Friday, October 26, 2007

Using Canon SpeedLite Transmitter ST- E2 As Focus Aid?

Just an idea...

Recently, Dr. Pimento did some pseudo scientific field testing with a Canon EOS 40D at his local pro camera shop. Straight out of the box, using several of his own professional Canon prime lenses and zooms, he took a series of ambient light, high ISO images to evaluate the 40D's focus accuracy and consistency under normal room lighting. His goal, to test for the dreaded front focus / back focus problems experienced by some of Canons other high end cameras. Using the unevenly stacked inventory boxes high on the shelf behind the counter, he focused and refocused on the same spot ( the large typeface on a Canon lens box ) making exposures after each new framing and refocus. Dr. Pimento was careful to use the singular focus spot in the viewfinder, zeroing in on the exact letter in the type face on the package front for each exposure.

Back at Dr. P's secret testing facility, the RAW images were processed and evaluated on his "state - of - the - art" imaging system, complete with Matrox video card and high resolution LCD monitor. His down and dirty in store focus experiment did not reveal the positive results he was hoping for, with frame after frame of inconsistently focused images, sometimes behind the subject, other times focused well in front.

Is it possible that Canon DSLR's just aren't capable of focusing on certain fonts? Or is it more likely that Canon autofucus ( purposely misspelled ) technology has an aversion to critical focus on cardboard boxes! Hmmmm..............?

That brings me to the title of this post....."Canon SpeedLite Transmitter ST-e2 As Focus Aid." I have heard rumors that these overpriced units for controlling multiple speedlite flashes are excellent for using strictly as a focus aid, emitting an LED beam at close proximity. Come to think of it, I have hardly ever taken an out of focus pic with a speedlite mounted on my Canon in a dimly lit room. At $209.95 before shipping at B&H Photo, they certainly aren't cheap, but coming back from an assignment with poorly focused images might cost you even more.

I might have to give one of these a try!


-Speedlite Transmitter ST-E2

- Compatible with 420EX, 550EX, 580EX, or MR-14EX and MT-24EX Macro flashes

- AF-assist Beam: Compatible with EOS-3's 45-point Area AF and 28mm and longer lens focal lengths

- Power Source : 2CR5 lithium battery x 1, Battery Life: Approx. 1,500 transmissions (At room temperature and with a new set of batteries).

Price: $209.95 at B&H Photo

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