Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
02-12-2020, 06:27 AM - 2 Likes   #1
Pentaxian




Join Date: Apr 2007
Location: Romania
Posts: 12,439
KAF4 is more than a good idea

I said it in the past, KAF4 is a superior solution to the old mechanical aperture coupling. Quieter, faster, and it gives you more freedom in lens design (specifically, where you put the aperture).

Lo and behold, the mighty (and still upcoming) Nikon D6 can shoot at up to 14fps with E-type lenses (those with electromagnetic aperture). Which means it can't with non-E-type lenses.

02-12-2020, 07:43 AM   #2
Pentaxian




Join Date: Jul 2011
Posts: 1,523
If you buy a D6 you are not using AiS lenses anymore...

I remember watching the aperture ring of a Canon ssc 50 move while running a T90 at full speed-just 4.5fps.
02-12-2020, 08:11 AM   #3
Pentaxian




Join Date: Apr 2007
Location: Romania
Posts: 12,439
Original Poster
QuoteOriginally posted by zapp Quote
If you buy a D6 you are not using AiS lenses anymore...
This isn't about AIS, but E-type lenses - or in Pentax terms, KAF4 with its electromagnetic aperture. Of course, proper in-lens AF motors are also a better solution - at least regarding speed and precision.

Interestingly enough, last Nikon lens without an electromagnetic aperture was launched in... 2017: the Nikon AF-P DX Nikkor 10-20mm F4.5-5.6G VR. However, this is a budget APS-C lens, not one you'd expect to drive at 14fps anyway.
02-12-2020, 09:23 AM   #4
Otis Memorial Pentaxian
Loyal Site Supporter
stevebrot's Avatar

Join Date: Mar 2007
Location: Vancouver (USA)
Photos: Gallery | Albums
Posts: 35,234
QuoteOriginally posted by Kunzite Quote
I said it in the past, KAF4 is a superior solution to the old mechanical aperture coupling. Quieter, faster, and it gives you more freedom in lens design (specifically, where you put the aperture).
Fair enough, though one's expectation of longevity under use might need adjusting.


Steve

02-12-2020, 02:54 PM - 3 Likes   #5
Loyal Site Supporter
Loyal Site Supporter
photocles's Avatar

Join Date: Nov 2015
Location: Connacht, Ireland
Photos: Gallery
Posts: 216
QuoteOriginally posted by stevebrot Quote
Fair enough, though one's expectation of longevity under use might need adjusting.
That's part of my thought process every time I think about buying the most modern lenses on the market (mostly for mirrorless).

Also, I think about this: Will we be able to use such lenses very far into the future (whether because they themselves survive or we have compatible bodies)? I doubt it.

With the purely mechanical iris driven by the body, we basically get a new motor assembly when we upgrade/replace the body. Same with in-body autofocus motors. But now, we're looking at fully-contained systems within each lens. Obsolescence and costs too great for repair will definitely follow. That's sad from a variety of viewpoints. All of that precision glass will be hostage to the out-of-date tech wrapped around it.
02-12-2020, 06:46 PM   #6
Pentaxian




Join Date: Dec 2016
Location: Southeastern Michigan
Posts: 2,184
QuoteOriginally posted by photocles Quote
That's part of my thought process every time I think about buying the most modern lenses on the market (mostly for mirrorless).

Also, I think about this: Will we be able to use such lenses very far into the future (whether because they themselves survive or we have compatible bodies)? I doubt it.

With the purely mechanical iris driven by the body, we basically get a new motor assembly when we upgrade/replace the body. Same with in-body autofocus motors. But now, we're looking at fully-contained systems within each lens. Obsolescence and costs too great for repair will definitely follow. That's sad from a variety of viewpoints. All of that precision glass will be hostage to the out-of-date tech wrapped around it.
I am of the same mind as you both. I am reasonably certain this is also the reasoning behind all Pentax Limited lenses remaining of the long-established screw-driven technology, with the exception of the only Limited zoom lens, the DA 20-40mm, which is of the DC variety.

