Sage
Well-known member
Yes, the adapter makes the 24mm a 17mm, by shrinking the image circle.
Metabones Speed Booster
- Thread starter nyvz
- Start date
Yes, the adapter makes the 24mm a 17mm, by shrinking the image circle.
Okay, now you've confused the heck out of me. If you take the image circle that is coming out of the back of a 50mm lens, pass it through a "reduction" lens and merely make the circle smaller so that it fits inside the area of a Super35 imaging chip, doesn't it still possess all the same visual characteristics of the 50mm lens albeit in a smaller circle?.....along with the intensity "gain" that comes along with packing all that light into a tighter circle?
This is exactly what is happening.
kainekainekaine
Well-known member
Maybe not quite 50mm technically, its something like 1.01 crop but its close enough. Put a 50 on a full frame side by side with a 5n with this on it and its gonna be the slightest of difference aesthetically from looking at eoshd's examples. In the end all that matters is that the full frame look is there for $400, never mind the nice speed boost.
nyvz
Veteran
No, you will confuse people, that is not right. The lens with adapter attached has a different focal length.
Yes if you put a 17mm lens it would look the same because a 24mm with the speed booster IS a 17mm lens.
alaskacameradude
Veteran
Actually, it doesn't 'make the 24mm a 17mm'. There are two things here. First is the Full Frame angle of view. Second
is the Super 35 angle of view. The angle of view of a 24mm on a Full Frame is roughly equal to the angle of view of
a 17mm on a Super 35. So in other words, a 24mm looks much wider on Full Frame than it does on Super 35 for the
same lens. But NOW, with the speed booster.....a 24mm on the Super 35 looks much the same as it would if it
were actually on a Full Frame camera! So it looks like what a 17mm normally would on a Super 35. The lens is still
24mm, it's just what 24mm looks like on Full Frame now, even though it's on a Super 35 camera.
Sage
Well-known member
It does. Full Stop.
Bingo. Its a new, different lens by adding 4 elements to the back.
Sadly I'll have to cross post this info because it's pertinent, but we have like eight different topics on the forums xD
Coming from the Blackmagic Design forums, here is a response form Conurus about the adapter and how it works:
And then--
Maybe that helps some!
Coming from the Blackmagic Design forums, here is a response form Conurus about the adapter and how it works:
rick.lang said:
And then--
conurus said:
Maybe that helps some!
kainekainekaine
Well-known member
Would like to know if its possible to get M43 version and use NEX/M43 adapter, so it can be used on both systems, it would probably vignette but you never know. Also sounds like both versions are optically different, so that might rule it out. Also if there's any problem with getting say EOS version and adding an extra adapter for Pentax/Nikon etc. They confirmed to me via email that ALPA mount is the smallest reg distance there going with for both mounts, that reg distance seems like the cut off point for this idea to work well. So anything with a reg distance further away than ALPA should be possible to have an adapter made for eventually. If mount conversion adapters can be stacked on top of the speed booster a lot of mounts become available whether Metabones make them or not.
http://www.graphics.cornell.edu/~westin/misc/mounts-by-register.html
http://www.graphics.cornell.edu/~westin/misc/mounts-by-register.html
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Yes, I'm curious as to why no passive EF earlier on for MFT... that's the most plausible one of all of the mounts, you can get M42 and Nikon onto that at least.
paulcurtis
Veteran
There's an interesting post from Brian Caldwell (the optical designer) on the CML mailing list countering a few claims, however i'm not so convinced, but he is the designer 
He's saying that it DOES change the focal length of the lens. But to my mind a 50mm on APS-C is cropped and all the adapter is doing is giving you what 50mm *should* look like in the first place. Brian talks about differences with the entrance/exit pupil and the optics and says that the f stop is also changed. Again i'd assumed that the T stop was different but the F stop was the same (i.e. more light getting through, but DOF characteristics would be the same albeit shrunk down).
Either way i'm badgering metabones for the CY -> E mount version, so i can have a go myself.
