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05-07-2021, 07:17 AM   #571
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QuoteOriginally posted by Rondec Quote
While PLM motors don't fail frequently, if you look at the rate, say 10 years after release versus the rate of failure of screw driven lenses, I am pretty sure the PLM lenses will have a little higher failure rate.
If a lens lasts "only" ten years, I would consider it to be a real success, especially at my current age of 73.
There may be a whole new set of motors in ten years - perhaps even a "KAF5" mount - we should not take a 'glass is forever' approach here.

05-07-2021, 08:19 AM   #572
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QuoteOriginally posted by reh321 Quote
If a lens lasts "only" ten years, I would consider it to be a real success, especially at my current age of 73.
There may be a whole new set of motors in ten years - perhaps even a "KAF5" mount - we should not take a 'glass is forever' approach here.
My K 2/28mm is forever. So is that lovely M 2/85mm. And I know quite a few more
But I do get your point and you're right.
05-07-2021, 09:11 AM   #573
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QuoteOriginally posted by Smolk Quote
My K 2/28mm is forever. So is that lovely M 2/85mm. And I know quite a few more
But I do get your point and you're right.
If someone will tolerate manual focusing, the story is different, but many of us are unwilling to manual focus or manual focus cannot accomplish what we need. Likewise, mechanical linkages have issues, as is demonstrated by K-3iii testing, and Pentax’s switching to in-lens motors. Taking full advantage of modern technology will require in-lens motors, and motors will wear out. I personally own an eight-element Takumar 50mm f/1.4 lens, but I seldom use it - partly because I have little use of that focal length on my “APS-C” cameras, but partly because AF lenses give me more “keepers”.
05-07-2021, 09:17 AM   #574
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QuoteOriginally posted by reh321 Quote
If someone will tolerate manual focusing, the story is different, but many of us are unwilling to manual focus or manual focus cannot accomplish what we need. Likewise, mechanical linkages have issues, as is demonstrated by K-3iii testing, and Pentax’s switching to in-lens motors. Taking full advantage of modern technology will require in-lens motors, and motors will wear out. I personally own an eight-element Takumar 50mm f/1.4 lens, but I seldom use it - partly because I have little use of that focal length on my “APS-C” cameras, but partly because AF lenses give me more “keepers”.
Apart from portraits, I tolerate MF, rain, wind, whatever ! But perhaps I'm not ‘we’. I have that 8-element Takumar as well - have a great keeper of it, not ultra-sharp, but ultra-lovely. I sold it once, then re-bought it.
I also have the Voigtlander Nokton 1.4/58mm, M 1.7/50mm. K 1.8/55mm, SMC Takumar 1.8/55mm, and of course the FA 1.9/43mm. So I'm really hoping to win the DFA 1.4/50mm raffle...

05-07-2021, 09:53 AM   #575
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QuoteOriginally posted by reh321 Quote
If a lens lasts "only" ten years, I would consider it to be a real success, especially at my current age of 73.
There may be a whole new set of motors in ten years - perhaps even a "KAF5" mount - we should not take a 'glass is forever' approach here.
I think "glass is forever" hasn't been a truism for most lenses for a very long time... if it ever really was...

M42 was ~20 years for Pentax, "K" was another 20, "KAF" was another 40 or so, and now the "KAF4" era starting a few years ago, where the prior generation loses significant functionality compared to the newest...
And yes, I lumped KA into "K"; and KAF2, KAF3 into "KAF", which is sloppy... and subject to very many different interpretations...

Canon had even more of a break, though EF has had close to 40 years.

I think of my F35-70... great little lens, but it's obvious it was not designed to be around 40 years after its manufacture...

-Eric
05-07-2021, 09:57 AM   #576
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QuoteOriginally posted by One3rdEV Quote
By default I would have expected basically the same lens optically with just the work required to bring it to PLM.
There's no such thing as a 'just the work required to bring it to PLM'.
The whole optical blue construction must be redone.
05-07-2021, 10:05 AM   #577
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QuoteOriginally posted by reh321 Quote
If someone will tolerate manual focusing, the story is different, but many of us are unwilling to manual focus or manual focus cannot accomplish what we need. Likewise, mechanical linkages have issues, as is demonstrated by K-3iii testing, and Pentax’s switching to in-lens motors. Taking full advantage of modern technology will require in-lens motors, and motors will wear out. I personally own an eight-element Takumar 50mm f/1.4 lens, but I seldom use it - partly because I have little use of that focal length on my “APS-C” cameras, but partly because AF lenses give me more “keepers”.
1/ There's a difference between lenses are forever and lenses do fail after 10 years.

