"New" K mount?

**i_trax** · 06-27-2021, 09:46 PM

HD Pentax-D FA 70-210mm F4 ED SDM WR Reviews - D FA Zoom Lenses - Pentax Lens Reviews & Lens Database

I just discovered a "new" / different K mount and I am puzzled.

There is no mechanical aperture coupling any more.
The only the same looking lens's mount I have is on DA 55-300 PLM but the 70-210 is NOT PLM??
Why , what is it?
The manual focus works without power , NOT like PLM.

Will it fully work with all Pentax DSLR cameras , or just with some?
Do we need a firmware update for the old bodies?
It actually works well on my broken K-30 ( dead solenoid ) , it behaves as PLM lens??
My K-30 has hacked 1.10 firmware from K-50.
It does NOT work on K10D but I have V1.20 ( not the latest) firmware so all SDM lenses using screw AF drive.

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cgchang · 06-27-2021, 10:08 PM

KAF4 mount The Evolution of the Pentax K-mount - Articles and Tips | PentaxForums.com

Quote:

Pentax KAF4 lenses are only fully supported by the Pentax K-1, K-S1, K-S2, K-3, K-3 II, K-70, KP and newer. Earlier models cannot operate the aperture mechanism due to the lack of a firmware update, and thus aperture adjustments are not possible.

The new D-FA* 50mm f1.4 and D-FA* 85mm f1.4 are also KAF4 mounts.

**i_trax** · 06-27-2021, 10:27 PM

Right , so that is independent from PLM "function"?
So why my old "broken" K-30 is working well with KAF4?

cgchang · 06-27-2021, 10:41 PM

From what I understand, the biggest difference of KAF4 is the aperture control and no screwdrive AF motor compatibility. The Pentax K-mount Camera Lens Compatibility Chart

Not sure about your K-30. Might have to do with the firmware hack you did. Updated list of KAF4 lenses - PentaxForums.com

Medex · 06-27-2021, 11:15 PM

Originally posted by i_trax

Right , so that is independent from PLM "function"?
So why my old "broken" K-30 is working well with KAF4?

K-30 works with KAF4 lenses - just does autofocus but no aperture control (even K200D does it). In case your K-30 has hacked FW, the aperture works as well. K-50 works fully with KAF4 mount Pentax lenses

**i_trax** · 06-28-2021, 12:47 AM

Thank you All.
I thought that PLM was permanent part of KAF4 mount but obviously not.
Need to get more lenses with KAF4 mount and do not bother to fix my K-30.

**ramseybuckeye** · 06-28-2021, 02:14 AM

Originally posted by i_trax

Thank you All.
I thought that PLM was permanent part of KAF4 mount but obviously not.
Need to get more lenses with KAF4 mount and do not bother to fix my K-30.

It’s your lucky day, and going forward all new lenses will most likely be KAF4. Unfortunately the revamped Limiteds weren’t, but that would have been a redesign of everything but optics.

**Kevin B123** · 06-28-2021, 03:50 AM

The revamped FA limiteds have an aperture ring, so they are still good.

biz-engineer · 06-28-2021, 04:14 AM

What's the advantage of electronically controlled aperture?

**Lowell Goudge** · 06-28-2021, 05:12 AM

Originally posted by biz-engineer

What's the advantage of electronically controlled aperture?

no pesky aperture solenoid like the K30/50/70 to fail

**Serkevan** · 06-28-2021, 05:34 AM - **1 Like**

Originally posted by biz-engineer

What's the advantage of electronically controlled aperture?

Theoretically, higher maximum burst rate. The Nikon D6 goes to ~11 fps with mechanical aperture lenses, 14 fps with electromagnetic aperture. Lack of mechanical linkage (and therefore springs) might also improve long-term reliability/accuracy, but I have several decades-old lenses which have no real issues here.

biz-engineer · 06-28-2021, 11:04 AM

Originally posted by Lowell Goudge

no pesky aperture solenoid like the K30/50/70 to fail

The solenoid in the lens can fail.

Originally posted by Serkevan

Lack of mechanical linkage (and therefore springs) might also improve long-term reliability/accuracy, but I have several decades-old lenses which have no real issues here.

To break a lens aperture level, you have to be strong. Electronic contacts will break long before mechanical aperture lever.

**Serkevan** · 06-28-2021, 01:14 PM

Originally posted by biz-engineer

The solenoid in the lens can fail.

To break a lens aperture level, you have to be strong. Electronic contacts will break long before mechanical aperture lever.

No, no, not break. The spring can lose tension over time and this might lead to slower/less accurate aperture.

(None of my 40-year old mechanical aperture lenses have issues, none of my 30-year old electronic contact lenses have any issues either).

Wheatfield · 06-28-2021, 03:55 PM

Originally posted by Serkevan

No, no, not break. The spring can lose tension over time and this might lead to slower/less accurate aperture.

(None of my 40-year old mechanical aperture lenses have issues, none of my 30-year old electronic contact lenses have any issues either).

I've had two lenses go flakey that way. My A100/2.8 macro and A50/1.2 both had to be repaired for sluggish aperture.
I think one reason to do away with the mechanical couplings is cost. I expect it's overall less expensive to build an electronic controller than a mechanical one.

**DWS1** · 06-28-2021, 05:41 PM

All new designs will be KAF4 mount.

