Pentax DA16-85 WR Query


tigershoot

Link Posted 15/01/2016 - 21:19
Hi Folks
This lens puzzles me. I have just got it and find that at 16mm it's sharper wide open at F3.5 than at F8. This sounds unbelievable but it's what I'm getting when testing it on a tripod in good sunshine. Has anyone else found this to be the case. It seems really odd to say the least. I have been testing it against the trusty 'old' DA16-45 and at 16mm struggle to notice any difference.
K3ii, K-5, K-x, DA150-450mm, DA16-85WR, DA16-45, DA18-55WR, DA18-135WR, DA35 F2.4, M100mm F4 Macro, DA55-300mm, FA50mm 1.4, AF360 Flash, AF540 Flash

johnriley

Link Posted 15/01/2016 - 23:59
In theory, every lens should be sharper wide open if it were a perfect lens. Diffraction would progressively reduce sharpness as we stopped down. However, lenses are not perfect, so typically they will peak maybe two stops down from wide open.

Without seeing the testing method or the lens in question though it's hard to see how you are getting the result you report.
Best regards, John

Nigelk

Link Posted 16/01/2016 - 10:12
Interesting findings Gavin.
I was reading the review of this lens on EPZ the other day and looking at the 16mm f6.3 I think it is sample shot at full size (the one with the glass building) and It was not good at all, even in the centre the clock is missing detail that is much sharper and clearer on other comparable lenses tested at this focal length. I thought perhaps it was a bit out of focus, know way to know but it was not as good as some other lenses. Enough for me to realise there is no point in changing from my 16-50 mm although I would like the convenience of the wider range.
There is no doubt in my mind there are lens to lens variations in all brands. It is a bit of a lottery of what strengths and weaknesses any one lens may have. My first Sigma 10-20mm was terrible down one side fortunately the good folk at SRS changed it for a new one which has served me very well ever since.
Then we have user variation and error as I recently found when trying my 03 fish-eye on my Q. I had dismissed it as a bit of junk when I first got it. I gave it another go this week and WOW! what a great little lens. The focusing is just far more sensitive than I would have ever imagined on a lens of this type, and with the focus ring not being very well dampened it is so easy to knock it out of focus.

Sorry to ramble on. I hope you get the lens to perform to your satisfaction

Regards

Nigel

johnriley

Link Posted 16/01/2016 - 10:53
You're right about the Q 03 Fisheye lens Nigel. It's a tricky one to focus properly, but when it's right it's actually pretty good.
Best regards, John
Add a Comment
You must be registered or logged-in to comment.