Archive for the ‘DIY’ Category

The Myth of Solarization

Monday, December 26th, 2011

Solarization of modern films while in the camera is largely a myth.   Evidence for this is all around you if you have been shooting film. Look at the leader on ANY negatives you’ve had processed, which would have been exposed to the light since it was sticking out of the canister.   Its black.  Here is an example…

The negative on the left was handled in typical way, so perhaps 2-5 minutes of cumulative exposure to ambient light. The one of the right sat on a shelf in my office for 14 months, fully exposed to the sun for about 2 hours per day! There is no noticeable inversion, only a slight difference in light leakage past the felt.

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Old Science

Monday, September 26th, 2011

I’ve been cleaning out my basement and unboxing huge amounts of my “science junk” that has been packed away since we moved a couple years ago.   There is a photo contest coming up that I occasionally enter, here are a couple test shots featuring some of my collection.

DIY Power Supply for Pentax K5 DSLR

Monday, July 18th, 2011

This is a follow-up to my prior post about a DIY DC to DC power supply for my FujiFilm S100fs camera.  I recently purchased a Pentax K-5 which I hope to use for time lapse work.   After doing some testing I found that the internal battery in the K-5 will power the camera for 3 hours and was capable of taking more than 10,000 6MP stills in continuous shooting mode.   However for longer term shooting, a DC power source is necessary.

The K-5 provides a strange DC-IN port labeled 8.3vdc.  This is the same port used on several of the K-series cameras and would normally be connected to Pentax’s D-AC50 AC power adapter.   But this would require me having an DC to AC inverter to power the AC to DC adapter.   This DC to AC to DC conversion would be very inefficient, requiring 5x the battery capacity.   So I built a similar DC to DC converter based on Dimension Engineering’s SWADJ-3 and D-SWADJ switching regulators.

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