06-27-2021, 10:08 PM	#2
cgchang Senior Member Join Date: May 2014 Location: Delta, British Columbia Posts: 148	KAF4 mount The Evolution of the Pentax K-mount - Articles and Tips \| PentaxForums.com Quote: Pentax KAF4 lenses are only fully supported by the Pentax K-1, K-S1, K-S2, K-3, K-3 II, K-70, KP and newer. Earlier models cannot operate the aperture mechanism due to the lack of a firmware update, and thus aperture adjustments are not possible. The new D-FA* 50mm f1.4 and D-FA* 85mm f1.4 are also KAF4 mounts. Last edited by cgchang; 06-27-2021 at 10:17 PM.

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06-27-2021, 10:27 PM	#3
i_trax Loyal Site Supporter Join Date: Jan 2011 Location: Perth Western Australia Photos: Gallery \| Albums Posts: 2,621 Original Poster	Right , so that is independent from PLM "function"? So why my old "broken" K-30 is working well with KAF4?

06-27-2021, 10:41 PM	#4
cgchang Senior Member Join Date: May 2014 Location: Delta, British Columbia Posts: 148	From what I understand, the biggest difference of KAF4 is the aperture control and no screwdrive AF motor compatibility. The Pentax K-mount Camera Lens Compatibility Chart Not sure about your K-30. Might have to do with the firmware hack you did. Updated list of KAF4 lenses - PentaxForums.com

06-27-2021, 11:15 PM	#5
Medex Pentaxian Join Date: May 2013 Location: Vilnius Posts: 1,020	Originally posted by i_trax Right , so that is independent from PLM "function"? So why my old "broken" K-30 is working well with KAF4? K-30 works with KAF4 lenses - just does autofocus but no aperture control (even K200D does it). In case your K-30 has hacked FW, the aperture works as well. K-50 works fully with KAF4 mount Pentax lenses

06-28-2021, 12:47 AM	#6
i_trax Loyal Site Supporter Join Date: Jan 2011 Location: Perth Western Australia Photos: Gallery \| Albums Posts: 2,621 Original Poster	Thank you All. I thought that PLM was permanent part of KAF4 mount but obviously not. Need to get more lenses with KAF4 mount and do not bother to fix my K-30.

06-28-2021, 02:14 AM	#7
ramseybuckeye Site Supporter Join Date: Apr 2009 Location: Hampstead, NC Photos: Gallery Posts: 17,292	Originally posted by i_trax Thank you All. I thought that PLM was permanent part of KAF4 mount but obviously not. Need to get more lenses with KAF4 mount and do not bother to fix my K-30. It’s your lucky day, and going forward all new lenses will most likely be KAF4. Unfortunately the revamped Limiteds weren’t, but that would have been a redesign of everything but optics.

06-28-2021, 03:50 AM	#8
Kevin B123 Loyal Site Supporter Join Date: Jul 2016 Location: Hampshire Photos: Gallery \| Albums Posts: 3,176	The revamped FA limiteds have an aperture ring, so they are still good.

06-28-2021, 04:14 AM	#9
biz-engineer Pentaxian Join Date: Feb 2015 Photos: Gallery Posts: 12,232	What's the advantage of electronically controlled aperture?

06-28-2021, 05:12 AM	#10
Lowell Goudge Site Supporter Join Date: Jan 2007 Location: Toronto Photos: Gallery \| Albums Posts: 17,888	Originally posted by biz-engineer What's the advantage of electronically controlled aperture? no pesky aperture solenoid like the K30/50/70 to fail

06-28-2021, 05:34 AM - 1 Like	#11
Serkevan Site Supporter Join Date: May 2019 Photos: Albums Posts: 5,976	Originally posted by biz-engineer What's the advantage of electronically controlled aperture? Theoretically, higher maximum burst rate. The Nikon D6 goes to ~11 fps with mechanical aperture lenses, 14 fps with electromagnetic aperture. Lack of mechanical linkage (and therefore springs) might also improve long-term reliability/accuracy, but I have several decades-old lenses which have no real issues here.

06-28-2021, 11:04 AM	#12
biz-engineer Pentaxian Join Date: Feb 2015 Photos: Gallery Posts: 12,232	Originally posted by Lowell Goudge no pesky aperture solenoid like the K30/50/70 to fail The solenoid in the lens can fail. Originally posted by Serkevan Lack of mechanical linkage (and therefore springs) might also improve long-term reliability/accuracy, but I have several decades-old lenses which have no real issues here. To break a lens aperture level, you have to be strong. Electronic contacts will break long before mechanical aperture lever.

06-28-2021, 01:14 PM	#13
Serkevan Site Supporter Join Date: May 2019 Photos: Albums Posts: 5,976	Originally posted by biz-engineer The solenoid in the lens can fail. To break a lens aperture level, you have to be strong. Electronic contacts will break long before mechanical aperture lever. No, no, not break. The spring can lose tension over time and this might lead to slower/less accurate aperture. (None of my 40-year old mechanical aperture lenses have issues, none of my 30-year old electronic contact lenses have any issues either).

06-28-2021, 03:55 PM	#14
Wheatfield Moderator Join Date: Apr 2008 Location: The wheatfields of Canada Posts: 15,981	Originally posted by Serkevan No, no, not break. The spring can lose tension over time and this might lead to slower/less accurate aperture. (None of my 40-year old mechanical aperture lenses have issues, none of my 30-year old electronic contact lenses have any issues either). I've had two lenses go flakey that way. My A100/2.8 macro and A50/1.2 both had to be repaired for sluggish aperture. I think one reason to do away with the mechanical couplings is cost. I expect it's overall less expensive to build an electronic controller than a mechanical one.

06-28-2021, 05:41 PM	#15
DWS1 Site Supporter Join Date: Aug 2018 Location: Arkansas, USA Posts: 1,169	All new designs will be KAF4 mount.