[simbon4o]

Compare them in corners, there is the difference you seek In the enter both are sharp. Did you shoot in RAW and are all the files with the same WB settings?

PS from today:

Looks like the M 28 3.5 is the best 28mm for F8.0-11 usage. DA 16-45 is sharper, much more sharper but the corners are awfully aberated.

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Last edited by simbon4o; 08-08-2012 at 03:11 PM.

[jt_cph_dk]

RMC Tokina II 28/2.8 (with *ist DS2, ISO400, f:4.5) quite shallow DOF for a 28 and the small sensor crops to the sharper centre of the lens, making it a nice ‘normal‘.

Full resolution size: http://www.flickr.com/photos/32108329@N08/6246692540/sizes/o/in/set-72157627765544949/

[cunesk8]

There is my comparison Pentax M28/2.8 vs. Pentax M28/3.5 :
http://www.ulozto.cz/xxtUuEk/28-vs-28-zip
password: pentaxfriends

Photos marked "a" is Pentax M28/2,8.
Photos marked "b" is Pentax M28/3,5.

All photos are in full size.
I am curious about your opinion.

[magkelly]

I'm liking those Viv shots the best actually. I wouldn't mind having one of those. I think it's doing a pretty nice job above for the most part.

[Just1MoreDave]

My opinions:
This is the first time I've seen that Vivitar model not perform that well, but it's up against some lenses that should be pretty good. I have a K11 and K13 model and they test very well. I'd say they are sharper than a M28/3.5 and equal to my F28/2.8.

The color differences between the M28/2.8 vII and M28/3.5 make sense. The M28/2.8 vII is essentially an A series optically and has coatings like the A series.

I agree with checking corner sharpness. Sure, these lenses were designed for a larger format but you'll see big differences even on APS-C.

I have a Tokina EL 28/2.8 in PK-A that is really competitive in sharpness with Pentax-A or -F f2.8s. I read someplace that these were not very good but I think that's wrong.

If a 28mm is going to be a normal prime for you, strongly consider a KA mount. It gets enough use to make it worthwhile. Unfortunately that rules out the f3.5 lenses.

Some day I might be able to get down to just two 28mm lenses.

[Jonathan Mac]

There is my comparison Pentax M28/2.8 vs. Pentax M28/3.5 :
http://www.ulozto.cz/xxtUuEk/28-vs-28-zip
password: pentaxfriends

Photos marked "a" is Pentax M28/2,8.
Photos marked "b" is Pentax M28/3,5.

All photos are in full size.
I am curious about your opinion.

I don't read Czech, I've no idea how to get to the photos, sorry.

I'm liking those Viv shots the best actually. I wouldn't mind having one of those. I think it's doing a pretty nice job above for the most part.

You mean mine? It does not badly, and I've been happy with the digital shots I've taken with it and the B&W film ones recently, but the green tint worries me enough to avoid using it on colour film. However, it's worth keeping for the speed if nothing else. It's also extremely well built, at least equal to the M series lenses.

My opinions:
This is the first time I've seen that Vivitar model not perform that well, but it's up against some lenses that should be pretty good. I have a K11 and K13 model and they test very well. I'd say they are sharper than a M28/3.5 and equal to my F28/2.8.

The color differences between the M28/2.8 vII and M28/3.5 make sense. The M28/2.8 vII is essentially an A series optically and has coatings like the A series.

I agree with checking corner sharpness. Sure, these lenses were designed for a larger format but you'll see big differences even on APS-C.

I have a Tokina EL 28/2.8 in PK-A that is really competitive in sharpness with Pentax-A or -F f2.8s. I read someplace that these were not very good but I think that's wrong.

If a 28mm is going to be a normal prime for you, strongly consider a KA mount. It gets enough use to make it worthwhile. Unfortunately that rules out the f3.5 lenses.

Some day I might be able to get down to just two 28mm lenses.

I don't use 28mm lenses that much on digital, though I now have four. "Unfortunately", they're four good ones, and choosing to get rid of some is difficult .

I can get a new-in-box FA 28mm from a place in Madrid, they have a LOT of older Pentax stuff still new - MZ series cameras, FA & even A lenses, 645s... but the FA 28 is €300, and that's too much for a standard prime that's only f/2.8, with no quick-shift, and plasticky build quality.

[ihasa]

Revivifying this thread (pardon the pun) - the Pentax 28/3.5s both look pretty good. I have the M 28/3.5 and think it's a superb lens for many things, but unfortunately, not landscape as the lens gets progressively (and noticeably) softer towards the edges, even stopped down. This is OK, cos where it does excel is shooting wide open to create soft backgrounds (the centre always stays tack sharp).

Any ideas for a similar FL lens with really good edge to edge sharpness? Something that could compete with my Sigma 24/2.8 which seems uniformly sharp across the entire frame? I do rather like the 28mm focal length.

[Just1MoreDave]

I really like the Pentax-F 28mm f2.8 for sharpness, size, colors and AF. I've never used the FA version but if it's like my FA35/2, I'd look at that one too.