I don't yet own a PLM type lens. I have a number of the DC type, which I do like, and of course many of the screw-driven lenses, and I am fine with these. My KP body has actually produced an upgrade in performance with these screw-driven lenses!
02-12-2020, 10:55 PM - 1 Like   #7
Site Supporter
Site Supporter




Join Date: Sep 2006
Location: midwest, United States
Photos: Gallery
Posts: 4,212
QuoteOriginally posted by photocles Quote
That's part of my thought process every time I think about buying the most modern lenses on the market (mostly for mirrorless).

Also, I think about this: Will we be able to use such lenses very far into the future (whether because they themselves survive or we have compatible bodies)? I doubt it.

With the purely mechanical iris driven by the body, we basically get a new motor assembly when we upgrade/replace the body. Same with in-body autofocus motors. But now, we're looking at fully-contained systems within each lens. Obsolescence and costs too great for repair will definitely follow. That's sad from a variety of viewpoints. All of that precision glass will be hostage to the out-of-date tech wrapped around it.
A cynic would say lenses have gotten a lot more complex electrically to ensure they can be obsoleted sooner. Look at all the people using 50+ year old lenses. Not good for a company's profits. The saying used to be "glass lasts for ever". Not anymore. How long do you think image stabilized lenses will last with all those moving elements?

thanks,
barondla
02-13-2020, 12:13 AM - 1 Like   #8
Site Supporter
Site Supporter




Join Date: Dec 2012
Location: Essex County, Ontario
Posts: 625
QuoteOriginally posted by barondla Quote
A cynic would say lenses have gotten a lot more complex electrically to ensure they can be obsoleted sooner. Look at all the people using 50+ year old lenses. Not good for a company's profits. The saying used to be "glass lasts for ever". Not anymore. How long do you think image stabilized lenses will last with all those moving elements?

thanks,
barondla

Very good point here. I also think that there is no way the electronics produced in the last few years will be around anywhere near as long as our Takumars and SMC lenses. If Pentax makes any future model incompatible with our old lens collections I suspect that myself and many others will never consider buying them. The upgrade ladder will stop where they orphan our gear. I would learn to live without whatever new feature is invented unless it can be a huge quantum leap with a price close to the present models.
Not much chance of that.

02-13-2020, 04:05 AM   #9
Site Supporter
Site Supporter




Join Date: Mar 2009
Location: Gladys, Virginia
Photos: Gallery
Posts: 21,361
QuoteOriginally posted by photocles Quote
That's part of my thought process every time I think about buying the most modern lenses on the market (mostly for mirrorless).

Also, I think about this: Will we be able to use such lenses very far into the future (whether because they themselves survive or we have compatible bodies)? I doubt it.

With the purely mechanical iris driven by the body, we basically get a new motor assembly when we upgrade/replace the body. Same with in-body autofocus motors. But now, we're looking at fully-contained systems within each lens. Obsolescence and costs too great for repair will definitely follow. That's sad from a variety of viewpoints. All of that precision glass will be hostage to the out-of-date tech wrapped around it.
It could be that you are partially right, although we have seen that this is not always a perfect situation. The new motor assembly on the K30/K-S1 (and maybe other) cameras, while new, was prone to failure. The interesting thing was that even though these cameras with aperture block issues could no longer open the aperture on lenses with mechanical aperture levers, they were able to operate KAF 4 lenses without a problem.

But technically, if you want to future proof things, you should only buy lenses with aperture rings...
02-13-2020, 06:06 AM   #10
Site Supporter
Site Supporter




Join Date: Dec 2012
Photos: Albums
Posts: 1,232
QuoteOriginally posted by From1980 Quote
Very good point here. I also think that there is no way the electronics produced in the last few years will be around anywhere near as long as our Takumars and SMC lenses. If Pentax makes any future model incompatible with our old lens collections I suspect that myself and many others will never consider buying them. The upgrade ladder will stop where they orphan our gear. I would learn to live without whatever new feature is invented unless it can be a huge quantum leap with a price close to the present models.
Not much chance of that.
Pentax isn't a charity or a non-profit. They probably can't exist by just making bodies that cater to people who only want to shoot 50-year-old Takumars. Stabilization and electronic apertures and in-lens focus motors objectively allow people to shoot better photographs. Pentax has done a very good job of considering the wishes of people who shoot old glass, but they have to continue to innovate and build systems with new technology or eventually the customer base will be three octogenarians with a K-1 and some screw-mount lenses.
02-13-2020, 06:17 AM   #11
Senior Moderator
Loyal Site Supporter
Loyal Site Supporter
BigMackCam's Avatar

