| Author: | | Veteran Member Registered: December, 2009 Location: Georgia, VT Posts: 1,657
19 users found this helpful
| | Review Date: January 3, 2014 | Recommended | Price: $896.95
| Rating: 9 |
| Pros: | Light, Small, Build Quality, Picture Quality | | Cons: | Small-ish Aperture, Slow Auto Focus | | Sharpness: 9
Aberrations: 10
Bokeh: 8
Autofocus: 8
Handling: 9
Value: 8
New or Used: New
Camera Used: K-3, K-5, K-x
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I have every SMC Pentax Limited lens with the exception of the 35mm Macro, and that's pretty much my carry-around kit (in addition to a Sigma EX DG 100-300mm F4 on occasion). Out of those lenses, the DA 21mm, FA 31mm and FA 43mm are my most-used, with the FA 31mm taking up the majority of time on my cameras. So when this 20-40mm Limited was announced, I was pretty excited. A Pentax Limited zoom that covers my most-used range? AND weather resistant? YES PLEASE!
I agonized over this lens vs the Sigma 18-35mm F1.8. I'm a real slave to wide apertures, and that Sigma has some mouth-watering specs at a lower price. It's a hard sacrifice going from F1.8 to a variable F2.8-4. But in the end the 20-40mm won me over with its weather resistance, much lighter weight and reasonable size. Also, it's a Pentax Limited.
Of course, the first thing I did when I received the DA 20-40mm is physically compare it to the FA 31mm since that's the one most often on my camera. Turns out the 2 are pretty close. The 20-40mm with the hood removed is almost exactly the same length as the 31mm. The hood is only 1/4" long and no wider than the lens, so it adds no real bulk. The 20-40mm has a slightly larger diameter than the 31mm, presumably to accommodate the focus motor. And surprisingly, the 20-40mm is 2 ounces lighter than the 31mm (10.5oz vs 12.5oz). As far as fitment on my cameras goes, the 20-40mm makes the setup lighter while keeping the overall size about the same.
Build quality is jaw-droppingly good. The zoom and focus rings are flawlessly damped, and there's no give anywhere. Everything is made of aluminum and finished to perfection. I got a silver one to go with my silver K-3 and K-5, and I'm in awe of how well made this lens is. It even surpasses my other Limited lenses. The zoom ring has a great machined look that's reminiscent of my old Super Takumar 50mm F1.4 (although it was a focus ring on that one).
Auto focus is impressive, though less than I'd hoped. The auto focus accuracy is spot-on with my K-3, even in ridiculously low light. It gets perfect focus without any need for the AF assist light, even when I can't see the object I'm focusing on with my own eyes. I guess that's as much because of the K-3 as anything else, but I expected the smaller aperture to have more negative impact.
But as far as auto focus speed, I expected the built-in motor to perform a little better. It's no faster than most screw-drive auto focus lenses I own, and noticeably slower than many, including the DA 15mm, DA 21mm and FA 31mm. Sure, it's silent, but I've never been bothered by the sound of screw-driven auto focus. I would've preferred a screw-drive mechanism in this case if it meant faster performance.
The aperture is something everyone's been talking about ever since this lens was announced. While no DA Limited has ever had a large aperture, for some reason many Pentaxians were surprised when this one followed the exact same trend. There's nothing terribly surprising about a small-ish aperture on a DA Limited lens. I *was* a bit surprised by the variable aperture, but then this is the first Limited zoom ever, so it's not like there was any precedent to make me think it should be otherwise. At first I wasn't sure if this aperture range would suit my needs. Lately most of what I shoot is my baby daughter indoors, for which the FA 31mm was perfect. I was spoiled by being able to shoot at F2.2 and low ISO and having perfect results every time. So the small aperture of the 20-40mm threw me for a loop, and initially I really didn't like it. It was annoying enough that I contemplated sending the lens back and waiting for the Sigma 18-35mm F1.8 after all.
But then I did something weird... I cranked up the ISO. All the way up to 3200! (I almost never went beyond 800 before). Lo and behold, the pictures turned out beautiful! Sure, there was grain, but there was also tons of fine detail. A quick trip through denoising software and a little sharpening made those pictures come out as clean as anything shot at ISO 800. It was a revelation. I'm sure the camera's denoising engine would do an admirable job as well, but I've been a RAW shooter for years and that won't be changing anytime soon. The point is, the small-ish aperture of this lens doesn't have to be a limitation as far as low-light shooting goes.
As for bokeh, the 9 rounded blades do an absolutely stunning job here. Sure, there's less out-of-focus area in the scene due to the smaller aperture, but even F4 gives some very nice bokeh at 40mm when the subject is close enough. It's creamy smooth in front and behind the plane of focus, and it transitions beautifully. On the downside, starbursts from points of light are somewhat disappointing. I needed at least F22 to get any respectable star shape, and having 18 points makes it look a bit odd.
If you read this whole review, I kept the best for last: picture quality! This is what ultimately convinced me that I made the right choice with this lens, despite the smaller aperture. The old cliché "like a prime lens at every focal length" might just apply here. The only softness happens wide open at 20mm, and then only away from the center. Anything else is amazingly sharp, especially on a K-3 with the AA filter disabled. I can't believe the amount of detail and micro-contrast this lens delivers, it's like magic. As far as zooms go, it's quite possibly the best I've ever seen.
edit: to clarify, the edges and corners ARE soft wide open at 20mm, but the center remains very sharp. This is the only range I came across where sharpness takes a noticeable dip. By F4, the sharpness has caught up to the rest of frame again. And I personally don't find the softness objectionable, it's what I'd expect from the wide end of a lens in this focal length range.
