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October 11th, 2009, 06:20 PM | #91 | |||
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However, when you compare a large single-chip camera vs. a small single-chip camera, there is no advantage in deep DOF. That is because the large chip can stop down for DOF and increase ISO to get the same brightness, as discussed here: http://www.dvinfo.net/forum/canon-eo...eeper-dof.html Quote:
Personally, I think the reason why we haven't seen a FF Canon video camera is the same reason that the RED ONE weighs over 10 pounds: 9 MP at 24 FPS and takes a lot of hardware. How much more for 21 MP at 30 FPS? It's a data rate of 8,800 Mbps! Of course, the 5D2 side-steps the problem by just skipping 2 out of every three rows and binning 3 pixels. That gets it down to just 980 Mbps, which a single DIGIC IV can handle. The result, of course, is the most terrible aliasing problems ever to disgrace the Canon brand name. I think the only reason Canon even let it out the door was because they thought quality didn't matter for PJ web videos. If they have higher standards for actual video cameras (and I would like to think that they do), then they'll delay the release of the camera until they can address the aliasing problem. Quote:
Furthermore, 3-chip has terrible color accuracy. The shape of the spectral response of color filter array sensors can be finely tuned at every wavelength, whereas dichroic beamsplitters always have color overlap crossover at exactly 50%, and it can't be changed because it's the very nature of a prism. Their delta-E is orders of magnitude worse than Bayer for certain colors. It doesn't give me that feeling at all. 3-chip will always have the advantage of gathering three times as much light without making DOF thinner (something no single-chip can do), so I think it will always have a place in low-light deep-DOF applications. |
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October 11th, 2009, 07:05 PM | #92 | |
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Thanks for the response, Peter.
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Second, there is no free lunch. I'm responding to the idea that it's impossible to make FF35 lenses that match the 1/3" lenses. It is possible, but one has to accept that they will only be the same, not better. If one is not content with the current low light performance on the 20X 1/3" lens, then there is nothing to be done about it without accepting higher cost, more weight, or smaller zoom range. Third, I think there will be a bit of lens design advantage, since the 3-chip lenses have more considerations (back focus, etc.) than a mirror-less (E.V.I.L.) 35mm lens. Furthermore, to achieve the same contrast in the final image, the FF lens only needs 50% MTF at (say) 20 lp/mm, compared to much higher spatial frequencies on 1/3", say, 120 lp/mm. Of course, the larger image circle balances this out somewhat, but one thing that doesn't balance out is manufacturing tolerances, which have to be much tighter for the same MTF. Fourth, the only sense in which I think it is absurd is the marketing challenge. It's the same problem as other industries. In astronomy, many people think the magnification of the scope is the most important factor in the buying decision, so they think a 1000X refractor (50mm) is better than a 30X newtonian (250mm). In fact, the 30X newtonian is an order of magnitude better. In the same way, camera buyers are now fixated on f-number as the most important factor. They think f/1.6 on a small sensor will give them a better picture than f/8 on a large sensor. In fact, the f/8 provide a far better picture in low light. Since 3-chip gives a 1.6 stop advantage over 1-chip, it would be poetic for the f-number to be 1.6 stops faster, so that the user could at least do the same in low light (though it will mean accepting thinner DOF). Ideally, the lens will be as fast as they can make it without sacrificing angle of view or zoom range, while still hitting a price that is commensurate for electronics in the rest of the camera. Maybe they could get it as fast as f/11 or even f/8. |
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October 11th, 2009, 07:26 PM | #93 |
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But Daniel,
You are ignoring the fact that the main reason people want large sensors is for shallow DoF. Better low light performance and less noise isn't going to be enough if the DoF gets no shallower than you'd get from a 1/3 or 1/2 chip. It's like building a Ferrari and limiting it to 85 MPH. Nice leather, beautiful paint, faster 0 to 60 than a Lexus, but if it can't sniff 185 MPH I don't want it. It doesn't matter that I might never floor the car for a 1/4 mile, I just want to know that if I do, I'll be going 120 MPH. And in truth, shallow DoF has been the trend in cinematography now for quite some time. So a low F stop couples w/ a large sensor is more than just a vanity issue. The deep focus shots we see in "Citizen Kane" and "Raise the Red Lantern" are seldom used now.
