What's the difference between K and M lenses?

**ismaelg** · 02-02-2010, 06:47 AM

Hi,

Sorry if this has been asked before, but I couldn't find any reference to it.
What's the difference between K and M lenses? And for that matter between F and FA?
I'm compiling a quick reference guide for lenses and I'd like to make sure I got it right.

K: original bayonet mount. Fully manual
A: Aperture automation capability
M: Fully manual *???????
F: First generation autofocus
FA: ????
DA: digital only lens (APS-C) will not work properly on full frame 35mm
*: The * after the lens type (A*, DA*) represents a premium grade

Any help will be appreciated. This is for a local photo club and I'm the only pentaxian so far......

Thanks,

whojammyflip · 02-02-2010, 06:53 AM

Rather than reinventing the wheel, take a look at Bojidar Dimitrov's excellent reference website for Pentax gear:
Summary of the K-Mount Evolution, Names, and Features

**ismaelg** · 02-02-2010, 06:56 AM

Thanks!
That is exactly what I was trying to find!

Regards,

wallyb · 02-02-2010, 06:58 AM

In layman's terms:

M42: first kinds of lenses Pentax produced, for old screwmount bodies such as the Spotmatic; they can be adapted to all K-mount cameras

K: first bayonet series, no actual "K" markings

M: second bayonet series, some say the "M" marking stands for "mini" as most comparable lenses are smaller than their K counterparts

A: in general, K- or M-series lenses updated with auto-aperture contacts, and sometimes worse build quality

F: first foray into AF lenses

FA: second foray, mostly just physical re-designs of F lenses, but also some new ones (I think)

DA: third line of AF lenses, usually deigned for APS-C sized sensors only (but NOT always)

*: higher build or optics quality for older lenses (before Limiteds were introduced)

Ltd.: Limited lens, arguably the highest-build-quality among lenses Pentax has made, very compact lenses for their focal length, and highly superior image quality to comparable lenses

wallyb · 02-02-2010, 06:58 AM

A little late, but hey, someone may like it.

**Lowell Goudge** · 02-02-2010, 07:43 AM

Originally posted by ismaelg

Hi,

Sorry if this has been asked before, but I couldn't find any reference to it.
What's the difference between K and M lenses? And for that matter between F and FA?
I'm compiling a quick reference guide for lenses and I'd like to make sure I got it right.

K: original bayonet mount. Fully manual
A: Aperture automation capability
M: Fully manual *???????
F: First generation autofocus
FA: ????
DA: digital only lens (APS-C) will not work properly on full frame 35mm
*: The * after the lens type (A*, DA*) represents a premium grade

Any help will be appreciated. This is for a local photo club and I'm the only pentaxian so far......

Thanks,

the real difference between K and M is that the M series attempted to retain most lenses with a 49mm filter, and be very compact. The idea was to keep 49mm filters as a standard to help the photographer in reducing the number of filters. WHile this did not impact some lenses, others disappeared or changed.

in the M series, there was no 50mm F1.2, the 85mm went from F1.8 to F2, the 135mm F2.5 was dropped, the 200mm F2.5 I think got dropped and only a 200mm F4.

Additionally I think many of the wide angle lenses went to F3.5 as opposed to F2 or F2.8, but I am not really sure.

There were some improvements, however, specifically in the 300F4 which was downsized a little, and the 400F5.6 which became auto aperture as opposed to preset.

While some people consider the K mounts as re-packaged SMC Taks some were much better optically.

Danny Delcambre · 02-02-2010, 07:58 AM

Hey I have my Pentax 50mm f1.2 here I got it yesrerday. I thought it was f1.4 but yesterday I looked and surprised f1.2. I think it is rare??

wallyb · 02-02-2010, 08:05 AM

Originally posted by Danny Delcambre

Hey I have my Pentax 50mm f1.2 here I got it yesrerday. I thought it was f1.4 but yesterday I looked and surprised f1.2. I think it is rare??

lol........

Danny Delcambre · 02-02-2010, 08:17 AM

I mean Pentax M 50mm f1.2. Smile

timo · 02-02-2010, 08:28 AM

Originally posted by Danny Delcambre

Hey I have my Pentax 50mm f1.2 here I got it yesrerday. I thought it was f1.4 but yesterday I looked and surprised f1.2. I think it is rare??

