On average most modern dSLRs have the slowest speed of ISO-100, many 50, I'm not sure. But I recently was given a couple rolls of film that would be rated at ASA-1.5, I decided to take it one stop lower and shoot it as ASA-0.75. How did I do it? Easy, my trusty Sekonic L-358 meter can go down to ASA-3, set the aperature on the meter to f/32, meter, note the shutter speed, and then open up the lens to f/16.
f/32 = ASA-3
f/22 = ASA-1.5
f/16 = ASA-0.75
Then taking advantage of a tasty weather day I went out and shot!
Of course the next problem is how to develop the film! This being more Ukrainian Film from the Svema factory there's very little information online about the rare beast that is Micrat-Orto. So a group of us has been working on developing (pun intended) formulas for the film. A good friend developed this in Kodak Xtol Stock for 8 minutes. But it was pretty grainy, so I wanted to cut that by duluting it 1+1 (so that's 150mL of stock to 150mL of water). But then I had to get a time, I could do a whole doubel the time and run it for 16 minutes. But then I looked at the diluted xtol times for the Svema Foto 200, the stock xtol time was 7 minutes the 1+1 dilution was 12 minutes. That's double minus two, so I ran it for the same, making it 14 minutes. And it worked! Probably could go with another 30 to 60 second reduction in time for the future. Another odd note...it develops as a positive!
Nikon F4 - PC Nikkor 35mm 1:2.8 - Svema Micrat-Orto @ ASA-0.75
Kodak Xtol (1+1) 14:00 @ 20C