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October 11th, 2009, 07:54 PM | #94 | |
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Great post, Peter.
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For example, if a vidoegrapher goes to the video store, and the XL-H2 (1/3") is $8,000 and the XL-5D (36x24mm) is $8,000, and they both have a 20X zoom with the same DOF, it would be perfectly acceptable to choose the XL-5D, even if the videographer doesn't plan on using it with thin DOF. He'll get the huge advantages when in ample light (far better image quality than 1/3"). In fact, if Canon could make them both for the same price, they might as well not bother even making the XL-H2, since the XL-5D could do everything it can, and more. (The trick is convincing the customer that 650mm f/11 really is just as good as 108mm f/3.4.) Other customers can buy the exact same camera, but instead of a 20X f/11 zoom, get the 4X f/4 (say, 28-135). Still others can go with 3X f/2.8 zooms or f/1.4 primes. I guess my point is that it's possible to "first, do no harm." If Canon came out with a new video camera that did not have a 32-650mm zoom, then the previous owners that depended on that functionality could not upgrade. If they kept 20X but added 10 pounds to the camera (by making it f/5.6), that too would hinder many buyers. But if they preserve the existing light-weight 20X functionality (and they can), then everyone can upgrade. Not that they will: just that they can. |
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October 11th, 2009, 07:57 PM | #95 | |
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Essentially, mask each sensor so it doesn't receieve crosstalk from the the adjacent color. Then estimate how much color was lost to the filters by evaluating each sensor's border wavelength values. It sounds complicated and imprecise, but I would think it's easier and more accurate than demosaicing. Is this not done? Does it make sense? P.S. I'm not convinced the filters would even be necessary, just the internal image processing "should" be enough. Anyway, thanks very much all your input, Daniel. It's always a learning experience reading your posts ;).
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October 11th, 2009, 09:42 PM | #96 | ||
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Thanks, Peter.
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In one sense, 3-chip goes beyond the capability of human vision; it's too precise to approximate our more relaxed perception. Image processing would be able to achieve excellent color accuracy if every pixel stored a chart of how much of the light came from each wavelength. 5% from 550nm, 10% from 560nm, etc. But it doesn't: all the wavelengths are mixed together in the pixel. |
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October 12th, 2009, 04:40 PM | #97 |
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You make some good, well thought out points, Daniel. I may not be 100% convinced, but...... :-)
In answer to one of Peter's points ("it would border on absurd to make a large sensor camera w/ a very slow lens so it could mimic the performance of a smaller sensor camera") then I suppose the answer is you get more options. Initially, I confess, I felt the same as Peter. Either get a long zoom with small max aperture (to mimic small sensor performance) or get a fast short ratio zoom (or prime) if DOF or low light ability is of more importance. |
October 14th, 2009, 02:27 PM | #98 |
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Take a Canon EF-S 18-200 f/3.5-5.6. Motorize it. Problem solved ;)
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November 1st, 2009, 05:38 AM | #99 |
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Oh! Canon! Get it together.
Canon. You burst on the scene with the famous XL1. Everybody wanted one. Then as the other manufactures got going to play catchup the cry from your loyal diehard troups began chanting.
