[timo]

Once upon a time, someone posted a comparison of short telephotos that included both the K105 and the M100, shooting the same subject at a variety of different apertures, looking at both center and corners. If anything, I thought the M100 looked better than the K105. I kind of suspect something went wrong in the Yoshihiko Takinami resolution tests of the M100/2.8, as well as the M85/2, as they seem out of step with what practical experience suggests is true.

For me, the difference between K & M in size weight for any of the focal lengths that interest me is much more significant than any difference in optical quality that I've seen demonstrated, and any differences in build quality (most say the K series is slight better) comes in a distant third.

I have both the M100/2.8 and the K105/2.8. From f4 upwards I can't tell the difference. Wide open the M is definitely sharper. The K has a sort of 'glow' round highlights at 2.8 which can look nice in moody shots but but for general purposes I would prefer the M.

I have used a K28 3.5 and I own an M28 3.5. In practice I don't think there is any difference. My K50 1.2 got stolen on a train (with everything else), and that was slightly better at comparable apertures than the M50 1.4 but not by much, and much heavier to lug around.

The K lenses are beautiful pieces of engineering, but in general use I also would favour the Ms - lighter and smaller.

[cpk]

A story I have told before in this forum. I bought my first Pentaxes when the M lenses were current:

Back in the early 80s I had a chance to test a Leicaflex side by side with my Pentax LX. I shot a series of pictures comparing the following lenses: Leica 35mm - Pentax-M 28mm f2.8 Leica 50mm - Pentax-M 50mm f4 macro Leica 135mm - Pentax-M 100mm f2.8.

I cannot remember the Leicaflex model or the maximum apertures of Leica lenses; but they were the ones current at that time. They were supplied by Leica Canada as part of a promotion to "try a Leica for a day" in the hopes that one would buy one.

The pictures were taken on Kodachrome 25 for maximum sharpness, and both cameras were mounted on tripods. The first slide on each roll of film was a photograph of the other camera. Both films were processed by Kodak Canada. When the films were processed and returned uncut in strips, I asked the son of the owner of the camera store where I dealt, to choose the Leica slides. He inspected both film strips with a Pentax 20X magnifier and selected one as being shot by the Leicaflex. I then asked him which camera was pictured at the front of the strip. It was the Leicaflex. The pictures he thought were taken by the Leicaflex had been taken by the Pentax LX. His father, who was a bit of a Leicaphile, also inspected the film strips and appeared somewhat upset by the results.

At the time of the tests I used Leica Ms for all of my available-light work. Therefore, having no need for high-speed lenses, when I purchased Pentax lenses, they were the slower f2.8 and f4 ones. These ones, I expect, would be easier to correct. Also the pictures were taken outside at around f8, rather than wide open. This was not a definitive test; but it proved to me that, certainly in some areas, the Pentax lenses could hold their own against some of the best. I was happy with the results because the circumstances of the test mirrored the situations in which I expected to use the Pentax and its lenses, outdoors for architectural and other work.

[Just1MoreDave]

Once upon a time, someone posted a comparison of short telephotos that included both the K105 and the M100, shooting the same subject at a variety of different apertures, looking at both center and corners. If anything, I thought the M100 looked better than the K105. I kind of suspect something went wrong in the Yoshihiko Takinami resolution tests of the M100/2.8, as well as the M85/2, as they seem out of step with what practical experience suggests is true.

For me, the difference between K & M in size weight for any of the focal lengths that interest me is much more significant than any difference in optical quality that I've seen demonstrated, and any differences in build quality (most say the K series is slight better) comes in a distant third.

Pretty much the same for the 135/3.5s. I was excited to get the K version, until I saw it in person. Next to the M, it was pretty clear that I would never use the K, even if I tested and found some IQ advantage. I've sold the K28/3.5 and K50/1.4 for the same reason. They're just too much larger than alternatives.

[selar]

something I would like to see, is a complete product range in a matrix, something like focal length and max aperture on the left, and lens series on the top, with perhaps one or two technical details in each grid. Maybe optical formula and weight for example.

it would give a really good snapshot of what was out there.

Doesn't Jim Collwell"s splosdb do just that. Last time I said what you and axl said, I had a mob of forum members nearly lynch me, watch out.

[hoanpham]

For me, the difference between K & M in size weight for any of the focal lengths that interest me is much more significant than any difference in optical quality that I've seen demonstrated, and any differences in build quality (most say the K series is slight better) comes in a distant third.

Pretty much the same for the 135/3.5s. I was excited to get the K version, until I saw it in person. Next to the M, it was pretty clear that I would never use the K, even if I tested and found some IQ advantage. I've sold the K28/3.5 and K50/1.4 for the same reason. They're just too much larger than alternatives.

I can't agree more ;-)

However the K50f1.2, K85f1.8, K135f2.5 are awesome for concert shoots. But I do prefer A50f1.7, M85f2 and M135f3.5 when no need for low light. And the K200f2.5 vs M200f4 ??

[Marc Sabatella]

No doubt, at some focal lengths, the K series offers a faster option, so when speed trumps all other concerns, that's the way to go. Still, given that there are M lenses within a half stop or so of the three you mention (OK, a full stop for the 135, but luckily there is 120/2.8 that has now replaced the 135 for me in concert kit), I'd still rather just go slightly higher in ISO to get the speed. I'll take half a stop more noise over the extra size/weight any day of the week.