Join Date: Mar 2010
Location: North-East of England
Posts: 14,453
QuoteOriginally posted by ThorSanchez Quote
Pentax isn't a charity or a non-profit. They probably can't exist by just making bodies that cater to people who only want to shoot 50-year-old Takumars. Stabilization and electronic apertures and in-lens focus motors objectively allow people to shoot better photographs. Pentax has done a very good job of considering the wishes of people who shoot old glass, but they have to continue to innovate and build systems with new technology or eventually the customer base will be three octogenarians with a K-1 and some screw-mount lenses.
Sadly, I think you're right. Progress - and it is progress, for sure - comes at a cost, but so does a lack of it.

I can live with - and benefit from - new lenses having electronically-controlled diaphragms, in-lens motors and even focus-by-wire (despite the fact that there's greater complexity and more to fail within the lens). I just hope Ricoh continues to maintain backward compatibility with old glass by retaining in-camera electro-mechanical diaphragm control and screw drive for future Pentax bodies. I'm rarely one to use the term "deal breaker", but lack of those facilities would be just that for my purposes (and I'm nowhere near octogenarian status yet... I have thirty years to go, if I make it that far )...
02-13-2020, 10:42 AM   #12
Pentaxian




Join Date: Apr 2007
Location: Romania
Posts: 12,439
Original Poster
I see this topic deviates toward old manual lenses and backwards compatibility. That's not the subject I opened, folks! The first is ancient history, the latter is pretty much a given (for now at least).

Screw-drive AF vs. in-lens motors; mechanical aperture coupling vs. in-lens electromagnetic aperture. Old vs. current.
Do you really think screw-drive AF is "better"? Longer lasting? Oh, it might keep working for longer (or not) than the good in-lens AF motors. It's also noisy (enough to drive customers away), it's particularly weak for AF tracking and it lacks accuracy due to gearing. It's not a solution Ricoh Imaging can push on their customer.
What's worse, its accuracy gets worse in time, particularly without any kind of maintenance.

As for the mechanical aperture coupling, I also don't see how Pentax could possibly be competitive with it. Same arguments - noise, speed, lack of precision.

Perhaps we should change our mindset from "longer lasting, at any cost".
It's not like Canon utterly failed because of their lenses' reliability while Pentax - with screw drive AF and mechanical aperture coupling until not so long ago - thrived, is it?
02-13-2020, 11:51 AM   #13
Senior Moderator
Loyal Site Supporter
Loyal Site Supporter
BigMackCam's Avatar

Join Date: Mar 2010
Location: North-East of England
Posts: 14,453
QuoteOriginally posted by Kunzite Quote
I see this topic deviates toward old manual lenses and backwards compatibility. That's not the subject I opened, folks! The first is ancient history, the latter is pretty much a given (for now at least).

Screw-drive AF vs. in-lens motors; mechanical aperture coupling vs. in-lens electromagnetic aperture. Old vs. current.
Do you really think screw-drive AF is "better"? Longer lasting? Oh, it might keep working for longer (or not) than the good in-lens AF motors. It's also noisy (enough to drive customers away), it's particularly weak for AF tracking and it lacks accuracy due to gearing. It's not a solution Ricoh Imaging can push on their customer.
What's worse, its accuracy gets worse in time, particularly without any kind of maintenance.

As for the mechanical aperture coupling, I also don't see how Pentax could possibly be competitive with it. Same arguments - noise, speed, lack of precision.

Perhaps we should change our mindset from "longer lasting, at any cost".
It's not like Canon utterly failed because of their lenses' reliability while Pentax - with screw drive AF and mechanical aperture coupling until not so long ago - thrived, is it?
With respect, the thread was always going to go this way - at least, to some extent

However much some folks might appreciate the potential benefits of KAF4 and lenses with full electronic control (I think I do), some - not least, SDM-driven DA* lens owners - also feel that the more technology you place inside the lens, the more there is to go wrong with it - and if the components are proprietary and/or have a limited production scale and lifecycle, future repairability - which is almost certain to require service-center involvement - might be less assured (then again, it might not... but we don't know). Of course, that situation already exists with our camera bodies. With KAF4, it may be increasingly relevant to the lenses too.

