Wednesday, June 19, 2019

Playing with Macro Photography

With flowers coming into bloom, I've been curious about "close ups" on them.

Macro photography has a couple (maybe more) qualities -- at best able to produce 1:1 or greater magnification on the image sensor (traditionally 35mm x 24mm); and able to focus from a very short distance.

My EF 50mm 1.4 USM lens has a minimum focusing distance of 1-1/2' (45cm).

That is a minimum of 240cm wide x 130mm high. Here's the PhotoPills application used to calculate that:



I was poking around on Craigslist, and a very well regarded Macro lens like the Canon EF 100mm L were going for around $500 used. Hmmm. As I was continuing to research whether to spring for it and came across the alternative of using "tubes" for the same purpose.

This Kenko stacking set of tubes was $130:
Canon EOS 50D,0.05 1/20, f/1.4, focal length 50, ISO 3200


Some test shotsI took pretty quickly without worrying too much about exposure or getting focus perfect. Focus and lighting are two of the challenges with macro -- you're so close you often need high aperture numbers to get a sufficient depth-of-field to have a whole subject like a flower in focus. But high apertures restrict the light so often you need flash to supplement available light. (The tubes also further reduce amount of light.)

If you're really observant, you'll note I've already pushed my ISO to 3200 (the highest the camera can go) to get a shot I could handhold and not use flash to begin with. I'm actually impressed I got these shots at 1/20th!
From the 50mm lens as-is:
Canon EOS 50D,0.05 1/20, f/1.4, focal length 50, ISO 3200


With 12mm tube:
Canon EOS 50D,0.05 1/20, f/1.4, focal length 50, ISO 3200


With 20mm tube:
Canon EOS 50D,0.05 1/20, f/1.4, focal length 50, ISO 3200


With 36mm tube:
Canon EOS 50D,0.05 1/20, f/1.4, focal length 50, ISO 3200


If (and it's a bit of an if) my math is right the 36mm tube provides 0.87x magnification. The tubes can be stacked as well.

12 0.39x
20 0.55x
36 0.87x
48 1.11x
56 1.27x
68 1.51x

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