Tzedekh Posted January 24, 2013 Share Posted January 24, 2013 The focal length is not really reduced. The f-stop is not altered. You're confusing yourself. That is why I said effective f/stop. And according to the documentation, with the Speed Booster, the effective focal length and f/stop are indeed changed. I'm not confused. Taxrummawoodo 1 Quote Link to comment Share on other sites More sharing options...
Sean Cunningham Posted January 24, 2013 Share Posted January 24, 2013 A change to the effective F/stop that would affect the DOF means a physical change to the size of the opening created by the shutter blades. Nowhere in the documentation does it state or even suggest that this happens. If you were to take a picture, print it out and hold it up to your face close enough that you couldn't see its edges, that represents pre-Metabones or how your smaller-sensor camera sees the scene depicted in the photograph. Now, hold the photograph out further, far enough so that you can see all the way to the edges or close. That represents how your smaller-sensor camera sees the scene depicted in the photograph after installing the Metabones adapter. No change in DOF. The optical reduction doesn't alter the FOV of the lens it alters how much of it your sensor can see. This isn't a wide-angle converter that also makes the image brighter. The effective T-Stop difference is from the compression of the light meant for a large aperture imaging layer into the space of a smaller one. Light is additive. In image processing terms, when you scale an image from 2K to 1K the brightness of the image doesn't change because neighboring pixels from the 2K source are averaged to create a new pixel for the 1K result. Light doesn't work that way. Resizing would do something similar to what this adapter does if, instead of averaging, you were scoot neighboring pixels from the 2K source inward such that the 1K final still contained all of the original pixels from the 2K but some of them were now stacked on top of the other and their values were now added to each other rather than averaged. The Metabones adapter doesn't stack the photons of light on top of each other because it's not limited to the spaces available in a fixed grid like an image but they are hitting the imaging surface much closer together now and so they produce an image that's brighter. Like how a magnifying glass makes the light passing through it brighter when focused. markm 1 Quote Link to comment Share on other sites More sharing options...
Rob Bannister Posted January 24, 2013 Share Posted January 24, 2013 So if I have nikon glass, I use an adapter to MFT this should work with the speed booster? If so where and when can I give money for this. Quote Link to comment Share on other sites More sharing options...
shijan Posted January 25, 2013 Share Posted January 25, 2013 seems in addition to sharpness loss at the frame edges this adapter produces additional aberration effect... Quote Link to comment Share on other sites More sharing options...
RossF Posted January 25, 2013 Share Posted January 25, 2013 Barrel distortion and not as sharp. Still a great product, but this hurts being used on narrative film. Doc users will be all over this. Maybe BMCC users as well because they are in dyer need of wide. I don't think F5 or F55 users would touch this if given for free. Would it even fit on their F5/F55 if they wanted to? They don't use the E-mount. Quote Link to comment Share on other sites More sharing options...
Administrators Andrew Reid Posted January 25, 2013 Author Administrators Share Posted January 25, 2013 True they use FZ mount but the flange is the same as E-mount ,18mm. That is the important thing - enough room to accommodate the Speed Booster. FZ just has a wider diameter to accommodate some rear elements on PL glass and has a tougher locking system, and adapters to PL out of the box. Quote Link to comment Share on other sites More sharing options...
Sean Cunningham Posted January 25, 2013 Share Posted January 25, 2013 seems in addition to sharpness loss at the frame edges this adapter produces additional aberration effect... Sharpness loss at the edge of frame is mostly a function of the lens itself. It's only apparent to the smaller sensor after using this adapter because it could never see it before, it only saw the "sweet spot". In point of fact, sharpness at the edge of frame is better through the adapter on a smaller sensor than the same lens mounted to a FF camera. Seems lots of people still aren't bothering to really investigate or grok what they've read so that they can add meaningful discussion. edit: it cracks me up that, even though the adapter IS performing a kind of magick, its critics now feel compelled to criticize the magick itself as if it just weren't miraculous enough for their standards.... "Yeah, you turned water into wine...but you didn't raise anyone from the dead. Fail. You suck." Julian and nahua 2 Quote Link to comment Share on other sites More sharing options...
noirist Posted January 26, 2013 Share Posted January 26, 2013 That is why I said effective f/stop. And according to the documentation, with the Speed Booster, the effective focal length and f/stop are indeed changed. I'm not confused. Tzedekh, you are correct. Using the speedbooster changes the lens. It reduces the lens image circle, decreases the lens f-stop, decreases the lens focal length, and increases its field of view. A lens with the speedbooster is optically very different than the same lens without the speedbooster. BurnetRhoades is confused on this and many other points. For example, he seems to (incorrectly) believe that depth-of-field depends on "the size of the opening created by the shutter blades". When in fact DOF depends only on the aperture of the lens, the lens focal length, sensor size, and the distance from the focal plane to the subject. THE SHUTTER DOES NOT AFFECT DOF IN ANY WAY. Also he does not understand what is an f-stop and how it differs from a t-stop. At any given f-stop setting, adding the speedbooster increases the actual f-stop of the lens at that setting. Yes, after you add the speedbooster, all the f-stop settings on your lens are now incorrectly labeled! Quote Link to comment Share on other sites More sharing options...
