| Author: | | Site Supporter Registered: May, 2013 Posts: 341
3 users found this helpful
| | Review Date: April 2, 2018 | Not Recommended | Price: $590.00
| Rating: 7 |
| Pros: | good autofocus, light and very portable | | Cons: | poor edge to edge sharpness | | Sharpness: 7
Aberrations: 7
Bokeh: 9
Autofocus: 9
Handling: 8
Value: 7
New or Used: Used
Camera Used: Pentax K-5iis
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I love the portability of the lens and the hood design which does not project out from the lens body and is easy to put on and remove. Unfortunately, for a prime lens, its not as sharp as it should be as edge to edge sharpness falls off even at higher aperture values, f8 and up. Flaring is also an issue.
| | | | | | | New Member Registered: March, 2017 Posts: 2
2 users found this helpful
| | Review Date: March 17, 2017 | Not Recommended | Price: $200.00
| Rating: 5 |
| Pros: | Size, quick-shift manual focus | | Cons: | soft | | Sharpness: 5
Aberrations: 7
Bokeh: 7
Autofocus: 8
Handling: 9
Value: 6
New or Used: Used
Camera Used: K7
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I've owned a Pentax-M 20mm f4 for over 30 years. I didn't use it very much in the film era. I wasn't fond of the distortion towards the edges, I thought it was soft and the colour was subdued unlike other Pentax glass I owned. When the digital era arrived with cropped sensors I gave it another try. Distortion was no longer an issue but it was too soft and continued to sit on the shelf and collect dust.
However, I found that I was using the 20mm focal range on a 17-50 Tamron quite frequently so when a 21mm Limited appeared on CL for a good price, I bought it.
When I was testing it the day of purchase there were a number of concerns, focus seemed soft and it had problems locking infinity focus at times. I thought the problems could be fixed with a fine focus adjustment so I completed the purchase.
I've now been testing the Limited for a number of days. I was surprised to find the IQ virtually identical to the Pentax-M 20mm. Actually I was more shocked than surprised, although colour and contrast tended to be better on the Limited if it was a shot taken in good light it was hard to tell them apart.
I thought that there must be something wrong with the Limited. I stripped it down and inspected everything but couldn't find a problem. The last step on reassembly was to set infinity focus and when that was done it was in the exact same position the factory had set.
Even though I found no mechanical issues with the lens I think there's a problem with the lens pack. Either the assembly wasn't adjusted correctly at the factory or some of the glass is sub-standard. I shoot a K7 and to correct focus I had to adjust the firmware to +40 UM and the lens +10. That's the equivalent of +14 when thinking of it in a menu equivalent adjustment, not something I consider normal.
What I do find surprising is that someone lived with this lens through the warranty period (in Canada I believe 2 years). When other reviewers extol the sharpness of their lenses I must believe that their copies really are that sharp. For what is marketed as a premium lens I would consider mine unacceptable. Pentax needs to improve quality control if they haven't already done so, in my opinion this lens shouldn't have been sold.
I consider it to be OK for street photography (what I bought it for) but unacceptable for landscape photography. Focus is soft and doesn't improve with smaller apertures although edge sharpness and contrast do.
| | | | | New Member Registered: July, 2010 Location: St. Petersburg Posts: 22
3 users found this helpful
| | Review Date: September 30, 2012 | Not Recommended | Price: $510.00
| Rating: 8 |
| Pros: | size, build quality | | Cons: | sharpness | | Sharpness: 7
Aberrations: 8
Bokeh: 8
Autofocus: 8
Handling: 8
Value: 7
New or Used: New
Camera Used: K20D, K-5iis
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Among all Pentax lenses I have this one provides shots with the lowest sharpness. Even when I focus on the infinity, I got an image that is not so sharp as I can expect from a prime lens. I admit that I may have a bad sample though. The hood fastening doesn't allow you to use 49mm filter while the it's on the lens, while 43mm is something hard to find.
