Wednesday, October 12, 2011

Macro Photography

I recently got asked about some of my macro shots and how I go about macro photography.

Anyone who has been around photography for a long time knows that there are MANY ways to shoot macro.

First off macro or micro pretty much means close-up, or life sized.

If you want to get technical, macro lenses are categorized and rated by the ratio of the actual size of the subject vs. the size it is on the image sensor or film. A 1:1 lens is about the best you can get. If you take a picture of a 35mm rectangle with a 1:1 lens at the minimum focusing distance, it will cover the whole frame. If you do the same with a 1:2 lens, it will cover half the frame. Most lenses are about 1:6 which means that a 10mm bug on a 35mm piece of film (or full frame image sensor) covers only 5% of the frame!

Of course, you have seen images that have a ratio much better than1:1, where a fly’s eye may take up the entire frame!! We are going to discuss some methods used to make a 1:1 lens a 4:1 lens or better! Or maybe you just want to make your kit 1:6 lens a 1:1 lens.

The great thing about macro photography is that you can get decent results for basically next to no cost.

The first thing I am going to talk about is the cheapest but also EXTREMELY simple. These handy gadgets are called macro filters or close-up filters. They are simply a filter that screws on the end of your lens. These filters look and act just like a magnifying glass. They come in different strengths from +1 to +4 to just stupid close. The great thing about macro-filters is that you can use them on auto-exposure mode on your camera. You can find a set of 4 with a nifty case for under $20 on e-bay. Some disadvantages are a slight sacrifice in image quality (especially along the edges) and it shortens your depth of field which can make it extremely difficult to get a sharply focused image. Also, you have to make sure that you get the right diameter filter for your lens (which is fine if you only plan on using one lens or lenses with the same filter size.)

The next fun macro toy is an extension tube, which is a…tube… that extends your lens. The difference in this and the macro filter is that an extension tube goes between your lens and your camera body rather than on the end of your lens. There are no optics (glass/lenses) in an extension tube, it just moves your lens farther away from the camera body. Like the macro filter, you can get different sizes or strengths of tubes. The more expensive tubes have electronic contacts that allow autofocus and auto exposure mode to be used. Some tubes cost less than $5 but they are nothing but a piece of metal, which means that you must use manual exposure mode and manually focus. The biggest drawback to the cheap tubes is that they MUST be used with a lens that has an aperture ring (you can change the lens aperture by turning a ring on the lens not just a dial on the camera.) If you put a cheap tube on a lens without an aperture ring, the lens will be stuck at its smaller aperture and render is useless. I like extension tubes because you do not lose any image quality. Some negatives are that they are more expensive than the filters (about $75 for the tubes with electronics) and like the macro filters, they decrease your depth of field.

Last is one of my favorite photography toys, a teleconverter. They (like everything else discussed) come in different “strengths”. You can get a 1.4x a 1.7x or a 2x. These numbers correspond to the amount of focal length added. A 2x teleconverter DOUBLES yours focal length, making a 50mm lens a 100mm or a 70-300mm a 140-600mm!! What is fun about a teleconverter is that it doubles your focal length but still allows you to focus at the same distance. This is fun for telephoto shots along with macro shots. If you have a 50mm lens that can focus at 1 foot, put a teleconverter on your lens and it is a 100mm lens that can focus at 1 foot… awesome :) A teleconverter looks almost like an extension tube because it goes between your camera and lens. Unlike an extension tube, it has glass in it, which means that it can lower your image quality because it magnifies any imperfections your lens may have. Another disadvantage is that it cuts your aperture in half which means that your awesome F/2.8 lens is now a so-so F/5.6 lens. A teleconverter can be found for about $75 also.

Now, let’s take a standard 50mm F/1.8 lens. This has a reproduction ratio of about 1:6. With this 50mm, you can focus at about 1.5 feet. Let’s put a 2x teleconverter on it and make it a 100mm F/3.6. That makes the lens have a 1:3 ratio. Let’s put an extension tube on it, allowing it to focus at .75 feet meaning it’s a 1:1.5. Hmmmm, let’s now add a macro filter and allow our lens to focus at about 4 inches!! A disadvantage of all of this is that your depth of field is going to be stupid small… like, half of a fly can be in focus but the other half completely blurry. Some ways to combat this is stop down your aperture (because that increases your depth of field.) You can also just lean back and forth to focus rather than use autofocus or try to manually turn to focus ring.

Macro is cool because you can do it anywhere, you do not need a busy city or a beautiful country landscape. All you need is a bug, or an eyeball, or a flower… anything God created looks amazing close up :) Buy a cheap set of macro filters and see what you come up with!

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