Well if you got it for the price of a manual f1.4 you've done a good deal. You've probably noticed it's a great chunk of metal and glass - I find focusing with that low-geared ring rather slow but it means you can be very accurate. I just did some comparisons with an M50 1.7 - although centre sharpness seems pretty similar at the same apertures, away from the centre the 1.2 won easily. (Although I understand that with blurry-bokeh stuff edge sharpness is irrelevant.) Just stop down half a stop and you get a wonderful tool for low-light conditions.

But I am not sure I will carry it around routinely - I like the lightness of the M50, just as I like the lightness of the M100 2.8 vs the K105 2.8. They all take great pics though.

Tim

wallyb · 02-02-2010, 08:40 AM

Originally posted by Danny Delcambre

I mean Pentax M 50mm f1.2. Smile

No you didn't, no such thing

Pentaxor · 02-02-2010, 08:42 AM

Originally posted by Danny Delcambre

I mean Pentax M 50mm f1.2. Smile

there's no M50 1.2. if you got it for 25 bucks or less, then it's nothing more than an M 501:2, which is slower than an M 50 1.4. if you would look at the aperture ring, the aperture number starts at 2 followed by 2.8. a 1.2 lens starts at 1.2 followed by 2. look if the 1.2 is missing in the aperture ring.

always take a closer look at the difference. it can really be tricky for some who haven't encountered a 1.2 lens just yet.

50 1:2
50 1.2

1.2's only come in 2 types, the "K" and "A". no "M" version.

timo · 02-02-2010, 08:46 AM

Originally posted by wallyb

No you didn't, no such thing

What a let-down - I was quite excited for him.

Pentaxor · 02-02-2010, 08:53 AM

Originally posted by timo

What a let-down - I was quite excited for him.

it's quite easy nowadays to determine if someone mistook a 1.2 lens for a 1:2. it's not that unusual that one would get excited especially if it is priced around below 100 bucks or somewhere near the price of a manual focus 1.4 lens. it happens more often for non-owners.

the price alone would tell you that it's not, let alone the "M" marking.

glasbak · 02-02-2010, 02:04 PM

I have a different view :

Originally posted by Lowell Goudge

the real difference between K and M is that the M series attempted to retain most lenses with a 49mm filter, and be very compact. The idea was to keep 49mm filters as a standard to help the photographer in reducing the number of filters. WHile this did not impact some lenses, others disappeared or changed.

No, for mysterious reasons, the first generation K mount lenses got a 52mm filter thread, although a lot of them are rebadged SMC takumars (and these had 49mm as standard).

Quote:

in the M series, there was no 50mm F1.2, the 85mm went from F1.8 to F2, the 135mm F2.5 was dropped, the 200mm F2.5 I think got dropped and only a 200mm F4.

Th 135/2.5 was never replaced by a M version, and dropped when the M series was dropped for the A series. Same for the 200/2.5

Quote:

Additionally I think many of the wide angle lenses went to F3.5 as opposed to F2 or F2.8, but I am not really sure.

like the M 28mm/2.8 , or the M 35mm/2.8 ?

Quote:

There were some improvements, however, specifically in the 300F4 which was downsized a little, and the 400F5.6 which became auto aperture as opposed to preset.

While some people consider the K mounts as re-packaged SMC Taks some were much better optically.

Can you give examples of first generation K lenses which are optically much better than its SMC predecessor ?

02-02-2010, 06:47 AM	#1
ismaelg Loyal Site Supporter Join Date: Apr 2009 Location: Puerto Rico Photos: Gallery Posts: 2,681	What's the difference between K and M lenses? Hi, Sorry if this has been asked before, but I couldn't find any reference to it. What's the difference between K and M lenses? And for that matter between F and FA? I'm compiling a quick reference guide for lenses and I'd like to make sure I got it right. K: original bayonet mount. Fully manual A: Aperture automation capability M: Fully manual ??????? F: First generation autofocus FA: ???? DA: digital only lens (APS-C) will not work properly on full frame 35mm : The * after the lens type (A, DA) represents a premium grade Any help will be appreciated. This is for a local photo club and I'm the only pentaxian so far...... Thanks,

