Macro photography part 12: Reproduction ratios beyond 2:1

Closeup of moth using bellow and reversed 50 mm lens.  Approximate reproduction ratio of 4:1.

Getting reproduction ratios greater than 2:1 requires specialized equipment.  There are numerous ways to do it that range from bellows, microscope objective lenses, specialized macro lenses, and various different microscopes.  What they all have in common is the need for good quality optics.  Herein lies the rub.  It can be very expensive if you want to do it well.

A second factor is that working distance tends to be measured in centimeters, sometimes millimeters.  Lighting your subject also is difficult because of that narrow working distance.  Lighting can only be done from the side as there is little room to put relatively large equipment in.   There are solutions, but often you will have to be inventive and adapt whatever stuff you have.  

I can tell you that any one photo represents a lot of time invested.  There is equipment setup, subject mounting, positioning of both, lighting manipulation, and then the fine tuning of that equipment.  Between the limited lighting from the increase in magnification and narrow working distance, your subject will not be easily seen.  You can overcome this by using mirrorless cameras or live view displays on DSLR cameras.  

I often use continuous lights instead of flashes when working with such high magnifications.  The advantage here is that you can see the shadows and tweek settings in real time instead of having to shoot, look, and adjust.  Diffusers will make a world of difference here as you can bring broad-source illumination onto your subject instead of harsh point-source.

Then there is the actual exposure.  You are no longer shooting at 1/200th of a second for flash, now you are shooting long exposures, perhaps 10 seconds or more, in order to capture your image.  That works well, as long as there is no vibration.  Trust me when I say that you can't walk around - the tiniest step can cause significant microscopic movements that will blur the image.  I will set my camera on mirror-up mode or use a 3 second delay between mirror up and shoot.  Then, you basically hold your breath.

At this point you may want to consider stacking your image.  The advantage here is that you can pick a low aperture (better sharpness), use shorter exposure times (less vibration), and stack as much as you like (more depth of field).  The incremental movement has to be in tiny steps, perhaps a quarter or half a millimeter at a time, and you can only do that using a motorized rail.  If your subject has a depth of 1 centimeter and you are using 1/10 of a millimeter increments, you will need 100 shots.

Given the size and weight of the camera gear, a motorized rail should be attached to the subject so there is little stress on the equipment.  The other factor is that heavier gear will likely vibrate a bit when moved and you want as little motion as possible in all the elements.  Below I have included a bellows setup without the additional illumination or motorized rail.  I have used this successfully for many of my macro shots.

Subject and camera should be independent of each other so that you can freely manipulate each one.

Thanks for reading.

Eric Svendsen     www.ercspix.com