As I said previously, progress isn't entirely without potential costs... but that doesn't mean I'm unsupportive of the move to KAF4. Quite the contrary. In terms of precision, functionality and performance, I agree that it's superior

Last edited by BigMackCam; 02-13-2020 at 12:27 PM.
02-13-2020, 12:29 PM   #14
Loyal Site Supporter
Loyal Site Supporter
photocles's Avatar

Join Date: Nov 2015
Location: Connacht, Ireland
Photos: Gallery
Posts: 216
QuoteOriginally posted by BigMackCam Quote
However much some folks might appreciate the potential benefits of KAF4 and lenses with full electronic control...
I certainly do! It's just that I also see the benefits of more simple/simplified systems. Not for everything (sports for one), but for many, many uses.
QuoteOriginally posted by Kunzite Quote
Do you really think screw-drive AF is "better"?
No, I don't. I am totally enamored by the precision and silence that (especially) linear motors bring to photography. I just hate the feeling that the lenses that have them will all end up in a landfill far quicker than what came before. (At least we won't be sitting around talking about how to de-yellow those with UV in 50 years!)


I would also like to point out, in the OP's favor, that Pentax's adherence to mechanical iris control probably hastened Sigma's and Tamron's dropping of the K mount. Pretty much everything they make these days is electronically controlled. If Pentax had gone KAF4 earlier, that might not have happened. (That may be total BS, too, but it least there's logic in it.)
02-13-2020, 01:47 PM   #15
Pentaxian




Join Date: Apr 2007
Location: Romania
Posts: 12,439
Original Poster
QuoteOriginally posted by BigMackCam Quote
With respect, the thread was always going to go this way - at least, to some extent

However much some folks might appreciate the potential benefits of KAF4 and lenses with full electronic control (I think I do), some - not least, SDM-driven DA* lens owners - also feel that the more technology you place inside the lens, the more there is to go wrong with it - and if the components are proprietary and/or have a limited production scale and lifecycle, future repairability - which is almost certain to require service-center involvement - might be less assured (then again, it might not... but we don't know). Of course, that situation already exists with our camera bodies. With KAF4, it may be increasingly relevant to the lenses too.

As I said previously, progress isn't entirely without potential costs... but that doesn't mean I'm unsupportive of the move to KAF4. Quite the contrary. In terms of precision, functionality and performance, I agree that it's superior
Yes, but I hoped it won't go as far as to the old Takumars...
After all, when discussing what Pentax could/should do, that is about products they can competitively sell; the diminishing number of such old lenses and the joy they bring to a diminishing number of us is irrelevant.

It's too bad we're letting the very first SDM lenses form our opinion about in-lens motors in general.
The KAF4 aperture... I hope they're standardizing to a few sizes. And I'm not expecting too many failures... as the 2 KAF4 lenses we have so far aren't particularly prone to aperture failures.

Lack of progress cost more, I'd say. For example, the slowness with which they migrated towards in-lens motors... how many people were put off, when their first contact with a Pentax DSLR was "screeeeeech! screeeeeech!"?
Say Pentax would launch a camera with very good video capabilities; what if it cannot properly control its aperture on a KAF3 lens?
And perhaps Sigma would've launched a few more lenses for K-mount if they had KAF4 figured out, years ago.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
aperture, k-mount, kaf4, lenses, pentax lens, slr lens
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Updated list of KAF4 lenses GregL65 Pentax SLR Lens Discussion 6 12-29-2019 04:34 AM
KAF3/KAF4 to E mount adapter? amstel78 Pentax SLR Lens Discussion 6 08-26-2019 10:36 PM
KAF4 Lenses cainmh Pentax SLR Lens Discussion 56 03-17-2019 10:33 AM
Petition - Please allow KAF4 firmware for the K3, K5 series, and K50 VoiceOfReason Pentax DSLR Discussion 227 12-28-2016 02:26 AM
K-3 firmware update: KAF4 mount support ScooterMaxi Jim Pentax K-3 26 12-14-2016 08:22 PM



All times are GMT -7. The time now is 11:19 AM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top