Dear MrPhotog... The cameras that I used on the Topcon 300 mm, F2.8 1959 lens were a Pentax SP1000 and a Pentax SPII. So, I bet you are correct and the M-42 mount with a 1.0mm pitch or universal or Pentax thread mount is what I should have ordered instead of the M-44.4 mount. Thanks for the heads up. Shooter41

Dear Morry...After I learned that there were three basic mounts in use in 1958 when my lense was manufactured, I looked up the specs and learned that my lens was listed as M-44.4 and not M-42 or M-39 which supposedly was the T-mount. When amazon delivers it tomorrow, we will see if my research turns out to be correct or not. Shooter41

Dear jerryc41...I discovered that my 1958 Japenese lens uses a T-mount and I ordered one from Amazon for $10.31. I will stop the lens down to get a wider depth of field to help me focus and hang my Sony A7R4 on the back end and create some digital images that I can edit in Photoshop and go to school. (If I have any success, I will post on UHH.)
Thank you for taking the time to comment. Shooter41

Dear Orphoto...You're correct. I am sure that my success rate will be far less due to the heavier weight and manual focus of the old lens rather than with my modern lighter 70-200mm zoom, auto focusing, eye focusing, Sony lens, etc. But the ability to get digital files instantly rather than shooting with film and getting negatives and prints while saving a couple of grand makes me want to try using a higher F stop, creating a wider depth of field and seeing what happens. Thanks for sharing. Shooter41

Dear zug55...My old 1958 lens uses a T-mount converter which I just bought on Amazon for $10.31. Thanks for taking the time to help me. Shooter41

Dear ORpilot...It does have a T-mount and I just bought one from Amazon for $10.31. Thanks for taking the time to share. Shooter41

Dear Alafoto...Thanks for taking the time to reply. My old lens does have a T-mount and I just ordered one from Amazon for $10.31. Shooter41

In 1983 I purchased a used Tokyo Kogaku R. Topcor, 300 mm, F2.8, manual focus telephoto lens that first appeared in America in 1958 and was discontinued in 1961. I would like to find out if currently any manufacturer makes a lens converter that would allow me to hang my Sony A7R4 mirrorless, digital camera on the back end of the lens to shoot outdoor soccer. I want to take advantage of the excellent prime lens and record digital images that I can edit in Photoshop and compare my results to modern 300mm lenses. Does anyone on UHH know if such a converter exists and the best place to buy one new or used? (I realize that all of the bells and whistles that my Sony A7R4 has with Sony lenses will not work on the old manual lens, but the Sony 300mm, prime telephoto lens is more than I can afford and I already own the old Topcor lens. Thank you for taking the time to share your knowledge. Shooter41

Dear plumbbob1...
After becoming a world famous author and philosopher who sold the most books of anyone in the world one year with the exception of THE BIBLE, Ayn Rand was photographed extensively to promote her many books and articles until she became old and requested that photographers like me please refrain from photographing her so that her friends will remember her appearance when she was younger. So at her tribute dinner I attended in Boston notl ong before her death, I honored her request and put my camera away. I suspect that Ayn was so involved and dedicated to her writing, television appearances and speaking annually at Ford Hall Forum, I don't think she had the additional time or energy to learn and practice photography. Shooter41

Dear joecichjr...Once again you proved yourself to be a gentleman and a scholar. Thank you, my friend. Shooter41

Dear mwsilvers...EXACTLY! Shooter41

Dear plumbbob1...Ayn Rand is the best name to learn about her. You asked if she was into photography. Ayn was into her husband handsome husband, Frank Oconer, a movie extra in "KING OF KINGS." She loved America, the movies, and individual responsibility for your own life. Even though she was not a beautiful woman on the outside, there are many stories of her inner beauty by her friends and admirers. I have a painting of her by llona in my home. Phyllis Cerf took this black and white portrait of Ayn Rand. ENJOY! Shooter41

Dear BebuLamar - Ayn Rand was born Alisa Rosenbaum on February 2, 1905 in Russia. She grew up hating Communism and chose to come to America alone at the age of twenty-one. She was a young writer and loved the movies, so she first went to work in Hollowood writing for others. She later became friends with Bennett Cerf who helped her get published, which was difficult because she wrote about individualism. They chose to use the the pseudonym Ayn Rand for the books she published. Ayn wrote "The Fountainhead" in 1943 which slowly became a best seller over time and later starred Gary Cooper in the movie made from the book. "Atlas Shrugged" came later, which led to the creation of The Ayn Rand Insitute, which still exists in California today. Miss Rand was best known for her ability to think on her feet while taking live questions at her lectures at Ford Hall Forum, as well as making major advances in philosophy and insight into living a fulfilling life here on earth. I enjoyed attending the Ayn Rand Tribute Dinner in Boston not long before her death. I felt fortunate to be able to sit close to her as she was honored. She passed away on March 6, 1982, at age seventy-seven. Ayn was the most patriotic American I ever met. Shooter41

Dear plumbbob1...Black under low light gives me problems. Shooter41

Dear DirtFarmer...Shooting RAW is superior. Shooter41