Dougg
Seasoned Member
Pentax has a long history of emphasizing optical excellence, with Zeiss as their quality target. The Super-Multi-Coated Takumars introduced about 1970 were their best yet, and featured a mechanical f-stop communication with the last of the M42 bodies, the Spotmatic F, ES, and ESII, for open-aperture metering. (They also work fine in the older way on the older stop-down bodies).
After the bayonet-mount came along in 1975, the basic body structure and the lens construction were direct continuations of the previous models. At this point they mostly dropped the "Takumar" lens name, substituting "Pentax", and the body model designations were all "K-"something; K2, KX, KM, and K1000. So these lenses were thought of as "K" mount.
The cameras had become larger and heavier in these years, and maybe spurred on by the little Olympus OM, Pentax began offering more compact models with "M" in the name... ME, MX, etc, and a line of more compact M lenses. While the MX developed a devoted following, and the M lenses were excellent, many users still preferred the "K" lenses as perhaps being more solidly made and more sophisticated optically, without the M compromises for size and weight. These "K" lenses were not marked as such, just SMC Pentax and not SMC Pentax-M, and sell for more in the used market. BTW, any bayonet-mount lens marked "SMC Takumar" like one variety of the 2.5/135mm is a further simplified price-leader.
The KA mount was a later development, I think at the time of the Super Program, adding body control of the lens aperture and an A setting on the aperture ring. And an "F" in the lens designation indicated auto-focus. And here I fade out, not having paid much attention to detail developments since! Our most modern 35mm Pentax is one of my wife's remaining battered LX bodies, the other gone missing, and it needs to be sent to Pentax in hopes it can be refurbished. I use a K2DMD, an MX, an ES and ESII, a Spotmatic Motor, an H3, and a 1958 model K with its slow-speed shutter dial separately mounted on the front as with a classic Leica or Canon RF.
All their lenses have a little rattle when shaken, surely due to the auto-diaphragm parts not being under tension with the lens off the camera, and I recall this same question also coming up about the big 6x7 Pentax lenses at Photo.net...
After the bayonet-mount came along in 1975, the basic body structure and the lens construction were direct continuations of the previous models. At this point they mostly dropped the "Takumar" lens name, substituting "Pentax", and the body model designations were all "K-"something; K2, KX, KM, and K1000. So these lenses were thought of as "K" mount.
The cameras had become larger and heavier in these years, and maybe spurred on by the little Olympus OM, Pentax began offering more compact models with "M" in the name... ME, MX, etc, and a line of more compact M lenses. While the MX developed a devoted following, and the M lenses were excellent, many users still preferred the "K" lenses as perhaps being more solidly made and more sophisticated optically, without the M compromises for size and weight. These "K" lenses were not marked as such, just SMC Pentax and not SMC Pentax-M, and sell for more in the used market. BTW, any bayonet-mount lens marked "SMC Takumar" like one variety of the 2.5/135mm is a further simplified price-leader.
The KA mount was a later development, I think at the time of the Super Program, adding body control of the lens aperture and an A setting on the aperture ring. And an "F" in the lens designation indicated auto-focus. And here I fade out, not having paid much attention to detail developments since! Our most modern 35mm Pentax is one of my wife's remaining battered LX bodies, the other gone missing, and it needs to be sent to Pentax in hopes it can be refurbished. I use a K2DMD, an MX, an ES and ESII, a Spotmatic Motor, an H3, and a 1958 model K with its slow-speed shutter dial separately mounted on the front as with a classic Leica or Canon RF.
All their lenses have a little rattle when shaken, surely due to the auto-diaphragm parts not being under tension with the lens off the camera, and I recall this same question also coming up about the big 6x7 Pentax lenses at Photo.net...
bmattock
Veteran
anandi said:
Yes, I put the lens on my Pentax *ist DS all the time - though somewhat less so since I got my SMC-A 50mm f/1.7. I have a M42->P/K adapter. Special note on those - buy them from Pentax, the 'generic' brands are crap and get stuck, very frustrating.
As to incident metering - when you are outdoors, as long as your subject is not in shade or too far away, the same light falls on you as falls on the subject. So use the incident meter as if you were the subject and there you go. However, in my case, I was able to physically walk up to the subjects, so I did, and metered that way.
Remember, with a reflective (or spot) meter you are taking a meter reading from the light reflected from your subject. With an incident meter, you are taking a reading from the light source itself, where it falls on the subject. As long as you are not under a cloud or a shadow or something, the light that falls on you is the same as the light that falls on your subject.
Best Regards,
Bill Mattocks
aad
Not so new now.
I really like my Pentax SLR outfit, my M50/1.7 has literally been around the world with me. I almost bought an LX-twice-lately, just in case my MEF stops working.
Kim Coxon
Moderator
Sorry to be pedantic but there are 3 main versions. The first is the SMC Takumar with a bayonet mount and is perhaps the best of the 3. Sometimes known as the K series but labeled SMC Pentax. The M version was made a bit more compact and some think the optical performace is not quite as good. LAbeled SMC-M. The A is the same optical formula as the M but with the addition of the A setting. Personally although there is little difference in optical performance, I don't think it is constructed as well and doesn't have the same feel.
All the Pentax "normal" primes are detailed here http://www.bdimitrov.de/kmp/lenses/primes/normal/index.html
Kim
All the Pentax "normal" primes are detailed here http://www.bdimitrov.de/kmp/lenses/primes/normal/index.html
Kim
bmattock said:
Meleica
Well-known
Jerevan
Recycled User
A bit off-topic: The f1.4 Takumar (M42) is one of my all-time favorite lenses. When I bought it together with my Pentax I didn't know anything about its performance - but I still got after 5 years. That says something of its qualities - I have had more cameras passing thru my hands than I will admit. And I don't plan to sell it, either. I just had to check mine too - a slight rattling sound when I tilt it forward. Second best SLR lens is the f2 Nikkor-H 50, but that's a different story... 
bmattock
Veteran
Kim Coxon said:
OK, I'm sure you are right! I know more about Canon lenses, but I sure like my M42 Pentax.
Best Regards,
Bill Mattocks
ChrisPlatt
Thread Killer
The Pentax 50/55 f/1.4 lenses are indeed venerated,
but many of us think the f/1.8 and 1.7's are even better.
And the f/2.0 "economy" models are prolly the best
lenses available in terms of image quality vs. cost.
In short, Pentax never sold a bad 50mm lens...
"Excelsior, you fathead!"
-Chris-
but many of us think the f/1.8 and 1.7's are even better.
And the f/2.0 "economy" models are prolly the best
lenses available in terms of image quality vs. cost.
In short, Pentax never sold a bad 50mm lens...
"Excelsior, you fathead!"
-Chris-
bmattock
Veteran
ChrisPlatt said:
I cannot make absolute statements with regard to which Pentax 50mm lens might be best. However, going from my own sample of two lenses (!), the 1.4 M42 is not only better than the 1.7 SMC-A, it is better than any other lens I have ever used.
I will certainly agree that they certainly seem to be winners all the way around.
Best Regards,
Bill Mattocks
nightfly
Well-known
I have to disagree about the f/2 version. It's not a bad lens for the cost but it is nowhere near the 1.4 version in terms of image quality. I've had both and used for long periods of time and had no problem selling the f/2 when I got rid of the K100 it came with but although I've since aquired a Leica, I don't think I'd ever get rid of the 1.4 and the Pentax MX it's attached to. The prices for this stuff just aren't even close to how good the equipment really is.