New, faster Metabones Speedboosters for BMCC & BMPCC

Samuel H said:
You are doing some double accounting there. Noise depends on the sensor, and it hasn't changed; signal is doubled with a 0.71x speedbooster. I will give you that full well is a sensor thing and it is unchanged, so DR is not altered.



I will add a small bit to my previous statement (and also correct it slightly, it is 0.58x, not 0.54x):

The math for the speedboosters is very simple: multiply the original crop factor (2.9x) for the speedbooster factor (0.58x) and you get the new crop factor (1.7x) --> Regarding FoV and DoF, the pocket becomes APS-C, as simple as that. The only complication is that ISO gets multiplied by 3 (divided by 0.58^2) (so, ISO 100 is now ISO 300, but with the same noise as you previously had at ISO 100).



I own a regular speedbooster which I use on my NEX, and this definitely the easiest way to think about it: the camera is now FF, ISO is twice as what the camera thinks (so it is 400 if the camera says 200), and ISO 3200 (1600 if you ask the camera) is now useful
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Right-o. Noise isnt' magnified, all still the same. Also Rick on the other forum(s) discovered some misprinted math, the 2.5K specific booster is actually truly S35, so slightly larger than what Metabones said.

Might get to test these out (both) soon here and with any luck, find out if the Mosaic 2.5K OLPF works with it as well. I'm more interested in the 2.5K booster + Mosaic combo, but a faux APS-C ProRes+RAW 13 stop Point-and-shoot-Frankencam sounds... fun.
 
I don't understand how a speed booster is going to give you thinner DOF for a given FOV compared to a shorter focal length lens of equivalent aperture. Optically an MFT speed booster is going to reduce the focal length of an FF35 lens by roughly half. A 50mm lens becomes a 25mm lens.
 
Samuel H said:
You are doing some double accounting there. Noise depends on the sensor, and it hasn't changed; signal is doubled with a 0.71x speedbooster. I will give you that full well is a sensor thing and it is unchanged, so DR is not altered.



I will add a small bit to my previous statement (and also correct it slightly, it is 0.58x, not 0.54x):

The math for the speedboosters is very simple: multiply the original crop factor (2.9x) for the speedbooster factor (0.58x) and you get the new crop factor (1.7x) --> Regarding FoV and DoF, the pocket becomes APS-C, as simple as that. The only complication is that ISO gets multiplied by 3 (divided by 0.58^2) (so, ISO 100 is now ISO 300, but with the same noise as you previously had at ISO 100).



I own a regular speedbooster which I use on my NEX, and this definitely the easiest way to think about it: the camera is now FF, ISO is twice as what the camera thinks (so it is 400 if the camera says 200), and ISO 3200 (1600 if you ask the camera) is now useful
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Not in a practical sense. It is changed. If you shoot a 2K crop of a 4K sensor the noise will be much more visible, because you are zoomed into it, so you will loose a stop or so from the noise floor. The noise floor is not an absolute objective figure, it depends on many factors, and this is one of them.

If you put 8 Full Frame 5K sensors in some array (theoretically with some super-lens of the future) that are natively 320 ISO, you could easily shoot at 3600ISO and not really see objectionable noise, because the noise would be so tiny, and such a huge surface would be used for gathering light. When you crop a sensor, you are effectively removing part of the data (sensor area) that would be used for defining correctly what the lens saw, while leaving the same amount of competing wrong data (sensor noise per surface area).

So to think that somehow you are getting something better now, out of your pocket BM, than what you would get out of a Red Camera or F3 or any other truly s35 camera is just fantasy and a misunderstanding of how light works. It's not. the DOF is not thinner than it would be on those cameras, the quality not magically better, it does not work that way. Everything is still less good, in all ways. Good enough? Depends on your standards. For me, no. No way. Anything that has son back focus adjustment is a joke, for one thing, and anything with no OLPF is another level of joke.

I would say a great Heli-cam, helmet-cam, etc just got truly amazing, for those specific applications.
 
Razz16mm said:
I don't understand how a speed booster is going to give you thinner DOF for a given FOV compared to a shorter focal length lens of equivalent aperture. Optically an MFT speed booster is going to reduce the focal length of an FF35 lens by roughly half. A 50mm lens becomes a 25mm lens.
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I don't think it will. To simplify the math, if the Speed Booster effectively widened the aperture two stops and cut the focal length in half -- say a 50-mm f/2.8 to a 25-mm f/1.4 -- I think that a true 25-mm f/1.4 lens would yield roughly the same results.
 
Robert Ruffo said:
Not in a practical sense. It is changed. If you shoot a 2K crop of a 4K sensor the noise will be much more visible, because you are zoomed into it, so you will loose a stop or so from the noise floor. The noise floor is not an absolute objective figure, it depends on many factors, and this is one of them.

If you put 8 Full Frame 5K sensors in some array (theoretically with some super-lens of the future) that are natively 320 ISO, you could easily shoot at 3600ISO and not really see objectionable noise, because the noise would be so tiny, and such a huge surface would be used for gathering light. When you crop a sensor, you are effectively removing part of the data (sensor area) that would be used for defining correctly what the lens saw, while leaving the same amount of competing wrong data (sensor noise per surface area).

