Originally posted by rmtschanz Thanks for the help hinman and Jewelltrail.
Ironically enough, I went during my lunch hour to another local shop and guess what they had...a used SP 60-300mm w/Box and Case and a New Adaptall KA mount (do they even make these mounts anymore?)! Picked them both up for $110, thought that was a good buy. Visually, the 70-350 is just an impressive looking lens when compared to the 60-300mm. I might still pickup the 70-350 f4.5 to check it out, as the store allows returns on used lenses.
By all means, I actually hope that you will attempt to get the 70-350mm f/4.5 and report back as I have curiosity and great interest in learning about the lens. Have you tried to hand-hold the lens alone, its spec says 4 lb or 1820 g, have you thought about using it on a tripod or you have no issues with hand-holding a 4 lb lens. My Tamron SP 80-200mm f/2.8 adaptall-2 with hood and a compatible tripod ring weighs close to 4 lb, perhaps 3.5+ pound and I feel the weight especially in portrait position. Weight factor in the ease of use of a lens.
The 60-300mm f/3.8-5.4 will serve you well as JewelTrail and many die-hard fans of Tamron adaptall-2 lens will attest to you. The strength is in its consistent performance across the range, lighter weight, and I heard that its close focus is quite good. You have a steal for that price with a p/k-a adapter. When you are settled with the lens, you may like to look for a 1.4x TC and 2.x TC in adaptall-2 mount as the 2.x TC can serve not only as a tele-converter but double up as an extension tube that may get you your close-focus to go from 1:2 to 1:1 at the expense of losing light and known degradation on IQ. A
Tamron 01F 2x TC usually costs around $30, that is something worth an investment for a cheap option for 600mm and 1:1 macro. It is not the best, but for $30, you have little to lose in my books.
Thanks,
Hin