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07-06-2018, 02:03 PM   #16
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Right on! /reh321

08-01-2018, 05:50 AM   #17
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QuoteOriginally posted by reh321 Quote
I'm not interested in the math.The accompanying images are what matter - and they show a wider view.
They show the correct view of that lens,... ie, the lens without it being cropped.

QuoteOriginally posted by Mistral75 Quote
Actually the focal reducer doesn't reduce the focal length of the lens it's attached to but the optical system made of the lens plus the focal reducer has a reduced focal length and a reduced image circle in comparison to the original lens.
Yaaaaaay.
Somebody, gets, it.
08-01-2018, 06:22 AM - 1 Like   #18
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QuoteOriginally posted by PiDicus Rex Quote
Yaaaaaay.
Somebody, gets, it.
So you were just being pedantic before. We knew that - but we aren't interested in arguing language.
08-01-2018, 07:06 AM   #19
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QuoteOriginally posted by reh321 Quote
So you were just being pedantic before. We knew that - but we aren't interested in arguing language.
Not pedantic, accurate, as is Mistral75's statement understanding that the lens doesn't change, the system of the lens AND the focal reducer is what allows the camera to see the whole of the Lens's image circle.

08-01-2018, 07:12 AM   #20
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QuoteOriginally posted by PiDicus Rex Quote
Not pedantic, accurate, as is Mistral75's statement understanding that the lens doesn't change, the system of the lens AND the focal reducer is what allows the camera to see the whole of the Lens's image circle.
I have a degree in mathematics, but I had no idea what you were saying, which is why I asked the questions I did. The important thing is that if I could mount (this + Takumar 50mm f/1.4) on my Q-7 (*) it would act exactly like a 25mm f/0.7 lens. Everything else is a detour.


(*) but they don't manufacture a K-mount or M42-mount version, so I won't be purchasing one
08-01-2018, 03:00 PM   #21
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QuoteOriginally posted by reh321 Quote
(*) but they don't manufacture a K-mount or M42-mount version, so I won't be purchasing one
theres adapters to link most lenses
08-01-2018, 03:44 PM   #22
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QuoteOriginally posted by surfar Quote
theres adapters to link most lenses
Metabones doesn't make a M42-Q one.

08-01-2018, 06:07 PM   #23
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QuoteOriginally posted by reh321 Quote
I have a degree in mathematics, but I had no idea what you were saying, which is why I asked the questions I did. The important thing is that if I could mount (this + Takumar 50mm f/1.4) on my Q-7 (*) it would act exactly like a 25mm f/0.7 lens. Everything else is a detour.


(*) but they don't manufacture a K-mount or M42-mount version, so I won't be purchasing one
Just a side note but the Metabones 666 work with a M42 adaptor?

FotodioX Pro Lens Mount Adapter for M42 Lens to M42-NIKF-PRO B&H
08-02-2018, 10:50 AM   #24
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QuoteOriginally posted by 2old4toys Quote
Just a side note but the Metabones 666 work with a M42 adaptor?

FotodioX Pro Lens Mount Adapter for M42 Lens to M42-NIKF-PRO B&H
The Metabones 666 provides a Nikon F mount right now.
At one time they were talking about two other devices - one that would provide a K- mount and one that would provide an M42-mount, but neither of those seems to have happened.

Right now, the only way to use a M42-mount lens would be to get a M42-to-Nikon converter {like the one you linked to}, but that contains glass and Nikon users I trust have told me that would diminish the image and make the Metabones device essentially useless.
08-02-2018, 06:38 PM   #25
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QuoteOriginally posted by reh321 Quote
I have a degree in mathematics, but I had no idea what you were saying, which is why I asked the questions I did. The important thing is that if I could mount (this + Takumar 50mm f/1.4) on my Q-7 (*) it would act exactly like a 25mm f/0.7 lens. Everything else is a detour.
Then why are you still getting the math wrong?

( Lens mm x Crop Factor ) x Focal Reducer Factor.

( 50mm x 4.7 ) x Focal Reducer Factor

235 x 0.666

156.51 mm NOT 25mm

Heck, even if you do it in the Optical System Order, - ( Lens x Focal Reducer ) x Crop Factor - You Get The Same Answer.

---------- Post added 03-08-18 at 11:48 AM ----------

QuoteOriginally posted by surfar Quote
theres adapters to link most lenses
Not if you want Infinity Focus.


QuoteOriginally posted by reh321 Quote
At one time they were talking about two other devices - one that would provide a K- mount and one that would provide an M42-mount, but neither of those seems to have happened.
Metabones have no intention to support K-mounts. I have that in writing from emails three years ago when I was chasing K-mount adapters for the Aja Cion before purchasing the camera - We made our own mounts for it.
I absolutely hope they prove me wrong and have changed their corporate bias against the Pentax lenses and produce their focal reducers in K-mount versions - Pentax film era lenses are astounding quality when used for 4K Cinema Production, I've used mine in front of Sony, Panasonic, Blackmagic and Aja cameras and gotten to record fantastic vision with them.
Annoyingly, Metabones support the C/Y mount, and the Zeiss-Yashica lenses, which are virtually unknown outside of the most dedicated lens enthusiasts,... yet the C/Y Mount has an identical Flange Focal Distance to the K-mount and M42 mount, so all Metabone have to do, is machine off some new brass rings to match the K bayonet and screw them to their existing products.
If that's not proof of a bias against Pentax lenses within a company, when it would be an almost no-cost item to support thousands of lenses, then I don't know what is.
08-02-2018, 07:30 PM   #26
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Has anybody actually worked with this adapter?
08-02-2018, 07:37 PM   #27
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QuoteOriginally posted by PiDicus Rex Quote
Then why are you still getting the math wrong?

