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03-04-2019, 02:13 PM   #1
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Difference between M and K lenses

Now that I have the K-5 body, I need to look for lenses. I would like to manual focus. Also, do I need an M42 screw mount for the M lenses? Just trying to figure this stuff out... Thanks

03-04-2019, 02:27 PM - 1 Like   #2
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QuoteOriginally posted by buzzardluck Quote
Now that I have the K-5 body, I need to look for lenses. I would like to manual focus. Also, do I need an M42 screw mount for the M lenses? Just trying to figure this stuff out... Thanks
DSLR Lens Terms and Abbreviations - Articles and Tips | PentaxForums.com
03-04-2019, 02:28 PM - 1 Like   #3
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QuoteOriginally posted by buzzardluck Quote
Now that I have the K-5 body, I need to look for lenses. I would like to manual focus. Also, do I need an M42 screw mount for the M lenses? Just trying to figure this stuff out... Thanks
No you dont. The earliest series of K-mount lenses are designated SMC or smc, and are often refered to as "K". After that came the M series, then the A series. All three are manual focus and will fit you camera without an adapter. The A series will operate in auto exposure modes if the aperture ring is set to the A position.
03-04-2019, 02:42 PM - 1 Like   #4
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Between K and M series; K typically has better IQ. M is usually cheaper and smaller.

As a first manual lens I suggest a K, M or A 50mm lens either f1.7 or 1.4. They are cheap, great IQ and easy to find.

03-04-2019, 05:42 PM   #5
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Great advice above. Personally, I find the 50mm K,M or A lenses a bit long on an APS-C camera (75mm or so equivalent), but the 35mm options (52mm or so equivalent) aren't plentiful or known to be of stellar quality. Despite my love of M series glass, I would recommend that if you go all manual focus that you look for the A series lenses - they are just easier to operate in the auto modes.

If it were me, I might look for the plastic fantastic DA35/2.4 of the FA35/2.0. The 35mm focal length will be better as an everyday focal length and I believe that these two lenses get better reviews than the older, strictly manual focus glass. The only drawback is that the manual focusing tools on these two lenses were a bit of an afterthought.
03-04-2019, 07:06 PM - 1 Like   #6
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If you do go with either the K series or M series, you'll want to read up on the use of green button, and catch in focus, if you're not already familiar. Great features on your camera.

Pentax Green Button Guide - Articles and Tips | PentaxForums.com

Catch-in-Focus Tutorial - Articles and Tips | PentaxForums.com
03-04-2019, 07:30 PM   #7
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Thanks! Lens terminology is complicated, and I'm still a little foggy after reading it. I have much to learn.

---------- Post added 03-04-19 at 08:34 PM ----------

QuoteOriginally posted by pschlute Quote
No you dont. The earliest series of K-mount lenses are designated SMC or smc, and are often refered to as "K". After that came the M series, then the A series. All three are manual focus and will fit you camera without an adapter. The A series will operate in auto exposure modes if the aperture ring is set to the A position.
With the A lens, can I manually set the apature as well? Or am I stuck with auto exposure.

---------- Post added 03-04-19 at 08:36 PM ----------

QuoteOriginally posted by iheiramo Quote
Between K and M series; K typically has better IQ. M is usually cheaper and smaller.

As a first manual lens I suggest a K, M or A 50mm lens either f1.7 or 1.4. They are cheap, great IQ and easy to find.
Hmmmm, so a K prime lens will allow me to manually focus and change my apature? Also what is IQ?

---------- Post added 03-04-19 at 08:39 PM ----------

QuoteOriginally posted by iheiramo Quote
Between K and M series; K typically has better IQ. M is usually cheaper and smaller.

As a first manual lens I suggest a K, M or A 50mm lens either f1.7 or 1.4. They are cheap, great IQ and easy to find.
So, if I use a K 50mm 1.4 prime lens then I can manipulate the apature and focus?
03-04-2019, 07:41 PM   #8
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these charts might help folks:

Pentax Lens Compatibility Chart
Copyright 2006-2018 Mosphotos.com. All rights reserved.

Pentax bayonet lenses labeled "SMC Pentax" are referred to as "K" lenses in the table below. Other Pentax bayonet lenses have the lens designation as a part of their name as in "SMC Pentax-FA".

Note that "star" lenses work like their "non-star" counterparts unless they are singled out in the table below. So for compatibility of a DA* lens, look under DA lenses, etc.
Exceptions: FA and F "soft" lenses behave like M lenses in terms of metering.