So to think that somehow you are getting something better now, out of your pocket BM, than what you would get out of a Red Camera or F3 or any other truly s35 camera is just fantasy and a misunderstanding of how light works. It's not. the DOF is not thinner than it would be on those cameras, the quality not magically better, it does not work that way. Everything is still less good, in all ways. Good enough? Depends on your standards. For me, no. No way. Anything that has son back focus adjustment is a joke, for one thing, and anything with no OLPF is another level of joke.

I would say a great Heli-cam, helmet-cam, etc just got truly amazing, for those specific applications.
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A Red or an F3? A 2K crop of a 4K sensor?
That's a completely different conversation.

What I'm talking is: pocket with standard adapter vs pocket with speedbooster. And in that comparison, yes, the speedbooster is giving you a great deal of awesomeness.
I have one (for my NEX) and I know what it's giving me. If you can't conceive how this can happen, well, think of it as magic, it's a lot easier that way :)



For those still struggling with the math and the equivalences:
There are two ways to think of a speedbooster: that it changes your focal length and aperture, or that it changes your sensor size. The first one is more correct, but it requires lots of calculations. The second one is a lot simpler, since you only have to run your calculation once. What you cannot do is run both calculations at the same time, then you'll just be wrong and confused.

So, easiest way to think about it:
My NEX with SpeedBooster is a FF camera, but it says ISO 100 when it's actually shooting ISO 200.
With that in my head, I know how a 35mm f/2.8 will look, how a 50mm f/1.4 will look, or how a 300mm f/4 will look. Just like it does on a FF camera.
And yes, I have checked this empirically (with a borrowed 5D2), because my mind also plays tricks on me sometimes so a reality check is always a good idea.

For the BMC and the pocket, you just have to calculate what's the new equivalent crop factor of the camera, and it will all make a lot more sense in your head.
 
For S35/APS-C to S16 conversion a speed booster essentially reduces focal length by about half and increases aperture by 2 stops. No magic here. To get the same FOV of a larger format on a smaller one you have to use a shorter focal length lens. To get the same relative DOF with a shorter focal length you have to have a larger relative aperture. Speed booster just trades focal length for aperture. A practical solution if one needs it.
 
If you know how 2x extender works on broadcast 2/3 lenses, than you know how speedbooster works.. Extender gives you narrower picture, two stops les light, less sharpness and same DOF..

well, speedbooster is an opposite..

Wider FOW, 1.5 stops of light more, sharper and same DOF..

50mm f1.4 lens have same DOF and same FOV on s35 cam or BMCC with speedbooster..
 
Robert Ruffo said:
Your seeming lack of desire to deeply understand technical details and learn new things is why you are not a top DP. Talk to David Mullen, or Deakins, or any of the top guys, they know all this stuff, like the backs of their hands.
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I have no desire to be a top DP. I'm an engineer for my day job so attention to technical details are not a problem. In the case of this camera with the metabones...i just don't care. I like what it puts out when they are married together.
 
In my opinion, the technical can actually slow you down, creatively speaking. Makes the emotional mind thick as molasses. The old hands have a hard time living in the moment and doing something new because they have gotten in their groove.
 
Ian-T said:
I have no desire to be a top DP. I'm an engineer for my day job so attention to technical details are not a problem. In the case of this camera with the metabones...i just don't care. I like what it puts out when they are married together.
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This site used to be for people who actually work in production. Perhaps you should move over to another site more oriented to consumers, or at least not sneer at those among us pursuing professional excellence as best we can - "I just don't care" has no place, in my opinion, on DVXuser.
 
Sage said:
In my opinion, the technical can actually slow you down, creatively speaking. Makes the emotional mind thick as molasses. The old hands have a hard time living in the moment and doing something new because they have gotten in their groove.
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Cinematography and filmmaking are highly technical, AND artistic, whether you like it or not. Either you master the technical aspects, or they master you.

Perhaps you should pursue writing instead.
 
Adam J McKay said:
I am still unsure how DOF is changed. You are essentially just putting wider albeit faster, lenses on a super 16 camera. I can't see how that will be the same as an equivalent focal length and speed on super 35mm.
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The Depth of field changes only in practice. Say you have a 50mm lens at F4 and you are 20 feet away from the subject using an fs100. Then you put on a speedbooster. Your lens is now .71 wider. As a result the subject is smaller. In order to keep the subject the same size in the frame you have to move 40% closer (or about 8 feet). As a result you are know focusing at 12 feet instead of 20. You are using the same lens so the DOF shrinks significantly

Please keep in mind that I am not 100% positive that my math is correct but the basic concept is. With a wider field of view you must move closer to the subject to maintain the same perspective which in turn means lens depth of field assuming the aperture does not change
 
Robert Ruffo said:
Cinematography and filmmaking are highly technical, AND artistic, whether you like it or not. Either you master the technical aspects, or they master you.

Perhaps you should pursue writing instead.
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There are plenty of great directors that are not very good camera operators or DPs, and vice a versa. Good directors that also camera operate are actually quite rare.

I am of course referring to directors of movies, narratives, not corporate video, weddings, etc.
 
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