I have recently acquired an M75-150 / 4 for less than £9, an M200/4 for £23 and a Teleplus PZ-AF 1.4x teleconverter for £35, Compared to these, my £85 A135/2.8 seems expensive.
The three lenses went with me to the Lodmoor Nature Reserve in Weymouth, Dorset and took turns on the genuine adapter. The M75-150/4 seems very promising, even wide open at 150mm, as was the case for the picture of the coot. The Q7 struggled with the highlights, though.
The M200/4 was less successful. Granted, the redshank did wander off to leave only a corner crop with less-than-perfect focus, but the colours were rather muted. The surprise was the combination of the M200/4 and the Teleplus - better than the lens alone, even at ISO640. Judge for yourselves from the picture of the wading gull.
I've seen this before, and put it down to problems with stray light. The M200/4 has a rectangular rear baffle which, I assume, Pentax judged it needed to solve problems with....stray light. Fitting the teleconverter prevents the reflections. I shall clean the M200/4 and then recoat the inner surfaces with optical black.
The A135/2.8 seems almost made for this combination. Taken on another day, the Canada Geese dutifully sat very still...
Last edited by Shedking; 11-06-2017 at 04:31 PM.