So here is an interesting story for you:
These two photos were taken about six months apart. I had a roll of film in the camera that I actually forgot about. When I shot the rest of the roll, I assumed it was ISO 400. (No, I didn’t label it, thank you…)
When I finally completed it, I realized that it was actually ISO 50, and that the last six pictures were at least 3 stops underexposed. The worst part is, I couldn’t remember whether the first six pictures were the ones worth saving, or the last six. As a result, I stand-developed them in Rodinal 1:150 (1 hour) and actually ended up with usable images on both ends of the roll. Here are two examples–both summer and winter.
The first two were taken on the Arax-60 with the Flektogon 50mm on RPX-400, pushed somewhere WAY north of ISO 3200. It was nearly pitch-dark when I shot them. And also cold.
The last four were taken on the Arax-CM with the standard 80mm Arsat (pronounced “Arse-HAT” I am really serious) lens using Tri X and developed in Rodinal. I was actually testing a new focus screen, and looking for “pillars” on the focal plane shutter–These are vertical bands of dark and light due to uneven movement of the massive shutter across film plane. This differential speed is essentially why Hasselblad abandoned focal plane shutters in their earlier models. The Ukrainians remained undaunted.