Difference between M and K lenses

**buzzardluck** · 03-04-2019, 02:13 PM

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

**jlstrawman** · 03-04-2019, 02:27 PM - **1 Like**

Originally posted by buzzardluck

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

pschlute · 03-04-2019, 02:28 PM - **1 Like**

Originally posted by buzzardluck

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.

**iheiramo** · 03-04-2019, 02:42 PM - **1 Like**

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.

**amalongi** · 03-04-2019, 05:42 PM

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.

**Riggomatic** · 03-04-2019, 07:06 PM - **1 Like**

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

**buzzardluck** · 03-04-2019, 07:30 PM

Originally posted by jlstrawman

DSLR Lens Terms and Abbreviations - Articles and Tips | PentaxForums.com

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 ----------

Originally posted by pschlute

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 ----------

Originally posted by iheiramo

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 ----------

Originally posted by iheiramo

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?

**aslyfox** · 03-04-2019, 07:41 PM

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

**buzzardluck** · 03-04-2019, 07:43 PM

Originally posted by amalongi

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.

**aslyfox** · 03-04-2019, 07:47 PM

Originally posted by buzzardluck

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

pschlute · 03-04-2019, 07:50 PM

Originally posted by buzzardluck

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.

**buzzardluck** · 03-04-2019, 07:54 PM

Originally posted by aslyfox

these charts might help folks:

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.

**iheiramo** · 03-04-2019, 11:45 PM

Originally posted by buzzardluck

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

**aslyfox** · 03-05-2019, 05:06 AM

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

**buzzardluck** · 03-05-2019, 12:29 PM - **2 Likes**

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!

03-04-2019, 02:13 PM	#1
buzzardluck Site Supporter Join Date: Mar 2019 Posts: 62	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, 07:54 PM	#12
buzzardluck Site Supporter Join Date: Mar 2019 Posts: 62 Original Poster	Originally posted by aslyfox 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.

03-05-2019, 05:06 AM	#14
aslyfox Seeker of Knowledge Join Date: Aug 2016 Location: Topeka, Kansas Photos: Gallery \| Albums Posts: 24,581	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.

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03-04-2019, 02:27 PM - 1 Like	#2
jlstrawman Site Supporter Join Date: Feb 2010 Location: Midwest US Photos: Gallery Posts: 1,058	Originally posted by buzzardluck 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
pschlute Moderator Loyal Site Supporter Join Date: Mar 2007 Location: Surrey, UK Photos: Gallery Posts: 8,202	Originally posted by buzzardluck 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
iheiramo Unoriginal Poster Join Date: Nov 2016 Location: Espoo Photos: Albums Posts: 3,182	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
amalongi Site Supporter Join Date: Oct 2010 Location: St. Paul, MN Posts: 167	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
Riggomatic Loyal Site Supporter Join Date: Nov 2014 Location: Auburn, Indiana Photos: Albums Posts: 3,886	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
buzzardluck Site Supporter Join Date: Mar 2019 Posts: 62 Original Poster	Originally posted by jlstrawman DSLR Lens Terms and Abbreviations - Articles and Tips \| PentaxForums.com 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 ---------- Originally posted by pschlute 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 ---------- Originally posted by iheiramo 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 ---------- Originally posted by iheiramo 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
aslyfox Seeker of Knowledge Join Date: Aug 2016 Location: Topeka, Kansas Photos: Gallery \| Albums Posts: 24,581	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
buzzardluck Site Supporter Join Date: Mar 2019 Posts: 62 Original Poster	Originally posted by amalongi 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
aslyfox Seeker of Knowledge Join Date: Aug 2016 Location: Topeka, Kansas Photos: Gallery \| Albums Posts: 24,581	Originally posted by buzzardluck 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
pschlute Moderator Loyal Site Supporter Join Date: Mar 2007 Location: Surrey, UK Photos: Gallery Posts: 8,202	Originally posted by buzzardluck 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, 11:45 PM	#13
iheiramo Unoriginal Poster Join Date: Nov 2016 Location: Espoo Photos: Albums Posts: 3,182	Originally posted by buzzardluck 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, 12:29 PM - 2 Likes	#15
buzzardluck Site Supporter Join Date: Mar 2019 Posts: 62 Original Poster	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!