Good morning, Bertil;
Funny thing that you should get a MINOLTA MC AUTO TELE ROKKOR-PF 1:2.8 f=135mm lens. Just today I was handed a MINOLTA AUTO TELE ROKKOR-PG 1:2.8 f=135mm lens. I believe that this is an ancestor to the one you have. Like yours, this one is also in excellent shape for an SR mount lens. Oddly enough, the front lens cap has the Diamond-EP engraving indicating "Export Permitted" or "Export Production" that was in vogue during the MIOJ (Made In Occupied Japan) time period from 1945 to the early 1950s, but there is no similar engraving on the lens itself, and the lens cap is of the type in the same time period as the lens, the 1960s. Strange. The lens back cap also is the early 1960s molded soft plastic push-on type with the Minolta Triangle logo.
Now. Your question. The first letter in the two letter group is for the number of lens groups in the lens design, while the second letter in the two letter group is for the number of glass elements in the lens design. The first letter is also for the first letter in the Latin ordinal number; Bi for two (2), Tri for three (3), Quad for four (4), Penta for five (5), Hex for six (6), Sept for seven (7), Oct for eight (8), Non for nine (9), and so on. The second letter is just for the order of the letters of the alphabet; B for two (2), C for three (3), D for four (4), E for five (5), F for 6 (6), G for seven (7), H for eight (8), I for nine (9), J for ten (10), K for eleven (11), L for twelve (12), and so on. This listing will cover almost all of the Minolta lenses you are likely to encounter, including most of the zoom lenses. A lens group may be made up of two or more lens glass elements cemented together to form that group.
So, your MC TELE ROKKOR-PF will have "Penta" or five (5) groups with "F" or six (6) glass elements. My AUTO TELE ROKKOR-PG has "Penta" or five (5) groups with "G" or seven (7) glass elements.
OK. Now you have a complete listing of the Minolta lens design codes. You can translate those cryptic letters into their true meanings and really impress the ladies at the cocktail parties.
Enjoy;
Ralph
Latte Land, Washington