[GoremanX]

modern lenses have different designs when it comes to camera focus. All use a focus ring, but the ring may be an electrical control.

I'm sorry, I misunderstood your post. Yes, the focusing ring is physically coupled to the focusing group and allows the lens to be focused manually without power.

[GoremanX]

I have this lens, and I find that the conclusions of the "In-Depth Review" regarding image sharpness are way off the mark. On my copy, 40mm is the strongest focal length of this lens, with solid overall sharpness across the frame even wide open. However at 20mm, the corners are softer wide open while the center is decently sharp. By F4, the corners have mostly caught up. By F5.6, the entire frame is very sharp. I'm not sure if this is due to sample variation or different testing methods, but in my opinion, this lens is a stunning performer as far as IQ goes. I mostly concur with the rest of the In-Depth Review, although I don't much care about the vignetting aspect. I tend to add vignetting in post to many of my pictures anyways.

It's worth mentioning, I tried VERY hard to find a reason to send this lens back for a refund. $900 is a lot of money for such a lens, and I was determined to be unhappy with it so I could get my money back and buy a Sigma 18-35mm F1.8 instead. I ended up being so satisfied with this lens, I've given up my intentions of getting that 18-35mm. You can read more of my impressions in the lens database.

[krebsy75]

This lens remains an enigma.

[crewl1]

Until we start seeing images in a lens club like the '15mm controls mind' thread I will withhold comment as to my propensity to buy or not buy this lens.

[krebsy75]

Until we start seeing images in a lens club like the '15mm controls mind' thread I will withhold comment as to my propensity to buy or not buy this lens.

The 16-50 seems to be a more versatile option.

[Mr Spocko]

The 16-50 seems to be a more versatile option.

Or the Sigma 18-35mm bigger but fast.
Or the Tamron 17-50mm

Have to say for such a short range zoom the optical performance is dissapointing, if that review sample is on the mark with what the buyer buys in a shop.

The Tamron pawns it wide open across the zoom range and has stunning sharpness at 40mm, smart folks know good build and a red ring cannot make up for these optical problems. Real shame

[GoremanX]

The 16-50 seems to be a more versatile option.

Twice as heavy, twice as big, not terribly impressive wide open and old-style SDM (bleh). There's more to a lens than its focal length range. "Versatile" depends entirely on the photographer's needs. If you don't feel this lens would meet your needs, then move on and find something that would.

[Terzof]

We have the Silver edition a month ago, a "Test Sample"

Our impressive: Half weight of 31 Limited, very high speed compare to old Limited, the color is surely Limited! Sharpness is perfect as Ltd define,

Negative: Expensive :|

[GXRUser]

I'm sorry, I misunderstood your post. Yes, the focusing ring is physically coupled to the focusing group and allows the lens to be focused manually without power.

understand...

If you look at the silver finished version on the silver K3, it is really sweet looking. I am sure it feels wonderful in hand.

One nasty trend at Nikon is to introduce lenses that do not even have a focus ring. All but one 1 Nikon lens does not have a focus ring and if you wanted to manually focus, there is an awkward method where you set focus to Manual in the menu then use the ring control on the back of the camera to adjust focus. On top of that, there is no focus peaking!

The 1 Nikon 32mm f1.2 does have a focus ring (like the 06 Pentax) since it has narrow depth of field, but there is no focus aid other than an enlarged image on the LCD/EVF. Thankfully for 1 Nikon owners, the AF is fast and accurate.

Lenes like the Pentax Limiteds are a special pleasure due to the quality and materials of their design and construction.

[GoremanX]

If you look at the silver finished version on the silver K3, it is really sweet looking. I am sure it feels wonderful in hand.

Yep, that's what I have:

[billy moon]

I suggest the reviewer test another copy or his own testing method. Like 'GoremanX' mine is very sharp at all focal lengths with a slight vignetting at 40 though. I use f5.6/f8 for most everything, in the studio f8 has always been my fstop. If I want to shoot wide open I use the FA43mm. I am so happy with this lens, 23mm and 33mm are awesome. I prefer this to my FA31 that does not like bright reflected light conditions, always having to use black flags around it in the studio. What I am getting at is I'm not sure why this lens is getting bashed when there are others that should including the famous FA31. Oh and another thing, no purple fringing like that wonderful FA31mm. This is a terrific lens worthy of it's price!

[jonby]

Good to get a detailed review of this lens at last - thanks to Adam.

Well, if the sharpness results are reliable for the lens model in general, then this is very disappointing. As some have noted here, there is some evidence to suggest that the performance at the longer focal lengths may not be representative of all copies of the lens (a number of user reviews on this site suggest that performance is actually strongest at the long end), so it is perhaps too early to condemn the lens on this aspect at this stage. However, even if this is the case, it suggests that quality control is pretty poor. Considering that the only real justification for a slowish lens with a high price and short zoom range is guaranteed image quality, this is a real let-down. I for one am not willing to take a pot-shot at this price level.

As primarily a landscape photographer, I feel that Pentax simply don't make any normal-range zoom lenses that meet my needs, and I am now considering moving to another brand. It should be technically possible to produce a lens which produces decent sharpness across the frame at f8 at least, through a 20-40mm zoom range, even in a compact design. Even taking into account the high resolution of the sensor, the tested lens fails dismally in this respect at the long end - in fact my 18-55 produces much better edges than this at 40mm. Some of the problem seems to be strong curvature of field rather than ability to resolve, but it's very difficult to mitigate for this in most scenarios. Unacceptable either way.

The K-3 is an excellent new camera release, but Pentax really need to support that hi-res sensor with some excellently resolving glass, coupled with good quality control, if they are to improve their credibility - particularly at a time where Sigma and Tamron seem to be reducing their support for the brand. I'm still hopeful that this is a 1-in-10 bad copy. If Adam ever has the time I'd like to see a couple more copies tested for sharpness.

[Adam]

Well, if the sharpness results are reliable for the lens model in general, then this is very disappointing. As some have noted here, there is some evidence to suggest that the performance at the longer focal lengths may not be representative of all copies of the lens (a number of user reviews on this site suggest that performance is actually strongest at the long end), so it is perhaps too early to condemn the lens on this aspect at this stage. However, even if this is the case, it suggests that quality control is pretty poor. Considering that the only real justification for a slowish lens with a high price and short zoom range is guaranteed image quality, this is a real let-down. I for one am not willing to take a pot-shot at this price level.

We had two separately-sourced copies of the lens to test, so I don't think the conclusion is inaccurate. It would be nice if the lens were a better performer at 40mm, but that's not to say that it can't take great pictures. It's quite a capable lens, after all.

[starbase218]

I get that it is one of the first Pentax-branded lenses to have USM-type focusing

Nope, it doesn't even have that. DC != USM.

To me, it looks like the reviewer doesn't want to state that this lens is just too expensive for what it is, even though I suspect that is exactly what went through his mind.

[krebsy75]

Twice as heavy, twice as big, not terribly impressive wide open and old-style SDM (bleh). There's more to a lens than its focal length range. "Versatile" depends entirely on the photographer's needs. If you don't feel this lens would meet your needs, then move on and find something that would.

Zooms are about practicality and getting the job done. This is where the 20-40 is puzzling and not convincing so far for $1,000.