Did you say Macro? Here’s a lil’ something about them macro lenses…
Written by: Tiffany Joyce
After I made the last post on insect photography, one of our readers sent me an email saying that he’s not getting ‘that magnification’ with his Canon 60mm macro lens, and how should he go about trying to achieve it. This I realized is a doubt in many people’s minds, so with today’s post, I try to make some clarifications regarding macro photography and lenses.
First of all, let us get through the boring part i.e. the definition. When the size of the subject in real life equals the size of the subject as exposed on your camera sensor i.e. when you get a sensor to real life ratio of 1:1 or higher, you’re said to be shooting macro. Understand that when you’re getting a life size impression of a bug on your sensor, you’ll get a really huge version of it on your screen or in print. Your sensor is probably something like 22mm x 15mm, and if even ½ or even ¼ of that area is covered by something, then that something will clearly appear a lot bigger on your screen.
The magnification provided by a lens is fixed and indicated on the lens. Most dedicated macro lenses offer 1:1 magnification, but there are available lenses that offer a magnification of 2:1 or higher. There are ways to increase this though, which I’ll discuss later.
The thing to be kept in mind along with the magnification, is the closest working distance i.e. the distance at which the lens provides its said magnification. For instance, if you’re taking a picture of a bug (I know, bugs are so awesome!), you would prefer to keep maximum distance lest the little creature get scared and scurry away. If you get too close, you may end up casting a shadow on your subject as well. The further you are, the more light you get as well, which will give you a brighter view and hence maybe also help you focus better. So ideally, you’d want the maximum working distance. Based on these factors, there are three main kinds of macro lenses:
1. 50-65mm macros that have the lowest working distance. They are also the cheapest, and are fine enough if you plan to use them for still life mostly, and if you don’t mind getting too close to the subject.
2. 100-105mm macros that are perhaps the most popular macro lenses because of two reasons: they offer almost double the working distance, and are still relatively cheap compared to the 200mm macros.
3. 200mm macros are as good as it gets. These lenses offer you the maximum working distance which means you get the same magnification as the others but from a much farther distance which any bug photographer would agree is a very welcome convenience. Like all pro equipment, these will usually cost you upwards of USD 1K.
If you want a higher magnification, you can use accessories like extension tubes (which allow you to focus at a closer distance) or teleconverters (which basically multiply the magnification by the said factor, usually 1.4x or 2x). When using a teleconverter, you also lose two stops of light which means less light enters your lens. Also, most teleconverters require you to focus manually, so keep that in mind if you decide to use one.
As for manual focusing for macro, well, you just have to get used to it. Some cameras have pentaprism viewfinders which are essentially brighter, and so make focusing easier. Also, if your dSLR has live view, that really helps in accurate focusing when taking macro shots.
Before I end, I just want to clarify that the closest working distance is not the same as the closest focusing distance. The former refers to the distance of the subject from the lens, while the latter refers to the distance of the subject from the focal plane which is usually further behind. This means that if I have a lens with a minimum focusing distance of say 15 inches, and my lens is say 10 inches long, then the effective working distance for me would be 5 inches.
Macro can be an endless discussion, but this post was basically meant to clear some basic stuff that many are unaware of (because so was I, and I assume there are many like myself when I say this). I hope you benefit from the post. Any comments/queries/suggestions are welcome
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