As promised, I’m posting my version of a macro rig. A couple of friends dubbed it the “Bratcam” (just why is a long story), and since that’s easier to say than “my photomacography rig,” I’ve continued to call it that.
The Bratcam handles all six axes of movement and is very steady. I’ve tested it with microscope objectives from 2.5x through 60x, and it handles them all pretty well. At 60x, I need to exercise a bit of care, but not too much. At 10x and 20x, I could probably tap dance while using it (that is, if I could tap dance). I see no vibration or slop during rough focus, fine focus, subject positioning, or focus stacking movement.
All axes of translation and rotation are adjustable with micrometers or microscope focusing blocks. Only movement along the through-the lens axis is handled on the camera platform (in a horizontal rig like this one, this movement is of course “y-axis translation”—but those familiar with vertical rigs might prefer to think of it as the equivalent of their z-axis). The other five axes of translation and rotation are handled on the subject stage.
Over the next few months, I hope to add a stepper motor and computer control to the camera movement.
Closeup of the subject stage
Major components labeled
A—Steel base plate. Measures 8x22x5/8 inches, 38 lbs. Additional holes along center line permit changing position of dovetail plate and stage post (to accommodate a wide range of bellows extensions). Powder coated. Made for me by Don Wilson, a fabricator whose contact information I’ll give below.
B—12-inch Arca-Swiss compatible dovetail plate from Chris Hejnar, who sells varied plates at economical prices as eBay seller krosno65. He also accepts custom orders.
This dovetail allows fore-aft camera positioning (y-axis, but may be thought of as z-axis to those more used to vertical rigs).
C—Kirk 4-inch Arca-Swiss compatible clamp, mounted upside down to clamp onto rail "B." The use of this clamp and the one labeled “G” allow the focus block to be quickly removed for use on a tripod for more standard macro work.
D—Adapter plate made for me by Don Wilson
E—Focus block cut out of Nikon microscope. Coarse and fine movements are coaxial, and the fine movement works for the entire length of travel. Travel is a bit over 2.5 inches. I think, but am not sure, that the focus block came from an Optiphot (it was already cut off when I bought it).
This allows focus and focus stacking movement along the y-axis (again, “z-axis” for those used to vertical orientations).
F—Adapter plate made for me by Don Wilson
G—Kirk 4-inch Arca-Swiss compatible clamp
H—Kirk 6-inch Arca-Swiss compatible plate (could save money with one of Chris Hejnar’s, but had this one already.) This plate allows quick mounting and dismounting of the bellows to the focusing block
I—Dovetail from Nikon PB-6E extension. Much longer than the standard dovetail supplied with the bellows, with more places to mount the Arca-swiss compatible plate. Therefore perhaps steadier than the standard PB-6 dovetail.
J—Nikon PB-6 bellows
K—Nikon F to T2 adapter
L—Beljan T2 to RMS cone-shaped adapter. (Maker sells on eBay as vendor beljanmfg.)
M—Olympus BHMJ microscope focus block and mounting post. Mounting post was machined on the bottom by Don Wilson to give it very solid, removable mounting on base plate. He made the bottom perfectly flat and pressed a new threaded bolt into the tube and brazed it in place. On the underside of the base plate, he bored a conical countersink at the bottom of the hole through which this post is bolted. This conical shape locks the post very tightly in place.
This block allows the subject to be raised and lowered—that is, “translation along the z- axis” (y-axis vertical equivalent).
N—Newport L-bracket model 360-90
O—Newport linear stage model 462. Allows subject to be moved right and left. That is, translation along the x-axis (also the x-axis in vertical setups).
P—Adapter plate made for me by Don Wilson
Q—Newport rotation stage model 481-A. Can be turned by hand—nice and smooth with excellent dampening. Can then be fine adjusted with micrometer. Allows subject to be rotated as if on a turntable—aka rotation around the z-axis (y-axis vertical equivalent).
R—Adapter plate made for me by Don Wilson
S—Thorlabs GNL goniometer (Edit--now called GNL20, as of June 2019), which consists of a stacked Thorlab’s GNL18 and GNL10. These produce tilt in two axes around a common “virtual point” one-inch above top of the assembly. Allows subject to be tilted side-to-side and front-to back—aka x and y-axis rotation (x and z axis vertical equivalent).
Quite a few of the above parts were made for me by fabricator Don Wilson. When I started building this rig, I was a torn between attempting the metalwork myself or hiring it done. I’m very glad I chose the latter. When I approached Don, he had never worked on this sort of project--but from past experience, I knew he can make just about anything with metal. He ended up contributing not just fabricating skills, but excellent ideas. The Bratcam is a much better instrument because of Don's input and work.
I asked Don if I could post his name and contact information, and he enthusiastically said “yes”—he’d like to do more projects like this one. He is local for me, but is happy to work at a distance with anyone by mail and phone. His charges were modest.
His contact info:
Wilson’s Welding & Fabricating
6620 Swamp St. NE
Hartville, OH 44632
Some of the optics
(left to right)
EL-Nikkor 50mm f/2.8 enlarging lens
Nikon M Plan CF 2.5/0.075
Nikon N Plan CF Apochromat 4/.20
Nikon N Plan CF 10/0.30 (front); Nikon M Plan CF 10x/0.25 (rear)
Nikon M Plan CF 20/0.40 ELWD (two copies)
Nikon M Plan CF 40/0.50 ELWD (four copies)
Nikon M Plan CF 60/0.70 ELWD
I hadn’t originally planned to collect multiple copies of the 20x ELWD and 40x ELWD lenses, but it happened, and I plan to test sample variation before parting with the extras. Will share results with this forum.
- Bratcam lighting stage documented. Click here for details. Posted 12-06-10.
Bratcam is now automated with a stepper motor and StackShot controller. Click here for details. Posted 12-12-10.
Bratcam can now swap between a bellows (for finite microscope objectives, enlarging lenses, and bellows macro lenses), and a Mitutoyo tube lens assembly (for infinite microscope objectives). Click here for details. Posted 4-18-2011.
Bratcam now has a laser to assist in aiming and focusing. Click here for details. Posted 11-07-2014.
Bratcam now has a clamp assembly to hold camera body in precise register. This clamp is adjustable to fit many cameras. Click here for details. Posted 03-31-2015.