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Metabones Speed Booster review


Andrew Reid
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@BurnetRhoades

 

I am 100% correct. It's not a sharp. Period. As for those films you mentioned shot on 16mm film with very nice budgets and a full 100 man + crew - yes, there are exceptions to every rule.

 

LOL, you obviously haven't read the actual tests being done (click the link above).  Resolution with the same lens on the adapted NEX is measurably higher than a 5DmkII in the center and averaged over the entire lens, only dipping slightly in the corners.  Right there, sharper than still the best value in full-frame motion picture shooting, so good still that Canon had to take it off the market to make their newer, more expensive cameras more attractive to Canon buyers.

 

Also, you haven't read how Slumdog Millionaire was shot with those cameras either. 

 

Please, continue to punt though.

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Strictly speaking, you are getting a wider and faster lens, that produces an image on a smaller sensor that is equivalent to the image produced by that lens on a larger sensor. If the metabones adapter were optically perfect, the two images would be mathematically indistinguishable. Creating a lens that is both wider and faster is a big deal. Video readout from the smaller sensors is currently more complete (higher resolution, less aliasing) than the video readout from larger sensors, which means the ultimate image coming from the smaller speedboosted sensor will be superior to the ultimate image coming from the larger sensor.

 

I can't say for sure, but perhaps it would be better to think of, and refer to, this adapter's "speed boosting" as effectively increasing the T-Stop of the lens, rather than F-Stop, which might be partly responsible for some of the confusion surrounding this thing (that doesn't seem to be going away no matter how much new information comes out daily).  

 

Perhaps it's naive but the fact of this device delivering a brighter, concentrated image shouldn't seem that difficult to wrap your mind around if you've ever killed ants or burned wood with the power of sunlight that's miraculously not even close to doing the same thing to your skin at that very moment.  Normal sunlight can be concentrated through summed reflection off of metal, without passing through a glass lens, to cut through steel.   I think it's the skeptics that need some physics lessons here, in some cases.

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I can't say for sure, but perhaps it would be better to think of, and refer to, this adapter's "speed boosting" as effectively increasing the T-Stop of the lens, rather than F-Stop, which might be partly responsible for some of the confusion surrounding this thing (that doesn't seem to be going away no matter how much new information comes out daily). 

 

If it increased only the T-stop rather than also the f/stop, then how does the depth of field remain comparable? To maintain the field of view, the adapter must effectively reduce the focal length, but to maintain the DOF at the reduced focal length, the effective f/stop must also be reduced.

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Sorry for the dumb question, but is this good news "only" for Canon EF lenses owners?

What other lenses with an EF adapter would work with the SpeedBooster (even in passive mode)?

 

Thanks,

 

Anything that adapts to EF mount works. I've tried M42, Contax Zeiss (CY), Nikon, OM, etc.

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thank you for this very informative test andrew.

 

but don´t be fooled. you are not getting a ff camera, you are getting a wider lens, that´s all.

 

a crop image with the same dof as a full frame or medium format will always look different. that´s why people shoot hasselblad. because the physical size of the sensor defines how space is rendered. it has little to do with the lens or that actual focal length. a large format shot at f64 with everything in focus from 1 meter to infinity will look very different from the same shot on a smaller format with the same dof. i can´t tell you why, but my eyes tell me. the larger the format the more "relaxed" the image looks i think.

 

also a lens is a complex system where each component is produced specifically for it. the same glass for every lens out there doesn´t sound like a great idea. that´s probably why nobody really did it yet. andrews great test shows it. works for some, for some it doesn´t.

 

i´d rather get an actual 35mm on s35 if i want the angle of view of a ff 50mm. especially if i have to stop down anyway for the same corner sharpness.

 

the added stop in sensitivity will come in handy no doubt, also for wide angle on the bmc this might be a blessing until someone builds fine lenses for that format (if it will survive the next 2 years.) but it is in no way a game changer.

 

That doesn't sound right. Depth of field looks the same as a full frame sensor to me.

 

I could put some unlabelled shots up from the 5D Mark III with a 50mm on full frame, and the same 50mm on APS-C with Speed Booster. You wouldn't be able to tell them apart. If you think you can, you're welcome to try and I will take some shots :)

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That doesn't sound right. Depth of field looks the same as a full frame sensor to me.

 

I could put some unlabelled shots up from the 5D Mark III with a 50mm on full frame, and the same 50mm on APS-C with Speed Booster. You wouldn't be able to tell them apart. If you think you can, you're welcome to try and I will take some shots :)

 

Perhaps best to crop the 5D3 to match the other camera (1.09 crop), else it's easy to spot the difference.

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Wow this puts a spanner in the works for camera manufacturers already coming off badly and a recent comeback from Sony with the f5 and 55. Now this..

 

This is an amazing answer for the BMC in gaining 35mm sensor size abilty.

 

Obviously your putting more glass in front of your sensor and has to have some effect. But probably not so you'd notice. Okay its not ground breaking but it does level the playing field quite nicely and in a magical way.

 

Now who wants a sony f5 over a BMC?

 

Really does mean the manufacturers can no longer hold back the flood gates. The camera is no longer the weak link. Just need to find a DP who has years of experience and can use it to it's full potential and a full cast and crew with lights sound oh and a few hollywood actors and a decent script. Oh dear better start making some test films for vimeo.

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First post...and my head hurts. All these numbers and equations do my head in. I just want to shoot stuff and have the best image I can get. So what I want to know, simply put, is will the M4/3 version (when it comes out) help me do that?