| | | | | New Member Registered: November, 2010 Posts: 16
2 users found this helpful
| | Review Date: November 17, 2011 | Not Recommended | Price: $400.00
| Rating: 7 |
| Pros: | Size, weight, construction, design, AF speed, bokeh, colors, focal | | Cons: | distorsion, vignette, not sharp, aberrations, odd hood and cap | | Sharpness: 6
Aberrations: 7
Bokeh: 8
Autofocus: 9
Handling: 10
Value: 7
New or Used: New
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Itīs a Limited, but for me itīs not a Limited... A very simple lens, itīs strengths are size and construction. But this is not so important when the optics are not in a level according to this. High distortion and vignette, low sharpness in general. The colors are accurate and Typically Pentax, with nice, high contrast.
The 21 is very nice for my purpose, as a street photography lens. I chose it because of its size and convenient focal, with is perfect for my purposes. Using a 35 for a long time, I wanted something wider and this was the best option. I reed a lot of websites and reviews of this lens, and my expectatives were a bit higher. Of course, I knew it is not as good as the 31 limited or as a Leica, but it is worse than I expected. I think itīs also overpriced.
I love Pentax, and I love that original, small pancake lenses, but I think the 21mm is not the perfect lens for my K5, in optical quality.
| | | | | | | Veteran Member Registered: September, 2006 Location: Tokyo Posts: 962
1 user found this helpful
| | Review Date: March 26, 2007 | Not Recommended | Price: $400.00
| Rating: 7 |
| Pros: | versatile focal length, size/weight, autofocus | | Cons: | hood and cap design; colours not great | | New or Used: New
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I was reluctant to write anything about this lens because it's the only auto-focus lens I've used extensively. As a mostly-manual shooter, I miss the aperture ring and tactile feeling of manual-focus gear.
That said, the ~31mm focal length equivalent on the 35mm frame is very versatile, suiting urban, landscape and indoor settings. It is a sharp lens with little distortion, making the entire frame useful.
I've made some of my favorite photos with this lens, but notice that these tend towards subtle colors in discreet lighting. This lens has disappointed me with weird color rending in bright light.
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The second sample shows the resolving power of this lens. At ISO 200 and f/8, in the RAW file you can make out facial features details of the fellow standing on the far side of the street, partially visible through the speeding bus.
Some "cons"
I've found this lens gives me curious color cast, with reds and violets becoming too livid or pronounced. I've even had photos of the sea turn out purple. I've never had this problem with my other Pentax lenses.
I don't find the rendering of shapes to be particularly engaging. My SMC 28mm f/3.5 and Zenitar 16mm do a much better job.
The design of the hood and cap puts form before function. The cap does not fasten to the lens for some reason. Mine fell to the street during the first week that I had the lens. The fall dented the hood rendering it useless but I didn't notice that it was dented until I'd tried putting it back on the lens, scratching the lens in the process. The clip-on hood makes the accessory thread unusable, so I shelved it in favor of using filters and a hood that can attach to the lens.
[edit: 2010.07.02 -- downgraded my rating on this lens, as I've essentially stopped using it. It is a good lens but not excellent. ]
| | | | | Forum Member Registered: September, 2021 Posts: 62
1 user found this helpful
| | Review Date: February 10, 2024 | Recommended | Price: $120.00
| Rating: 9 |
| Pros: | Size, built quality, lens hood, focal length | | Cons: | Sharpness outside of the center, sharpness in general | |
Like many users said before, the size is just awesome and the lens hood is something I like a lot.
The focal length is perfect for a lot of purposes.
But one thing to notice is, that this lens does produce horrible images if it has not been stopped down to at least F8 !!
Purple areas are simply dramatic of not stopped down, as well as a significant lack of sharpness in the corners.
If there is enough light, or you are using a tripod so that stopping down is possible, it produces really nice pictures.
