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Archive 2013 · Metabones Speed Booster
  
 
cputeq
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p.6 #1 · Metabones Speed Booster


Makten wrote:
You're having it the wrong way. It will be transformed into a shorter focal lenght. And by the way, there is no such thing as "effective" focal length.




I know it's a shorter focal length, though I should have typed "effective 120mm FOV."

However my math is correct. One applies the Metabones multiplier of 0.7x for APS-C, then the sensor crop factor back, essentially negating the 1.5x. So for APS-C there is no internal math to do for a lens.

So, Metabones+NEX = FF FOV, essentially (small difference)

Same thing with m43 (which is what my post was about), but now we work with 2x on the sensor crop. This works to an effective FOV of 1.4x for any FF lens mounted to m43. 85 * 1.4 = ~ 120mm FOV.

Or, (0.7 - Metabones) * (focal length) * (2x sensor crop) = ~120mm FOV.


I am unsure if this also causes the m43 to magically gain 2 stops of light, though.



Jan 15, 2013 at 12:49 PM
alundeb
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p.6 #2 · Metabones Speed Booster


cputeq wrote:
I would love for them to create simplified adapters for Minolta MD to m43, etc. An image-stabilized Minolta 85 1.2 at effective 120mm f/0.9? Yes please.

Makten wrote:
You're having it the wrong way. It will be transformed into a shorter focal lenght. And by the way, there is no such thing as "effective" focal length.

cputeq wrote:
I know it's a shorter focal length, though I should have typed "effective 120mm FOV."

However my math is correct. One applies the Metabones multiplier of 0.7x for APS-C, then the sensor crop factor back, essentially negating the 1.5x. So for APS-C there is no internal math to do for a lens.

So, Metabones+NEX = FF FOV, essentially (small difference)

Same thing with m43 (which is what my post was about), but now we work with 2x on the sensor crop. This works to an effective FOV of 1.4x for any FF lens mounted to m43. 85 * 1.4 = ~ 120mm FOV.

Or,
...Show more

If you mount the 85mm f/1.2 lens on a NEX with a simple adapter, you get essentially the same result, in every aspect, as going via the Speedbooster and a smaller sensor. Just sayin'.



Jan 15, 2013 at 01:08 PM
nalahm
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p.6 #3 · Metabones Speed Booster


Who's gonna be a pioneer of medium format lens > Dslr adapter with reducer glass ?

I mean a whole look of medium format frame shrunk on to dslr sensor , not only center part , shall we?



Jan 15, 2013 at 01:16 PM
Makten
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p.6 #4 · Metabones Speed Booster


cputeq wrote:
I know it's a shorter focal length, though I should have typed "effective 120mm FOV."

However my math is correct. One applies the Metabones multiplier of 0.7x for APS-C, then the sensor crop factor back, essentially negating the 1.5x. So for APS-C there is no internal math to do for a lens.

So, Metabones+NEX = FF FOV, essentially (small difference)

Same thing with m43 (which is what my post was about), but now we work with 2x on the sensor crop. This works to an effective FOV of 1.4x for any FF lens mounted to m43. 85 * 1.4 = ~ 120mm FOV.

Or,
...Show more

This is the same confusion as usual. If you "translate" the FOV to FF, you also have to translate the aperture. So, if the 85/1.2 gives a FOV corresponding to 120 mm when you mount it on MFT with adapter, it will also get a DOF and collect the same amount of light as an f/1.7 lens on FF.

So no, there is no magic.



Jan 15, 2013 at 01:17 PM
Mescalamba
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p.6 #5 · Metabones Speed Booster


nalahm wrote:
Who's gonna be a pioneer of medium format lens > Dslr adapter with reducer glass ?

I mean a whole look of medium format frame shrunk on to dslr sensor , not only center part , shall we?


Ive sent this suggestion to Metabones about 10 minutes after I saw their Speedbooster. They said they will look into it. For 645 lens they could probably just increase size of whole thing as x0.71 would work for 645 to FF perfectly. Which would make from lets say Mamiya 80mm f1.9 - 55mm f1.3 (or 1.2). And that would be quite interesting..

Tho it depends if they will really make it or not..



Jan 15, 2013 at 01:32 PM
cputeq
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p.6 #6 · Metabones Speed Booster


alundeb wrote:
If you mount the 85mm f/1.2 lens on a NEX with a simple adapter, you get essentially the same result, in every aspect, as going via the Speedbooster and a smaller sensor. Just sayin'.