 

I'm in the process right now of getting money together to finally get in the game so to speak. Before this, the choice was between a GH3 and a cheaper GH2 that will allow me to pick up more lenses and equipment within my modest budget. But with the Speed Booster, I now have the dilemma what those lenses should be. 

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If it increased only the T-stop rather than also the f/stop, then how does the depth of field remain comparable? To maintain the field of view, the adapter must effectively reduce the focal length, but to maintain the DOF at the reduced focal length, the effective f/stop must also be reduced.

 

The DOF is determined by the f/stop.  These characteristics are set prior to passing through the Metabones adapter.  The effective reduction in focal length is an optical reduction of an image with its characteristics already set.  This is pretty clear from their documentation and the observed and measured results of the device.  Then, either through design or as a byproduct of this optical reduction, so that the larger image can be seen by the smaller sensor, you get an optical "gain up".

 

Though the mechanics are different the net effect of this device is similar to what you get with a Redrock M2 or one of the other 35mm lens adapters for video cameras.  There's no spinning "ground glass" here and you gain a stop rather than lose one.

 

The T-stop of a lens measures the light performance after the lens, what's there for the exposure but DOF and F-stop must be managed by the operator independent of this.  I think you have your mechanics backwards and imagining mechanical functions that aren't there.  It's simplicity seems to be causing all kinds of confusion.  

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RossF, your reasoning is correct. The only tricky part is that if you use the speedbooster on an aps-c sensor, then the aperture setting shown on a full frame lens will be the full-frame equivalent aperture setting, which is one stop more than how the aperture setting appears to the aps-c sensor.  So if you set a full frame lens to f1.4 without the speedbooster, it looks like f1.4 to the aps-c sensor, and is equivalent to setting the same lens to f2.0 on a full frame sensor. If you set a full frame lens to f1.4 with the speedbooster, it looks like f1.0 to the aps-c sensor, and is equivalent to setting the same lens to f1.4 on a full frame sensor. So when Andrew is comparing pictures taken on the speedboosted FS100 versus 5D Mark III, he needs to set the lens to the same aperture settting to have equivalent pictures.

 

Andrew's review incorrectly states "It is perhaps fairer to compare the same lens wide open on a full frame camera and stopped down 1 stop on the Speed Booster to match the effective F-stop. For example compare optical performance shooting wide open at F1.4 on the 5D Mark III to shooting stopped down to F2.0 on the FS100. In that situation sharpness is always better in the centre with Speed Booster and almost evenly matched in the corners with the right glass."  The fair comparison is to compare the same lens at the same marked aperture setting on a full frame camera versus a speedboosted aps-c camera.

 

Ah, I see what you mean. I do agree but I think I get what Andrew was saying. I guess he meant in terms of image brightness rather DOF. If my thinking's right, you could, for example, shoot a 50mm f/1.4 wide open on S35 with the Speed Booster at ISO1600 and have more or less the same image (exposure and DOF-wise) as shooting the same lens wide open at ISO3200 on full-frame. Does that sound about right? I think this might be what Andrew was referring to.

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That doesn't sound right. Depth of field looks the same as a full frame sensor to me.

 

I could put some unlabelled shots up from the 5D Mark III with a 50mm on full frame, and the same 50mm on APS-C with Speed Booster. You wouldn't be able to tell them apart. If you think you can, you're welcome to try and I will take some shots :)

 

The depth of field will be the same with the Speed Booster on APS-C as a full frame. It's worth noting however that just because the image is brighter by a stop doesn't mean that the depth of field will be shallower by a stop. For instance an EF 24-105mm f4 lens used with a Speed Booster adapter on an Sony FS100 at f4 will behave like it is f2.8 (brighter) but the image will still only have the depth of field characteristics of f4 on a full frame body.

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The brightening is an effect of the Speed Booster that happens after the DOF is set by the lens.  Brighter or darker doesn't affect DOF when the physical stop of the lens remains constant.  Similarly you don't affect any change in DOF one iota raising or lowering your ISO sensitivity.  The Metabones adapter does not alter the physical stop of the lens so there is no reason for any expectation of any change in DOF.

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That doesn't sound right. Depth of field looks the same as a full frame sensor to me.

 

I could put some unlabelled shots up from the 5D Mark III with a 50mm on full frame, and the same 50mm on APS-C with Speed Booster. You wouldn't be able to tell them apart. If you think you can, you're welcome to try and I will take some shots :)

 

 

it is true of course that the difference between ff and crop sensor is small.

 

but it would be fun to do the experiment. some medium dof shots, some interior, some exterior. probably i will fail!

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The T-stop of a lens measures the light performance after the lens, what's there for the exposure but DOF and F-stop must be managed by the operator independent of this.  I think you have your mechanics backwards and imagining mechanical functions that aren't there.  It's simplicity seems to be causing all kinds of confusion.  

 

I don't understand how the depth of field can effectively remain constant if the the focal length is reduced to a factor of .71 unless the effective f/stop is opened up (i.e., the f/number reduced) about a stop. As the lens' elements and coatings don't change, any factors that prevent the T-stop and f/stop from being identical remain. Therefore the effective f/stop must change. So if the lens is marked as a 100 mm and is set at f/2.0, it will effectively be roughly 70 mm at f/1.4 with the Speed Booster. Which is exactly what the whitepaper ("The Speed Booster™ – a New Type of Optical Attachement for Increasing the Speed of Photographic Lenses") says: "A focal reducer . . . is basically a positive lens that fits behind an objective lens, and its function is to reduce the focal length. However, the entrance pupil D remains fixed. Because of this, the f/#, given by f/# = (focal length) / D, is reduced. In other words, the speed of the lens is increased – for the same reason, why a teleconverter reduces the speed of the lens."

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