Review: Pentax K SMC 28mm 1:3.5

Pentax SMC 3.5/28 K front

The Pentax is a rather small and affordable 28mm lens and  Pentax had a reputation for their very effective coatings. Read on if you want to know why I like it so much on my 24MP fullframe Sony a7.

Specifications

  • Diameter: 63mm
  • Length: 47mm
  • Weight: 261g
  • Filter Diameter: 52mm
  • Number of aperture blades: 5
  • Close Focusing Distance: 0.3m
  • Mount: Pentax K

The Pentax K SMC 1:3.5/28 usually sells for around $45-90 at ebay.com (affiliate link). 
In Germany you can buy it for 40-85€ at ebay.de (affiliate link). 

Sample images

Sony a7 | Pentax SMC K 1:3.5/28 | f/11 | full resolution
Sony a7 | Pentax SMC K 1:3.5/28 | f/11 | full resolution
Sony a7 | Pentax SMC K 1:3.5/28 | f/11 | full resolution
Sony a7 | Pentax SMC K 1:3.5/28 | f/11 | full resolution
Sony a7 | Pentax SMC K 1:3.5/28 | f/3.5 | full resolution
Sony a7 | Pentax SMC K 1:3.5/28 | f/3.5 | full resolution

Versions

The Version I review is the K version. There is also a M version which is smaller but, from the reports I have read, not on the same levels optically.Pentax SMC 3.5/28 K on Sony a7

Sharpness

Pentax_28mmf3p5_infinity2

You can find the full resolution test images in the Pentax SMC 3.5/28 flickr album.

 

f/3.5: Good sharpness across the frame with moderate contrast. The corners are a bit softer and somewhat hazy.

f/5.6: Excellent to very good in the center and midframe region with very good contrast. The corners are still a bit hazy.

f/8: Very good sharpness across the frame.

f/11: A little softer in the center due to diffraction.

Comment

The Pentax 3.5/28 is my favorite wideangle lens at the moment.

The lens is very well built with very low tolerances and an all metal housing. It is also quite small so handling is very pleasant. Only the reversed travel direction of the focusing ring is a bit bothersome for me who is used to Minolta SR/Canon FD/ Zeiss C/Y lenses.

Pentax SMC 3.5/28 K Product image

Optically it leaves little to be desired. At shorter distances you get decent bokeh and good sharpness from f/3.5.

Sony a7 | Pentax SMC K 1:3.5/28 | f/8 | full resolutionSony a7 | Pentax SMC K 1:3.5/28 | f/8 | full resolution

Sony a7 | Pentax SMC K 1:3.5/28 | f/8 | full resolutionSony a7 | Pentax SMC K 1:3.5/28 | f/8 | full resolution

Stopped down to f/8 it is very sharp across the frame. There is some field curvature but of the good kind where the corners are focused in front of the center. CA correction is exceptional (better than the Zeiss Distagon 2.8/28).

Sony a7 | Pentax SMC K 1:3.5/28 | f/8 | full resolution
Sony a7 | Pentax SMC K 1:3.5/28 | f/8 | full resolution
Sony a7 | Pentax SMC K 1:3.5/28 | f/8 | full resolution
Sony a7 | Pentax SMC K 1:3.5/28 | f/8 | full resolution
Sony a7 | Pentax SMC K 1:3.5/28 | f/8 | full resolution
Sony a7 | Pentax SMC K 1:3.5/28 | f/8 | full resolution

What surprised me the most was the truly exceptional flare resistances and very high contrast. I didn’t know that a 40 years old lens could be that flare resistant. The Pentax is even better than the Zeiss Distagon 2.8/28 in this regard.

Sony a7 | Pentax SMC K 1:3.5/28 | f/8 | full resolution
Sony a7 | Pentax SMC K 1:3.5/28 | f/8 | full resolution
Sony a7 | Pentax SMC K 1:3.5/28 | f/8 | full resolution
Sony a7 | Pentax SMC K 1:3.5/28 | f/8 | full resolution
Sony a7 | Pentax SMC K 1:3.5/28 | f/8 | full resolution
Sony a7 | Pentax SMC K 1:3.5/28 | f/8

The Pentax K 3.5/28 has only 5 aperture blades which result in reasonably well defined sunstars.

Sony a7 | Pentax SMC K 1:3.5/28 | f/11 | full resolution
Sony a7 | Pentax SMC K 1:3.5/28 | f/11 | full resolution

Conclusion

Pentax SMC 3.5/28 K on Sony a7

The Pentax SMC K 3.5/28 doesn’t have any real weakness. It delivers surprisingly good performance in a small package.

If you consider the very good performance the lens offers a great value. That is if you can find one, it was sold for only a short period of time so it is quite rare and it’s successor the Pentax SMC M 3.5/28 isn’t as good.

The Pentax K SMC 1:3.5/28 usually sells for around $45-90 at ebay.com (affiliate link). 
In Germany you can buy it for 40-85€ at ebay.de (affiliate link). 

If this review was helpful to you, please consider using one of my affiliate links. I will earn a small commission on your purchase and it won’t cost you anything. Thanks!

Further Reading

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I like to be outside with my camera and I am also a gear head with a love for manual lenses.

23 thoughts on “Review: Pentax K SMC 28mm 1:3.5”

  1. Anybody knows the difference to the Asahi Pentax Takumar 28mm 3.5? And any opinions about the Olympus Zuiko 28mm f/3.5?

    1. No personal experience but anything I have read about the Takumar was less than enthusiastic.

      The Oly 3.5/28 is actually a tad sharper in the corners but it flares easily and the Pentax is noticeably more contrasty.