When someone gets one here it will be interesting to compare a shot with the adapter and without and see whether the one without the adapter is exactly the same as the central portion with the adapter (confirming f stop vs t stop)
cheers
Paul
He's saying that it DOES change the focal length of the lens. But to my mind a 50mm on APS-C is cropped and all the adapter is doing is giving you what 50mm *should* look like in the first place. Brian talks about differences with the entrance/exit pupil and the optics and says that the f stop is also changed. Again i'd assumed that the T stop was different but the F stop was the same (i.e. more light getting through, but DOF characteristics would be the same albeit shrunk down).
Either way i'm badgering metabones for the CY -> E mount version, so i can have a go myself.
When someone gets one here it will be interesting to compare a shot with the adapter and without and see whether the one without the adapter is exactly the same as the central portion with the adapter (confirming f stop vs t stop)
cheers
Paul
"But to my mind a 50mm on APS-C is cropped and all the adapter is doing is giving you what 50mm *should* look like in the first place". Yes, yes, yes! You are right! A lot of people are confused and mislead lots of information on the web and its really annoying. Simply because they either don't know how it works or heard from someone who heard it from someone.There's an interesting post from Brian Caldwell (the optical designer) on the CML mailing list countering a few claims, however i'm not so convinced, but he is the designer
He's saying that it DOES change the focal length of the lens. But to my mind a 50mm on APS-C is cropped and all the adapter is doing is giving you what 50mm *should* look like in the first place. Brian talks about differences with the entrance/exit pupil and the optics and says that the f stop is also changed. Again i'd assumed that the T stop was different but the F stop was the same (i.e. more light getting through, but DOF characteristics would be the same albeit shrunk down).
Either way i'm badgering metabones for the CY -> E mount version, so i can have a go myself.
When someone gets one here it will be interesting to compare a shot with the adapter and without and see whether the one without the adapter is exactly the same as the central portion with the adapter (confirming f stop vs t stop)
cheers
Paul
paulcurtis
Veteran
Ah but my point is that Brian Caldwell himself implied that's not the case. Now Brian is someone that obviously knows what he is doing (apparently also designed or helped design the new prime lenses for Panavisions new 70mm digital system. The booster is a 4 element reducer but perhaps it's not as simple as just shrinking the full frame image circle down to APS-C...
cheers
Pual
Haha now I'm totally confused! So what he is saying is that 50mm which is 75mm on FS700, won't look like a real 50mm on the full frame? But even wider?
nyvz
Veteran
Yes you are confusing yourself with crop factor speak which is a common confusion. A 50mm is not a 75mm on the FS700, a 50mm is a 50mm on an FS700. It would be accurate to say a 50mm on a FS700 has a similar FOV to the FOV a 75mm would render on a FF35 camera. But without any additional optics, a 50mm is a 50mm no matter what sensor or film put behind it. You will always be confused if you think primarily in terms of crop factors and "equivalent focal lengths" since "equivalent focal lengths" are not real focal lengths and you are talking like you think equivalents are actual focal lengths. It would be better to simply understand the correlation between actual focal length and actual FOV for whatever format you are using. FF35 FOV comparisons are really only useful if you have only ever used FF35 before and are not familiar with the perspectives and effects you get from focal lengths on any other format. If you don't use FF35 that much, just get used to what the focal lengths look like on the format you are using.
For what it's worth, I sent Metabones an email requesting earlier release of a dumb EF-MFT speedbooster based on its flexibility to other mounts.
jpardon
Active member
Practically speaking, switching between using the Metabones Speed Booster and the original Metabones Smart Adapter would be a similar workflow to using a teleconverter, no? I know it wouldn't be *technically* the same because the FOV would be different....but *practically* speaking would it not be similar?
With the Speed Booster, my Canon 70-200 f2.8L II effectively becomes a 70-200 f2.0 with a FF FOV. With the original Metabones Smart Adapter my Canon 70-200 f2.8L II effectively becomes a 105-300 f2.8 with a S35 FOV.
Right?
With the Speed Booster, my Canon 70-200 f2.8L II effectively becomes a 70-200 f2.0 with a FF FOV. With the original Metabones Smart Adapter my Canon 70-200 f2.8L II effectively becomes a 105-300 f2.8 with a S35 FOV.
Right?