Flare? Glare? Nope, not with this lens. I shot right into the sun on a bright Winter morning and only got the faintest amount of glare in the frame, barely discernible at all. I got no flare whatsoever, though. Shot wide open, I can make out the merest hint of purple fringing in the far corners of the frame, but that's it. And that's pixel-peeping at 2x magnification. This is unbelievable, and puts the CA-monster FA 77mm Limited to shame.
I read some comments from other people who ended up with decentered samples of this lens. I know that feeling too well, I experienced the same thing with my DA 15mm Limited. But with this 20-40mm, I struck gold; no quality control issues that I can see whatsoever. Call me lucky... this time.
I've found my new favourite lens, and it is the 20-40mm Limited. I'll be sure and try the Sigma 18-35mm F1.8 as soon as I have a chance, but it would have to be absolutely perfect to get me to change my mind. For now, the 20-40mm is taking the honored place of the FA 31mm as the featured lens on my camera.
UPDATE - January 6th, 2014
I just read the PentaxForums.com "In-Depth Review" for this lens, and I find it interesting that their findings on image sharpness are completely reversed from my own. They found this lens softer wide open at 40mm, but sharper wide open at 20mm. I guess it's either due to sample variation or different testing methods.
In any case, to give an idea of how sharp this lens is, here's a photo I took at 40mm, F8 and ISO 3200 using a K-3:
You can click on the image to see a full size version. Pay close attention to the eye closest to the camera at 1:1 magnification. That's where the camera was focused.
Second example (sorry, all I have are baby photos recently). This one was taken at 40mm, F4 (wide open), ISO 3200 using a K-3:
Again, on the full size version, pay attention to the eye closest to the camera. The eyelashes are about as sharp as can be. Also, if you look at the right edge of the picture, you can clearly see some in-focus texture in the cushion fabric. Same on the left edge with the blanket, the fabric texture can clearly be made out. Again, this is wide open.
UPDATE - February 1st, 2014
I continue to love using this lens daily for all kinds of different subjects. As far as I'm concerned, this is a constant aperture F4 lens, with F2.8 available to me as a bonus when I really need it. Some of the best zoom lenses ever made have an F4 constant aperture (Sigma 100-300mm F4, Pentax 60-250mm F4, 20-35mm F4, 24-50mm F4, 12-24mm F4, Nikon 16-35mm F4, etc, etc) so when I look at it that way, this lens becomes even more awesome.
UPDATE - July 13th, 2014
I'm starting to think there are some serious issues with quality control regarding this lens' manufacturing. Apparently I got a perfect copy, unfortunately other pentaxians haven't been so lucky. It's impossible to dismiss the complaints from people who have received a decentered copy, or are getting poor results. My copy of this lens continues to excel in every way, not least of which is autofocus accuracy. The focus for ALL my shots taken with this lens is always spot on, it's almost magical. I've needed no focus adjustment on either my K-5 or K-3 with this lens, even at F2.8. Based on this, I've had to increase my autofocus rating from 5 to 8, despite the occasional slowness of the focus motor.
Today I had a chance to try the other lens I was considering before deciding on this 20-40mm: The Sigma 18-35mm F1.8. Sure enough, the image quality with that lens was amazingly good, just as good as the 20-40mm in most cases and somewhat better in extreme cases (like at full zoom). However about 1/3 of my shots with the 18-35mm ended up being misfocused, usually not enough to be obvious on the camera's LCD at a glance, but enough to make some pictures disappointing. It's like the 18-35mm induces a bit of front or back focus, but only randomly, so it can't really be corrected for in the camera. Very frustrating. It even happened on 2 nearly identical shots, back-to-back. One shot was in perfect focus, the other was slightly back focused. This is never an issue with the 20-40mm.
Also, the 18-35mm is HUGE and HEAVY for the type of shooting I've been doing lately. All in all, I'm glad I decided on the 20-40mm rather than wait for the 18-35mm. It turned out to be the perfect choice for my needs. But then I'm lucky I got a good copy... apparently not everyone is so lucky  | | | | | | | Site Supporter Registered: February, 2008 Location: Emeryville, CA Posts: 1,122
12 users found this helpful
| | Review Date: December 16, 2013 | Recommended | Price: $900.00
| Rating: 9 |
| Pros: | Lightweight, WR, Rendering, sharpness, | | Cons: | Slightly cooler color than other DA ltd. primes | | Sharpness: 10
Aberrations: 9
Bokeh: 9
Autofocus: 10
Handling: 10
Value: 10
New or Used: New
Camera Used: K-5
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I had high hopes for this lens. I had been using my 15, 21, 35, 40 and 70 for about 3+ years but I wanted a light WR zoom with those same lovely ltd. qualities. I can say that the 20-40 has met my high hopes and carries all of the qualities I was looking for. The build quality is excellent. The zoom ring is smooth and in my opinion nicer than the DA*. I had the 16-50 and still have the 50-135. Although larger than any of the DA primes it still carries that small and light design forward if you compare it to other zooms in this focal range. On my k-5 you can easily 1 hand this although that is not my typical shooting style. It looks and feels great on the k-5. One big benefit over the DA primes is the quiet focus. The other for me is not having to constantly change lenses or locked into a single focal length. I do a lot of hiking in all types of weather so the short time I've had the lens, I find that I'm really loving the convenience of not being locked into a focal length.
The lens is sharp wide open throughout the zoom range. I did have to fine tune the autofocus to get it operating at its best, but that is not unlike all of my other lenses. I tend to think it is more a function of my K-5 rather than any lens. The sharpness was pretty consistent across the frame as well. I will do some testing against the DA35 ltd to test absolute sharpness. That lens is the sharpest I have in my bag and I am curious mainly because from looking at the images that I took with the DA 20-40 it looked impressively sharp.
