Just received my Pinhole Pro… a multiple aperture pinhole that attaches to my Fuji X-T1 like a lens. I bought it through a Kickstarter page, but it's now available through Thingyfy. I have always had a great interest in pinhole photography… my Masters thesis was all about it. But as with all things, I got busy with other projects in my life and haven’t explored pinholes for years. The Kickstarter campaign gave me an excuse to start again in the digital age. Sure, I could have bought a body cap and created my own pinhole, but the clean lines and multiple apertures of the Pinhole Pro intrigued me. And at $50, who could say no?
So what is this product anyway? Well, according to the Thingyfy specs, it's an anodized aluminum alloy body with a focal length of 50mm, it comes in multiple camera mounts (Canon, Nikon, Sony, etc.), and has a ring of multiple apertures, from 0.10 to 0.80 in size. The camera meter doesn't work with the Pinhole Pro attached, so I needed to consider exposing images without it. I had to determine the f/stop for each of the apertures and convert that into an exposure time. The first issue… was it actually 50mm? I have a mirrorless APS-C camera, and I was unsure if the 50mm body size was actually 50mm on my Fuji. It has been a long while since I had to think of film planes and nodal points, and, honestly, I’ve forgotten more that I remember. I knew that angle of view equivalents to 35mm (full frame) were about 1.5 times for APS-C. Would that mean the length converted to 75mm or 33mm? Or did it matter… 50mm is 50mm. Ah, the trials and tribulations of getting old and addled. I finally decided it was all rather moot… I just had to go out and take some test images. But me being me, I wanted to know at least an approximate exposure time. So I make a quick chart based on the sunny f/16 rule. You know the one… subject lit by a bright sunny day should be exposed at f/16 at a shutter speed equivalent to the reciprocal of the film speed. Everyone knows that, right? So anyway… my I.S.O. was 200, which meant my exposure was close to 1/250th of a second. All I had to do was find out the f/stop for each aperture. Easy. Taking the 50mm length and dividing that by the apertures sizes gave me the following, rounded to the nearest one-third f/stop: 0.80 = f/64 0.50 = f/102 0.35 = f/114 0.30 = f/160 0.25 = f/204 0.20 = f/228 0.15 = f/320 0.10 = f/512 So, on an f/16 day (subject in bright sun) at I.S.O. 200, my exposure times in seconds would be: 0.80 = 1/15 (+4 stops) 0.25 = 1/2 (+7 stops) 0.50 = 1/8 (+5 stops) 0.20 = 1 (+8 stops) 0.35 = 1/4 (+6 stops) 0.15 = 2 (+9 stops) 0.30 = 1/2 (+7 stops) 0.10 = 4 (+10 stops) Notice the 0.30 and 0.25 exposures are the same (1/2 second, or +7 stops). This is because I’m rounding everything off to the shutter speeds I have on my camera. Cameras with 1/3 shutter speeds, (and very picky photographers behind them!), can be exposed more accurately. But let’s face it, this is a pinhole we’re talking about, and I’ve already "techified" it enough. It was time to go take some real photos… But that’s for next time.
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