articles/Macro/getting-very-close-page2

Getting very close - Part 3 - part 2 of 1 2 3 4

by Christopher Algar Published 25/01/2018

Vitamin C, 10x objective, stack of 42 frames

When we finally decided to buy a microscope, we knew that we would have to modify it. This modification would have to be reversible and non-destructive so that the instrument could easily be returned to its original condition. For a start, we decided that we would try using the Nikon microscope lenses that we had been using for extreme macro photography. As these lenses are of finite design, no secondary (tube) lens is required to form an image in a camera. We removed the upper part of the microscope and replaced it with a home-built twopart tube. This tube has a round dovetail on one end to fit the microscope and a Canon camera adapter on the other.

Copper sulphate, 10x objective, stack of 54 frames

Our previous experience with manually changing focus for stacked images taught us that we needed to use Stackshot for this purpose. We decided to use a stepper motor sold by Cognysis that can be plugged into and use their control unit. The question then was how to fit it to the fine-focus control on the microscope. We wanted to avoid putting any side strain on the control and did not want to damage the control knob in any way. We finally settled on driving a home-built spindle via a miniature timing belt and pulley system. At one end of the spindle shaft there is a tapered, hollow cup that matches the control knob. The cup is lined with a soft material that grips the knob with only light pressure. The pulley system allows for altering the gearing between the stepper motor and the focus control but we have not needed to change from 1:1. We have slowed the speed at which Stackshot operates to roughly match the speed at which one would turn the knob manually. All the components for the stacking system have been bolted down to an aluminium and wood base plate rather than to the body of the microscope. The tapered sides of the microscope made it easy to hold it down to the base plate with some home-built padded fittings.

• Getting very close - Part 3 page 1
  
• Getting very close - Part 3 page 2
  
• Getting very close - Part 3 page 3
  
• Getting very close - Part 3 page 4
  

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