The one aspect of the lens that will take some getting used to is the color. The ltds. primes rendered slightly cooler than other lenses i had and the 20-40 is slightly cooler than the primes. Again I'm going to do some side by side testing to make sure it isn't just a figment of imagination. I took some landscape and portraits and I really like how the zoom renders its images. I also like the bokeh. It tends to be more smooth and has a nice transition. The other positive aspects of the lens are how contrasty the images are.
Overall, I think Pentax has produced a really stellar performer and like my DA*50-135, the DA20-40 feels like having a bag of primes packed into a single lens. Yes 900 is a lot of money but considering, I already don't miss the DA21, 40, and may consider selling the 35, I'd say it is worth its cost.
12/20/13 Update. I have taken side by side testing with my DA35 and I can say it produces images of equal quality and sharpness. Which for me still seems hard to believe. So I bumped up the Value to 10. Again many may question the cost but, for me it easily replaces 3 excellent primes.
I'd also like to update that if you are coming from using the DA primes and were used to creating sharp star-like patterns with your night shots shot against a bright light source, the rounded aperture blades do take some of that away. You can still create them they are just not as sharp.
2/23/14 Last Update. After a lot of shooting with this lens, I finally decided to let go of my DA35 Macro. For me that says a lot for the DA20-40. The close focusing of the DA20-40 was good enough to for how I shoot. And I just didn't see enough of a difference in sharpness for me to keep the 35 Ltd. Macro. I will also update that the lens does a very good job of flare control. Not quite to the degree of the DA15 but more than commendable. In very high contrast situations you will get some purple fringing if you shoot wide open. I find it more prevalent in the corners rather than throughout the image. Overall I could be not be happier with this lens. Don't let the reviews scare you away.
| | | | | Veteran Member Registered: April, 2014 Location: Cambridge, MA Posts: 935
9 users found this helpful
| | Review Date: August 18, 2016 | Recommended | Price: $600.00
| Rating: 10 |
| Pros: | Compactness; fantastic sharpness, color, and clarity | | Cons: | Nothing major | | Sharpness: 10
Aberrations: 9
Bokeh: 9
Autofocus: 9
Handling: 10
Value: 10
New or Used: New
Camera Used: K-3
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I wanted a small-ish all-around weather-sealed lens to take with me on my recent cross-country road trip. This lens was perfect, and I love it. It's my shiny silver buddy who's fun to be with.
This lens filled the "travel lens" niche perfectly. It's lightweight and reasonably small (about the same size as my 31mm Limited, but lighter), so I can carry it with me almost everywhere. The 20-40mm zoom range covers the focal lengths I most commonly use, though I should note that I brought along a second K-3 with the 15mm Limited. The f/2.8-4 maximum aperture seems a little slow, but in practice, I never had trouble using it indoors. When I'm visiting museums, I tend to use the wide end anyway, and f/2.8 is fine. I never had to test the weather sealing, but it was very good to have it.
As far as image quality goes, the 20-40mm Limited is fantastic. The sharpness, color saturation, and clarity are simply outstanding. It stacks up well against my other Limited lenses. (I put together a whole gallery here, if you're interested).
-- It's sharper than the 21mm, and has comparable bokeh; at this point, the choice of which one I bring with me mostly depends on whether I want the smaller lens, and whether I need the weather sealing.
-- It's very slightly less sharp than the 31mm Limited, but you'll only see the difference if you are a fanatical pixel-peeper. The rendering and the bokeh are noticeably different to me between the two lenses. I think the 20-40 reproduces colors more vividly, but I think the bokeh of the 31 is smoother, and I generally prefer its rendering.
-- The 40mm Limited wins for sharpness, but then again, it's the sharpest lens I own; the 20-40 is also very, very sharp. The color saturation and rendering are generally comparable.
I only have a few complaints, and they're relatively minor. The autofocus is noticeably worse than the 21, 31, or 40-- sometimes it hunts around for a while, and sometimes it latches on to something, and sometimes it doesn't. I'm not sure what's going on, but my primes don't have this problem. Next, there's noticeable vignetting at 40mm at f/4.0, but this can be cleaned up unproblematically in post. There's noticeable distortion at 20mm, so if you really like to photograph straight vertical lines near the edges of the frame, you might be sad. Finally, the silver finish on the lens hood rubs off relatively easily.
In short, it's a wonderful little lens, and unless you really need a wider zoom range or a larger aperture, you won't be disappointed.
Enough talk! Now photos!
20mm @ f/11. You can see how well this lens nails textures...
...and colors.
20mm @ f/7.1 You can see a noticeable amount of distortion at 20mm, more than the 21mm Limited, I think.
23mm @ f/3.5. Just throwing in a photo at a relatively wide angle and a relatively wide aperture.
29mm @ f/5.6. See, it does reasonably well indoors.
30mm @ f/3.5. An example of the bokeh. It's quite nice!
31mm @ f/11. It's still sharp at the middle of its zoom range.
34mm @ f/11. Ditto.
40mm @ f/4.0. You can see what I was talking about with the vignetting, but IIRC there were more egregious examples.
40mm @ f/11. Still sharp.
40mm @ f/4.0. It's not a fast telephoto lens, but it still does reasonably good portraits.
Anyway, if you really cannot get enough example photos, the entire road trip album is here.
