Pentax LX + K-series manual lens?

Lucid · 05-19-2022, 11:37 AM

Hi there -- I hope this question has reached the correct subforum.

I've acquired an entire set of vintage K-series lenses -- all manual of course. But I was curious if these manual lenses work with the aperture priority mode on the Pentax LX, or if I will need to purchase additional "A" series lenses.

Not a Number · 05-19-2022, 12:00 PM - **1 Like**

The LX pre-dated the A (Program) series of bodies. So M and K series should work in Av mode.

Lord Lucan · 05-19-2022, 12:30 PM - **1 Like**

They certainly do. The LX was designed to work with the K and M series lenses. "M" seems to have meant " minimised" in that they were smaller than the earlier equivalent K lenses, but functionally they were identical. Some K series lenses continued in production after the M series was introduced, for example the 50mm f1.2. The A series introduced automatic aperture setting but still worked on the LX (albeit still with manual aperture setting) and were sold with the LX as its kit lenses later on.

Pentax has always maintained as much forward and backward compatibility between lenses and bodies as possible. I'm still using a K series lens on my most recent DSLR, which was manufactured 45 years after the K-series first made their appearance.

gylfimag · 05-19-2022, 12:55 PM

As others have pointed out, the LX works well in aperture priority mode with the older K series lenses. I might add that it works in this mode with all K mount lenses that have an aperture ring, so not the very latest lenses but all the old ones. Manual mode on the LX works as well for the same lenses.

**UncleVanya** · 05-19-2022, 01:28 PM

As long as it has an aperture Fong and the aperture simulator it will work. In practical terms that means L, M, F, FA (not FAJ) all should work while the aperture ring is in use (not in A setting).

**aslyfox** · 05-19-2022, 04:41 PM

@Lucid

I have found these charts to be helpful:

Quote:

Pentax K-mount Lens Compatibility Chart
Copyright 2006-2020 Mosphotos.com. All rights reserved.

The Pentax K-mount Camera Lens Compatibility Chart

Quote:

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

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

regarding information on the Pentax LX, this thread might be of interest:

Quote:

Sources for information about the LX, please add your knowledge to this thread

Sources for information about the LX, please add your knowledge to this thread - Page 5 - PentaxForums.com

Lucid · 05-19-2022, 07:27 PM

Originally posted by aslyfox

@Lucid

I have found these charts to be helpful:

The Pentax K-mount Camera Lens Compatibility Chart

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

regarding information on the Pentax LX, this thread might be of interest:

Sources for information about the LX, please add your knowledge to this thread - Page 5 - PentaxForums.com

Thank you very much

jjdgti · 05-21-2022, 02:43 PM

Originally posted by Not a Number

The LX pre-dated the A (Program) series of bodies. So M and K series should work in Av mode.

Agree. I have an LX and I used all K and M lenses. The 50mm 1.2 definitely is a great companion for the LX. You will need a good eye sight.

---------- Post added 05-21-2022 at 05:46 PM ----------

Originally posted by Lord Lucan

They certainly do. The LX was designed to work with the K and M series lenses. "M" seems to have meant " minimised" in that they were smaller than the earlier equivalent K lenses, but functionally they were identical. Some K series lenses continued in production after the M series was introduced, for example the 50mm f1.2. The A series introduced automatic aperture setting but still worked on the LX (albeit still with manual aperture setting) and were sold with the LX as its kit lenses later on.

Pentax has always maintained as much forward and backward compatibility between lenses and bodies as possible. I'm still using a K series lens on my most recent DSLR, which was manufactured 45 years after the K-series first made their appearance.

Yes, The LX and the SMC 50mm 1.2 was sold as a pair (expensive then, expensive now). I was lucky to get a set a while back. Have not use it lately. My eye sight is not what it used to be.

05-19-2022, 11:37 AM	#1
Lucid New Member Join Date: May 2022 Posts: 2	Pentax LX + K-series manual lens? Hi there -- I hope this question has reached the correct subforum. I've acquired an entire set of vintage K-series lenses -- all manual of course. But I was curious if these manual lenses work with the aperture priority mode on the Pentax LX, or if I will need to purchase additional "A" series lenses.

