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03-22-2018, 03:54 AM - 6 Likes   #16
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There are 10 examples in the patent. The shortest focal distance goes from 16.46mm to 16.52mm. The longest focal distance goes from 48.35mm to 48.83mm. Maximum aperture is always f/2.9. Image circle is APS-C (radius = 14.24mm).

Five examples include 16 elements in 13 groups. Three examples include 17 elements in 13 groups. Two examples include 15 elements in 12 groups.

In the description of the benefits of the invention, emphasis is put on the minimisation of chromatic aberrations.

---------- Post added 03-22-2018 at 12:15 PM ----------

The current smc Pentax-DA★ 16-50mm f/2.8 ED AL[IF] SDM includes 15 elements in 12 groups



The two examples of the patent which include 15 elements in 12 groups too (example 4 and example 7) are pretty close to the current DA★.

Example 4:



Example 7:



I therefore think that this patent is that of a revamped DA★ 16-50mm f/2.8, close to the current lens but with some tweaks in its optical formula aimed at mitigating one of the main weaknesses of the current lens, its high level of chromatic aberrations.

03-22-2018, 04:20 AM   #17
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Mistral, where did you found the images? The ipforce.jp site is showing me only the text...
03-22-2018, 04:33 AM   #18
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QuoteOriginally posted by ChristianRock Quote
They say my A 70-210 is actually a 75-205 and the 50 1.7 is in fact a 52mm and the FA 28 2.8 is actually 29.5mm or so... So that is not uncommon...
How you have checked this values?
03-22-2018, 04:53 AM   #19
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QuoteOriginally posted by Kunzite Quote
Mistral, where did you found the images? The ipforce.jp site is showing me only the text...
Patent & Utility Model Number Search(Search) | J-PlatPat

Type 2018-45172 in the second box from the top, click on Search and browse through the various tabs.

03-22-2018, 05:06 AM   #20
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Thanks.
Any way to get an up to date list of patents, assigned to Ricoh Imaging (or other companies)? I'm using the ipforce.jp site for that, but I'm not sure if it's the best... (and then, there's the image issue)
03-22-2018, 06:22 AM   #21
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Very good news, however, It probably means it won't be out for the next 2 to 3 years. Keep shooting with what you already have. 😊
03-22-2018, 06:50 AM - 1 Like   #22
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We'll see - lenses replacing existing ones aren't put on the public roadmap (which would impede clearing old stocks). I still don't want to be as optimistic as to expect it at Photokina.
03-22-2018, 06:55 AM - 1 Like   #23
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QuoteOriginally posted by asahi man:
Next also old DA* lenses with new motor and electronics.

Maybe official information September.
Source: 70-200/4 added to roadmap.: Pentax SLR Talk Forum: Digital Photography Review

QuoteOriginally posted by asahi man Quote
Current plan is 16-50 + 50-135 first.


03-22-2018, 07:15 AM   #24
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QuoteOriginally posted by Kunzite Quote
Thanks.
Any way to get an up to date list of patents, assigned to Ricoh Imaging (or other companies)? I'm using the ipforce.jp site for that, but I'm not sure if it's the best... (and then, there's the image issue)
The European patent office keeps a pretty comprehensive collection and their site is easy to use. Do note that they only have published applications, and in some cases it can be up to 2 years between invention and publication if they started with a provisional.
03-22-2018, 07:50 AM - 1 Like   #25
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QuoteOriginally posted by Andrea K Quote
How you have checked this values?
Magazines used to publish these things.

You can still find some information on older lenses online at sites like photodo. I could not find the A 70-210, but it registers the F 70-210 as being a 71-203mm lens: Pentax SMC-F 70-210mm f/4-5.6
And here's their registering the testing of the Pentax 50mm lenses as being in fact 52mm:
Pentax SMC-A 50mm f/1.7
Pentax SMC-F 50mm f/1.4
Their record of the F 28 2.8 is at 29mm: http://www.photodo.com/lens/Pentax-SMCF-28mm-f28-274. The 29.5 I found was from somewhere else but I can't find it now.

Look for the "Effective Focal Length" values.
03-22-2018, 08:09 AM   #26
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QuoteOriginally posted by Kunzite Quote
We'll see - lenses replacing existing ones aren't put on the public roadmap (which would impede clearing old stocks). I still don't want to be as optimistic as to expect it at Photokina.
I don’t think they’d be working on these (nor would we be hearing about it) unless the remaining stock was already low enough to clear itself.

.:
03-22-2018, 08:10 AM   #27
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I'm talking about putting it on the public roadmap with 1-2 years in advance. Maybe in some cases it won't have an impact.
03-22-2018, 08:21 AM   #28
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QuoteOriginally posted by ChristianRock Quote
Magazines used to publish these things.

You can still find some information on older lenses online at sites like photodo. I could not find the A 70-210, but it registers the F 70-210 as being a 71-203mm lens: Pentax SMC-F 70-210mm f/4-5.6
And here's their registering the testing of the Pentax 50mm lenses as being in fact 52mm:
Pentax SMC-A 50mm f/1.7
Pentax SMC-F 50mm f/1.4
Their record of the F 28 2.8 is at 29mm: Pentax SMC-F 28mm f/2.8. The 29.5 I found was from somewhere else but I can't find it now.

Look for the "Effective Focal Length" values.
I'm asking because the Pentax 50 f/1,2 is a bit more wide than the many Pentax 50 f/1,4 iterations and I would to know (calculate?) by how much....

Last edited by Andrea K; 03-22-2018 at 08:37 AM.
03-22-2018, 09:15 AM   #29
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Should here somewhere:
US4702568A - Photographic lens with large aperture ratio - Google Patents
03-22-2018, 12:52 PM - 2 Likes   #30
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QuoteOriginally posted by lytrytyr Quote
16.52 rounds to 17, not 16.
48.35 rounds to 48, not 50.
So this looks more like a DA*17-48/2.9.
Not unusual at all. One has to look at stated camera lens focal lengths as being in the ballpark and not as actual facts. An awful lot of 300mm lenses out there that are have an actual focal length closer the 280mm than 300mm.

Been this way since I got my first SLR in 1970.
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