Intro: Another DIY Micro-Macro Lens
While experimenting with a variety of "other-purpose" lenses. I discovered I had the makings of a really amazing micro lens in my telescope eyepiece collection. While you may not already have the eyepiece described, you can buy one cheap. I have seen them on eBay for $10.
The following Instructable shows how to create an adaptable mount for this eyepiece (or any 1.25" eyepiece for that matter) on ANY digital camera. My total financial investment, including the eyepiece, is $25. I could have bought a ready-made adapter for a mere $200. That's more than I bought the camera for on eBay.
And if that is not enough for you, this Instructable requires no special tools, like laser cutters, oscilloscopes, SLA rapid prototype machines, nor nuclear centrifuges!!!
Step 1: Gather Your Tools
1. A compass with one sharp point.
2. A rotary tool, like the Dremel, with a cut-off tool, small drill bit, and grinder. (handy, but not mandatory)
3. An X-Acto knife or other utility knife.
4. Needle-nose pliers.
5. A very small screwdriver.
6. A can of flat black spray paint, if desired.
7. 1/8 inch black crepe tape (optional)
8. Black marker
9. Fine sand paper
10. Small rubber bands
11. Needle file (optional)
This is what used. However, being the ever-resourceful people that you are, feel free to substitute as desired.
Step 2: Raw Materials
1. A wide-angle telescope lens.
I chose a 25mm KE (Kellner) lens from my collection. The wider the angle, the less vignetting you will have. The bigger the mm measurement, the wider the angle. There are three standard barrel sizes: .965, 1.25, and 2 inch. This is a 1.25. The KE lens is an inexpensive "starter" lens. They are about $30 new, but I have seen them for $10 or less on eBay.
2. A PVC coupler set: 1 1/4 to 1 1/2 inside diameter.
There are two pieces sold separately with a threaded base that joins them. You can find them in any hardware store in the plumbing dept for about $5 total. I chose these flared pieces so that I can add a DIY ring light to the front end surrounding the telescope eyepiece, but that's for a later project.
Three small computer screws and four really small screws. My "really small screws" were from the inside of a kid's battery powered toothbrush that I took apart for the little electric motor.
Step 3: Install Set Screws in PVC Upper
Drill 3 holes slightly smaller than the threaded end of the screw. Place them as equally as possible around the narrowed down portion at about the last thread of the PVC. These holes should go all the way through.
Now, screw your set screws in with pliers or a computer sized nut-driver, if you are lucky enough to have one. The PVC is soft enough, that the screws will tap their own threads and hard enough to hold the threads without stripping.
These will hold your eyepiece firmly in place.
Step 4: Try Out the Fit
Put your telescope eyepiece in backwards. That is, the glass part that would normally be close to your eye will now be facing out from the camera.
Lesson for the day: If you hold any camera or telescope lens backward and in front of your camera's lens, you will create a de facto Macro lens. I like to try every lens that I come across in front of every camera I own to test various configurations.
There is enough play that you can adjust the angle of the eyepiece a small amount to square it to the camera's lens.
Step 5: Fit the Lens Mount
You want a fairly close fit to the camera body. Place the lower portion of the PVC set on the face of the camera, centering the camera's lens as close as possible. You may need to prop up one side to make it level. I used a washer under the left side, as seen in the photo.
Using a pair of dividers or a compass, trace a line onto the PVC, while holding the dull point against the camera face, riding over every bump. If you do this carefully, you will get a line that closely matches the camera face scribed into the PVC surface. An added precaution might be to cover your camera face with masking tape, so that you won't scratch it.
I traced over the line with Chartpak 1/8 inch crepe tape. This helps me see the line while cutting. You could also trace it with a permanent marker.
Step 6: Trim the Lens Mount
Using a high-speed rotary tool, like the Dremel, trim to your line.
Please clean the dust off the PVC. All that fine dust can muck up your camera's lens mechanisms.
Now, check the fit. It does not have to be perfect, but it should be level and square to the camera face. The camera's lens should be roughly centered.
Make adjustments with a grinding attachment to the Dremel, if necessary.
Step 7: Drill Holes for Lens Mount
Drill four very small holes in the lower PVC piece, slightly smaller than your very small screws. These holes only need to be about 1/16 to 1/8 inch deep. Don't go all the way through, if you can help it. If you do, it's not a show-stopper.
I have noted the location of the two upper holes in red in the image. There will also be two symmetrically opposite on the lower part of that little PVC flange that you can't see from this view.
NOTE: Take the PVC piece off the camera first.
Step 8: Paint the Lens Housing
Screw the upper and lower PVC together and take out the screws. Lightly sand the PVC with 150 grit or finer. The paint will adhere better. Paint the whole thing, in and out, flat black.
This helps block scattering of light inside and makes people think you have some mega-expensive lens attached to your camera, instead of some plumbing. If you are particularly mischievous, you might consider adding some white lettering decals with technical-looking numbers and nomenclature for added effect.
Let it dry 24 hours. Flat black paint "looks" dry in about 15 minutes. Don't be fooled.
Step 9: Replace the Screws
Put your screws back into the Lens Housing. The paint will give you a little tighter fit. Crank the very small screws in pretty tight. Use your judgment here. You don't want to strip the little buggers out. But if you do, stick them back in with some epoxy. They should never need to come back out again.
Admire your creation. It's like a little piece of sculpture.
Step 10: Put It All Together
Put the lens in the upper and gently tighten the set screws until the lens seems tight.
Use rubber bands to hold the whole enchilada onto the camera. I found four small rubber bands worked well, two on each side. The very small screws are your attachment points.
The other objects in the image will be my test subjects.
Step 11: Take Some Test Shots
Find some objects with really fine detail, some flat, some with more depth.
My Canon S50 has 3X optical zoom. Zoom all the way out to your camera's max OPTICAL zoom (don't bother with digital zoom, it won't help) to minimize vignetting (that's the black outer circle you see through microscopes.)
With such a high magnification, there is a serious shake issue. Either put your camera on a tripod or set it on a table. Now, scoot the object up to the lens until it is in focus. In my set up, the object needs to be within 5mm of the glass surface of the lens.
Or, if you like a challenge, try to hold it in your hands. You will need LOTS of light. White LED booklights and flashlights work reasonably well.
Step 12: Test Depth of Field
This is not mandatory, but I like to know what I got.
Place an accurate scale on a 60 degree angle and take a shot. You can measure your DoF. The bold numbers pictured are tenths of an inch. The lines are hundredths of an inch.
In a 30 60 90 right triangle, the short leg (depth) is one half the hypotenuse (the image). It looks to me that the in-focus portion is about 6 or 7 hundredths of an inch. That makes my DoF about 3 to 3.5 hundredths of an inch (.03 in) or .89mm. Wow! Almost a whole mm!
Step 13: Take Some Fun Pictures
1. A dandelion bud with a little red mite who wouldn't stand still.
2. A strand of braided picture hanging wire.
Step 14: Make Adapters
Now I must make the adapter for my digital elph S320 and I will be able to use the same lens set up by screwing it into the new adapter. This one only costs an additional $3.50.
Have fun. I have work to do.