This Sigma is not bad:

It's sharp enough anyway. It flares more than the Pentax, maybe less saturated colors but not by a lot. Compared to the Pentax it's large, but it's not outrageously big, 58mm filter, and you get some speed for the size. The new model is a 77mm filter, I don't know why, but that's not really convenient. I have the MF version but AF ones are around.

[whojammyflip]

My M 28mm f3.5 is the sharpest 35mm lens I own, for what its worth, sharper than the Tamron sp 90mm f2.5, when at f8 (excluding my Oly OM lenses, which I am going to compare to Pentax when the light is good this summer).

Its hard to believe the difference until you see the exact same scene side by side (obviously a test target and distance adjusted, for such measure-bating). I'd say the M 28/3.5 is 30% sharper than the Tamron (my next sharpest taking lens).

[glasbak]

What unifies the K series is the labeling and the fact that all were available for the K-series bodies. Many were direct descendents of the M42 SMC Takumars and some were the predecessors of the M-series lenses that followed. Many of the K-series lenses carried over unchanged (including labeling) to the M-series bodies due to adequate existing inventory, not that they represented some sort of proto-m variant. The K24/2.8 is a good example of this. Its size and build as well as its year of release (1977) is typical for a K-series lens. It was, however, a rather specialized and expensive lens and even though production ceased shortly after the M-series bodies hit the market, existing inventory was sufficient to meet demand for several years. It was only with the advent of the A-series mount that a new version was needed.

Steve

I think that K lenses (except very few) did not get the M labeling, even though they were produced well after the introduction of the M series.
They just kept their name without the '-m'.
Later produced lenses did get the newer lens text as was introduced with the 55mm 1:2.0, which was the K1000 kit lens.

The relative compact K24/2.8 replaced the bulkier takumar to K converted 24/3.5.

[Jonathan Mac]

Some K lenses were produced for several years after the M series lenses started production.

Yes, the M 28/3.5 is extremely sharp, no less so than the K version, but I prefer the overall rendering of the K, unfortunately its size and 52mm filter thread make it inconvenient for travelling.

[simbon4o]

Those 3.5 28mm pentaxes are so soft in corners... why everybody says they are sharp. Yes colors are great, aberations are well controlled to almost none, but in corners they are soft even at F8.0, I have tested two copies since now and both are soft in corners, only F11 solves that problem. My M 28 2.8 II is sharper at all apertures excluding F16 and F22.
The previous test that I have posted was on K200D, now on K30... 28 3.5 is veery soft in corners compared to 2.8 II version.

[whojammyflip]

could be due to them not being optimised for digital sensors...
Ask Olympus: Advantages of digital camera specific lenses

"Question:
What are the advantages of lenses that are designed specifically for digital camera use?

Answer: Although the small size of the individual pixels in CCD and CMOS image sensors enables them to capture even more detail than film, the sensitivity of the sensor elements is highly directional. That is, they respond best to light that strikes the elements straight on. With lenses designed for use with film, the light rays passing through the periphery of the lens strike the image sensor at an angle, and this tends to degrade picture quality at the periphery of the image area. On the other hand, lenses developed specifically for digital camera use can be designed to match the imaging characteristics of CCD and CMOS sensors, ensuring high image quality at both the center and the periphery of the frame."

[stevebrot]

Those 3.5 28mm pentaxes are so soft in corners... why everybody says they are sharp. Yes colors are great, aberations are well controlled to almost none, but in corners they are soft even at F8.0, I have tested two copies since now and both are soft in corners, only F11 solves that problem. My M 28 2.8 II is sharper at all apertures excluding F16 and F22.
The previous test that I have posted was on K200D, now on K30... 28 3.5 is veery soft in corners compared to 2.8 II version.

Lucky you! Looks like you have the exception that proves the rule. The M 28/2.8 (both versions) was priced and marketed as a consumer-level lens. (street price new was less than a Vivitar 28/2.8) with the 28/3.5 positioned as the higher quality option. I was in the market back-in-the-day (1982) and passed on the Pentax in favor of the Tamron 28/2.5 based on published test results even though the Tammy cost almost 3x more when you add the price of the adapter.


Steve

[glasbak]

Those 3.5 28mm pentaxes are so soft in corners... why everybody says they are sharp. Yes colors are great, aberations are well controlled to almost none, but in corners they are soft even at F8.0, I have tested two copies since now and both are soft in corners, only F11 solves that problem. My M 28 2.8 II is sharper at all apertures excluding F16 and F22.
The previous test that I have posted was on K200D, now on K30... 28 3.5 is veery soft in corners compared to 2.8 II version.

My experience is from the film days, and although the performance of the 28/2.8 versions is good in the center, the (35mm film) corners are much worse compared to the pentax 28/3.5 versions (not to confuse with the smc takumar 28/3.5).
On APS-C you do not see those mediocre corners of the 28/2.8.
This 'good center, bad corner' performance on 35mm film, is something I see in a lot of compact M generation designs.
When the FF pentax comes (if it comes), and is still compatible with the K-mount, I think people will dump their M-primes and replace them with K versions.