It's a great lens! It got, I think, unfairly slammed by confused lens reviewers who didn't think through the handling/portability implications of the relatively slow maximum aperture, and who didn't appreciate the pixie dust. The original price of $1,000 was pretty steep, and I certainly wouldn't pay that much for it, but $600 is entirely reasonable. If you do end up buying it, I hope you enjoy it as much as I have!
| | | | | Veteran Member Registered: July, 2011 Location: Eastern Oregon Posts: 856
9 users found this helpful
| | Review Date: April 21, 2015 | Recommended | Price: $695.00
| Rating: 10 |
| Pros: | Sharp, great contrast, thick lush color saturation | | Cons: | none | | Sharpness: 10
Aberrations: 10
Bokeh: 10
Autofocus: 9
Handling: 10
Value: 10
New or Used: New
Camera Used: K3, K5IIs
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I LOVE this lens. The review(s) are wrong. They must have got a bad sample. This lens is as good as the primes it covers, namely the 21/31/35/40/43 LTD's. And most importantly it has that LTD magic photo dust sprinkled all over it, the shots are rich, lush and have that "artistic" something that we all crave. This lens (and the LTD's in general) make me want to photograph things just to see what they look like through it. This lens covers my 17-50 Tamron with WR and better IQ. I still use the 17-50 for weddings as a backup etc, but this 20-40 is my goto everything lens. With the 15 and 70, it is my travel/landscape foundation lens. I don't find the zoom range limiting at all. It's a very convenient fine tunable normal. If I need wide or tele, then I switch lenses. But for everything else it's perfect. Just buy one. At $695 USD it's a great deal.
| | | | | | | New Member Registered: May, 2013 Posts: 13
9 users found this helpful
| | Review Date: July 29, 2014 | Recommended | Price: $825.00
| Rating: 9 |
| Pros: | Sharp, Color, Weather Sealed, Light, Compact, Flare Resistance | | Cons: | Slow Autofocus, Price, Lens Cap | | Sharpness: 9
Aberrations: 9
Bokeh: 10
Autofocus: 6
Handling: 10
Value: 8
New or Used: New
Camera Used: Pentax K-5IIs
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I bought this looking for an upgrade over the DA SMC 18-135 which I had used for a year or so and actually liked but I purchase a few of the limited series lens and was astounded at much better they rendered color and, in general, how much sharper they were over the 18-135. The HD 20-40 obviously doesn't have the zoom range and it isn't as useful in that regard but it renders colors so much better and is much sharper. I apparently got a good copy since I have found mine to be decently sharp wide open and very sharp when stopped down just a little more. The new HD coating works amazing well in tough, high contrast conditions. The autofocus motor is quiet. Not as quiet as SDM but much quieter than screw drive. It is a bit slow sometimes to lock onto a subject. Can be a tad frustrating at times.
Construction is top level and then lens feels good on the camera. Not too heavy but substantial enough. The weather sealing works very well. I was recently involved in a kayaking mishap where mine and my wife's tandem kayak sprung a leak in the middle of a bay in the Florida Keys. Eventually the kayak became too unstable to paddle and flipped. My wife saved the camera but it did get partially dunked in the bay. We were stranded out there for a couple hours till a boat came by and rescued us. The lens held up totally fine and the camera has of course okay as well. I was impressed! We of course were exhausted, dehydrated, and glad to be out of the water.
The price is steep for what it is but I wasn't willing to pay the equivalent to get the DA* 16-50 with potential SDM issues and the extra weight. I did find a good deal on this lens lurking Amazon but I do think the lens is a little too expensive for what it is. Maybe $799 for it brand new.
The lens cap is 62mm in size, the filter size is 55mm, and expensive! Don't lose it because it costs $40 to replace! It fits over the "lens hood" if you can call it a lens hood. My opinion is that flare is such a minimal problem with this lens that it could go without the lens hood the majority of the time.
I really enjoy using this lens. It stays on my camera 90% of the time.
 | | | | | Veteran Member Registered: October, 2007 Location: France Posts: 804
9 users found this helpful
| | Review Date: December 16, 2013 | Recommended | Price: $890.00
| Rating: 9 |
| Pros: | IQ, color rendering, "limited" style | | Cons: | Slow AF, price | | New or Used: New
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For the IQ, this lens outperforms the DA21 by a large margin, and it is a f2.8 lens, not a 3.2. The border are a bit soft at 20 mm f2.8 but at F4 it is already largely homogeneous. Flare resistance is excellent.
At 40 mm it is beyond the FA43 limited on the center resolution, but the FA43 is a high performer here, and he challenges the FA43 for the border resolution.
At 30 mm the FA31 outperforms this lens in terms of sharpness, but it is the FA31. CAare very well controlled, better than on the FA31.
In every aspects this lens is a very good performer. The price is a bit steep, though, but expected to be reduced. And we have to pay for the WR and DC engine.
An ideal lighweight combo could be the DA15, this zoom and the DA70.
| | | | | Site Supporter Registered: January, 2013 Location: Ottawa, Canada Posts: 4,189
8 users found this helpful
| | Review Date: April 10, 2020 | Recommended | Price: $500.00
| Rating: 9 |
| Pros: | Compact, Lightweight, Excellent Image Quality, Weather Resistance, Design and Construction | | Cons: | AF Fine Adjustment on my K-3 II (see below) | | Sharpness: 9
Aberrations: 9
Bokeh: 8
Autofocus: 8
Handling: 10
Value: 9
New or Used: New
Camera Used: Pentax K-3 II
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Why I acquired this lens
Although I’ve used my DA 18-135mm lens extensively for several years, I have not been entirely happy with it. I had purchased it mainly for the shorter half of its focal length range (i.e., 18-50mm), and treated the longer telephoto reach as a bonus. The 18-135 is fairly sharp between 20 and 60mm when stopped down, and it’s a versatile ‘walk-about’ or travel lens, as many users attest. However, I find its inherent contrast to be relatively weak; the bokeh is often not as pleasing as I’d like; the corners can be mushy or softer than in comparable images from some of my other lenses; and I've never seen any ‘pop’ or ‘dazzle’ in my pictures. Occasionally, I've missed having a wider aperture. In searching for a replacement zoom, I considered the Sigma 17-50 f/2.8, the Pentax DA 16-85, and other possible options. I wanted a weather-resistant lens and something that would compare well to my DA Limited lenses in terms of image quality. The DA 20-40mm Limited fit my needs.
