I don’t have “test cards” or “sheets” to check the sharpness and IQ of the photo a lens will produce, and not really interested in them either.
But there is an old blanket/cover with a color and weave some lenses seem to struggle with, so occasionally I will use it as a test.
The above is the result of a Super Takumar 100mm f2.8 mounted on a K50 set to the manual mode taken indoors without flash – judging by the results I’d say it is an excellent lens. Accurate color and well defined detail with the lens set wide open.
When stopping down this lens incrementally becomes even sharper – I seem to favor the vicinity of f5.6 to f8 across the board, or maybe a little more depending on the situation with any lens I may be using, though some have a particular sweet spot and that’s the place to go.
No scenic vista, no dreamy waterfall, no bracketed composition or carefully enhanced color, just an old blanket that says this is a lens worth keeping.
Shooting in RAW manual or aperture priority isn’t rocket science, the RAW format captures more information and detail – those unfamiliar with the process should give it a try -jpeg can be convenient, but RAW puts it to shame.
The interesting thing about vision is that at least for humans it is center focused – we see everything within our field of vision but the focus is on the center.
A lens has the same attributes but with the added ability to manipulate depth of field by “stopping down” aperture.
When wide open a lens more closely resembles the human eye in that it focuses to the center and produces a blur or bokeh moving away from that point.
Takumar lenses are noted for their center focus and the bokeh they produce, stop down the aperture and the focus, or depth of field, increases.
That’s true of any lens, but what separates them is how good they are at it – I’ve seen lenses you would swear needed a visit to the optometrist, others that are natural born wonders.
There is said to be a silver lining to every cloud, mine is though I can’t afford those new lenses people rave about that inability led me to vintage lenses, and thankfully the Taks…I’m convinced I’m not missing a thing.
Pentax Taks and SMCs, add a little Yashinon, Chinon, Zeiss, and Voightlander into the mix and you’re as good to go as anyone at a fraction of the cost.