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02-22-2018, 07:31 AM - 1 Like   #2866
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QuoteOriginally posted by photoptimist Quote
[...]
But the Pentax and Tokina seem extremely unlikely to come from the same designer given that their focus rings move in opposite directions.
Maybe they come from two brothers?

02-22-2018, 08:01 AM   #2867
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QuoteOriginally posted by photoptimist Quote
(...)

But the Pentax and Tokina seem extremely unlikely to come from the same designer given that their focus rings move in opposite directions.
This is a ring ultrasonic motor and a 'focus by wire' command. It's pretty easy to program the effect of the sense of rotation, as demonstrated by the Tokina opera lens which uses one direction for the Canon mount and the opposite one for the Nikon mount to conform itself to the 'rule' followed by the respective OEM lenses.
02-22-2018, 09:27 AM   #2868
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QuoteOriginally posted by robjmitchell Quote
Have we seen an optical formula for the DFA*50 yet?
I wonder if this is accurate
No optical formula has been published for the HD Pentax-D FA★ 50mm f/1.4 SDM AW yet.

Don't tell me it has 13 elements in 10 groups...
02-22-2018, 09:27 AM - 1 Like   #2869
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I surely hope not - 13 brings bad luck.

02-22-2018, 10:08 AM   #2870
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I wonder why Pentax aren't releasing a 20mm f/2 ?
02-22-2018, 10:12 AM   #2871
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QuoteOriginally posted by ffking Quote
I wonder why Pentax aren't releasing a 20mm f/2 ?
Because they hate me.
Although I'd want an ƒ4.
02-22-2018, 10:13 AM   #2872
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Maybe they will - but not on Sony FE mount

By the way, the "it might be a collaboration with Tokina" is the first such supposition that actually makes sense. And not only the optics, but also the ring-type SDM motor - which might need the higher volumes to become feasible. Or not.
But, we should wait at least for detailed specs - if not confirmation.
02-22-2018, 10:17 AM - 1 Like   #2873
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QuoteOriginally posted by ffking Quote
I wonder why Pentax aren't releasing a 20mm f/2 ?
Because that 20/2 is a mirrorless lens?

02-22-2018, 10:32 AM   #2874
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QuoteOriginally posted by Mistral75 Quote
Not only do the Tokina opera 50 mm f/1,4 FF and the HD Pentax-D FA★ 50 mm f/1,4 SDM AW look very similar, so do the available specifications:

【噂】トキナーが「FíRIN 20mm F2 FE AF」と「opera 50mm F1.4 FF」を近日中に発表
  • AF lens for full-size digital single lens reflex cameras
  • Mounts: Canon and Nikon
  • Ring-type ultrasonic motor
  • Dust-proof and drip-proof
  • First Tokina lens to adopt an electromagnetic iris system (Nikon version)
  • The direction of rotation of the focus ring is the same as that of a OEM lens for both Canon and Nikon mounts
  • Scheduled release date: Summer 2018
  • Should be announced on February 28.

We'll have to wait for the detailed specifications to be sure but I'm pretty certain these two lenses have a lot in common. A shared development could explain the delay since it's always more complicated when two corporations are involved in the same project.
You were the first to "speculate" that Pentax would release a 25mm, 50mm and and 85mm based on tokina's Cine lenses and I came around to that as a strong possibility. This only further cements that. If true Im only sad that now other cameras will get to have access to the same optics as Pentax users.
02-22-2018, 10:59 AM   #2875
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QuoteOriginally posted by jatrax Quote
Those who talk know nothing, those who know don't talk.
Too much camera update news and even an official announcement by Pentax with specs for K1. All that during the extended year of the primes where one woould expect lenses. This may change soon as we all now, but a sign of live would be nice.

Now even Tokina is showing a new 1.4/50 before Pentax ...
02-22-2018, 11:25 AM   #2876
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QuoteOriginally posted by Mistral75 Quote
No optical formula has been published for the HD Pentax-D FA★ 50mm f/1.4 SDM AW yet.

Don't tell me it has 13 elements in 10 groups...
Finally someone wants to play the guessing game!
My guess was actually 13 groups.
Now we just need a cut away of a known lens to figure out how to interpret these things.
Your guess does make much more sense than mine btw
02-22-2018, 11:42 AM   #2877
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I will re-post this since it has gone largely unnoticed. It appears that the DFA* 50 was used for some of the sample images for the K-1 II:
QuoteOriginally posted by JBox Quote
Go to the page here for K-1 II sample images. The last few images claim to have used the lens "HD PENTAX-D FA*50mmF1.4 SDM AW". Below it says: "The lens used is Beta version, and the name is tentative."
02-22-2018, 11:44 AM - 1 Like   #2878
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Ok Folks i have found the equivalent photo for the Da*55/1.4. Link to formula
smc PENTAX-DA?55mmF1.4 SDM / Telephoto Lenses / K-mount Lenses / Lenses / Products | RICOH IMAGING


So this is almost certainly and accurate representation of the DFA*50/1.4 optical formula.

Let’s get interpreting!
02-22-2018, 12:05 PM   #2879
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If that is the actual formula for the lens, I am counting more than 14 elements...that is one complicated prime lens and definitely a unique formula...and its gonna be 1.5k lens...
02-22-2018, 12:33 PM - 1 Like   #2880
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QuoteOriginally posted by zapp Quote
during the extended year of the primes
"year of the primes" never came from Pentax. Only from a certain internet rumor source who is correct about 50% of the time. Perhaps we should pay more attention to what Pentax says than anonymous internet posters.

Remember: Those who know are not talking, those who talk do not know.
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