cd. I used a 1/16" bit. Don't use any pressure whatsoever. The weight of the drill is more than sufficient. Too much pressure will tend to crack or warp the cd. Once you've drilled your hole, hold it up to your face and use it as a mirror. Make sure the reflection of your face is crisp and undistorted like a mirror. My first try, I pushed too hard on the drill and my reflection was distorted. The second try was perfect. It should look like this:
Step 3: Level your USB microscope by eye: Take your time and look at the camera from multiple angles to try and make it perfectly 90 degrees to your backlit platform. I'm using an old ipad as platform because I know it's dead flat, and it has backlighting built in. No turn the your USB microscope on. Check and see how you did. If you did it perfectly, the 4 lights will be perfectly centered in your viewer/picture. Here is how I did:
Step 4: Now level it for real: Use the lights for a guide. When they are perfectly centered in your viewer, you are dead perfect level. Here is what this looks like:
Step 5: Level Your Razor to the Camera: Turn on your iPad for backlighting and put a piece of wax paper down to cut the glare. Put your razor on the wax paper and line up the razor in the viewer by eye. Try to put the camera and the razor on exactly the same plane with the apex of the blade in the center of the viewer/picture. The use of a wedge or two make it easy to dial this in. Ensure as best you can that there is no skew in the picture. Here is how I did. I'm pretty happy with this.
Step 6: Check for level with the Optical Leveler: Now place the optical leveler you made onto the face of the razor. Move the little hole over apex of the blade. Check with the lights to see whether the plane of the razor matches the plane of the razor. The lights will be perfectly centered in the viewer if you did it right. I came pretty close by eye, but you can see the lights are up and to the right:
Step 7: Now level it for real: Use the micro-adjuster knob on your $13 harbor freight indicator stand to center the lights and the apex of the blade in your viewer. That's better!
Step 8: Trade the Optical Leveler for a Ruler: Gently remove your optical leveler, and place your metal ruler on the face of the razor to add scale to the final picture. Do this with an absurd amount of care not to disturb the razor in the slightest.
Step 9: Take the shot: Take the picture with your USB camera
In actual practice, all of this takes about 60-90 seconds after you've done it a couple of times. Obviously you only need to make the optical leveler once. Adjusting by eye is pretty quick because you now that you just need to get in the ballpark. Leveling with the optical leveler is a little fiddly, but pretty quick because it's obvious when you get it right. I dim my USB lights pretty low, because all I care about is the profile, and it brings the USB lights into crisper focus when they're dim. Also, I trimmed my Optical Leveler a bit because I felt it was too wide and that made it harder to balance.