"Where's the XL2?" Out came the wishlists and the prophesy of how it will be. We waited with baited breath, couldnt sleep at night. Then, Drumroll, it's coming. Out poped a XL1s. Umm we all said, "Looks a bit like the xl1" we thought. Canon assured it was a totally new camera. Only the paint was the same, but it's innards are entirely new. So we grabbed one, raved over it. Many said this is the xl2, but it's got a new name. We were still loyal Cannonites and hung in there with religious verver. In the mean time we looked over our shoulders and saw Sony, and Panasonic and others leaping ahead and were breaking into HDV. Were's the xl2, Surely as God made apples the xl2 hd version will be released at the next NAB. We waited, waited, and anticipated the new xl2 in hd. After a long gestation out poped another camera. They'd run out of red paint so used white. and gave birth to the xl2. This what indie and ENG , pro's and wannabe pros were waiting for. A totally new camera Canon boomed again. The only thing that's not new is the microphone. We thought the only thing not new was it's SD. So we rushed out, bought one and found when we're in a media bunfight we were the only ones with a white camera and not hd capable. So here we are again. The remenant, waiting for a revolutionary new super lens one inch chip daddy of em all canon hd camera. In reality so many I know have given up. The EX1 and EX3 have finally done it. All the loyal Canon users here are leaving or have left their Canon and embraced the EX1 and EX3, buying them in ones, twos and threes. So I've had a xl1, xl1s and a xl2. I'm about to go to hd. I've been loyal to Canon for 10years, but it's time to stop waiting and look else where. I've been loyal to Canon all the way through. I even had a Super 8 Canon film camera once. It's nearly next year, I'll wait a bit longer, but not forever.
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November 1st, 2009, 08:40 AM | #100 |
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Canon's always slow, Canon's always late, but Canon always comes with high quality products. I think the XL-H1 or whatever it will be called will be a revolution again. You can't be market leader for 10 years in a row in this industry.
And the build quality of the EX1 and EX3 is so poor. Fisher price plastic microphone holders that break, paint that peels off... my XL-H1 still looks new. The EX1 and EX3 have a nicer chip and great image quality but their build quality makes me cry. |
November 1st, 2009, 02:43 PM | #101 |
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I agree. Everything about the Canon XL H1S is fantastic, from build to image quality. I sure hope Canon delivers again!
I absolutely love my Canon XL H1S and the fantastic HD images it creates. All of my clients have found it's footage stunning and it has paid itself off over and over again already, so I am ready to buy if the next camera meets or exceeds our expectations. |
November 2nd, 2009, 11:20 AM | #102 | |
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Quote:
Yoda Martin |
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November 4th, 2009, 12:52 PM | #103 |
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Owen I don't know if you recal or not, but the xl-h1 came out just a year after the xl2 (I two was about to buy one and fortunately I had my vendor stop me and say, hey, are you sure want to buy an SD camera, see what happens by the end of the year, then the xl-h1 came out. Also it was the Second HDV camera to hit the market (well third both the z1u and the fx1 came out and it smoked both of them) it beat the hvx200 to shipping and edged out the the jvc-hd1u. Now, yes after that release they slowed things down again quite a bit, but I really don't believe its fair to say canon was late to the market with an HD camera. In fact, uh I mean, if you really want to split hairs, canon developed and released the 5d and 7d in the time it took red to announce, and change, and announce, (and change again) the scarlet.
The Ex-x are good cameras but let's not say that canon hasn't offered up suitable cameras, yes I want to see the next xl just as much (probably more) as any one else but Canon has actually really pushed things and delievered a lot of aspects that filmmakers and eng-ers want and for a multi-billion (maybe trillion?) dollar company to innovate that fast is pretty impressive. Of course having said all of that, I think now a days it's probably silly to just stand by and wait for a camera from any specific manufacturer, I too have been in the canon camp for a while but if I was in the market for a better camera and the specs I was looking for were being offered by Sony I'd get the Sony. Camera's aren't supposed to badges that we wear they're supposed to be tools that we use... unless, uh, canon wants to sponser me then, ya know, uh, brand loyalty all the way...
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November 11th, 2009, 04:55 PM | #104 |
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Nick.....you're a poet
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December 2nd, 2009, 10:12 PM | #105 |
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The latest rumors on the elusive camcorder is 12MP APS-CMOS sensor, support for EF and EF-S lenses, fully manual controls, shoot 720p/30/60 and 1080p/24/30/60 to 56Mbit/s MPEG-4, and sporting a $8000 price tag.
They look pretty reasonable to me, although I really cannot understand why to utilize such a large sensor if they have to skip lines for HD, unless of course they can do full resolution different aspect ratio frames like 1.85 and 2.35 by utilizing the extra pixels of the sensor. That would be awesome. |
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