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Pentax K 28mm f/3.5 M vs pentax 28mm f/2.8

Matt Ricardson , Nov 15, 2009; 12:42 a.m.

I"m considering purchasing a 28MM lens for my K10d, I'm looking at the Pentax K 28mm f/3.5 M.
Does anyone have/had this lens or other 28's what are your opinions about the quality of these lenses.
Also what is the approximate street value in AUD$.


Matt Richardson


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Don Laing , Nov 15, 2009; 03:16 a.m.

Hi Matt,
I have the 28mm 2.8 F lens, which I think was the first autofocus 28 by Pentax. Its main virtues are that it is light and compact. The 28mm focal length is suitable for around town/street photography and the compact size does not draw undue attention. Image-wise, it is an average performer, but lacking the digital coatings, it is sometimes prone to flare and lack of contrast. I don't have the 3.5 to compare it with. Under the right lighting conditions you should be able to make an A3+ size print using this lens.

Matt Ricardson , Nov 15, 2009; 04:42 a.m.

Thanks Don
The 28 f/2.8 seems to be a popular lens in both auto focus and non auto focus, i plan on making prints A3 or bigger with the lens, which is part of the reason i desire a lens with good optical performance, but i would I am definitely considering the 2.8.

Matt Richardson

Douglas Stemke , Nov 15, 2009; 06:04 a.m.

I used to have the 28mm f2.8 M version and would echo Don's notes, good, but probably not outstanding. As he notes it is VERY light and I would add it uses a 49mm filter common to many of Pentax's primes. The lens size and filter size were my main reasons for owning the lens.
Although I have never used it, the 28mm f3.5 K has a very loyal group of followers; it sounds like optically it is the better of the two lenses. I think most of the positive comments have come from film users and I would imagine digital users were be just as happy with the lens although it will be lacking electrical contacts.

Tony Cunningham , Nov 15, 2009; 07:30 a.m.

Hi Matt - I have both the M 28 mm f3.5 and the M 28 mm f2.8. I kept the f2.8 because it was lighter. The f3.5 is supposed to be better. I will compare the two on a K20D this afternoon (European time) and report later.
In the meantime there is some info here:

Tony Cunningham , Nov 15, 2009; 09:53 a.m.

I tested the DA* 16-50 mm at 28 mm, the M 28 mm f3.5 and the M 28 mm f2.8 on a K20D at ISO 100 on a heavy tripod at 1/50 f8 in all cases. Processing was with Silkypix Pro, all settings default.
Examination of the images at 100% indicated that the DA* 16-50 was best, very closely followed by the 28 mm f3.5 and trailing somewhat the f2.8.
The DA* 16-50 was much better than the others at the center bottom of the image, but apart from that there was little difference between it and the f3.5.
The best looking image overall at 25% was actually the f3.5, because the lighting was nicest at that moment. I imagine you will be happy with the f3.5. I don't know what it is worth, but a lot less than the DA* 16-50 that's for sure.

Laurentiu Cristofor , Nov 15, 2009; 12:26 p.m.

Some tests:
Based on the above, it looks like the 3.5 is sharper wide open, while the 2.8 gets to be sharper stopped down.
There's another summary of results here:
Alternatives to Pentax:
28mm is indeed a nice focal length and there appear to be tons of models available from a variety of brands. What I find really interesting about these lenses is that many also allow close focusing, which makes them very versatile.
I've also seen some lenses under lesser known brands that look very much like some of the Vivitar models - my impression is that some designs were released under various other brands. I just got a Gemini 28mm with the smallest distance scale marking of 0.25m and it looks very much like a Vivitar model made by Komine. While the distance marking is 25cm, it feels like it focuses closer than that. The smallest scale marking I've seen was 0.23m on some models labeled macro or close focus. For comparison, the Pentax 28s scale markings go down to "just" 0.30m - same as the 31mm Ltd. Sigma has some interesting lenses in this range as well.
Hope this helps

Javier Gutierrez , Nov 15, 2009; 02:18 p.m.

I seriously have 8 28mm primes and my personal two favorites are the SMC-A 28F/2.8 and Tokina 28/F2.8. Bothare ''A'' lenses and both have excellent quality when used with a hood. With out the hood, they are all prone to lens flare and as was stated by Don, for the lack of modern coatings. My 2 cents.

Matt Ricardson , Nov 15, 2009; 03:34 p.m.

Thanks everyone very helpful.
Seems like either the 2.8 or 3.5 would be great lenses, unfortunately i don't have the money for the DA* 16-50, hence my interest in purchasing old film lenses.
I will try to find a hood, as i sounds as though flare could be a slight issues.


Matt Richardson

Richard Harris , Nov 15, 2009; 06:18 p.m.

Just bought an ultra cheap 28mm M42... so expect some tragic photos soon ;)

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