( Lens mm x Crop Factor ) x Focal Reducer Factor.

( 50mm x 4.7 ) x Focal Reducer Factor

235 x 0.666

156.51 mm NOT 25mm

Heck, even if you do it in the Optical System Order, - ( Lens x Focal Reducer ) x Crop Factor - You Get The Same Answer.
You are answering the wrong question. You are talking about "35mm effective focal length", which is merely a convenient thinking crutch for those of us who began with 35mm cameras, while I am talking about actual focal length. If I mount a 50mm lens on my Q-7, which is roughly a "4.65 crop", then I will get the same view I would get mounting a 150mm lens on my "1.5 crop" K-30, or mounting a 282.5mm lens on a K-1, but the lens has not changed .... it is still a 50mm lens, but its behavior has changed because of the way the Q-7's sensor interacts with the resulting cylinder of light. That is the question you are answering for the Metabones system.

I have an '06' lens; if I set that lens at 25mm and f/2.8 I will get exactly the same image I would get by using a 50mm lens set at f/5.6 via the Metabones adapter. Thus, light passing through the system of 50mm lens + Metabones device acts exactly the same as light passing through a lens of half the focal length and twice {numerically 1/2} the physical aperture. That is actual focal length and actual aperture. That is the question I am answering.

Last edited by reh321; 08-02-2018 at 08:00 PM.
08-02-2018, 07:54 PM   #28
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QuoteOriginally posted by PiDicus Rex Quote
Metabones have no intention to support K-mounts. I have that in writing from emails three years ago when I was chasing K-mount adapters for the Aja Cion before purchasing the camera - We made our own mounts for it.
I absolutely hope they prove me wrong and have changed their corporate bias against the Pentax lenses and produce their focal reducers in K-mount versions - Pentax film era lenses are astounding quality when used for 4K Cinema Production, I've used mine in front of Sony, Panasonic, Blackmagic and Aja cameras and gotten to record fantastic vision with them.
Annoyingly, Metabones support the C/Y mount, and the Zeiss-Yashica lenses, which are virtually unknown outside of the most dedicated lens enthusiasts,... yet the C/Y Mount has an identical Flange Focal Distance to the K-mount and M42 mount, so all Metabone have to do, is machine off some new brass rings to match the K bayonet and screw them to their existing products.
If that's not proof of a bias against Pentax lenses within a company, when it would be an almost no-cost item to support thousands of lenses, then I don't know what is.
I would not be surprised if that were true, because I've seen no progress from them. However, all I can depend on is their press release for this device, published two years ago, one year after your letter,
which said near the end "Planned lens mounts for the Speed Booster Q666 include a Pentax-K version and a Nikon F/G version with the most advanced Nikon G aperture adjustment mechanism in the industry."

As of a few minutes ago, that press release is still on their website, and they have done nothing on their website to renounce that that statement, so I have to assume that it is still "operative".
http://www.metabones.com/article/of/Metabones_Devil_Speed_Booster_Q6660.50x_Press_Release

added:
The following appears in the FAQ portion of the Metabones web-site
http://www.metabones.com/article/of/faq

"Will there be Speed BoostersŪ for M42 and Pentax K? We will be looking into M42 and Pentax K in the future. We do not have an estimated date yet. Disclaimer: this shall not be construed as a commitment to ship - we are not done prototyping any of these yet but we will conduct testing to decide if these lenses are free of interference issues with the optics of the Speed BoostersŪ before we will be able to turn them into actual products."

so officially they are still pursuing M42 and K-Mount devices; however, they must be doing this in whatever spare time they might have, which is why I am simultaneously hopeful and dubious that they will ever produce such a thing

Last edited by reh321; 08-02-2018 at 11:07 PM. Reason: Metabones FAQ info
08-02-2018, 09:10 PM   #29
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QuoteOriginally posted by PiDicus Rex Quote
Then why are you still getting the math wrong?

( Lens mm x Crop Factor ) x Focal Reducer Factor.

( 50mm x 4.7 ) x Focal Reducer Factor

235 x 0.666

156.51 mm NOT 25mm

Heck, even if you do it in the Optical System Order, - ( Lens x Focal Reducer ) x Crop Factor - You Get The Same Answer.
That's rich.

It's amusing to me that the same person who complained that others are not sticking to the semantics of "focal length of a lens" in the strictest sense (i.e. "effectively shortens the FL of a lens" is false because, well, let's just ignore "effectively" which might bring some context sensitive wiggle room for interpretation, it's false and so "NOPE !, No, not ever!") can also blame another person who is talking about physical property without ambiguity, i.e. focal length of a compound optical system.
08-03-2018, 06:57 AM - 1 Like   #30
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The Q section has always been special for its happy explorer mood without silly internet opinion squabbles. There is no value in ad hominem arguments.
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