[adrianpglover]

I'm thinking of getting a new prime lens to go with my other equipment and was wondering what people think is the sharpest prime lens available for the Pentax mount? It doesn't have to be made by Pentax or autofocus.

I'm really starting to like using my old M 50/2, but just wish it were a bit sharper wide open than it is. I'm fine with manually focusing the lens since this will probably be a necessity when shooting in dark situations.

I've been tossing around the idea of the various Limited series lenses and have even looked into some of the Zeiss lenses.


So...
If cost weren't a factor and we include all lenses that ever used the K mount or a vairant thereof...
What would you consider to be the sharpest prime lens for a Pentax camera?

[yeatzee]

Sharpest lens wideopen? Sharpest lens @ F/2? Be more specific

[paperbag846]

Easily the FA 43.

However, a lot of lenses will be a lot sharper than your 50/2.

On a tighter budget consider the DA 40, DA L 35, FA 50 (needs to be stopped down but is wicked sharp past 2.8).

DA 70 is crazy sharp, but tele.

Oh yeah, the 50mm f1.7 is CHEAP and sharp as a tack from f2.4 on. Highly recommended for sharpness (not bokeh).

[dgaies]

As yeatzee asked, does it have to be at f/2? The FA50/2.8 macro lens has to be right up there as one of the sharpest lenses I've every used.

[KxBlaze]

Agreed with the FA 43 (with the 31mm slightly behind). Do some searches for photos with those lenses and you will see what we are talking about. Since you asked that $ not be a factor those are my options but if you want a extremely sharp lens under $300 I would highly suggest the F 28mm. Search for that lens and you will see that it can hold it's own with those FA limiteds.

[adrianpglover]

I guess I'm really looking for something sharper than my M 50/2 or my DA* 16-50/2.8. I've been debating about the FA 43 or 31 for a while. I have also been looking at some of the Zeiss lineup, but I'm just not as familiar with their lenses and can't find many reviews on them.

I'm really looking for something sharp below 2.8 or at least something that will out perform anything I currently have.

[dasuhu]

...and sharp across the field, or just center sharpness?

[adrianpglover]

across the field

[Eagle_Friends]

DA 40mm is one of those underrated extremely sharp lenses.

Out of all Pentax mounts, the FA 200mm Macro is legendary for its sharpness. For the ones available now, I say the DFA 100mm Macro WR has to be up there too.

Sigma 70mm Macro for outside of Pentax.

[Rondec]

Easily the FA 43.

However, a lot of lenses will be a lot sharper than your 50/2.

On a tighter budget consider the DA 40, DA L 35, FA 50 (needs to be stopped down but is wicked sharp past 2.8).

DA 70 is crazy sharp, but tele.

Oh yeah, the 50mm f1.7 is CHEAP and sharp as a tack from f2.4 on. Highly recommended for sharpness (not bokeh).

Actually, if you check Photozone, the DA *55 is sharper at all apertures than the FA 43, both in the center and borders.

[Pentaxor]

sharper at f2? DA*55/1.4, FA31, FA43, 50/1.2, 50/1.7, 55/1.8, 58/1.4 Nokton, Sigma 50/1.4.

going for the Zeiss, although sharp, is more of a preference and have that certain look that you look for. although the 50mm f2 macro planar is consistently sharp all through out, it is just not fast. personally, I would just advice you to get the Sigma 50 or DA*55 since both are sharp wide open, fastest aperture AF duo and have the benefit of AF for the same price of that of other manual focus fast and sharp 50mm lenses.

[TOUGEFC]

Actually, if you check Photozone, the DA *55 is sharper at all apertures than the FA 43, both in the center and borders.

Dont think so-

CENTER/ BORDER (sharper lens in red)

43 @ f/2.8 2311/1993
55 @ f/2.8 2103/1988

43 @ f/4 2422/2244
55 @ f/4 2318/2064

43 @ f/5.6 2323/2211
55 @ f/5.6 2235/2150


43 @ f/8 2152/2000
55 @ f/8 2144/2035

looks to me like the 43 has the sharper scores

[Wormtographer]

The SMCP-FA 50mm f/2.8 Macro.

I start bleeding even before I mount it on a body.

[paperbag846]

If you need sharp across the field just go with the DA 40. It's not the sharpest, but it's so sharp that I would argue it does not matter one bit.

[timo]

If you need sharp across the field just go with the DA 40. It's not the sharpest, but it's so sharp that I would argue it does not matter one bit.

Agreed. In fact, as the OP's original question was actually a bit broad-brush, just getting an M50 1.4 or 1.7 would be a good way of getting familiar with the kind of improvement one can expect in a better lens vs the f2, at very low cost.

How critical is sharpness anyway, once you get beyond a certain point....?

Any of the lenses mentioned are as sharp as you could need stopped down a bit; wide open, characteristics other than sharpness tend to be more important.