Thursday, June 3 2010

Pennies from Sony

One of the first things I did when I got home with my shiny new Sony Alpha 850 camera was try to find out if it could honestly deliver on its 24 megapixel resolution. The image is 6048x4032, but does it actually resolve?

First off, is it physically possible? If you break out an optics textbook and do the math on a full-frame 24x36mm sensor, it is possible to keep the circle of confusion below the pixel size at apertures wider than about f/8. With a terrific lens. And a tripod. And a cable release. And mirror lockup. And no wind.

Mind you, the actual measured lines per inch matters far less to me than the fact that it’s a full-frame DSLR that takes all my old Minolta lenses; I’d have been perfectly happy with a 12-megapixel full-frame body, but since 24 is what’s available…

I didn’t feel like breaking out my big tripod or my good lights, so I settled for getting into the ballpark: a decent lens (Tamron 90/2.8 Macro) at 100% magnification, a sturdy table-top tripod, cable release, mirror lockup, indoors, available light. ISO 100, f/8, 6-second exposure. Developed from RAW using Sony’s app, resized and cropped in Photoshop with no other modifications.

Complete image:

quick macro shot of a penny, overview

50% crop:

quick macro shot of a penny, 50% size, cropped

100% crop:

quick macro shot of a penny, 100% size, cropped

Not bad at all.