Sean Cunningham Posted January 26, 2013 Share Posted January 26, 2013 Wow, that is a magic trick then, changing a lens after the fact and not changing how much of what the lens already saw your sensor can now see. Some kind of optical reach-a-round I suppose. Quote Link to comment Share on other sites More sharing options...
jcs Posted January 26, 2013 Share Posted January 26, 2013 This is an image of the Canon 24-105 F4L at 50mm on a 5D3 and FS700+Speed Booster blended 50/50. Max aperture set on 5D3 (F4) and FS700+SB (F4 full-frame DOF with F2.8-like light transmission performance). [attachment=393:FS700+SB_5D3_DOF.jpg] Close up of bokeh: [attachment=394:bokeh_match.jpg] The FS700 S35 sensor with Speed Booster gives full-frame performance with a 1.09 crop, approximately same DOF and FOV performance as full frame, and effectively 1-stop faster light transmission performance. In this example, F4 DOF for both cameras, with the FS700+SB providing F2.8-like light transmission. Where a T-stop is exactly the same as an f-stop with 100% light transmission, then a lens rated with a T-stop of 4 on the 5D3 would have a T-stop rating of 2.8 with the FS700 + Speed Booster. nahua 1 Quote Link to comment Share on other sites More sharing options...
Tzedekh Posted January 26, 2013 Share Posted January 26, 2013 Wow, that is a magic trick then, changing a lens after the fact and not changing how much of what the lens already saw your sensor can now see. Some kind of optical reach-a-round I suppose. The lens itself doesn't physically change. The lens plus Speed Booster has different properties. The same with a teleconverter -- putting a 2x extender on a 10-100 mm f/2.4 renders it effectively a 20-100 mm f/4.8. Quote Link to comment Share on other sites More sharing options...
jcs Posted January 26, 2013 Share Posted January 26, 2013 Where F2.4 has an Aperture Value of 2.5, then the next Aperture Value is 3.5, the next stop is 3.4. sqrt(2^2.5) = 2.378 or 2.4, sqrt(2^3.5) = 3.364 or 3.4. Wolfram Alpha is an excellent tool: http://www.wolframalpha.com/input/?i=sqrt%282%5E3.5%29 (not just for simple calculations- can solve complex equations). Either I'm doing the math wrong or some of the tables on the internet aren't rounded correctly. http://en.wikipedia.org/wiki/F-number http://www.fineart-photography.com/fstop.html Quote Link to comment Share on other sites More sharing options...
Tzedekh Posted January 28, 2013 Share Posted January 28, 2013 Why don't manufacturers combine something like this with backside-illuminated smaller (1/2- to 2/3-inch) sensors? Beats me. Because there's more profit in making a larger CMOS sensor and a lens that covers that I suppose? I suppose that with too small a sensor size, the required optics would probably introduce too many aberrations. Also, with a crop factor of about 3.9-4 for a 2/3-inch sensor, you might expect, in theory, a .25 factor and a four-stop decrease in f/stop. Well, the latter seems especially unlikely. Quote Link to comment Share on other sites More sharing options...
joe1946 Posted January 30, 2013 Share Posted January 30, 2013 The lens itself doesn't physically change. The lens plus Speed Booster has different properties. The same with a teleconverter -- putting a 2x extender on a 10-100 mm f/2.4 renders it effectively a 20-100 mm f/4.8. That should be effectively a 20-200mm f4.8 . Quote Link to comment Share on other sites More sharing options...
Shield3 Posted January 30, 2013 Share Posted January 30, 2013 It appears that the 5d3 "sharpened" has much more detail than the FS100; at least the 1:03 to 1:04 mark. Look at the differences in detail in the snow as well as the trees on the left. We all sharpen (at least everyone I know) our 5d3 footage; why not just always include that? Thanks, Shawn Quote Link to comment Share on other sites More sharing options...
Marino215 Posted January 31, 2013 Share Posted January 31, 2013 Great review, insightful and wow! what a great product. Wonder what took them so long? Thanks Quote Link to comment Share on other sites More sharing options...
jgharding Posted January 31, 2013 Share Posted January 31, 2013 So basically, it gets brighter, wider, and usually only looks softer at the edge cos the centre gets sharper. Man, people will moan about anything in video these days! I'm guilty too, but deep down I'm just glad I don't have to shoot on DV anymore. This is pretty fucking awesome... Sean Cunningham 1 Quote Link to comment Share on other sites More sharing options...
Scott Goldberg Posted February 3, 2013 Share Posted February 3, 2013 There is definitely a little more noise due to the glass...or so it seems... I just shelled out $399 on the Smart Adapter II... Gonna be a while before I splurge some cash on the Speed Booster. I've seen some clips that I am impressed with and some that I am not. Hopefully the price lowers sooner than later. $599 is understandable to a degree, but a lot of us don't have loads of cash to spend on these adapters...unfortunately, ha! Well some do..but yeah. Quote Link to comment Share on other sites More sharing options...
zenpmd Posted February 7, 2013 Share Posted February 7, 2013 Can anyone offer me any advice as a new GH2 shooter before I invest in lenses? To me, this changes everything. I'd rather not buy 4/3 lenses as I am in no other way invested in the system (I am a Fuji X-E1) user. Therefore, I'd like to use something like Nikon primes, and naturally with the GH2 I don't like the inherent loss of shallow DoF due to its sensor. So a 1.8 prime becomes very attractive. Is this thinking right? Shall I hold off buying anything till its ok next month? Thanks! Quote Link to comment Share on other sites More sharing options...
Robbie_C Posted February 21, 2013 Share Posted February 21, 2013 Has anyone tested this for Moiré and false colour yet? Quote Link to comment Share on other sites More sharing options...
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