    2. Soso, the Takumar is different optically (as is the Pentax M as Phillip noted.) I have not tried it but everything I have read supports that the original K mount version in this review is the one to get.

      The Olympus 28mm f/3.5 is very good, but is only single coated. It has lower contrast, is less resistant to flare, and even though the corners are very good….my copy suffers from a midzone dip.

      The Pentax that Phillip reviewed is my favorite 28 as well, after trying many.

      Great review Phillip!

      -Tim

  2. I was initially put off by it being a slow lens–but it’s a real performer with great sharpness and colors on my a7. I concur about the great flare resistance. The colors are just wonderful. Outperforms my Contax G 28mm f2.8 on my a7 which has the dreaded magenta cast.

    https://flic.kr/p/GvY9TN

  3. Awesome photos, Phillip! I mean all of your pics across the whole site – really like your work and style. I stuck with Pentax for decades because I loved their lenses, especially the 6×7 stuff. However, have recently moved to A7ii because the Sony E mount is so versatile, and I also gave up waiting for a Pentax full frame. I have never shot the K 3.5/28 but it does not surprise me that you have found an excellent performer. I very rarely shoot wide angle these days but if and when I do I rely on a Distagon 2.8/28. If I want to capture sonething really wide then I default to my handy Pentax Q with its native 3.8-5.9mm wide angle zoom (21-32 equiv or 17-27 on the later body), which is a surprisingly excellent EDIF optic in a toy-like package!

  4. Hat jemand eine Idee wo ich diese Objektiv zu einem Normalen Preis in Deutschland bekomme auf E-Bay gibt es nur das M in ganz Europa😭 irgendwo muss man es doch bekommen?

    1. Du kannst dich in Online-Kleinanzeigen auf die Suche machen, ich habe z.B. gerade eins auf kleinanzeigen.ebay.de aufgeschnappt (60€ inkl. Versand).

  5. Man muss einfach Geduld haben ! A very good lens indeed. The AWB of the A7 is lost with this lens so you have always some work in PP .
    From Pentax :
    I am using also the M50 1.4 . It is good from f2 and has a really beautiful bokeh . Everybody should have a SMC Takumar 55 1.8/2 , cheap, sharp stopped down and a lens with character at wide apertures ( soft bokeh, unique rendering).

  6. I’ve got a mint Sony a7r on the way from eBay! I’m digging around for one of these Pentax 28mm lenses but sellers on the Bay are jacking the prices up on this model. I will find one and utilize it!

  7. These Pentax 28/3.5 lenses are really hard to find! I have one that I use on my A7r. It’s a nice lens for landscape photography, but I’m not as enthusiastic as Phillip. This lens really wants to be at f/11. I find the corners and edges are really bad at f/3.5 and even f/5.6. At f/8 corners are so-so. By f/11 it’s at its best for me (balancing a bit of diffraction versus over all sharpness). It’s still great value if you can find one at a good price, but beware the larger apertures.

    One word of caution: all the Pentax K to Sony E adapters I’ve been able to find position the lens off-centre compared to most other lenses (in other words, the aperture and distance scale are rotated away from “up top”; this is because of the “fin” on the K mount. (Stop reading now if you don’t like lens mutilation… I had to snip the fin to make it work on my Tilt-Shift adapter because it got in the way!)

    I’ve also owned and tested (and then sold) the Super-Multi-Coated Takumar 24/3.5 and 28/3.5 The 28/3.5 is mechanically the most beautiful lens I’ve every owned — so smooth and solid and pleasant to use… I used to enjoy just holding the darned thing and operating the rings. Unfortunately, both the Takumar 24 and 28 are terrible on the A7r and A7 — as in completely unusable. They never got decent. In contrast, the Super-Multi-Coated Takumar 35/3.5 is remarkably good, and my Super-Multi-Coated Takumar 55/1.8 is astonishing for an old lens (and even compared to much newer ones). If you’re interested in Pentax and Takumar, there are reliable reviews on the Pentax Forum.

    1. Oops… I shouldn’t comment at the end of the day! As Phillip’s picture shows, the Pentax K to Sony E (NEX) adapters don’t position the numbers off-centre. It’s the Pentax K to Canon EOS adapter that does that (because of the design of the Canon internals). This is a problem for me only because all my Takumar and Pentax lenses are adapted to mount on Canon EOS, which is the mount used by my Mirex Tilt-Shift adapter (Canon EOS to Sony E).

  8. Probably the A7r is a difficilt camera in the corners. The performance of my K28 3.5 is good from f5,6 on my A7.

  9. Wondering how it compares to the Sony FE 28mm f/2? I currently have the Sony FE, wondering if it is worthwhile to pick this up. Manual focus not a problem, though f/3.5 is my drawback.

    Thanks!

  10. I did a little comparison of my 28mm lenses (Pentax K28/3.5, Canon nFD 28/2, Minolta MC 28/2.5):
    http://forum.mflenses.com/canon-nfd28-2-vs-minolta-mc28-2-5-vs-pentax-k28-3-5-t75946.html

    Results are as expected (and in line with yours), the K28/3.5 wins handily on all counts except max. aperture. The MC28/2.5 is sharp in the center from f/2.5 but the corners are fairly weak, stopping down improves them but they never catch up with the other two. The nFD is a good overall performer, center sharpness is decent wide open and on par with the MC28/2.5 stopped down. The corners are usable wide open and sharpen up quickly (a lot better than the Minolta, not quite as good as the Pentax). Contrast is fairly low at large apertures and remain rather low in the corners.

    I’m not sure if the field of view really suits me but I suspect I’ll end up like you: K28/3.5 + FE28/2

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