Funky shutters

A neat G1 shutter experience

I confess that when I first saw this image, taken just before Christmas, I almost erased it. It’s another focusing on the theme of lone individuals in the big city – what I call my ‘Edward Hopper series’ after the great American painter.

The key element is the figure and is lost in gloom. But right before I hit the ‘Delete’ key I noticed something strange. The ‘up’ escalator is blurred whereas the ‘down’ one is sharp as can be. That’s an interesting little mystery, and it suddenly struck me that despite all it’s electronic magic, the Panasonic G1 which I used to snap this still uses a conventional focal plane shutter, with vertically traveling blinds. While it happens to default to an open state, thus permitting the sensor to receive and transmit the image to the electronic viewfinder (the camera has no prism or mirror) it’s conceptually identical to those used in some cameras a hundred years ago.

So I decided to manipulate the image and started messing with selective-this and slider-that in Lightroom, ending up with this:

Escalators and lone figure. G1, kit lens at 28mm, f/5.6, 1/30, ISO 320.

The camera’s shutter was moving with the down escalator and in the opposite direction to the up escalator, which accounts for the differential sharpness of the two.

Here’s a detail screenshot:

You can see what I’m rambling on about by checking this video, taken with a high frame rate video camera to show things in slow motion:

Perhaps the most famous example of funkiness from focal plane shutters is this picture by Jacques Henri Lartigue, where the wheel’s seeming elongation is the result of …. you guessed it, a vertically traveling focal plane shutter, the effect further magnified by the photographer’s panning with the motion:

Early focal plane shutter distortion. Taken in 1913.

Modern focal plane shutters travel too fast for this sort of extreme distortion which is a shame!

There really is little new under the sun, but the strange effect in my picture and a bit of manipulation make for an interesting snap. It seems that the 1/30th second used (excuse me, the 1/30th second the camera’s electronics chose, as I invariably use aperture priority exposure automation) was perfectly in sync with the speed of the down escalator.

One thought on “Funky shutters

  1. Thomas,

    These days I had a discussion with friends why Sony Cybershot DSC-H50 Super-zoom camera (CCD with electronic shutter, up to 1/4000 sec) had no flash sync limit like Canon, Nikon or my Panasonic GH1 (1/160 sec). I learned a lot. Your images are a very nice demonstration of slit shutter consequences.

    Happy new year

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