Design, Construction, and Handling
In my opinion, the HD Pentax-DA 20-40mm Limited features a refined design and solid construction. Taking cues from the classic S-M-C Takumar line, of which I have several models, this lens is a handsome impression of simplicity and elegant appearance, perfectly complementing the other lenses of the DA Limited series.
On my copy, the zoom action is smooth yet sufficiently tight, while the lens also affords a perfectly usable, slightly-damped manual focus movement with a finely-ribbed ring at its front. The general construction seems to be tight. Although it’s not overly heavy at nearly 300 grams, this compact lens has a certain heft for its size that hints at its metal-and-glass construction.
The lens is handled easily and securely, fitting in the palm of my hand, and it fits readily in any of my camera bags. The slip-on lens cap still fits tightly after a year of use, although the flocked interior of the cap tends to attract dust over time. The included lens hood appears to be relatively shallow, but I haven’t observed any instances where it has failed to provide adequate shading.
Autofocus
I tend to take pictures mainly of static subjects with this lens, and I find that the autofocus is sufficiently quick on my K-3 II. As I have done with my other lenses, I conducted a rigorous AF Fine Adjustment (AFFA) for my DA 20-40, assessing the settings at 20, 30, and 40mm; at focus distances of at least 60 x FL; and variably focusing from the minimum focus distance and infinity positions. I found that the optimal AFFA calibration at 20mm is significantly different from that at 30mm and 40mm; the only setting that gives the sharpest autofocus at all focal lengths is AFFA = +2 when focused from infinity. So, I simply preset the focus to infinity before each shot, which is not a big deal, but this detail is reflected in my lower rating of ‘8’ for AF. Note, however, that the AFFA is a function of both the lens and the camera acting together, so this issue may not be entirely a fault of the lens itself.
Update 30 July 2021: AF calibration on K-3 Mark III. The variation of optimal AFFA settings is much less pronounced on my K-3 Mark III. Acceptable sharp focus is obtained at all focal lengths when focusing from the far or near focus positions. AFFA = -4.
The AF accuracy and shot-to-shot consistency are very good, which might suggest that the lens is constructed to tight mechanical tolerances and its in-lens AF motor is a good match.
Optical Quality
Here are my subjective observations, based on many images that I've taken with this lens. My copy is fairly sharp across the field at almost all focal lengths and aperture settings, although not as sharp at the corners at wide-open apertures. In my typical usage, I have no concerns with edge and corner softness; in fact, I am often pleasantly surprised at its good corner performance, especially compared to my DA 18-135. I’ve not noticed any serious field curvature effects, which a few other users have reported.
Its excellent colour, contrast, and overall image rendering are similar to my DA Limited primes. The out-of-focus areas exhibit pleasing bokeh most of the time, although not as smoothly as, say, my DA* 50-135mm. The lens seems to resists flare and ghosting very well.
The apparent vignetting at the widest apertures and geometrical distortions are corrected easily either in camera or in post processing (I use RawTherapee’s lens profiles), as are the minor aberrations. I’ve taken advantage of the relatively short minimum focus distance of 28 cm, especially when shooting wide open at 20mm.
Versatility, Comparisons, and Value
In short, I find the DA 20-40 to be an excellent lightweight zoom. I have used it in a variety of settings, including classic car shows, trail hikes, and city walks. I often carry it in a two-lens kit with the DA* 50-135, or sometimes three lenses adding the wide-angle DA 15mm Limited or FA 43mm Limited if I need a faster lens. While the zoom range is modest, it has a useful range on either side of ‘normal’, which provides a surprising degree of versatility. I’ve used this lens instead of carrying both the DA 21 and DA 35 Limiteds; I’ve not noticed any practical penalty in image quality although I have not compared these lenses rigorously.
As with other lenses, this one has pros, cons, and trade-offs. Compared to my DA 18-135, for example, I think the image quality is definitely better with my DA 20-40, but at the expense of less reach (hence, I may also carry my DA* 50-135). One might opt for the DA 16-85 – a good lens in its own right – but at the expense of slower apertures at the common focal lengths; a 60% heavier lens; a larger filter diameter; and perhaps an inferior manual focus action. The affordable Sigma 17-50mm is praised by many users; however, it’s not weather resistant and is significantly heavier and bulkier. The 20-40's widest aperture of f/4 at 40mm is perhaps a notable disadvantage, but that's a trade-off against lens size and mass.
When the DA 20-40 appeared on the market, I balked at its introductory price of CAD $1000, and acquired the DA 18-135 instead at $450. When the Limited zoom was offered eventually in Canada for CAD $725 (~ USD $500), the price was more palatable and I had saved up some funds in my ‘camera kitty’ so I jumped at it.
Conclusion
Overall, I find that the lens is a joy to use and it produces wonderful images with beautiful colour, high contrast, and 'depth'. It's one of my most-used lenses.
