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03-30-2018, 05:07 AM   #91
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QuoteOriginally posted by D1N0 Quote
I wasn't talking about the DA* 11-18 which is a KAF3 lens. The 16-50 maybe KAF2 because it still has a screw drive, but still it is an update to an older design. The screw drive will probably be dropped but Ricoh may want to keep the lens compatible with older models since they did in the DA* 11-18.
I appreciate Ricoh's move to go back to kAF3 mount. I wouldn't have the chance buy this and use it on my k5II if it were in kAF4 mount. Maybe if they would provide a software update for older cameras then it would be fine. But as of the moment, there are still a lot of older cameras being used.

Old Pentax cameras never die. They just fade away.

03-30-2018, 05:20 AM   #92
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The fact that there is a KAF4 mount maybe be more important than to use it on all lenses. Is there real advantage to it? Maybe in video, but if you do video, what are you doing with Pentax? The other advantage is that it may become easier for Tamron and Sigma to support Pentax again. But I doubt that is why Ricoh did it....
03-30-2018, 05:56 AM - 1 Like   #93
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The main advantage to KAF4 is that, once developed, it lowers manufacturing costs.
03-30-2018, 06:27 AM   #94
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QuoteOriginally posted by Mistral75 Quote
The main advantage to KAF4 is that, once developed, it lowers manufacturing costs.
And as I see it, that extra money they save can go to improving AF/better lenses/etc.

03-30-2018, 07:13 AM   #95
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QuoteOriginally posted by monochrome Quote
Key words being ‘will support’. K-1ll Mount is KAF2 for backward compatibility.
The K-1 II must fully support all current lenses, which includes the screw drive FA Limiteds. However, there's no reason why a 2018 lens would still support screw drive AF.

---------- Post added 30-03-18 at 05:23 PM ----------

QuoteOriginally posted by Mistral75 Quote
The main advantage to KAF4 is that, once developed, it lowers manufacturing costs.
It's also a superior solution.
03-31-2018, 01:59 AM - 5 Likes   #96
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QuoteOriginally posted by Andrea K Quote
How you have checked this values?
To check the actual FL of a lens at infinity, use two stars:

Using 2 stars to determine the actual focal length of a lens (at a distance) - PentaxForums.com

I got quite a difference for the max. FL of the DA* 60-250/F4. Quoting from my 2011 post:
Last night was a clear enough sky in the last few days to see some stars again. So I decided to measure the max. FL of the DA*60-250/F4. I used 2 shots of the separation between Acrux (Alpha Crucis) & Mimosa (Beta Crucis). The angular separation between them is 4.243376 .

The 2 FL results I got were:
240.9mm
241.6mm

I then used the 2 outside stars in the line-of-three in Orion's belt, Alnitak (Zeta Orionis) & Mintaka (Delta Orionis). The angular separation is 2.735777. The FL result I got was:
242.3mm

However the larger angular separation in the first two shots compared with the third should be a bit more accurate due to the greater pixel separation in the image.

So I think this zoom lens has a 241mm max. FL.

Dan.

Last edited by dosdan; 03-31-2018 at 02:06 AM.
03-31-2018, 06:17 AM   #97
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QuoteOriginally posted by Mistral75 Quote
The main advantage to KAF4 is that, once developed, it lowers manufacturing costs.
QuoteOriginally posted by Kunzite Quote
It's also a superior solution.
My understanding is that the main advantage of the KAF4 is that it allow a more precise control of the aperture and therefore of exposure.
03-31-2018, 06:39 AM   #98
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Yes, exactly. Precise control in every condition - even when shooting in rapid sequence with a rear converter attached.

03-31-2018, 07:27 AM   #99
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Precisely why a lot of Pentaxians don't need it.
03-31-2018, 07:49 AM   #100
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Pentax needs it.
03-31-2018, 07:55 AM - 1 Like   #101
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I think an electronic aperture might be cheaper to produce and integrate. Will benefit later when applied industrialy. Probably progressively as i bet all next body will allow KAF4.

Allow third party to produce lenses too because it's common with Nokin and Canon and Sony mount(even if it doesn't bring money to pentax, it does attract user).
03-31-2018, 12:50 PM   #102
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QuoteOriginally posted by pres589 Quote
If this new 16-50 works on a K-5/II/IIs I will be surprised. KAF4 going forward seems like the safe assumption.
In this case, I have one more excuse to get a new APS-C body
I guess this new 17-50 will not come out before K3-III, maybe both come out together?
Speak of APS-C, how did the KP go? It seems like the silent kid in the class.
03-31-2018, 05:39 PM - 1 Like   #103
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QuoteOriginally posted by bigfoxkiB Quote
In this case, I have one more excuse to get a new APS-C body
I guess this new 17-50 will not come out before K3-III, maybe both come out together?
Speak of APS-C, how did the KP go? It seems like the silent kid in the class.
Check out this portion of the forums Pentax KP - PentaxForums.com for multiple discussions. Also many of the photo threads have KP images in them also but that is for the search function or luck. I love my KP after a short acquaintance with it.
04-01-2018, 02:45 AM   #104
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QuoteOriginally posted by SSGGeezer Quote
Check out this portion of the forums Pentax KP - PentaxForums.com for multiple discussions. Also many of the photo threads have KP images in them also but that is for the search function or luck. I love my KP after a short acquaintance with it.
Thank you, I will go check it out.
Now I serious hope Pentax brings out more lenses than body in the future.
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