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02-02-2010, 06:53 AM	#2
whojammyflip Veteran Member Join Date: Aug 2009 Posts: 417	Rather than reinventing the wheel, take a look at Bojidar Dimitrov's excellent reference website for Pentax gear: Summary of the K-Mount Evolution, Names, and Features

02-02-2010, 06:56 AM	#3
ismaelg Loyal Site Supporter Join Date: Apr 2009 Location: Puerto Rico Photos: Gallery Posts: 2,681 Original Poster	Thanks! That is exactly what I was trying to find! Regards,

02-02-2010, 06:58 AM	#4
wallyb Veteran Member Join Date: Nov 2008 Location: The Untied States Photos: Albums Posts: 1,881	In layman's terms: M42: first kinds of lenses Pentax produced, for old screwmount bodies such as the Spotmatic; they can be adapted to all K-mount cameras K: first bayonet series, no actual "K" markings M: second bayonet series, some say the "M" marking stands for "mini" as most comparable lenses are smaller than their K counterparts A: in general, K- or M-series lenses updated with auto-aperture contacts, and sometimes worse build quality F: first foray into AF lenses FA: second foray, mostly just physical re-designs of F lenses, but also some new ones (I think) DA: third line of AF lenses, usually deigned for APS-C sized sensors only (but NOT always) *: higher build or optics quality for older lenses (before Limiteds were introduced) Ltd.: Limited lens, arguably the highest-build-quality among lenses Pentax has made, very compact lenses for their focal length, and highly superior image quality to comparable lenses

02-02-2010, 07:43 AM	#6
Lowell Goudge Site Supporter Join Date: Jan 2007 Location: Toronto Photos: Gallery \| Albums Posts: 17,886	Originally posted by ismaelg Hi, Sorry if this has been asked before, but I couldn't find any reference to it. What's the difference between K and M lenses? And for that matter between F and FA? I'm compiling a quick reference guide for lenses and I'd like to make sure I got it right. K: original bayonet mount. Fully manual A: Aperture automation capability M: Fully manual ??????? F: First generation autofocus FA: ???? DA: digital only lens (APS-C) will not work properly on full frame 35mm : The * after the lens type (A, DA) represents a premium grade Any help will be appreciated. This is for a local photo club and I'm the only pentaxian so far...... Thanks, the real difference between K and M is that the M series attempted to retain most lenses with a 49mm filter, and be very compact. The idea was to keep 49mm filters as a standard to help the photographer in reducing the number of filters. WHile this did not impact some lenses, others disappeared or changed. in the M series, there was no 50mm F1.2, the 85mm went from F1.8 to F2, the 135mm F2.5 was dropped, the 200mm F2.5 I think got dropped and only a 200mm F4. Additionally I think many of the wide angle lenses went to F3.5 as opposed to F2 or F2.8, but I am not really sure. There were some improvements, however, specifically in the 300F4 which was downsized a little, and the 400F5.6 which became auto aperture as opposed to preset. While some people consider the K mounts as re-packaged SMC Taks some were much better optically.

02-02-2010, 07:58 AM	#7
Danny Delcambre Veteran Member Join Date: Oct 2008 Photos: Gallery \| Albums Posts: 550	Hey I have my Pentax 50mm f1.2 here I got it yesrerday. I thought it was f1.4 but yesterday I looked and surprised f1.2. I think it is rare??

02-02-2010, 08:05 AM	#8
wallyb Veteran Member Join Date: Nov 2008 Location: The Untied States Photos: Albums Posts: 1,881	Originally posted by Danny Delcambre Hey I have my Pentax 50mm f1.2 here I got it yesrerday. I thought it was f1.4 but yesterday I looked and surprised f1.2. I think it is rare?? lol........