Yes of course I know this. The point being, now the 85 1.2 is "more usable" on the m43 as opposed to being a strange 170mm FOV, so there is no sour grapes in the m43 camp as far as I'm concerned. The IBIS on the OM-D makes legacy glass amazing to use and now m43 guys are "on par" with APS-C usage, which before was a sticking point for some people because 2x crop makes lots of legacy glass harder to use.

Also, it's not like NEX-5N is expensive - if someone really has "sour grapes" over the m43 and 1.4x, one can certainly move over to NEX mount.

If you "translate" the FOV to FF, you also have to translate the aperture. So, if the 85/1.2 gives a FOV corresponding to 120 mm when you mount it on MFT with adapter, it will also get a DOF and collect the same amount of light as an f/1.7 lens on FF.

Yes correct, I failed at my aperture/DOF math in my initial post by calling it a ~120mm f/0.9, instead of f/1.7



Jan 15, 2013 at 02:00 PM
kj_vogelius
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p.6 #7 · Metabones Speed Booster


Found another article with a few samples:

D-SLR News Shooter

The samples are very compressed & it's a bit hard to get an overview the way they're embedded, but to me they too look promising.



Jan 15, 2013 at 06:52 PM
sebboh
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p.6 #8 · Metabones Speed Booster


_julian_ wrote:
Here's a comparison between the NEX 7 + adapter and 5diii using the same Sigma 24/1.8.

http://www.eoshd.com/content/9474/prototype-metabones-speed-booster-equipped-nex-7-vs-full-frame-5d-mark-iii

Unfortunately the larger image comparison jpeg downloads don't work


thanks for the link. it looks promising, but even at web sizes the reall FF camera obviously produces better detail and less purple fringing.



Jan 15, 2013 at 07:40 PM
buggz2k
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p.6 #9 · Metabones Speed Booster


While I'm not certain how this 'magic' works, have to read more,
I'd love to try my 50/1.0L on an XPro1!



Jan 15, 2013 at 09:51 PM
Tarocco
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p.6 #10 · Metabones Speed Booster


Here's a better look at the DSLR News Shooter samples:

http://extrazoom.com/image-2704.html

http://extrazoom.com/image-2705.html

http://extrazoom.com/image-2707.html

http://extrazoom.com/image-2712.html

http://extrazoom.com/image-2710.html

The first one looks very sharp in the center when zoomed in.






Jan 15, 2013 at 10:09 PM
 

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Mescalamba
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p.6 #11 · Metabones Speed Booster


Seems to add some PF.


Jan 15, 2013 at 11:05 PM
mortyb
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p.6 #12 · Metabones Speed Booster


I'd be interested to see if Zeiss lenses used with this adapter retains all the magic or if microcontrast etc. takes a significant hit. I have a feeling it's too good to be true. Hope I'm wrong.


Jan 15, 2013 at 11:17 PM
twelveish
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p.6 #13 · Metabones Speed Booster


Yes, will be most interesting to see the examples from various mounts coming in. If I'm getting on of these it will almost certainly be the C/Y for NEX. Currently have the Distagon 35/2.8, Planar 50/1.7 and Sonnar 135/2.8 in said mount. If the Speedboster works out really well I fear for my poor bank account.


Jan 15, 2013 at 11:28 PM
HelenB
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p.6 #14 · Metabones Speed Booster


buggz2k wrote:
While I'm not certain how this 'magic' works, have to read more,
I'd love to try my 50/1.0L on an XPro1!


Sadly there is an f/1.2 limit for the input aperture and f/0.9 for the output, at least for the NEX and mFT versions. The adapter isn't big enough to allow the necessary exit pupil diameter for lower f-numbers.



Jan 15, 2013 at 11:29 PM
HelenB
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p.6 #15 · Metabones Speed Booster


Makten wrote:
This is the same confusion as usual. If you "translate" the FOV to FF, you also have to translate the aperture. So, if the 85/1.2 gives a FOV corresponding to 120 mm when you mount it on MFT with adapter, it will also get a DOF and collect the same amount of light as an f/1.7 lens on FF.

So no, there is no magic.


Don't you have to be careful about what you mean by 'same amount of light'? The 85 mm f/1.2 becomes a true f/0.9 lens, and in terms of image brightness that is what it stays at regardless of format (ignoring transmission losses of course). The f/1.7 approximation only applies to DoF comparisons.



Jan 15, 2013 at 11:36 PM
mortyb
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p.6 #16 · Metabones Speed Booster


I'll be using it with the C/Y 35/1.4, 50/1.7 and 100/2. I just have a hard time believing it will retain enough of the Zeiss look. I really, really hope it does though.


