[veato]

Thanks for the comparison. Personally I'd be happy to have either. #BeggersCantBeChoosers

[Madaboutpix]

Thank you ever so much for investing the time, effort, and skill to put this together. Interestingly, the DFA seems to offer better contrast with distant subjects and has a clear edge in close-up work. In the other scenarios, the Sigma holds its ground.

[redpit]

Thank you for the comparison! I had done mine between the DFA and the Bigma 50-500 OS before I sold the Bigma. I believe the DFA is an excellent zoom lens but the Sigmas are good and cheap alternatives and moreover the 50-500 OS offers some advantages over the DFA that are up to the user to decide what is more important for her/his photgraphic needs...

[ecostigny]

Thanks for the great comparison. It's given me some very useful information for deciding on a ultra telephoto zoom.

[marcusBMG]

There are two more little plus points for the sigma: a better case comes with it (decent thick foam padding), and the sigma has a built in strap attachment point on the tripod mount foot. However I think the tripod mount on the D FA is more rigid, the sigmas' flexes a bit too easily for my liking. Don't touch the lens if you want the best results while tripod mounted, and woe betide the effect of any breeze...

[pentageek]

Thanks for extensive comparison. I have Sigma 150-500 OS, and I wondered how DFA performs when compared to it. Well, looks like it in fact performs better (especially at long end), but for me the difference is not big enough to justify extra cost of DFA. Have you had opportunity to compare effectiveness of AF? I do not mean another extensive test, just first impression.

[marcusBMG]

opportunity to compare effectiveness of AF?

Not really - I acquired the sigma after i dropped my k3 which affected AF, so not representative. The 150-450mm was good for me with AF, although if the subject was very OoF the camera might hunt ineffectively - qiuicker to manually spin the focus in the right direction until the camera picked up the focus.

[marcusBMG]

I have now added another set of test pics at the "birding" distance of ~ 5m.

[redpit]

I have now added another set of test pics at the "birding" distance of ~ 5m.

Thanks one more! The focus breathing is more than I would expect but otherwise the results are as I’d expect them. The Sigma lens is good option for Pentax tele work.

[Rondec]

Thanks for the comparison. As others have said, this took a lot of work, but is very useful.

[James also]

Thanks for the time and effort that went into this comparison.

[stevebarnes]

Thanks too. I've been looking at a longer lens and will probably save up for the Pentax

[fuzzyphotos]

A very timely post for me as well, I've almost decided the DFA 150-450 is the best option for me right now. Thanks for the comparison.

Tim

[marcusBMG]

I would be interested in seeing some test pics from the 170-500mm that offer an indication of how it compares to the pentax and the 150-500mm sigma. Maybe you could find something similar to the test subjects I used, and take some controlled pics...?
I suggest your interesting pics in your post would better suit the 300mm plus lens club.

[kypfer]

Too be honest I THINK the shots would have been cleaner at 500mm and cropped. Uncertain the extra range afforded by the 1.4TC is giving me better results than without. Close up it does, maybe a hundred feet out or so. these are relatively long range, 200-300 yards away.

Much the same as my conclusions with my "bigma" and the Kenko 1.5x … on a 24MPixel camera with a 500mm lens one can reach the limits of available detail at a distance without having to magnify it further


I'll also take the opportunity to thank the originator of this thread, marcusBMG, for his extensive set of comparisons, it's posts like that that help convince me I don't need to "upgrade" my lens