Originally posted by geomez I was seriously considering getting the 21mm adapter, but ended up getting a Rokinon 16mm F2.0 for my K-3 for around the same price. I figured I was future proofing myself a little better with a K mount lens.
I'm under the impression the 21mm glass screws onto the 49mm threaded filter adapter? If so have you tried screwing it onto any ILC glass with a 49mm filter thread?
No - I hadn't even THOUGHT of that. Good idea!
It's interesting - I haven't done the math, but in speaking about these other k-mount wides, your Rokinon 16mm (i've looked at that myself actually) and the 15mm ltd... The focal length equivalent of the 21mm conversion lens on the Ricoh more closely resembles my 15mm ltd on the Pentax, which makes sense since the Pentax glass lists their lens as actual, while Ricoh lists them as their 35mm format equivalents. Bottom line, I got a much wider lens than I had a occurred to me at first which is great.
I put up a comparison several posts apart in the 15mm controls my mind thread, and I'll repost them here. Both these shots were taken right after I'd received each, respectively, a couple nights apart. It's a quick and dirty comparison of the first DA 15mm and the second one, taken with the Ricoh GR with the 21mm conversion. It's out the same window, processed as closely as I could, working quickly. Not an entirely fair comparison, the Pentax had the benefit of a city-lit clouds passing by, while tonight it's clear and black up there. Nevertheless... I'm awfully impressed with the Ricoh in this case.
The 15Ltd
The 21coversion