Jan 15, 2013 at 11:52 PM
Makten
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p.6 #17 · Metabones Speed Booster


HelenB wrote:
Don't you have to be careful about what you mean by 'same amount of light'? The 85 mm f/1.2 becomes a true f/0.9 lens, and in terms of image brightness that is what it stays at regardless of format (ignoring transmission losses of course). The f/1.7 approximation only applies to DoF comparisons.


F/0.9 on APS-C equals f/1.2 on FF, both for DOF and collecting of light per time. I really don't get why this is so hard to understand and thus comes up every time different formats are compared and discussed.

A sensor with the area X will have to get twice the exposure compared to a sensor with the area 2X, to get the same noise per image height. Forget about ISO. What you want is photons.



Jan 16, 2013 at 12:07 AM
Michael Gordon
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p.6 #18 · Metabones Speed Booster


I wonder how OM lenses will fair with a chipped OM-EF adapter. Perhaps Exif data will be
transmitted?



Jan 16, 2013 at 12:14 AM
cputeq
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p.6 #19 · Metabones Speed Booster


Makten wrote:
F/0.9 on APS-C equals f/1.2 on FF, both for DOF and collecting of light per time. I really don't get why this is so hard to understand and thus comes up every time different formats are compared and discussed.

A sensor with the area X will have to get twice the exposure compared to a sensor with the area 2X, to get the same noise per image height. Forget about ISO. What you want is photons.


It's not hard to understand at all. The reason this stupid argument comes up is because people are arguing two different things when they bring this up, and unfortunately one of those things is completely irrelevant to the discussion when practically applied to photography, however technically correct it may be (with certain assumptions). Because of the difference in "vocabulary", this argument perpetuates.


The first "thing" one could be arguing is referring to resultant shutter speeds from various apertures. This is a relevant argument. Shutter speed is a known parameter as displayed by the camera and can be altered by the photographer through a variety of means, one of which is to alter the aperture of a lens.

The second "thing" is this completely irrelevant "photos per unit time" and its association with differing sensor sizes and performances. I say irrelevant because there are a hell of a lot assumptions made when talking this point (and the assumed conclusion, then, that the FF sensor is always better)

1) The sensor ISO steps are calibrated exactly the same between the sensors,
2) The sensors are equally efficient at gathering light in the first place
3) The sensors have exact the same noise read characteristics from underlying electronics, etc.
4) The camera metering performance and algorithms are exactly the same.


Unfortunately, there is no such thing as a "photos per unit time" parameter to alter in the camera. Furthermore, because of differences in items 1-4 above, to equate FF camera as "better" in light vs a crop is folly.

While yes, on a purely technical level the FF sensor area "catches" more photos in, say 1/60s than a crop camera, that doesn't really mean much. The items 1-4 can be varying wildly, such that the crop sensor is so much advanced over the FF that given the same shutter speeds and ISOs, it's still better than the FF.

An example of this would be something like the Canon 5D vs an Olympus OM-D or NEX camera, Fuji, etc.

All cameras are excellent, but on a purely noise performance basis, the crop cameras above are close (if not tied, or ahead) of the 5D.

Yet, per the second irrelevant item of argument (photons per unit time), this shouldn't be possible...because the 5D's sensor receives much more photos per unit time!

This argument is ridiculous - there is no setting at all which a photographer can change in the camera that would directly modify this parameter - it is a useless, "false argument" parameter.

Instead, we can look at resultant noise (as modified through the changing of ISO), we can look at aperture (or effective aperture), we can look at depth of field, and we can look at shutter speeds, when talking various apertures.


In effect, I just metered a lamp on my desk using a Canon S95 and an OM-D at the same apertures and ISOs. These photos, framed exactly, gave the same shutter speeds.

I know at f/5.6, metered this way at this ISO, I get this shutter speed. I don't get, in an operationally relevant way, "8x photons" from the OMD (or whatever the number is).

I can say, knowing the noise characteristics of my S95 vs my OM-D, that pushing my ISOs is much easier for acceptable levels of noise on the OM-D vs the S95 -- because of performance characteristics 1-4.

That's not to say in the future, the Canon S950 won't actually be better at resultant noise than my ancient Olympus OM-D, regardless of the photos utilized. That is why I believe people have an argument about this - photos/time is not really a field-relevant parameter.




Jan 16, 2013 at 12:47 AM
douglasf13
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p.6 #20 · Metabones Speed Booster


I think it's pretty safe to assume that one is talking about like sensor technology when considering lens equivalency.


Jan 16, 2013 at 01:40 AM
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