- Craig
 | | | | | Senior Member Registered: October, 2009 Location: Montreal (Quebec) Posts: 117
8 users found this helpful
| | Review Date: October 29, 2018 | Recommended | Price: $700.00
| Rating: 10 |
| Pros: | Colour Signature, CA Control, Sharpness, Useful Focal Range, Built Quality, Quiet AF, SMALL! | | Cons: | Would LOVE a bit Wider, with a Fixed 2.8 Aperture | | Sharpness: 9
Aberrations: 10
Bokeh: 9
Autofocus: 10
Handling: 10
Value: 10
New or Used: New
Camera Used: K-3
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In spite of its high price tag, and a somewhat limited production, this "HD Pentax DA 20-40mm" by Ricoh luckily ended up in my camera bag alongside an ageless K-3; it has quickly become one of my favourite normal zoom lenses ever!
Perhaps not the sharpest in theory versus the sharpest primes, nor with the broadest focal range either... Yet this tiny gem offers a sweet window of opportunity to travelers on APS-C sensor, for in practice things get mesmerizing as soon as the fireworks start dazzling:
A strickingly BRIGHT & CLEAR glass design; an especially RICH & VIBRANT color signature; a GENEROUS viewpoint refreshingly free from some of the most dreaded optical aberrations; a relatively FAST & QUIET, PRECISE AF too! All of these valued qualities in a STURDY, COMPACT retro-looking format.
An unduly under-explored PENTAX-Mount ASSET!
 | | | | | Senior Member Registered: November, 2009 Location: San Jose, CA Posts: 103
8 users found this helpful
| | Review Date: February 24, 2014 | Recommended | Price: $996.00
| Rating: 10 |
| Pros: | light, sharp, great build, WR, zoom range | | Cons: | lens hood, price | | New or Used: New
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For me, this is a great lens. And I may be the only one who actually likes the strange zoom range, but I do. First a little background. I have all the DA limiteds and use them whenever I have the time to play around with composition and enjoy shooting - which mostly means whenever I am by myself. When I go out with group of non-photography friends though, or whenever the weather isn't exactly right, I would end up going out with my 18-135. Which is WR and very small for the zoom range, but slow, not very great optically and no fun to use. It's much more fun to use limited primes (limited in more then one sense), because creativity often comes from that limitation. With 18-135, I just get complacent, zoom from where I stand and shoot.
But 20-40 changes all of that. It's a zoom, but still very limited. It gives me that possibility to go from 20-40 without changing the lens, and it gives me beautiful photos, very much comparable to limited primes.
It also creates beautiful travel kit with other DAs. My goto ultra light travel kit could easily be 15 for wide angle, 20-40 as basic walkaround and WR lens if it starts raining, 70 for short small telephoto. Replace 70 with macro for little extra reach and macro at the price of added weight. Or with 55-300 for real telephoto. Can't ask for much more. See I do like to travel light.
Scared by reviews here, I did some of my testing when I got the lens. It's sharp as sword in the center! And, I do not think there's a significant issue with corner sharpness, at least on my copy. The lens does have, though, a significant field curvature. If you focus the center at the open aperture, corners, especially at the close focus will be very much out of focus. You can focus the corners - then of course center will be out of focus. I believe for this type of lens it's normal behavior and refuse to be bothered by that. It pretty much disappears once you close the aperture enough, it gets much better at distance. Would I take this lens to take pictures of the artwork in the dimly lit gallery? Hell no, but that's not its purpose either. That's what macro lenses are for. Other then that, the lens is perfectly sharp on my K-3.
Some comparisons.
Compared to DA 21
21 pros:- tiny (this may actually play big role sometimes)
20-40 pros:- better sharpness over the field
- WR
- zoom
Compared to DA 40
40 pros:20-40 pros:
Compared to DA 35 Macro
35 pros:- macro
- uniform sharpness across the field
- I believe picture quality is a tiny bit better overall
20-40 pros:- WR
- faster focus, especially when macro start hunting
Compared to 18-135
18-135 pros:- zoom range
- price
- internal focus
20-40 pros:- much better optically (it better be for twice the price though)
- faster
- lighter
- parfocal! - this lens is completely parfocal, which allows you to do nice things, like focus on the (40mm) end, then zoom out and the focus stays the same.
 | | | | | Senior Member Registered: February, 2010 Location: California Posts: 142
7 users found this helpful
| | Review Date: September 29, 2016 | Recommended | Price: $600.00
| Rating: 9 |
| Pros: | Sharp, WR, light weight, build quality, flare resistance, lack of CA | | Cons: | focus is not super fast, and sometimes inconsistent, vignetting at 40mm | | Sharpness: 9
Aberrations: 9
Bokeh: 7
Autofocus: 7
Handling: 8
Value: 8
New or Used: New
Camera Used: K3 II
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One thing about upgrading to the K3 is that it really shows you how sharp your lenses are (or aren't!). Anyway, one of my film era zooms was really soft at the edges on the wide end, and having sold my DA 21 limited to help purchase the K3 II, I had nothing that could deliver the goods between my DA 15mm and my DA 40mm limiteds. Also, I was looking for a general purpose zoom.
I was leaning toward the DA 16-85mm or the Tamron 17-50 f2.8. I had initially discounted the DA 20-40mm because of rather negative reviews and the high price. The DA 16-85mm was appealing for the range, WR, and good IQ, but is a bit slow at the long end, and a bit big and heavy. The Tamron is appealing for its f2.8 and good IQ, but no WR.
Trying to figure out what being limited to f5.6 at 85mm meant, I started looking at pics on the web from the DA16-85mm. I found many nice photos, but nothing that was really saying wow. Not very scientific, but still telling. While doing this I came across a number of shots from the DA 20-40mm that caught my eye. I found the reviews on this site that are generally positive, and full size images that were definitely sharp across the frame. That, along with the substantial price reduction this summer, made me reconsider this lens.
