You live and you learn, sometimes the hard way. When I had decided to test the Pocket Light Meter App for iPhone X against my Sekonic L-358 light meter, I also decided to pair it with one of my medium format cameras had not tested; The Mamiya RZ67 Pro.
First a little back history on my RZ67, I bought this camera “as-is” last year, the electronics didn’t work, but the camera was still usable at the emergency shutter speed of 1//400th of a sec, The bad news is that since the cameras electronics were not operable, there is no warning that the dark slide was still in the film back, and unlike my other “manual” medium formats; the shutter button can not be engaged if the dark slide was still in the film back. So during the test, there were a lot of missed shots, I mean a whole lot of missed shots.
My test included the following:
Mamiya RZ67 Pro camera body
Mamiya Sekkor 50mm C lens
Mamiya RZ67 Pro II 120 film back
ilford HP5+ black and white 120 film
Pocket Light Meter for iPhone X
Sekonic L-358 light meter
For the most part of my test. the iPhone app pretty much kept up my handheld meter (Sekonic L-358) The readings for the highlights were point on, the Shadow readings were for the most part about a third off, no game killer though.
As stated above, the test would have been more in depth if I had not forgotten to remove the dark slide from the film back, resulting in many missed opportunities.
Will I trust this app for any future shoots: The short answer is Yes and No. If the shoot is for a client, I would always opt for my trusty handheld meter, personal projects on the other hand, I would switch between this app and my Sekonic.
The next time I plan to use this app will be when I shoot some 4x5 film in the next week or so. I’ll post the results from that shoot soon.