I'm always a bit curious about older lenses. I'm a cynic. I think camera makers use new lens design tools not necessarily to make lenses that are distinctly better than their ancestors but to make the new lens designs easier to manufacture and cheaper to make. I'm sure new glass types are wonderful and some of the newest lenses can do amazing things, in the right hands, but I am equally sure that there is a general race on to make lenses more uniform; more consistently consistent, and if they get some optical improvements then that's considered a bonus...
To a degree I think lens design is driven by an uninformed and loud group of consumers who have different ideas about what is essential in a lens than the lens designers themselves did a decade or so ago. The emphasis now is on lightweight, fast apertures and (because of very poorly conceived lens test interpretations) sharpness across a flat field (to the detriment of potential sharpness in the center 2/3rds of the lens).
I was shopping for a 70-200mm lens last week, knowing that I'd soon be shooting some theater productions with the newly acquired Nikon cameras. I was shocked to see the price of the current 70-200mm f2.8 Nikon lens was $2800. I was so miffed at the rampant inflation for this product category that I abandoned my search for a current product all together and decided to plumb the opposite end of the market. I had in my own inventory a Nikon 70-210mm f4.0-5.6 manual focusing zoom that I'd picked up cheap a while ago. I subsequently read that Nikon doubled the focusing speed on the "D" series version of the same lens and I searched out a copy of that version. The one I found is very functional but a bit beat up. That's okay since I spent only $75.
I took it along with me last night to do technical scout of Zach Theatre's newest production in anticipation of the "official" shoot we'll be doing on Tuesday. I didn't have overly optimistic expectations that the old 70/210 would be anywhere near as good as a modern lens but I wanted to try it: under stage lighting (this play has a very contrasty lighting design...), handheld (no VR back when this lens was made and originally sold) and at it's wide open aperture (look, I figure I'd just be using this for the longer end and it's already f5.6 from about 105 onward). Seems like a viciously unfair test for a lens that's decades old --- right?
Well, I'm not so sure. Below are three variations from the same digital frame. The older screw drive lens was able to nail focus quickly and well. The lens also resisted flaring. But the thing that I appreciated is that the image is nicely sharp. As sharp as I expected it could be on a Nikon D800 set to 3200 ISO.
After seeing the results and comparing similar files shot with the 24-120mm f4.0 and the Sigma 50mm f1.4 Art lens I've called off my shopping and researching for a newer or faster telephoto zoom. While it may not check all the boxes for you this one delivers enough image quality for me. If I need a better lens I'll pull one of the Olympus Pro lenses out of the drawer and put it on a Panasonic GH5. Not a bad deal for a whopping $75. Sorry, no link. You'll have to find your own.
The full frame.
A tight crop.
Getting into the 100%, pixel peeping realm.