I am so glad that I did. I ended up ordering the 16-85 and the 20-40, with the intention of keeping one of them. I did a quick test to make sure neither were decentered or otherwise defective. I was mostly concerned with across the field sharpness at infinity, as that was what I was not getting with my film era zoom. Neither lens was obviously decentered, but the 20-40 was definitely a little sharper than the 16-85 across the 20-40 range. I wasn't expecting this. Sharp enough wide open, (much better at the deges than my DA 21mm f3,2 was) and razor at f5.6
My first outing was an overnight ski trip above Lake Tahoe to shoot panos of the Milky Way. Admittedly I used the 15mm for the star shots, but I got some beautiful sunsets with the 20-40mm. The rendering was definitely showing that limited quality, and shooting right into the sun is no issue with this lens. Sharp across the frame, no flare, no CA, great color. You got to love it! The next outing was in the High Sierra and I got the same results.
I tried some Miky Way shots, and I was disappointed that the combination of coma and sagittal astigmatism at f2.8 is quite bad. The good news is that is way better at f4. With the astrotracer, f4 is doable for the Milky Way.
My last outing was on the San Francisco bay shooting sailboat races. Once again, sharp and no flare. The wind really came up, and I was getting splashed frequently. It was really nice to be able to put the camera under the faucet at the end of the day to get the salt water off.
I am very happy with the lens, and I would recommmend it to anyone looking for a light, well made, good IQ lens in this focal range.
Here are some example shots:
The last two were using a polarizer.
| | | | | Site Supporter Registered: May, 2014 Location: Minnesota Posts: 2,047
7 users found this helpful
| | Review Date: December 25, 2014 | Recommended | Price: $574.00
| Rating: 9 |
| Pros: | Small, Light, Weather sealed, Quiet | | Cons: | Limited range | | Sharpness: 10
Aberrations: 9
Bokeh: 8
Autofocus: 9
Handling: 10
Value: 8
New or Used: Used
Camera Used: Pentax K-5 IIs
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First of all I can't give an extensive review for this lens since I only had it a couple of weeks. Maybe after a few months I'll update this review to give you a better perspective on how I feel about this lens. I have lusted for this lens for quite a while now, but the thing that held me back was the price. Due to the limited range and due to some negative reviews I was hesitant to fork over that much money for it. A few weeks ago I was looking at the BH website and saw that this lens was selling for only $574 Used in 9+ condition !
This was about the lowest price I had yet to see for this lens new or used, so I got it. I figured I could always send it back within 31 days if I did not like it.
So, lately I have been testing this lens under as many real-life conditions as possible, hoping I would not have to send it back. Like I said, it's only been a few weeks if that many, but so far I'm pleasantly surprised. This lens is a marvel of engineering and so fits well with my K-5 IIs which is a marvel of it's own.
First I will describe the Aperture which some people have complained about being too slow. At 20mm you can open up to f2.8, at 25-30mm f3.5, at 35-40mm f4.0. Not bad considering that even some limited primes within those focal ranges are not much faster.
I compared the Sharpness of this lens against my 16-45mm f4 and 35mm Macro f2.8. The good thing about this lens is that it does not extend much from the body like my 16-45mm does. At 20mm it extends about 2/3 of an inch. at the other focal lengths it does not extend past 1/2 of an inch from the body. The distance scale on this lens is quite limited in that after 5 feet it goes straight to infinity with nothing in between, but that might have to do with lens design for zooms which I now little about
From what I can tell, this lens is a tad sharper than my 16-45mm across all focal lengths except maybe the 30mm focal length, why I don't know ? What this lens got going for it, is the way it renders the colors and the contrast. Not artsy, not over-saturated, but amazingly life-like. At 35mm, my 35mm f2.8 Macro is sharper across the length of the frame, but to tell you the truth, there is not much difference between all 3 lenses unless you really pixel-peep. If you really want sharp though, set the camera to ISO 80. Then you start moving into 3D territory...
Handling : Although this lens is supposed to be all metal, it is very light to the point where I think it's some kind of aluminum instead of real metal ? Nevertheless it is very well built, but I wish it had the heft of my other limited lenses just my opinion... The focusing is very well damped as well as the Zoom dial. So there is no problem there. One thing is the very fancy lens cap. I am so afraid that I might drop it and lose it (@$40) that I keep it in my left hand when shooting. This lens is light and well balanced enough for me to do that thankfully.
Autofocus is nearly silent and pretty quick. You really have to put your ears pretty close to the camera to hear it. This is perfect for places like museums, operas, churches, funerals, where the loud buzzing whirl of other lenses might become annoying. One thing I noticed is that the AF is faster and much more accurate if you limit the auto focusing points. I set my AF to Sel Mode and only use one focusing point, so far this has worked best for me.
Bokeh is reasonable mild/smooth a little better than on my 16-45mm, but not better than on my 35mm, or 77mm. I have not had the time to test this much so I can't say much about it.
Aberrations: What I like about this lens is this new Pentax Anti Flare coating. This really helps when shooting into the light, not just sun light, I'm talking about street lights and car lights and things like that. This lens does not fall apart like my Limited and other lenses do in those conditions. Another thing I noticed though is that this lens produces a little bit more CA under certain circumstances than my 16-45mm. It could be my copy, but I'm still investigating.
If you take all the features into consideration, not just pixel-peeping sharpness, this is a wonderful lens and a marvel of engineering. Time and experience will tell whether I will send it back, but so far so good. | | | | | Moderator
Site Supporter Registered: February, 2012 Location: Adelaide Hills, South Australia Posts: 11,272
7 users found this helpful
| | Review Date: December 14, 2013 | Not Recommended | Price: $900.00
| Rating: 7 |
| Pros: | Physical beauty and handling, DC AF and WR | | Cons: | Weak at the short end, too big for a DA limited | | Sharpness: 7
Aberrations: 8
Bokeh: 9
Autofocus: 9
Handling: 10
Value: 6
New or Used: New
Camera Used: K-3
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I had high hopes for this lens. It looks and feels amazing, and it focusses quickly, quietly, and nice and close. Flare resistance is pretty reasonable. It is disappointingly big though.
