Extreme macro

Started 2 months ago | Questions thread
Gerry Winterbourne Forum Pro • Posts: 17,501
Re: Extreme macro

Jim Lewis NJ wrote:

Is there a very low cost macro lens that would allow me to photograph an object that is only about a half inch, without the lens getting closer than about 3 inches? This is for a Canon DSLR.

The usual requirement for a macro lens is 1:1 magnification - that is, the image on the sensor is exactly life size. On your camera a 1/2 inch insect would be roughly double life size - 2:1 - so a normal macro lens won't do it and there is no cheap lens that can do it directly.

But don't worry - there are other methods. There are auxiliary lenses (filters) that increase magnification but I don't know if they are powerful enough to reach 2:1. But you can do it with extension tubes. There are some very cheap extension tubes but they only work with old lenses that have aperture rings; if your lenses are modern you'll ned automatic tubes. These are moderately priced. Or you could buy cheap tubes and a second-hand old macro lens.

Whatever method you se there is an inescapable problem, though - the closer you get and the more magnification, the shallower your depth of field. It might well be less than 1mm. The way out of that is to take several photos at slightly different focus distances and stack them, which is done with various types of software.

If your subject stays put stacking is tedious but easy; tricky if the subject moves.

This is a stack of 29 shots of a subject about the same size as you are asking about (it's the seed head of a tulip). I used a 70mm non-macro lens with 34mm of extension tube.

For a bit more expenditure you can add a teleconverter into the mix: this is a single grain of salt using 105mm lens (macro this time) with 65mm of tubes and a 2X TC. I didn't stack this one and you can see it isn't all within the DOF.

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Gerry
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I'm happy for anyone to edit any of my photos and display the results
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First camera 1953, first Pentax 1985, first DSLR 2006
http://www.pbase.com/gerrywinterbourne
gerry.winterbourne@ntlworld.com

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