Originally posted by BobKG I was playing with my 500 mm f4.5 Takumar lens (non-SMC) the other night and came up with the attached photo. I took 3 shots; one of the moon, one of Saturn and one of Jupiter. All taken with the K5 and the 500 mm lens set at f8.0. Enlarged the photos in Lightroom and then combined them in Photoshop Elements 12. It is amazing to me that this 50+ year old lens is still sharp enough to resolve the ring around Saturn and the two moons of Jupiter.
I one an MGM contest with a Takumar 135 preset on my Pentax (1957) in 1962 when HMS Bounty replica entered Vancouver harbour.
I'm not surprised at the resolution of your 500/4.5. What the early lenses were missing was modern coatings, not optical characteristics.
My "long gun" (or as the Creston Wildlife Refuge interpreters call it "bazooka") is an M 400/5.6 used often enough with the 1.7x AFA convertor giving me 680 mm. On the back wall of our local library there is a 16x20 of loons taken with that combo on my K10D, slightly cropped for format.