>>2660744I misunderstood you. I thought you meant that the range between 24mm-85mm was the one that got the most effort from manufacturers. I didn't know you meant that the most popular focal lengths get the most effort put into them like the 35mm and 85mm.
You are still wrong about that however.
The best lenses in the pentax line up are not a 35mm and a 50mm or an 85mm but the 31mm and 77mm. Leica doesn't even make an 85mm but they do make a 75mm which is in their APO range and they put a lot of effort into it. The best lens Zeiss makes for 35mm DSLRs are the 85mm and 55mm otus which some consider the best in the world. Notice it's not a 50mm but a 55mm and they did put a lot of effort into it and it is really good. There is another zeiss 55mm which is in the Sony E lineup which competes with the Otus as being a great lens. The Contax G lens line up doesn't even have a 50mm but it does have a 45mm and it's considered a great lens. Speaking of Zeiss, they don't even make 24mm lenses, they make 25mm lenses unlike most manufacturers. Like I mentioned before, Leica doesn't make an 85mm lens anymore their standard short telephoto is the 90mm.
Say you look at some 24mm, 35mm, 50mm, 85mm lenses from Canon or Nikon there is a good chance those are not the exact focal lengths of those lenses. A 50mm for example could actually be a 49.5mm or a 51mm. Today companies just release the lens close to the most popular focal length. Because nobody wants to buy a 49.5mm lens.
If you look at old lenses the standard 35mm, 50mm, 85mm weren't established. You could find lenses in 38mm, 52mm, 57mm focal lengths. The standard focal lengths we know today were the birth of standardization by popularity. Manufacturers just see the figures and see those are the lenses that sell so they try to make them. Modern lenses are designed on computers so it's not like before where it was cheaper to improve a known design than start one from scratch.
