In 1973, I preformed a test similar to the one Mick performed. Major differences in methodology were:Originally Posted by Mick Fagan
1. Instead of testing the mirror lock-up feature, I was comparing the performance of two ASA 50 black & white films (H&W Control VTE and Kodak High Contrast Copy
2. Instead of a Nikon F3, I was using a Nikon F2.
3. Instead of the 55mm micro, I was using a 50mm f2 Nikkor.
4. In addition to shooting with the mirror locked up and without the mirror locked up, I also tested with UV protective filter and without UV protective filter.
My results were identical to Mick’s. At the higher enlargements, I too noticed better image quality with the mirror locked up. At the higher enlargements, I also noticed better image quality without the UV protective filter.