|Posted by caseycrockerphoto on April 22, 2010 at 6:09 PM|
The Micro on Macro
(written for the June 2009 Camren Newsletter)
This month's photography magazines and industry business papers are full of talk of new accessory gear, the popularity of digital photo frames, and of the rise of the cellular phone camera.
However, there is one timely and popular thing occurring lately, something the cell-phone cams perform poorly at. (Though you can set your phone's wallpaper with these pretty images of nature). This thing is the macro photography of flowers. Even during a walk, macro photos are everywhere. You have to get close to the subject and simply be fascinated. Depth of field is a critical thing to consider when photographing flora. Cell-phone cameras cannot render the richness in depth of field that a DSLR or 35mm camera can. In turn, the DSLR and 35mm do not perform as precise in depth of field separation as medium or large format cameras do. Its physics and smaller format cameras simply have trouble separating layers of space in a photograph from other layers of space. The purpose of this article is to help apply control over the DSLR or 35mm camera's aperture so refinement of depth of field can be attained.
Fine-tuning the aperture setting is something people tend to have trouble with. Now, most SLR camera are equipped with a depth of field preview button, which allows you to see what depth of field a particular aperture will render before a photograph is captured. This subtracts wasted shots and adds more accurate ones. (Remember, the smaller the aperture number, i.e. f/4, the shallower the depth of field, meaning the less is in focus. Vice versa for, f/22). So, after you have set up your tripod, gained your composition, chosen to use or not use a polarizer or reflector or diffussion of some kind, have set your ISO and shutter, the time for aperture has come. Press the depth of field preview button if your camera has one. If you do not like the result, alter the aperture setting.
For instance, click on the above photo of the Spiderplant blooms. (In doing so a larger version will appear in your browser). These photos were taken in the shade with a small reflector bouncing light onto the scene. Tripod was in place and the ISO was set low, for tonality and color reproduction (very important). A range of photos were captured, but none of which were taken at anything less then f/8. F/8 is an excellent starting point with anything macro. Typically, faster apertures will not give you a desirable beginning field of depth. Like the photo illustration above, a starting point of f/11 helped, but the depth of field offered by f/11 and f/16 were more of the desired effect. And the difference between f/11 and f/16 is significant (a single f-stop makes a large difference the closer the photographer becomes to the subject).
A lens' focal also effects depth of field. A wide-angle lens at f/16 pictures depth entirely differently than a telephoto lens at f/16. The Spiderplant bloom was photographed with an 80-200mm lens (set at 200mm) specifically because it gives working distance from the subject and has an excellent macro reproduction. This lens paired with a Nikon pk-12 extension tube gives a 1:2 magnification ratio, meaning the object is recorded at half its life size. (1:4 ratio would grant a quarter of life size magnification and 1:1 would be life size). Beginning with a slightly telephoto lens is helpful when you want to have more of a dramatic effect from one aperture to the next when photographing your macro world. There are other tools out there that increase magnification, but approaching apertures with a desire for mastery is an excellent way to improve your macro image making.
Click here for illustrations: