a "dumb" motorized macro rail with no synch between the rail motor and camera shutter, based on- a cheap manual macro rail- a super-slow gear motor- a voltage regulator to change the motor speed- intervalometer (I am using in-camera one from Magic Lantern) to make a sequence of shots while the rail is slowly and continuously moving camera relative to the object- flash-based lighting to freeze the motion (no blur due to the fact that the camera is continuously moving), operated by the camerato be able to generate shots for focus stacking with DoF larger than what one can achieve by using e.g. AF telephoto lens + reversely mounted MF prime lens. (E.g., my 135L + reversed 50mm f2.0 combo produces frame width ~5mm and DoF 2mm, so I cannot make the whole extended object, like a fly, sharp.) With a motorized macro rail one can in principle get DoF 10, 20mm and more, with frame width ~5mm.(some are optional; all from China, ordered from ebay and aliexpress; prices include shipping):- Manual macro rail (16$):- Gear motor - 12V, 0.5 RPM (17$):- DC-DC step down 2A converter (optional; 3$):So the total was ~33$. I already had the macro bellow (~45$ from dx.com) , but one can use other macro lens options - telephoto lens + a reversely mounted MF lens, or even the Magic Mole. Anything will work because no AF is required.I already had things like 12V 200mA AC adapter (actually 18V with no load). The DC-DC adapter needs at least 2V difference between the input and output DC voltage, so if you want to power the motor up to its rated voltage of 12V you should provide at least 14V DC voltage with no load (the load due to the gear motor is pretty low).I also already had a 12-way switch, and a bunch of resistors. (This is optional; one can use an external variable resistor, or even simply use the one in the DC-DC converter, which is not very convenient.) From my measurements, the variable resistor in the DC-DC adapter has maximum resistance of 10 kOhm, and resistance of 100 Ohm ... 3.0 kOhm when the output voltage is 1.2V ... 12V. To prevent serious jumps in voltage when you switch between different switch positions, the best strategy is to set the variable resistor on the converter to 12V (3.0 kOhm), and then solder the switch with a selection of resistors in parallel to the variable resistor. In my case, I covered the whole range 1.2V ... 12V reasonably well by using the following resistors for each switch position from 1 to 11 (the position 12 doesn't need a resistor): 100, 150, 180, 330, 470, 670 Ohm, 1.0, 1.5, 2.2, 4.7, 10 kOhm. I haven't tested voltages <2.4V, but at 2.4V the motor already provides enough of torque to move my macro rail + Canon 50D + 50mm f2.0 MF lens (reversely mounted) smoothly.Other minor items: a sturdy plastic lunch box from dollar store, wires, bolts and nuts etc.The most critical component is a coupler between the gear motor (diameter 6.00 mm) and the knob on the macro rail which moves the rail (diameter 12.00 mm). The biggest challenge was to come up with a setup where one could easily disengage the motor from the rail knob, so one could adjust the camera position much faster by turning the knob with your fingers. (The motion under motor is too slow even at 12V - only 12 mm/min). I came up with this setup, which is not perfect (probably not very durable), but seems to work: Untitled by this_is_not_art , on FlickrThe internal diameter of the coupler (a small piece found in a home reno store, water pipe coupler) is larger than 12 mm, so I used three screws (two fixed small ones, and one large one with a knob for engage/disengage operations) to attach it to the macro rail knob.One could try other solutions. E.g., on aliexpress I saw ready motor couplers 6-12mm (4.50$), which could be an almost ready solution. But one still has to figure out how to engage/disengage the motor.Once you have the coupler, you can design the metal base which connect the gear motor to the macro rail. It will go between the bottom of the macro rail and the tripod (it's best to screw it into the macro rail), will have a gap for the large knob on the coupler, and one side bent at 90 degrees where the motor will be attached: Untitled by this_is_not_art , on Flickr Untitled by this_is_not_art , on Flickr Untitled by this_is_not_art , on Flickr Untitled by this_is_not_art , on Flickr