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10-04-2012, 06:13 PM   #16
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QuoteOriginally posted by goubejp Quote
I read October 3, 2011 ?
On the Japanese document

10-04-2012, 06:19 PM   #17
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A 70-200 lens isn't on the roadmap so.....
10-04-2012, 06:29 PM   #18
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QuoteOriginally posted by Vylen Quote
A 70-200 lens isn't on the roadmap so.....
The D-FA 100mm F/2.8 WR was never on the road map..... until it was announced. It was a surprise lens. I'm sure Pentax knew that if they put a new FA lens on the road map the rumor mill would instantly assume a FF body was in the works.

Last edited by Winder; 10-04-2012 at 06:35 PM.
10-04-2012, 06:42 PM   #19
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It's interesting that Pentax have never done a classic 70-200 f2.8 before.

Lots of 50-200s and 80-200s (but only one f2.8 80-200), some 70-210s etc, and one 70-200 f4-5.6, but never a 70-200 2.8.

Good move, if anything from a marketing perspective. Conventional specs like that are I think easier to sell.

10-04-2012, 07:01 PM   #20
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A little off subject, but while looking for other patents I found this which I thought was interesting.

Canon patents for 600mm f/4 and 400mm f/2.8 lenses | Photo Rumors

Both of these Canon lenses filed at the same time have "image height" of 21.64mm. There is also a 35mm F/1.4 and a 180mm F/3.5 Macro from Canon that have the 21.64mm image height.

I think the "Image Height" is misleading.

21.64mm x 2 = 43.28mm which would be 0.15mm larger than a full frame image circle needed to cover a 24x36mm sensor. I think "Image Height" is actually the radius of the image circle.

The Canon 24-70L F/2.8 II has an Image circle of 43.28mm. This seems to the Canon standard for image circle.

That would make the Pentax 70-200 F/2.8 with an "image Height" of 21mm a "near" FF lens with an image circle of 42mm or 1.13mm smaller than a TRUE 24x36mm. You need 43.13mm to cover the FF sensor.

Last edited by Winder; 10-04-2012 at 07:15 PM.
10-04-2012, 07:07 PM   #21
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QuoteOriginally posted by Winder Quote
That would make the Pentax 70-200 F/2.8 with an "image Height" of 21mm a "near" FF lens with an image circle of 42mm or 1.13mm smaller than a TRUE 24x36mm. You need 43.13mm to cover the FF sensor.
see:

QuoteOriginally posted by goubejp Quote
Image circle needed for 24*36 = sqrt (12*12 + 18 * 18) = 21,633 mm precisely
The patent is for a lens with an image circle of 21,64 mm so it fits;
10-04-2012, 07:14 PM   #22
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So the new lens gives us an image circle of 43.28mm. Identical to Canon's specifications for a FF image circle.

That leave 0.15mm for IBIS.
10-04-2012, 07:32 PM   #23
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0.15mm for the SR, mmm... what about including the SR in the lens, like the 645 90 macro. Although that, plus 4 ED elements, plus internal focus, plus internal zoom.... VERY expensive.

10-04-2012, 07:53 PM   #24
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QuoteOriginally posted by Warpig Quote
0.15mm for the SR, mmm... what about including the SR in the lens, like the 645 90 macro. Although that, plus 4 ED elements, plus internal focus, plus internal zoom.... VERY expensive.
Would have to compete with the Sigma 70-200.
10-04-2012, 08:10 PM   #25
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QuoteOriginally posted by Warpig Quote
0.15mm for the SR, mmm... what about including the SR in the lens, like the 645 90 macro. Although that, plus 4 ED elements, plus internal focus, plus internal zoom.... VERY expensive.
Looking at the lens schematic compared to the Canon IOS & Tamron VC 70-200 It looks like this lens has IOS.
10-04-2012, 08:30 PM   #26
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QuoteOriginally posted by Winder Quote
Looking at the lens schematic compared to the Canon IOS & Tamron VC 70-200 It looks like this lens has IOS.
Yes. That was what I was wondering about. There is a slightly different arrangement of the lens groups compared to the 80 to 200 f2.8. Could one of them be an in-lens image stabilisation group?

Regards

Chris
10-04-2012, 08:39 PM   #27
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Funny....Pentax had a lot of patents for lenses, but 99% of this lenses are never produced.
10-04-2012, 08:41 PM   #28
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This is good news and it does give us some new hope for an eventual FF release. Any indication as to it having weather sealing or not?
10-04-2012, 09:57 PM   #29
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A very interesting find. Thanks!

Is the distance behind the rear element consistent with K-mount? It seems to me that previous patents showed a greater distance but I find it difficult to judge the scale. Why would it need image stabilisation when all K-mount bodies have SR?

I keep thinking back to the interview with Kitazawa-san last year where they discussed the feasibility full frame mirrorless.
https://www.pentaxforums.com/forums/pentax-news-rumors/168982-translation-kit...ml#post1749610
10-04-2012, 10:02 PM   #30
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QuoteOriginally posted by goubejp Quote
Image circle needed for 24*36 = sqrt (12*12 + 18 * 18) = 21,633 mm precisely
Huh? Perhaps a different calculator? The image circle (diameter to provide minimum coverage) would be sqrt(24^2 + 36^2) = 43.3mm. Good design would indicate a little larger to accommodate variance in manufacturing tolerance.


Steve
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