Speed Booster: full frame fov on an APS-C size sensor

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Actually they are called focal reducers. They have been around for some time typically used on telescopes and spotting scopes. While they say they can correct for aberrations you can be sure that wont be the case with anything but one lens. Further it's highly unlikely that thy would improve the mtf and in all likelihood would make it worse.

It's a cool gimmick but just like extenders you won't get something for nothing. If it were that easy we would have extenders that would improve resolution as well.
 
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East Wind Photography said:
Actually they are called focal reducers. They have been around for some time typically used on telescopes and spotting scopes. While they say they can correct for aberrations you can be sure that wont be the case with anything but one lens. Further it's highly unlikely that thy would improve the mtf and in all likelihood would make it worse.

It's a cool gimmick but just like extenders you won't get something for nothing. If it were that easy we would have extenders that would improve resolution as well.

Read the white paper. The analogy with extenders doesn't hold, because it does exact opposite of a extender. Extenders magnify the image and also magnify aberrations, while focal reducers reduces it by compressing the image. There are up and downsides using a focal reducer. Good design is the key here.
 
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You are mistaken, and its a common misconception. The effect on image quality has nothing to do with magnification, or reduction, but everything to do with additional optical elements that are not optimized for any one optical system. People conceptualize the ray traces and think "spreading" them or "compacting" them, but ... that's not exactly how it works.

Consider - all the different lens aberrations. The IQ is all about controlling those aberrations. No "fits all" design, of any magnification, will do that effectively. You'll find lenses that the device works acceptably well on, and other lenses that it does not work well on.

Also have to consider ghosting and flare.

Also have to consider mechanics - as the lens to sensor (or film) lateral alignment is not well controlled, and adding other elements will introduce some de-centering in the entire optical path.

There is a reason there are dedicated extenders, or extenders that work only on certain lenses. And even with the latter, we know that performance varies quite a bit.

Having said all that, its an interesting concept, and I'm sure it will have its fair share of use, as well as its fair share of refinement, should it do well in the marketplace.
 
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May 12, 2011
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NormanBates said:
Sorry, this will only work on short focal flange mounts, which basically means mirrorless. So, there might be an EF-to-EFM version, but never an EFS-to-EF version.

One more reason to support my belief that mirrorless is the future.

It's still an amazing product and makes the Sony FS700 and FS100 even more desirable. This makes me glad my Blackmagic Design Cinema camera hasn't shown up yet, now I want the MFT version without a doubt.
 
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A year and a half ago I posted the idea of a wide-converter for FF lenses to APS-C image circle.

Source:
http://www.canonrumors.com/forum/index.php?topic=1564.msg22452#msg22452

EF 0.625x converter for APS-C cameras (keep the original angle of view of EF lenses on crop sensors and gain 1-1.33 stops of light)

I was pretty close, except for the fact the the flange distance needed to be reduced to make that a possibility (hense the need for Sony NEX or Fuji X series).
 
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rs

Dec 29, 2012
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NormanBates said:
Sorry, this will only work on short focal flange mounts, which basically means mirrorless. So, there might be an EF-to-EFM version, but never an EFS-to-EF version.

One more reason to support my belief that mirrorless is the future.
Why does it require a short flange mount? A telecompressor is like an inverse teleconverter.

An optic free adapter such as an EOS to NEX, F to EOS, or M to X-mount all require the adapter to be of a precise depth to bridge the gap between the two flange depths, placing the lens at the correct distance to maintain the usual focus range.

However, optics placed between the body and lens such as teleconverters and the Canon FD to EOS adapter overcome this limitation. As long as its got the correct distance from the lens to the telecompressor, and the rear of the telecompressor is able to project it's image correctly from its rear element to the sensor, all is good.

There is a diagram near the top of this page about the telecompressor in the Nikon E2, and it indicates the lens focuses its image to a point far in front of the sensor - much like the way a teleconverter works.

As far as I can see, an EF to EF-S telecompressor is theoretically possible.
 
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Mar 25, 2011
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NormanBates said:
Sorry, this will only work on short focal flange mounts, which basically means mirrorless. So, there might be an EF-to-EFM version, but never an EFS-to-EF version.

One more reason to support my belief that mirrorless is the future.
This particular adapter is designed for the flange mount on a micro 4/3, but it could be designed for any flange length. However, it requires a larger format lens in order to eliminate viginetting, so to use it on FF, you would need at least a medium format lens. Since MF lenses have a long flange length, the same principle would work.
Don't expect to see one for FF, probably not for APS-C either, there are just not enough people with MF lenses laying around to make it economically practical.
 
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P

pharp

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KyleSTL said:
pharp said:
it'll be interesting to see who produces the first FF mirrorless with interchangeable lenses

Leica M9 - 2009
Leica M9P - 2011
Lecia M-Monochrom, M Typ 240, M Typ 220 - 2012

FF mirrorless with autofocus or affordable FF mirrorless is a different story, waiting to be written.

Thats what I meant to say :eek: Especially one with an eye level EVF ala OM-D!!
 
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