02-02-2010, 08:17 AM	#9
Danny Delcambre Veteran Member Join Date: Oct 2008 Photos: Gallery \| Albums Posts: 550	I mean Pentax M 50mm f1.2. Smile

02-02-2010, 08:28 AM	#10
timo Veteran Member Join Date: Nov 2006 Location: former Arsenal football stadium Photos: Gallery Posts: 431	Originally posted by Danny Delcambre Hey I have my Pentax 50mm f1.2 here I got it yesrerday. I thought it was f1.4 but yesterday I looked and surprised f1.2. I think it is rare?? Well if you got it for the price of a manual f1.4 you've done a good deal. You've probably noticed it's a great chunk of metal and glass - I find focusing with that low-geared ring rather slow but it means you can be very accurate. I just did some comparisons with an M50 1.7 - although centre sharpness seems pretty similar at the same apertures, away from the centre the 1.2 won easily. (Although I understand that with blurry-bokeh stuff edge sharpness is irrelevant.) Just stop down half a stop and you get a wonderful tool for low-light conditions. But I am not sure I will carry it around routinely - I like the lightness of the M50, just as I like the lightness of the M100 2.8 vs the K105 2.8. They all take great pics though. Tim

02-02-2010, 08:40 AM	#11
wallyb Veteran Member Join Date: Nov 2008 Location: The Untied States Photos: Albums Posts: 1,881	Originally posted by Danny Delcambre I mean Pentax M 50mm f1.2. Smile No you didn't, no such thing

02-02-2010, 08:42 AM	#12
Pentaxor Veteran Member Join Date: May 2009 Location: Vancouver, B.C. Photos: Gallery Posts: 6,513	Originally posted by Danny Delcambre I mean Pentax M 50mm f1.2. Smile there's no M50 1.2. if you got it for 25 bucks or less, then it's nothing more than an M 501:2, which is slower than an M 50 1.4. if you would look at the aperture ring, the aperture number starts at 2 followed by 2.8. a 1.2 lens starts at 1.2 followed by 2. look if the 1.2 is missing in the aperture ring. always take a closer look at the difference. it can really be tricky for some who haven't encountered a 1.2 lens just yet. 50 1:2 50 1.2 1.2's only come in 2 types, the "K" and "A". no "M" version.

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02-02-2010, 08:46 AM	#13
timo Veteran Member Join Date: Nov 2006 Location: former Arsenal football stadium Photos: Gallery Posts: 431	Originally posted by wallyb No you didn't, no such thing What a let-down - I was quite excited for him.

02-02-2010, 08:53 AM	#14
Pentaxor Veteran Member Join Date: May 2009 Location: Vancouver, B.C. Photos: Gallery Posts: 6,513	Originally posted by timo What a let-down - I was quite excited for him. it's quite easy nowadays to determine if someone mistook a 1.2 lens for a 1:2. it's not that unusual that one would get excited especially if it is priced around below 100 bucks or somewhere near the price of a manual focus 1.4 lens. it happens more often for non-owners. the price alone would tell you that it's not, let alone the "M" marking.

02-02-2010, 02:04 PM	#15
glasbak Veteran Member Join Date: Apr 2009 Location: Netherlands Posts: 369	I have a different view : Originally posted by Lowell Goudge the real difference between K and M is that the M series attempted to retain most lenses with a 49mm filter, and be very compact. The idea was to keep 49mm filters as a standard to help the photographer in reducing the number of filters. WHile this did not impact some lenses, others disappeared or changed. No, for mysterious reasons, the first generation K mount lenses got a 52mm filter thread, although a lot of them are rebadged SMC takumars (and these had 49mm as standard). Quote: in the M series, there was no 50mm F1.2, the 85mm went from F1.8 to F2, the 135mm F2.5 was dropped, the 200mm F2.5 I think got dropped and only a 200mm F4. Th 135/2.5 was never replaced by a M version, and dropped when the M series was dropped for the A series. Same for the 200/2.5 Quote: Additionally I think many of the wide angle lenses went to F3.5 as opposed to F2 or F2.8, but I am not really sure. like the M 28mm/2.8 , or the M 35mm/2.8 ? Quote: There were some improvements, however, specifically in the 300F4 which was downsized a little, and the 400F5.6 which became auto aperture as opposed to preset. While some people consider the K mounts as re-packaged SMC Taks some were much better optically. Can you give examples of first generation K lenses which are optically much better than its SMC predecessor ?