2/ I don't think anyone here is against in-lens motors. But if in-lens motor (PLM in this case) prevents me from proper manual focussing a lens, the said lens will be bought by someone else. Simple as that.

05-07-2021, 11:21 AM   #578
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QuoteOriginally posted by thibs Quote
1/ There's a difference between lenses are forever and lenses do fail after 10 years.
I think you are way off on your estimate.
I switched from Pentax to Canon in 1995 because of their EF lenses.
I used the 28-80mm "usm" lens kitted with that body for most of the next 11+ years - then occasionally thereafter when I moved to digital Rebels - and it was still going strong when it accidentally fell out of my camera bag and down a ravine ,,,,, as far as I know, it could still be working if I had remembered to close my bag.
05-07-2021, 11:44 AM   #579
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QuoteOriginally posted by reh321 Quote
If a lens lasts "only" ten years, I would consider it to be a real success, especially at my current age of 73.
Quoting you then...
05-07-2021, 12:36 PM   #580
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QuoteOriginally posted by thibs Quote
1/ There's a difference between lenses are forever and lenses do fail after 10 years.

2/ I don't think anyone here is against in-lens motors. But if in-lens motor (PLM in this case) prevents me from proper manual focussing a lens, the said lens will be bought by someone else. Simple as that.
I've used focus-by-wire in some applications where it was, if I'm gentle, unacceptable...
But I would be OK with focus-by-wire if it did what I wanted it to do, when I wanted it done...
And I turn off the autofocus often enough where that is important to me.

I certainly don't want a lens I can't manual focus.
And yes, Canon, I'm looking at you...
EF35-80mm f/4-5.6 PZ
(and I have shot with one of these. Anyone who says bad things about the Pentax power zoom lenses needs to use this one... wow...)

-Eric
05-07-2021, 01:08 PM   #581
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QuoteOriginally posted by thibs Quote
Quoting you then...
My statements are in agreement - I expect many more than ten years service from current motors, but I would be satisfied with that.
05-07-2021, 09:10 PM - 1 Like   #582
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Look guys, do you want that ‘next level’ performance with Pentax or not. If yes, then there is no other way.
05-08-2021, 02:52 AM   #583
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QuoteOriginally posted by reh321 Quote
If a lens lasts "only" ten years, I would consider it to be a real success, especially at my current age of 73.
There may be a whole new set of motors in ten years - perhaps even a "KAF5" mount - we should not take a 'glass is forever' approach here.
I suppose so. I have a 30 year old FA 135 I still use. It focuses fast and is nice and sharp. It is probably smaller than it would need to be if it had an in lens motor. I actually like having smaller lenses and I don't mind having a little noise with autofocus.

That said, I'm also fine with Pentax creating new PLM lenses (I know the two go together). I guess I would just prefer not focus by wire. The idea that a lens becomes a paper weight if the motor fails isn't great to me. Most of Pentax's lenses are still usable with manual focus in such a situation, even those with in lens motors.
05-08-2021, 06:10 AM   #584
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It's not just the motor. There's more to the survival of a lens. My almost 14yo DA*16-50/2.8 was indeed serviced twice for the SDM, and then hacked to screw drive, but also it's not as sharp across the frame as it used to be and the hood, while it does hold, no longer locks into position.

The latter two actually bother me more than the screw drive, and are the real reason why I want the new one.

05-08-2021, 02:01 PM   #585
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QuoteOriginally posted by Rondec Quote
I suppose so. I have a 30 year old FA 135 I still use. It focuses fast and is nice and sharp. It is probably smaller than it would need to be if it had an in lens motor. I actually like having smaller lenses and I don't mind having a little noise with autofocus.

That said, I'm also fine with Pentax creating new PLM lenses (I know the two go together). I guess I would just prefer not focus by wire. The idea that a lens becomes a paper weight if the motor fails isn't great to me. Most of Pentax's lenses are still usable with manual focus in such a situation, even those with in lens motors.
I suppose that you’ll be able to service that PLM as well, should it fail. I do not know if 55-300PLM is focus by wire. Suppose that this will be a lot like that. Many has praised the performance from it. I have the 55-300 WR and it is quite fast too.

While most of the time I don’t mind screwdrive, it is not so handy all of the time. It will gather ‘looks’ and your kind of I’m just photographing, don’t mind about me, goes to. What is going on. What sound is that. (They might not be disturbed, but they become interested. So attention is gained in other way. That is helpful sometimes too..
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