[HawaiianOnline]

Aloha Everyone! I humbly ask for you expert recommendations on autofocus prime lenses in the vicinity of 50mm (appx 40mm - 60mm). My primary requirements are:

1) Fast autofocus on a K5 IIs body
2) Sharp
3) I don't care about motor noise
4) Did I mention fast autofocus?
5) f2.8 or faster
6) Readily available within 2 weeks


Thank you!

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Last edited by HawaiianOnline; 05-16-2018 at 11:00 PM. Reason: Added additional info

[Unregistered User 8]

Aloha to you. The 50mm 1.8 " plastic fantastic " is a very worthy lens at a great price. Check the review below. Good luck with whatever lens you choose.

Pentax-DA 50mm F1.8 Review - Introduction | PentaxForums.com Reviews

[buberfan]

If it's sharpness you are after, then it's hard to beat the 50mm 2.8 macro. I have the F-series version and it's one of my favourites on the K1.

[Madaboutpix]

You might want to consider our inexpensive plastic-fantastic DA 50mm F1.8. The AF may not be super-decisive (i.e. there may occur occasional hunting), but otherwise it will likely be the fastest-focussing fifty in the whole current line-up, bar the announced but not yet available DFA★ 50mm F1.4.


Stopped down a tad, it's tack-sharp too.


Oh, just seeing pjv beat me to it. (Which doesn't hurt the recommendation though.)


If you should opt for the DA50, order a serious K Mount rear lens cap and a third-party rubber lens hood (like the JJC one specially made for this lens) along with it, since it comes with a cutting-corners cap and minus hood.

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Last edited by Madaboutpix; 05-16-2018 at 11:49 PM.

[AndrewN]

DA 50 f1.8, absolutely lovely lens and fantastic value.

[mikesbike]

Much also depends on intended use. On your K-5 IIs, which is an exceptionally fine camera- I have one, a 50mm FL is a very good choice for fairly tight portraitures as shown above. For this purpose, the fast aperture of f/1.8 or even f/1.4 is often very useful for rendering the background out of focus to make the subject stand out from it.

For other uses, or even less tight head and shoulders/or chest portraits, where f/2.8 is sufficient, the DA 40mm f/2.8 Limited is a very sharp lens edge-to-edge, as well as being very compact. I find its AF to be quite good.

[MrMojo]

DA 50, or if you don't mind second hand, the F or FA 50s are quick to focus and available at high apertures. They're readily available on auction sites.

[Saltwater Images]

HD DA 40 f/2.8 no question. A more versatile focal length on a crop sensor. Faster AF on my K-5II than the FA 50. Super sharp.

[UncleVanya]

I own the k-3 so my comparison may be slightly different, but I'm going to also suggest the DA 40. There are three versions all of which are fast and good. The DA 40 Ltd SMC I have smokes my F 50 f1.7 in focus speed but realistically both are fast focusing enough that your choice should be based on focal length and rendering.

The DA 40 on crop is a very nice close portrait and general lens, the 50's are s little longer and that can be a plus or minus depending on your eye and your preferences.

For what it is worth I owned the DA 50 and didn't love it. I prefer my F 50. The DA 40 is a jewel that is hard to dislike.

[Saltwater Images]

I own the k-3 so my comparison may be slightly different, but I'm going to also suggest the DA 40. There are three versions all of which are fast and good. The DA 40 Ltd SMC I have smokes my F 50 f1.7 in focus speed but realistically both are fast focusing enough that your choice should be based on focal length and rendering.

The DA 40 on crop is a very nice close portrait and general lens, the 50's are s little longer and that can be a plus or minus depending on your eye and your preferences.

For what it is worth I owned the DA 50 and didn't love it. I prefer my F 50. The DA 40 is a jewel that is hard to dislike.

Completely agree this point of view. I sold my FA 50 f/1.4 after owning the 40 for a while. I found the 40 was used a lot more and the drawing style of the Limited's is dynamite.

[bdery]

Certainly the best choices would be the DA 50 F1.8 if you want cheap, or the FA 43 Limited if you want magical.

I find that both on APS-C and on FF, 40-43 is a more natural focal length than 50, by the way.

[bassek]

There is not simply a bad choice available in your suggested focal range.

Seb

[UncleVanya]

There is not simply a bad choice available in your suggested focal range.

Seb

My first reaction is, "That's got to be wrong." LOL - but at least with the examples I know of it isn't. The 40mm-60mm AF lenses available for K mount are generally very very good. The worst possible choice may be the very sharp DFA 50 macro /2.8 due to the potential for missed focus and the long focus throw but only due to the desired fast focusing the OP requested. That is a stunningly good lens otherwise.

[cyberjunkie]

I wholeheartedly agree with the appreciation for the Pentax-F 50mm Macro. One of the best Pentax lenses ever.
Unfortunately the ring for manual focus is a joke. Better to set the reproduction ratio first, then focus moving the camera back and forth.

I have different feelings for the ever popular 40mm Limited.
It's a Tessar Limited... but still a Tessar. Nobody, not even the sorely missed optical team that designed the Limiteds, can make miracles with those 4 elements in 3 groups
Contrast and flare control are good, sharpness is more than decent but not impressive (for a modern prime), bokeh is not ugly but not the nicest.
The lens is beautiful and a real pleasure to use, because it has much better ergonomics than the XS version (which is the only other pancake with AF).
Though I think that those willing to do without AF could get a similar performance from vintage Tessar pancakes, like the Pentax-M 40mm, or the Cosina-made 2.8/45mm or 2.5/40mm, sold at the time under various brands, and rather inexpensive today on the second-hand market.

[SSGGeezer]

not even the sorely missed optical team that designed the Limiteds, can make miracles with those 4 elements in 3 groups

5 elements in 4 groups on the DAs and the DA XS.