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07-18-2021, 06:59 PM   #106
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QuoteOriginally posted by reh321 Quote
Isn't weather-sealing more reliable on internally zooming lenses, because there are fewer places where water could get in??
While I'm not a lens designer, speaking as a mechanical engineer I'd say most certainly.

07-19-2021, 05:49 AM   #107
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QuoteOriginally posted by biz-engineer Quote
Whether the front element moves or not probably has an impact on optical properties of the lens. All macros lenses that I'm aware of focus with moving front group, there must be a good reason.
Of course, anything a designer does to his/her design impacts the performances one way or another.

Many macro lenses move the whole apparatus when focusing, essentially changing the distance between the lenses and the sensor. In other words, applying the thin lens equation, simply using 1/f = 1/o + 1/i .

QuoteOriginally posted by reh321 Quote
Isn't weather-sealing more reliable on internally zooming lenses, because there are fewer places where water could get in??
In theory, yes. In practice, the difference might be difficult to notice.
07-19-2021, 08:55 AM - 1 Like   #108
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QuoteOriginally posted by FozzFoster Quote
...but this lens is on my must have list. Be it a year or two from now... I will own this lens.
Kinda the same for me. I'd want to see how it compares to the Sigma 17-50mm 2.8 first, though. No doubt it'd be great for my racing photography, but being realistic, can't really justify full price on this one for 1 or 2 non-paid events a year. Sure I could use this for other subjects, but I already have plenty of other lenses for other things. My likely outcome will be getting a used Sigma and then this one once prices come down, I find a used one, or a giant pile of money lands in my lap (Covid stimmy checks excluded).
07-19-2021, 09:06 AM   #109
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Why not build this as a FF with ASP-C compatibility? I love the lens, but it won't cut it on my K-1 MII, so it's not even a starter.

07-19-2021, 09:50 AM   #110
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Regarding the price, the earlier version had a list price of about US$1,000 when it was introduced in 2007. An inflation calculator tells me that's just over US$1,300 today. And Pentax probably sells fewer copies of each item today, which normally results in higher prices. I don't think an introductory list price of US$1,400 price is out of line.

That said, it's going to be many years before I own one..
07-19-2021, 10:16 AM   #111
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I hope they keep the SDM drive motor. So smooth and precise!
07-19-2021, 10:40 AM   #112
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I'll be interested to see comparisons with the old 16-50. Mine has a new lease on life with te screw drive conversion and K-3iii.
It would have to be a lot better to get me to buy the new version but maybe it is.

07-19-2021, 10:44 AM   #113
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QuoteOriginally posted by Driline Quote
I hope they keep the SDM drive motor. So smooth and precise!
If you are OK with possible conversion to screw-drive, I suppose it is OK.
I have never seen a screw-drive which is smooth nor quiet.
07-19-2021, 11:45 AM   #114
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QuoteOriginally posted by Driline Quote
I hope they keep the SDM drive motor. So smooth and precise!
You should get familiar with the post-2008 in-lens AF motors Pentax is using. SDM micromotors have no place in a * lens, and Pentax abandoned them for good reasons.
07-19-2021, 12:15 PM   #115
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QuoteOriginally posted by Driline Quote
I hope they keep the SDM drive motor. So smooth and precise!
You aren't shooting with Pentax any more, but Pentax doesn't use any "true" SDM motors in new designs. All of them have either ring motors, PLM motors or DC motors. The Tamron designed and manufactured motors are listed as SDM motors, but obviously it is the same USD motors that they use in their own lenses and don't seem prone to failure.
07-19-2021, 12:20 PM   #116
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QuoteOriginally posted by mattb123 Quote
I'll be interested to see comparisons with the old 16-50. Mine has a new lease on life with te screw drive conversion and K-3iii.

It would have to be a lot better to get me to buy the new version but maybe it is.
From the samples we've seen so far the difference with the old one seems to be immense...

07-19-2021, 12:24 PM   #117
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QuoteOriginally posted by Driline Quote
I hope they keep the SDM drive motor. So smooth and precise!
Introducing the HD Pentax-DA★ 16-50mm f/2.8 ED PLM AW

Says it all, really...
07-19-2021, 02:02 PM   #118
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It looks nice but I already have the DA 16-85 3.5-5.6 and I don't need the extra speed.

Unrelated question. I see posts about converting the lens to use the manual screw autofocus. If I need that done sometime in the future, where do I get it done, and about how much is it?
07-19-2021, 02:34 PM   #119
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QuoteOriginally posted by butchblack Quote
It looks nice but I already have the DA 16-85 3.5-5.6 and I don't need the extra speed.

Unrelated question. I see posts about converting the lens to use the manual screw autofocus. If I need that done sometime in the future, where do I get it done, and about how much is it?
You cannot convert the new 16-50 PLM to screwdrive, only the old one.
The old one had dual SDM and screwdrive AF (since they barely launched SDM capable cameras). Most lenses are either screwdrive, or include some AF motor - but not both.
07-19-2021, 02:40 PM   #120
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QuoteOriginally posted by butchblack Quote
It looks nice but I already have the DA 16-85 3.5-5.6 and I don't need the extra speed.

Unrelated question. I see posts about converting the lens to use the manual screw autofocus. If I need that done sometime in the future, where do I get it done, and about how much is it?
That's only for the old DA* 16-50/2.8 SDM. The 16-85 does not have provision for screwdrive AF.
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