Macro photography - Part 1: Which axis to photograph along

Genus Sphaerophoria - long-tailed hoverfly - species uncertain.  Both images shot at f/14.

Photographing insects is a passion of mine.  I keep a camera system set up specifically for macro photography that involves a DSLR, 105 mm macro lens, extension tube, and macro ring flash.  I will talk about equipment in another blog.  

One of the great challenges with macro photography is getting everything in focus.  There are numerous ways to enable this, but the issues can be reduced by simply photographing the subject perpendicular to the long axis, which usually means from the side or top.  Shooting parallel to the long axis (usually from the front) means getting only portion of the insect in focus.  This can be countered with stacking, but that is rarely an option when live insects won't wait around while you set up for such shoots.

The above photos were taken at f/14.  I will discuss depth of field in greater detail in another blog, but in macro photography, f/14 does not boast a great deal of depth of field.  As an example, the image below was shot at f/45 (Nikon value).  There is much greater depth in focus on this as you can see the top of the fly and the flower detail beneath it.

Hoverfly on daisy.  Aperture was f/45.  

Although the advantage of shooting at small apertures means greater depth of field, the caveat is that sharpness falls off at smaller apertures.  Most lenses show their best sharpness at aperture values a stop or two past wide open.  Closing apertures further results in softness, especially towards the edges.  

In conclusion, shoot perpendicular to the long axis for your macro subjects.  Choosing small apertures will produce greater depths of field, but you may sacrifice sharpness.  Stacking images provides the best of both worlds where you can use the sharpest apertures in conjunction with many focal points to produce a single, remarkable image.  Such efforts though means a great deal of time and a subject that is cooperative - usually meaning dead.  

I recommend playing with aperture values in your photography and determining which apertures are acceptable.  Although sharpness takes a hit, I find that most of my macro images have enough depth of field using smaller apertures.

Thanks for reading.

Eric Svendsen     www.ericspix.com