The Pentax Camera Lens Compatibility Chart

_______________________

Pentax K-Mount Lens Series Explained: The differences between various Pentax lens series

In a nutshell

There are several series of Pentax K-mount lenses; the ones currently being produced include the DA (digital), DA L (cheap digital kit), D FA (full-frame, digital optimized), and FA (full-frame) series. While all Pentax K-mount lenses ever produced are compatible with all current Pentax DSLRs (in some cases with restrictions in that not all exposure modes of the camera are supported by old lenses), there are significant differences between each lens series and each has different features. Furthermore some of the newer lenses do not work with older cameras. We'll be exploring the differences between the various K-mount series lenses in this article. Read more about specific K-mount lens/camera compatibility here.

The DLSR designation below encompasses the mirror-less K-01.


Pentax K-Mount Lenses Explained: The differences between various Pentax lens series

__________________________________________________


and of course, the early Pentax lenses used a screw mount, not a bayonet mount :


The M42 lens mount is a screw thread mounting standard for attaching lenses to 35 mm cameras, primarily single-lens reflex models. It is more accurately known as the M42 1 mm standard, which means that it is a metric screw thread of 42 mm diameter and 1 mm thread pitch. (The M42 lens mount should not be confused with the T-mount, which shares the 42mm throat diameter, but differs by having a 0.75mm thread pitch.) It was first used in Zeiss' Contax S of 1949; this East German branch of Zeiss also sold cameras under the Pentacon name; after merger with other East German photographic manufacturers, the name Praktica was used. M42 thread mount cameras first became well known under the Praktica brand, and thus the M42 mount is known as the Praktica thread mount.[1] Since there were no proprietary elements to the M42 mount, many other manufacturers used it; this has led to it being called the Universal thread mount or Universal screw mount by many. The M42 mount was popularized in the United States by Pentax; thus, it is also known as the Pentax thread mount, despite the fact that Pentax did not originate it.

M42 lens mount - Wikipedia

an adapter is needed to use the screw mount lenses on modern Pentax lenses:


https://www.pentaxforums.com/accessoryreviews/pentax-mount-adapter-k.html

03-04-2019, 07:43 PM   #9
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QuoteOriginally posted by amalongi Quote
Great advice above. Personally, I find the 50mm K,M or A lenses a bit long on an APS-C camera (75mm or so equivalent), but the 35mm options (52mm or so equivalent) aren't plentiful or known to be of stellar quality. Despite my love of M series glass, I would recommend that if you go all manual focus that you look for the A series lenses - they are just easier to operate in the auto modes.

If it were me, I might look for the plastic fantastic DA35/2.4 of the FA35/2.0. The 35mm focal length will be better as an everyday focal length and I believe that these two lenses get better reviews than the older, strictly manual focus glass. The only drawback is that the manual focusing tools on these two lenses were a bit of an afterthought.
What do I lose by using the A series lenses? Just curious? Thanks.
03-04-2019, 07:47 PM   #10
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QuoteOriginally posted by buzzardluck Quote
What do I lose by using the A series lenses? Just curious? Thanks.
smc PENTAX-A

The third generation of manual focus lenses
Sub-categhory: A*
Image format covered: 24 x 36 mm
Suitable for APS-C digital sensor format and 24 x 36 mm "full frame" format
Automatic aperture setting is available
In production: No
Remarks: smc PENTAX-A lenses are manual focus. Regarding exposure control they work like FA lenses.
The A series also includes 9 "star" lenses (A*) that exemplify the finest in Pentax optical and engineering.

Pentax K-Mount Lenses Explained: The differences between various Pentax lens series

___________________

you can find reviews of the various Pentax lenses ( and some third party lenses ) in the " lenses " section above
03-04-2019, 07:50 PM   #11
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QuoteOriginally posted by buzzardluck Quote
With the A lens, can I manually set the apature as well? Or am I stuck with auto exposure
No, you are never stuck in auto.. The "A" setting on the aperture ring just allows the aperture to be set from the camera. So you can use Program (AUTO)/Aperture Priority/Shutter priority/TAv/Sensitivity/ as well as Manual exposure. But in aperture priority or Manual you set the aperture by turning the rear e-wheel on the camera.

K and M lenses can only be fully used in Manual exposure mode. With these you set the aperture on the lens and use the stop-down metering method to establish a shutter speed.

You can if you wish use the aperture ring on an "A" lens off the "A" setting and then it behaves like a K or M lens. But you lose all the auto capability then....ie no aperture priority or Program mode.
03-04-2019, 07:54 PM   #12
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QuoteOriginally posted by aslyfox Quote
these charts might help folks:

Pentax Lens Compatibility Chart
Copyright 2006-2018 Mosphotos.com. All rights reserved.

Pentax bayonet lenses labeled "SMC Pentax" are referred to as "K" lenses in the table below. Other Pentax bayonet lenses have the lens designation as a part of their name as in "SMC Pentax-FA".

Note that "star" lenses work like their "non-star" counterparts unless they are singled out in the table below. So for compatibility of a DA* lens, look under DA lenses, etc.
Exceptions: FA and F "soft" lenses behave like M lenses in terms of metering.