Just don't buy this lens if shooting wide open is something you need :-)
| | | | | New Member Registered: April, 2019 Posts: 7
1 user found this helpful
| | Review Date: May 28, 2023 | Recommended | Price: $260.00
| Rating: 9 |
| Pros: | Colour & contrast | | Cons: | Bit soft at the edges.. but not by much | | Sharpness: 9
Aberrations: 8
Bokeh: 7
Autofocus: 8
Handling: 10
Value: 9
New or Used: Used
Camera Used: K3
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This is my most used lens for walking about. Love the images it produces, great colour and contrast. Lightweight and compact. Sharp and focus is good.
Anyway not much of a lens reviewer... here's some images taken on a recent walkabout.
You can make your own mind up - all SOOC jpegs.
     | | | | | New Member Registered: November, 2019 Posts: 1 | | Review Date: March 19, 2023 | Recommended | Price: $280.00
| Rating: 9 |
| Pros: | Sharp | | Cons: | None | | Sharpness: 9
Aberrations: 8
Bokeh: 8
Autofocus: 8
Handling: 9
Value: 8
New or Used: Used
Camera Used: Pentax K-3
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My 'walkabout' lens for my K-3, on which it represents the full-frame equivalent of approx. 31.5mm.
Very sharp with nice colour rendition.
Personally I'm uncertain of the merits of its unique lens hood - mine has been replaced with a NOS Pentax 49mm standard 50mm 1.4/1.7/2.0 round plastic hood that gets covered with an Optech/USA mini Hood Hat in lieu of a lens cap.
Occasionally pressed into action on my K-1, it works rather well at it's 21mm focal length with my preferred 1x1 crop option.
| | | | | New Member Registered: September, 2016 Posts: 8
1 user found this helpful
| | Review Date: February 2, 2021 | Recommended | Price: $470.00
| Rating: 9 |
| Pros: | my standardgo to lens since 2007 | | Cons: | none | | Sharpness: 8
Aberrations: 8
Autofocus: 8
Handling: 8
Value: 10
New or Used: New
Camera Used: K-10 through K-1
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I bought this lens for my first digital K-10 Pentax in 2007 and it has been my primary go-to lens through a succession of Pentax bodies, through the K-20d, K-5, K-3, K-1, and K-70 and, although I have added other limited primes since then, it is still my favorite.
FWIW, I almost always default to an f/8 aperture priority. Had to have it repaired locally for loose screws, but been great since. Given the opportunity, I might someday update to the newer version (red band, versus the green band). And waiting to see what the 21mm full-frame will be (and cost).
For many examples, see: https://originalrefrigeratorart.blogspot.com and https://ora2.blogspot.com | | | | | Veteran Member Registered: December, 2011 Location: Melbourne + Malvern East Victoria Australia Posts: 377 | | Review Date: January 3, 2021 | Recommended
| Rating: 10 |
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great lens
| | | | | Site Supporter Registered: October, 2009 Location: Dublin, Ireland Posts: 385
2 users found this helpful
| | Review Date: October 30, 2020 | Recommended | Price: $250.00
| Rating: 10 |
| Pros: | perfect starbursts, small size, clever lens hood | | Cons: | slightly soft corners | | Sharpness: 7
Aberrations: 8
Bokeh: 8
Autofocus: 9
Handling: 10
Value: 10
New or Used: Used
Camera Used: K-S2, K200D
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So much more than the sum of its parts!
The standout features of this lens don't fit neatly into the provided boxes. The colors are rich yet balanced. The lens is tiny and sturdy. And the starbursts (or sunstars) are astonishing.
I bought this lens second-hand because I wanted a green SMC Pentax-DA 15mm Limited for landscapes, but I couldn't find an affordable copy. So I got this, hearing that the starbursts were comparable. Well, they are not "comparable," they are "every bit as good." It has become my favorite lens, with the possible exception of my DA Fish-Eye.
