Macro Rail


Inspired by DVD/CD RW macro rail i embarked on this project.

This rail can carry either the camera and lense assembly or the object to be photographed. The macro rail moved in extremely small increments for the application of focus stacking in macro and micro photography. This technique resolves the shallow depth of feild (DoF) issue normally related to macro photography.

The control system is based on a PICAXE 28x2 and uses a uM FPU v3.1 to calculate the DoF from user input, it also uses the FPU to calculate the distance between each shot depending on the chosen percentage of overlap. Further to this operation there is provision to split a stack if memory space on the the camera memory card runs low, variable settle time to allow any small movement in the camera/ tripod to settle and to allow for even crisper shots the use of mirror lock ensures zero vibration remain.

There are 2 operation modes, depth an conintuous shooting. the depth allow the user to set the depth of the object and start postion of the stack. using the information about the camera settings the rail automatically calculate the number of shots that need to be taken from the entire distance to be covered. Continuous shoot simply move the camera the entire length of the rail taking a picture at the calulated distance dpending on the user input settings. Any settings that maybe used again can be stored in upto 256 memory slots on the i2c EEPROM. the speed of the movemnt of the rail cold be sped up, this maybe achieved by having variable step size.

The micro-step controller allows for various step sizes and using a deadicated controller which wold operate all of the motor functions. This could improved responce time for canceling or simply allow a user to check information and storing it for future use while the stack is being photographed. the hight of the camera mount need to be increased to make it easier to mount the camera onto the rail. I higher quality ball screw and nut could be used to reduce baclash still further (current one is in spec with about 0.05mm backlash)

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