The View Up Here

Random scribblings about kites, photography, machining, and anything else

Tethered

Posted by Tom Benedict on 09/06/2011

During World Wide KAP Week I had a lunch meeting with a fellow photographer.  One of the topics we touched on was doing photography from a tripod.  Familiar ground, or so I thought. I’ve own two heavy sets of legs I got back when I first started doing photography. I used them for 35mm as well as large format work. I know all about photography from a tripod, right?

Wrong.

One of the first things he said was, “I always shoot tethered.” Tethered? What was that? And why would someone want to do it?

To answer that question I have to back up a little and talk about the good old days of film. My wife and I got into photography through 35mm gear. Our first camera was a Canon A2, and over the next few years we got other bodies and lenses. I also got into large format photography, and wound up spending more time focusing on a ground glass than I did through a viewfinder. My eyes are fine for distant viewing, but I have almost no close-focus. Even with the diopter adjustments available on 35mm and DSLR viewfinders, focusing through a viewfinder has never been possible for me. One of the reasons I enjoyed doing large format photography was that I could focus in a ground glass using a 30x loupe. So long as I took care of camera flex and wind shake, I knew my negatives would come out tack sharp.

Since switching to digital I’ve had to go back to relying on autofocus rather than focusing on a ground glass. Modern autofocus algorithms are quite good, but they’re still not as good as careful manual focus with a loupe. Most algorithms allow for the possibility of offsets, and just as no two lenses of a given make are identical, no two camera bodies will autofocus quite the same.

My T2i has live view, a feature that drove me to make this poster some years ago:

Old School Poster

I thought of it as little more than a gimmick until that lunch time conversation. That’s when I learned you could zoom in, almost to the pixel level, with live view.

I had my ground glass back! It was smaller than I like, a 3″ LCD instead of a 4″x5″ piece of glass, but I found I could actually focus with it. That’s when he told me when the camera was tethered to a laptop that was running the EOS software, you could zoom in to the pixel level and have it take up the entire screen. Well I just had to play with that!

Last weekend I went back through the scissor-and-thread photography I’d done and fixed some of the problems with my most recent set: thread too thin, lighting too uniform, no shadows, no strong reflections, etc. I set everything back up with different thread and different lighting, and my camera tethered to my computer. Boy what a difference. I set a manual exposure of eight seconds at f/11, manually focused on the pivot screw, and gave it a try.

Ghingers

It worked wonders.

I’m still not 100% happy with the photograph itself. There’s a stray shadow from one of my tripod legs coming up from the lower right. It’s possible to fix this in Photoshop, but why do that when it can be fixed in the setup? I have one more round of scissor photography to go before I think I’ll be satisfied with the images. From now on I plan to do all my studio work tethered.

– Tom

P.S. After looking at the image resolution and realizing I could print this 24″ high, I passed this information on to my wife. She told me she had absolutely no interest or desire to have a giant pair of scissors hanging on the wall. Ah well…

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One Response to “Tethered”

  1. […] this article: Tethered Posted in Canon DSLR Tags: a-ground-glass, education, facebook-photo, Images, legs, log-in, […]

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