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05-19-2022, 12:00 PM - 1 Like	#2
Not a Number Moderator Join Date: Mar 2012 Location: Venice, CA Posts: 10,526	The LX pre-dated the A (Program) series of bodies. So M and K series should work in Av mode.

05-19-2022, 12:30 PM - 1 Like	#3
Lord Lucan Pentaxian Join Date: Sep 2017 Location: South Wales Photos: Gallery Posts: 2,978	They certainly do. The LX was designed to work with the K and M series lenses. "M" seems to have meant " minimised" in that they were smaller than the earlier equivalent K lenses, but functionally they were identical. Some K series lenses continued in production after the M series was introduced, for example the 50mm f1.2. The A series introduced automatic aperture setting but still worked on the LX (albeit still with manual aperture setting) and were sold with the LX as its kit lenses later on. Pentax has always maintained as much forward and backward compatibility between lenses and bodies as possible. I'm still using a K series lens on my most recent DSLR, which was manufactured 45 years after the K-series first made their appearance.

05-19-2022, 12:55 PM	#4
gylfimag Forum Member Join Date: Aug 2012 Photos: Gallery Posts: 90	As others have pointed out, the LX works well in aperture priority mode with the older K series lenses. I might add that it works in this mode with all K mount lenses that have an aperture ring, so not the very latest lenses but all the old ones. Manual mode on the LX works as well for the same lenses.

05-19-2022, 01:28 PM	#5
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,454	As long as it has an aperture Fong and the aperture simulator it will work. In practical terms that means L, M, F, FA (not FAJ) all should work while the aperture ring is in use (not in A setting).

05-19-2022, 04:41 PM	#6
aslyfox Seeker of Knowledge Join Date: Aug 2016 Location: Topeka, Kansas Photos: Gallery \| Albums Posts: 24,583	@Lucid I have found these charts to be helpful: Quote: Pentax K-mount Lens Compatibility Chart Copyright 2006-2020 Mosphotos.com. All rights reserved. The Pentax K-mount Camera Lens Compatibility Chart Quote: Pentax K-Mount Lens Series Explained: The differences between various Pentax lens series Pentax K-Mount Lenses Explained: The differences between various Pentax lens series regarding information on the Pentax LX, this thread might be of interest: Quote: Sources for information about the LX, please add your knowledge to this thread Sources for information about the LX, please add your knowledge to this thread - Page 5 - PentaxForums.com

05-19-2022, 07:27 PM	#7
Lucid New Member Join Date: May 2022 Posts: 2 Original Poster	Originally posted by aslyfox @Lucid I have found these charts to be helpful: The Pentax K-mount Camera Lens Compatibility Chart Pentax K-Mount Lenses Explained: The differences between various Pentax lens series regarding information on the Pentax LX, this thread might be of interest: Sources for information about the LX, please add your knowledge to this thread - Page 5 - PentaxForums.com Thank you very much

05-21-2022, 02:43 PM	#8
jjdgti Veteran Member Join Date: Jun 2008 Location: NJ Posts: 1,824	Originally posted by Not a Number The LX pre-dated the A (Program) series of bodies. So M and K series should work in Av mode. Agree. I have an LX and I used all K and M lenses. The 50mm 1.2 definitely is a great companion for the LX. You will need a good eye sight. ---------- Post added 05-21-2022 at 05:46 PM ---------- Originally posted by Lord Lucan They certainly do. The LX was designed to work with the K and M series lenses. "M" seems to have meant " minimised" in that they were smaller than the earlier equivalent K lenses, but functionally they were identical. Some K series lenses continued in production after the M series was introduced, for example the 50mm f1.2. The A series introduced automatic aperture setting but still worked on the LX (albeit still with manual aperture setting) and were sold with the LX as its kit lenses later on. Pentax has always maintained as much forward and backward compatibility between lenses and bodies as possible. I'm still using a K series lens on my most recent DSLR, which was manufactured 45 years after the K-series first made their appearance. Yes, The LX and the SMC 50mm 1.2 was sold as a pair (expensive then, expensive now). I was lucky to get a set a while back. Have not use it lately. My eye sight is not what it used to be.