Originally posted by stevebrot From what I can tell, you are saying that you sold your Pentax gear because a Nikon/Sigma combo was better for your style of shooting. Fair enough, though it seems a bit strange to join an online forum just to post an off-topic comment.
1. I didn't sell my Pentax gear.... I just sold K-1 and DFA 150-450.
2. As you can see in my profile, I didn't join this forum recently. And the reason to answer in this thread is, that beholder3 posted the link in my favourite german Pentax forum (pentaxians.de)
But ok: believe in his "test" an be happy to take pictures of roofes with your Pentax stuff!
Originally posted by rawr Ugh.
Which TC was used w. K-1 and 150-450? The DA 1.4 TC isn't officially FF compatible. In K-1 crop mode it might perform OK optically, I guess, but it will still make the 150-450 a f5.6-f8 lens, so the AF may struggle.
Also put a 1.4 TC on any Tamron or Sigma 150-600 + D810, and the optical or AF results won't be great either, particularly at the longest end.
The optical performance has nothing to do with crop oder non-crop mode. The DA 1.4 TC produces dark corners, that's all. The problem was the af accuracy, not the vignetting!
And why should I use a 150-600 with a TC? It HAS the 600mm I need!