The Pentax Camera Lens Compatibility Chart

_______________________

Pentax K-Mount Lens Series Explained: The differences between various Pentax lens series

In a nutshell

There are several series of Pentax K-mount lenses; the ones currently being produced include the DA (digital), DA L (cheap digital kit), D FA (full-frame, digital optimized), and FA (full-frame) series. While all Pentax K-mount lenses ever produced are compatible with all current Pentax DSLRs (in some cases with restrictions in that not all exposure modes of the camera are supported by old lenses), there are significant differences between each lens series and each has different features. Furthermore some of the newer lenses do not work with older cameras. We'll be exploring the differences between the various K-mount series lenses in this article. Read more about specific K-mount lens/camera compatibility here.

The DLSR designation below encompasses the mirror-less K-01.


Pentax K-Mount Lenses Explained: The differences between various Pentax lens series

__________________________________________________


and of course, the early Pentax lenses used a screw mount, not a bayonet mount :


The M42 lens mount is a screw thread mounting standard for attaching lenses to 35 mm cameras, primarily single-lens reflex models. It is more accurately known as the M42 1 mm standard, which means that it is a metric screw thread of 42 mm diameter and 1 mm thread pitch. (The M42 lens mount should not be confused with the T-mount, which shares the 42mm throat diameter, but differs by having a 0.75mm thread pitch.) It was first used in Zeiss' Contax S of 1949; this East German branch of Zeiss also sold cameras under the Pentacon name; after merger with other East German photographic manufacturers, the name Praktica was used. M42 thread mount cameras first became well known under the Praktica brand, and thus the M42 mount is known as the Praktica thread mount.[1] Since there were no proprietary elements to the M42 mount, many other manufacturers used it; this has led to it being called the Universal thread mount or Universal screw mount by many. The M42 mount was popularized in the United States by Pentax; thus, it is also known as the Pentax thread mount, despite the fact that Pentax did not originate it.

M42 lens mount - Wikipedia

an adapter is needed to use the screw mount lenses on modern Pentax lenses:


Pentax Mount Adapter K (M42 Screwmount to K Mount) reviews - Pentax Camera Accessory Review Database
These charts are very helpful, thank you.
03-04-2019, 11:45 PM   #13
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QuoteOriginally posted by buzzardluck Quote

Hmmmm, so a K prime lens will allow me to manually focus and change my apature? Also what is IQ?

So, if I use a K 50mm 1.4 prime lens then I can manipulate the apature and focus?
IQ is image quality. K series lenses are typically sharper than M series lenses, thought there are some exceptions. I don't have enough knowledge to compare difference in contrast, colors and other features affecting IQ. I believe difference is due to size. M series was desinged very compact. I have found M series to be more than enough for my work at this point of my hobby. Much cheaper to aqquire and I like that they are easy to carry on holidays.

With K and M lenses you have standard K mount to use, so no adapters needed. You control focus manually and aperture from aperture ring on the lens. With A lenses you gain auto setting on the lens aperture ring, which allows you to control aperture from camera body. This gives you the option to let camera set aperture automatically or you can set it manually from one of the camera dials.
To be able to use aperture ring you need to allow it from camera menu: How to use/meter Manual & M42 Lenses on all Pentax DSLRs (K-1, K-3, K-5, K-30, etc) - PentaxForums.com
03-05-2019, 05:06 AM   #14
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I wonder if the OP has the Operating Manual for the K 5

http://www.ricoh-imaging.co.jp/english/support/man-pdf/k-5.pdf

and has looked at page 45 which explains these settings

green - camera sets everything explained on p. 103 of the manual

P hyper-program explained on p. 104 of the manual

Sv sensitivity priority explained on p. 105 of the manual

Tv shutter priority explained on p. 107 of the manual

Av aperture priority explained on p. 109 of the manual

TAv Shutter and aperture priority explained on p. 112 of the manual

M hyper-manual explained on p. 115 of the manual

_________________________________________

according to the chart, http://www.mosphotos.com/PentaxLensCompatibility.html,


AF, K and M mount lenses limit which of above " modes " the K 5 can use to:

M''' Manual exposure with stop down metering. You set the aperture on the lens, press the green button/AE-L button which stops down the lens and sets the shutter speed as per the metered value.

Av Automatic exposure, you set the aperture, the camera sets the shutter speed

Last edited by aslyfox; 03-05-2019 at 05:18 AM.
03-05-2019, 12:29 PM - 2 Likes   #15
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A special Fat Tuesday thank you for all of those who reached out to assist me. I studied and learned and decided to purchase a SMC Pentex A 50mm prime F 1.4 lens, to work with my recommended K-5 camera body. It was very affordable and I'm looking forward to receiving it. Thank you again, I love this place!
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