P., the reason modern lenses that open to f/5.6 are usually recommended for use at around f/22 is that they gain coverage when stopped down from wide...
The ledger show what appears to be the completion date of each lens. So we know 1559 (the serial number at which the ledger starts) was completed on...
Usually I use my lenses from f11 to f32, being f22 the one used in the majority of the cases (because it was told that modern lenses are designed to...