Between 30mm and 40mm the IQ is excellent, and the bokeh is superb despite only being f/3.5-4.0 in that range.
Unfortunately edge performance is pretty hopeless wide open at the wider end, and only really becomes useable beyond f/5.6, and good beyond f/8.0.
Unacceptable in such an expensive lens.
I will be sticking with my DA*16-50 for weather-proof zooming in that range, and with my limited primes for fun/ultimate IQ.
| | | | | Senior Member Registered: November, 2012 Location: Copenhagen, Denmark Posts: 105
6 users found this helpful
| | Review Date: November 29, 2020 | Recommended
| Rating: 10 |
| Pros: | | | Cons: | | | Autofocus: 10
Handling: 10
Value: 10
New or Used: New
Camera Used: K-3
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The reviews and the evaluation of this new HD Pentax Limited zoom lens have been very different - some very negative and some very positive. I think that PentaxForums' test and evaluation of the lens is unfair with regard to sharpness (sample variation?). As soon as I received the lens I made some test footage, and I was admittedly a little confused about the results, but after some time I noticed an issue with back focus. It was subsequently adjusted to Back Focus + 5. Since then the results have been excellent. Back Focus + 5 was applied on two camera bodies (both K-3) with the same excellent result. The lens is sharp throughout the entire zoom range from 20 mm to 40 mm. I haven't noticed any decrease in picture quality in the long end of the zoom range. The color rendition is warm and very appealing - it can be compared with the DA *16-50 mm 2.8. The external parts of the lens are made of metal. I can highly recommend the lens. The reviews that have been negative may have forgotten that the lens is only one parameter of several in the process: photographer + camera/sensor + lens + image processing software + the photographer's ability to get all the qualities above. Lens quality is obviously very important - ultimately decisive, but so too the photographer's ability or skills. Thank you Ricoh/Pentax for this wonderful lens. It has lifted the pleasure of photography up to a higher level!
| | | | | New Member Registered: December, 2013 Posts: 7
6 users found this helpful
| | Review Date: June 8, 2019 | Recommended | Price: $450.00
| Rating: 9 |
| Pros: | 3d, great handling, WR | | Cons: | AF, limited zoom range. | | Sharpness: 9
Aberrations: 9
Bokeh: 9
Autofocus: 6
Handling: 10
Value: 8
New or Used: Used
Camera Used: K70
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This zoom looks and feels great to use. I love having the Limited look and feel with added Weather Resistance, although it is quite a bit more chunky than a Limited prime. The AF on my k70 struggles to lock sometimes, oddly just like my 35mm Limited. Might be better on a different camera.
The zoom range feels slightly short. I have been using the 16-85 which is a very convenient range, and before that an 18-135 which is suppose you'd call a super zoom, so maybe if you are coming from 18-50 it won't seem too bad. It actually encourages me to use my wonderful 55-300plm and some nice telephoto primes more often, although that means carrying extra gear. I do use it as a one lens walk about option, and honestly it's fine, but I do sometimes miss a bit of extra reach. If you tend towards shooting at the wide end you may well find it's perfect.
It's good indoors, where the wider end offers a fairly fast aperture.
The colours are typical Limited. The sharpness is very good. Sharpness is a weird thing, it sometimes doesn't look as crisp as some lenses, with quite a smooth buttery look. However, if you pixel peep, there is actually plenty of detail. It's a bit like some vintage lenses in that respect, but I think that HD coating gives slightly more modern looking saturated colours.
By comparison the 16-85 is certainly quite crisp looking, with that fantastic super-handy focal range, and the AF is better. I can use a smaller bag for the 20-40, but where it really wins is with the sense of 3D depth. Some shots, even at f11, look like you can reach into the picture. It's classic Pentax through and through. It could simply be due to a relatively low number of elements? It's a bit like having a couple of Takumars in one, but with AF, weather sealing and all the other mod cons. It even looks like a Tak on steroids! I don't think it's just a coincidence, there is a retro vibe inside and out.
The 16-85 is convenient, and very competent. The 20-40 just has a slight touch of magic.
| | | | | Senior Member Registered: October, 2011 Location: Cambridge, Ontario Posts: 179
6 users found this helpful
| | Review Date: December 8, 2013 | Recommended | Price: $999.00
| Rating: 10 |
| Pros: | Beautiful construction, IQ, very light | | Cons: | Cost, but you get what you pay for. 55 mm filters | | Sharpness: 10
Aberrations: 10
Bokeh: 9
Autofocus: 10
Handling: 10
Value: 9
New or Used: New
Camera Used: K3
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In my opinion, the first Limited Zoom is a winner. If you like Limited primes, this is the zoom for you. At under 300 grams it is lighter than an FA 31 and is well balanced on the camera. This lens is a great walkabout lens for a landscape photographer and just right for my general use. It is weather sealed which is a bonus. It complements my fleet of Limited primes very well.
Image quality is stunning and the DC motor is quiet. Autofocus is fast even indoors. The ergonomics are amazing, you can carry this lens all day and the camera is not nose heavy. It is plenty fast for my use, weight is a greater concern to me.
Many people will consider this lens expensive. My Canikon friends disagree, they pay much more for good glass. The new Sigma 18-35 is faster but rivals a telephoto lens in size and weight. There is no way I would carry that all day.
I would highly recommend this lens. If you like Limited lenses before, you will like this one.
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