It's hard to explain why this lens is so good. It's sharp, but not perfect. /3.2 isn't all that fast. 21mm on APS-C isn't particularly wide. This should be a ho-hum lens.
And yet. And yet. This lens delivers. It is so tiny, the colors are so good, and the starbursts are so sharp. I now own four Limiteds: the 15mm, 40mm, 70mm, and this one. This is the pick of the litter.
| | | | | Pentaxian Registered: May, 2015 Posts: 3,306 | | Review Date: June 2, 2020 | Recommended
| Rating: 8 |
| Pros: | size, focal length, contrast | | Cons: | barrel distortion, speed | | Sharpness: 8
Aberrations: 8
Bokeh: 8
Autofocus: 8
Handling: 8
Value: 7
New or Used: New
Camera Used: K-5, K-3II
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Nice compact lens with very flexible focal length. I had this lens practically glued to my camera for long periods of time. The focal length can do everything and gives a wide but somehow normal looking perspective.
The colours, contrast and rendering are all very good.
My copy developed a distinct wobble of the barrel despite the short length but no visible impact on optical performance.
The barrel distortion isn't huge but for someone shooting architecture it made me miss the perfectly vertical framing far more often than I'd liked.
| | | | | Pentaxian Registered: November, 2014 Location: Washington, DC Posts: 1,749 | | Review Date: January 9, 2020 | Recommended | Price: $270.00
| Rating: 9 |
| Pros: | Size; Image Quality; Fast Aperture; | | Cons: | A little wobbly construction? | | New or Used: New
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My first limited! I got this for a trip abroad where I was attracted to the relative speed (3.2 is basically 2.8) for the small profile, with a wide-normal field of view for general scenes including landscapes and people. At first I thought, I might buy it and then sell it after the trip, but it fit its purpose so well that I kept it and got more limiteds! Shoot.
I've noticed CA but nothing major, it's a good sharp lens. I like placing my subjects on the edges of the frame, and sometimes if they're farther away and i'm shooting wide open the softness is not great and it looks like they're out of focus. So not great for that particular purpose. But for landscapes, general travel photography, grabbing shots with great color and sharpness, it's a killer lens! Unfortunately, it did not really help too much with avoiding attention. It's better than a big 24-70 lens of course, but attached to a K-3 and up to my face it's still obvious what's up. (I've found it's easier to not be noticed with a smaller point and shoot like the GR) A more concrete benefit to the slim profile is the ease of taking it anywhere and packing it. Other notes: I got a 43mm filter and screwed it into the flat lens hood, also the focus ring wobbles a bit, which isn't too worrying but a little unfortunate.
| | | | | Senior Member Registered: June, 2018 Posts: 131
1 user found this helpful
| | Review Date: January 5, 2020 | Recommended | Price: $220.00
| Rating: 9 |
| Pros: | Small, lovely colours | | Cons: | Could be faster, but I wouldn't want it any heavier | | Sharpness: 8
Aberrations: 8
Bokeh: 9
Autofocus: 9
Handling: 10
Value: 9
New or Used: Used
Camera Used: K50, K3ii
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As others have said, an excellent walk-around focal length. Colours (especially blues) are beautiful. Centre sharpness is very good from f4. Floaty light, lovely to use. Out of focus areas look very natural. Would replace immediately if I lost it.
 | | | | | Pentaxian Registered: September, 2018 Location: Poland Posts: 1,800
2 users found this helpful
| | Review Date: December 23, 2019 | Recommended | Price: $200.00
| Rating: 9 |
| Pros: | build quality, IQ | | Cons: | nothing | | Sharpness: 9
Aberrations: 9
Bokeh: 9
Autofocus: 9
Handling: 10
Value: 9
New or Used: Used
Camera Used: K-50
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This little lens has a lovely color rendition. Its focal length makes it a perfect walk-around prime for APS-C sensor. Very good build quality and a clever lens hood. Sharpness is ok when wide open and gets very good stopped down.
F/3.2:
F/4
F/5.6
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