[northcoastgreg]

I have used a K28 3.5 and I own an M28 3.5. In practice I don't think there is any difference

I have no experience with the M 28/3.5, but I do have the M 28/2.8 and the K 28/3.5, and I have found the K 28 to be without question the better lens. While there's not a significant difference in resolution, the K 28 produce images with richer, deeper colors and significantly more contrast.

I have 4 lens from each series, and while 2 of my M lenses are very fine, optically, and wonderfully small and light, in terms of color rendition, contrast, and beauty of rendering, they don't measure up to any of my K glass.

[8540tomg]

No doubt, at some focal lengths, the K series offers a faster option, so when speed trumps all other concerns, that's the way to go. Still, given that there are M lenses within a half stop or so of the three you mention (OK, a full stop for the 135, but luckily there is 120/2.8 that has now replaced the 135 for me in concert kit), I'd still rather just go slightly higher in ISO to get the speed. I'll take half a stop more noise over the extra size/weight any day of the week,

I agree with Mark in every instance above save his final conclusion. I'll take the extra size/weight and "feel" of the K over the M series any day of the week. It's all subjective of course. You can't go far wrong either way. Both series are very good.

Tom G

[Jonathan Mac]

As much as I like my K55/1.8 (my only K), I do most of my photography while away from home. For that reason, the Ms almost always win, as they´re the compact option.

Having said that, I´d love to get my hands on some of the fast legendary K lenses: 28/2, 135/2.5, 200/2.5 or 50/1.2.

I´ve seen them all for sale at one time or another, but the prices are astronomical.

At the end of the day, what I really love about these old lenses is using them. The feel of the quality, the clicks of the aperture & the smoothness of the focusing. From my experience, these are the same across both lines.

[RioRico]

My first-ever K just arrived, the 50/1.2. The weights of my fastest lenses:

400g - SMC (K) 50/1.2
310g - Tomioka 55/1.4
300g - Yashica ML 50/1.4
240g - SuperTak 50/1.4
210g - SMC FA 50/1.4

And my f/1.7-1.8 Fifty's all weigh between 160g (Zuiko-S 50/1.8) and 230g (Yashinon-DX 50/1.7, Rikenon 55/1.8). So that K50/1.2 is really a tank, and the FA50/1.4 is in the next lower weight class. Other than a Vivitar-Komine 90/2.8 macro (470g), all the other camera lenses weighing more than the K50 (out of my ~200 lens accumulation) are 200mm or longer.

Yes, the K50 is massive. So what? I need the exercise! And a too-light lens on my K20D makes the balance funny. Ewww, that Industar-50-2 is only 70g... Not to forget that a more massive camera+lens package helps to dampen vibrations a bit. Think of it as a little extra SR, eh?

[axl]

something I would like to see, is a complete product range in a matrix, something like focal length and max aperture on the left, and lens series on the top, with perhaps one or two technical details in each grid. Maybe optical formula and weight for example.

it would give a really good snapshot of what was out there.

I have PDF file that shows this from K series all the way to FA. I don't think DAs are there. It also shows timelines when each lens was manufactored. I have it on another PC but will try to link it to this thread tomorrow.

[selar]

I have PDF file that shows this from K series all the way to FA. I don't think DAs are there. It also shows timelines when each lens was manufactored. I have it on another PC but will try to link it to this thread tomorrow.

Thought I'd save you the trouble, here it is:

http://www.jcolwell.ca/_SPLOSdb/SPLOSdb-2004-09-31.pdf

[yeatzee]

I think a great example to look at is the K 28mm F/2 vs. the M 28mm F/2. Yes they are not the same optically blah blah blah but both lenses are fantastic according to the reviews (~9.5 rating for both) yet the K is an absolute beast comparatively speaking

The K is essentially TWICE the weight of the M (423g vs. 215g), is 2.75 cm bigger (6.9cm vs. 4.15cm), has a larger filter ring (52 vs. 49), etc. etc.

I own only one K lens currently (K 50mm F/1.2) but have had the opportunity to play with a couple and they are just to large for what they are. The K 50mm F/1.2 I understand and respect greatly but I was very disappointed when comparing build quality/feel between tak M and K ~50mm's. They are all fantastic and I felt like there was no discernible difference apart from their size, weight, and in the tak's case its focusing ring. All my opinion of course

I wouldn't worry about which series lens it is when considering K vs. M, just get the better lens you can afford. *


*I personally HATE the feel of A series lenses though and if you want that built like a tank old lens feel do not get an A lens

[.a.t.]

There are dinosaurs still walking around, and I'm one of 'em. I know I'm in the minority, but I like big and heavy lenses. The first time I held my K 50 f/1.2, I was surprised -and thrilled- at its heft.

For me, the look and feel of a lens is a big part of my enjoyment quotient.

Tim

[selar]

K 28mm F/2 vs. the M 28mm F/2

The M 28 f2 is actually a better rated lens than the K 28 F2 according to the splosdb. The splosdb ratings are based on lens resolution tests by Yoshio Takinami and Frank Wasti from the PDML. However, this seems to be the exception that proves the rule, in general the K versions were better rated.