Macro Photography 101, Part 2
Written by: Tiffany Joyce
In Part 1 of Macro Photography 101, we discussed what a true macro lens is. In Part 2, we will be discussing depth of field, lighting, and specialist lens in Macro Photography.
DEPTH OF FIELD
We all know that when you use a wide open aperture then you will get a shallow depth of field (DOF) and vice-versa. One thing we also have to keep in mind is that the closer you are to your subject, the shallower the depth of field will be. To illustrate this point, take a landscape photo at f/4 and using the same aperture, take a photo of an object that is close to your lens’ minimum focusing distance.
Since you’ll be really close to your subject in macro photography, shallow depth of field will be a constant no matter how small your aperture setting is. The first photo below was shot with an aperture of f/2.8 while the second one was shot with f/11. You can see that the difference in depth of field is very minimal.
Shot with 100mm Macro f/2.8
Shot with 100mm Macro f/11
There are two ways for you to make shallow DOF work for you:
1. Use it creatively
You can make shallow DOF work for you since it can effectively isolate your subject from a potentially distracting background. You can also just isolate a part of the subject that you want to highlight and blur the rest. This technique is similar to using bokeh for non-macro shots.
2. Change your viewpoint
The area where the subject is sharp is called the range of focus. The boundaries of your photo’s range of focus are parallel to your camera’s sensor. In the illustration below, line A shows where the camera sensor is. Lines B and C represents the boundaries of the range of focus. Lines A, B and C are parallel. You can see that only the front part of the battery is in the range of focus much like the two previous photos.
By changing your viewpoint, you can align your camera’s sensor to the part of the subject you want in focus. Using the battery example, I simply moved to one side so that all the text on the battery’s label is in focus. Notice how everything looks much sharper even at f/2.8.
Shot with 100mm Macro f/2.8
Below is the illustration showing how changing your viewpoint will also change your range of focus. Compare this to the first illustration.
Lighting can be tricky when doing macro shots. For one thing, you will need a lot of light to get really clean images. If you plan on getting really close to your subject, you will not be able to use built in flash since the lens barrel will block its light and cast a shadow on your shot. It would be better to use a flash unit with a rotating head.
In all the photos in this article, I used a 430EX flash while shooting at ISO 200 with a shutter speed of 1/125. The flash unit was on camera and I was bouncing the light to the ceiling to get even diffused light on both the bottle cap and battery. Again, this technique will not always work since having your lens near the subject will limit your options in bouncing the light. This is where macro lights come in.
Macro lights are attached to the front of the lens so as not to cast any shadow on your subject. The light will also be even no matter how close you are to your subject. These lighting units are also called ring lights since they are circular in shape.
You can also try making a macro studio DIY-style, which would be your cheapest alternative.
As I’ve mentioned before, true macro lenses are those that have a reproduction ratio of 1:1 but it doesn’t end there. Canon has released the MP-E 65mm f/2.8 1-5x Macro Photo lens. The lens is not much to look at from the outside not being much larger than a kit lens. It does, however, have a maximum reproduction ratio of 5:1.
This thing will turn your DSLR into a microscope. Well, not really, but you know what I mean. I could be wrong, but I think this is the only interchangeable DSLR lens with this much magnifying power.
With all that being said, is buying a dedicated macro lens for you? If you don’t want to spend on a dedicated macro lens then there are other ways for you to get started.
• Close Up Filters
This would be the cheapest alternative available in getting macro shots. It attaches to the front of the lens like any other filter and works by allowing you to get closer to your subject. The maximum magnification you get is dependent on the focal length of your lens and the dioptre rating of the filter. +1 dioptre is the weakest and +10 is the strongest. The trade off with using close up filters is that it can affect image quality. (To learn more about filters, read Filters 101.)
Extension tubes are hollow tubes that attach between your lens and camera. Since the tube is hollow, it will not affect your lens’ performance. By moving the lens away from the camera body, the magnification factor you get increases. The computation for magnification factor and reproduction ratio is as follows. If the length (in millimeters) of extension tube is half the focal length of your lens then the you will get a magnification of 0.5x or a ratio of 1:2. If the length of the extension tube is equal to the focal length of the lens then you get a magnification of 1x or a ratio of 1:1 like a true macro lens. You can even combine several extensions to get even greater magnification.
When purchasing extension tubes, its better to get the same brand as your camera. Proprietary extension tubes have electronic contacts that retain the connection between your camera and lens. This means that you can still use auto-focusing and TTL metering. The down side of using extension tubes is that you will require more light to get the correct exposure so much so that tripods are necessary most of the time.
And that pretty much concludes Macro Photography 101. If you have any questions or would like to add something, pop in and leave a comment. Happy Monday, folks!
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