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large sensor for large format


paulso

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<p><em>A one shot full frame 4x5 digital back could happen; so could practical low cost flying cars like I have seen in Popular Science for the last 50 years.</em></p>

<p>The fundamental physics and engineering technology behind most cars and aircraft (I'm not talking an F-22) is much simpler, older, and more stable than the counterparts for digital photographic imaging. Therefore, it seems that unexpected, unpredictable, and/or radical progress is much more likely in photographic sensors than in cars or aircraft. This does not <em>prove</em> it will happen, much less when or how it will happen. But if I had to bet on which would come first, a practical personal flying car or a roughly 4x5-size sensor/back for less than the inflation-adjust price of today's medium-format digital backs, I'd bet on the latter in a heartbeat.</p>

<p><em>Lay folks cannot understand that doubling the sensors size causes the cost to more than double.</em></p>

<p>I don't dispute that <em>today</em> the cost rises exponentially with the sensor area. But you are assuming that (1) the current sensor / IC paradigm will persist for many years and (2) the cost will always be non-trivial. The latter point is easier to address: so what if, say, a "full-frame" sensor costs 100x as mcuh a a digicam sensor, if one costs $1 and the other only $100? As to the former point, in fact, we may well be on the verge of some very different technology. The problems with current commercial fabrication of camera sensors may be rendered trivial. By what? I don't know. Does Joseph? Well probably more than I do, but there's a heavy element of guess in any such discussion. All I'm saying is, it would not surprise me in the slightest if, a decade from now, there is some sensor fabrication technology that allows the small-scale production of a 200 MP photo sensor of 100 x 125 mm or so at a price that the average pro photographer can afford. It would also not surprise me if this does <em>not</em> happen, and I have no way of estimating the odds of whether it will. Neither do you, if you're honest about the limits of your knowledge of what is an extremely technical and fairly rapidly changing field.</p>

 

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<p>Here's a timely little news item: <a href="http://www.dpreview.com/news/1008/10083101canonlargestsensor.asp">http://www.dpreview.com/news/1008/10083101canonlargestsensor.asp</a></p>

<p>Canon has developed a roughly 8x8 inch CMOS sensor. Yeah, I'm sure fabriacting it cost a pile of money. Yeah, it's probably a one-off, or part of a very small series. But clearly the idea of LF-size sensors is under consideration by companies with the capability to make it happen. A decade from now, who knows?</p>

 

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<p>@Dan South:</p>

<blockquote>

<p>120 MP on 645 format is possible at the P40+ pixel density.</p>

</blockquote>

<p>Dan, no. Check your sums. At the P40+ pixel size of 6um, you get only 65.3 MP for full 645 coverage. Copy this formula into Excel or OpenOffice (all length units are mm):<br>

=56*42 * (1/(6*10^-3)^2) / 10^6<br>

...evaluates to 65.33 MP</p>

<p>In fact, what puzzles me is that you made this assertion <em>after</em> Joseph had already explained that you get only 65 MP for full 645 coverage! </p>

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<p>Frank;<br>

Re : "Is this something for backpackers? =)"</p>

<p> With my Phase One 35 and 50 megapixel 4x5 scan backs the requirements are really only a Pentium CPU. A 166Mhz Pentium is fine. Thus to mess with a 103 or 145 meg file one just wants some ram.</p>

<p>For portable use:</p>

<p>I use to use an Old IBM Thinkpad with Windows 98SE that had a Pentium and was maxed out at 512megs of ram.</p>

<p>Today I use a newer:) IBM T30 that is 1.8 GHZ and has either 1 or 2 gigs of ram; and has either win2000 or XPPro. I have two laptops. You have a SCSI card in the laptops PCMCIA slot. One powers the back's AC supply off an invertor off a 12Volt gel cell,</p>

<p>The Phase One's software for the old scan backs is rather old; it is from 1996 to 1998:</p>

<p>You do a prescan and note where "scene" is on the exposure control slider. One can vary the iso of the scan; the exposure (how long it sits/exposes that single line) and one of course can fiddle with the cameras fstop setting; or add more light if manmade.</p>

<p>There is an Infrared filter one places on the front of ones lens to block IR; scan times are many minutes andthing that moves gets blurred.</p>

<p>Here I have done some building shots and landscapes with the scan backs; it is a rather planed event; often not so practical.</p>

<p><img src="http://i4.photobucket.com/albums/y148/ektar/scanback/PhaseOneScanBack.gif" alt="" /></p>

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<p>Most folks use these old scan backs to shoot artwork or odd items and it is INDOORS!.</p>

<p>This old p-38 Lockheed blueprint from 1942 is 54 inches high and way wider.</p>

<p>The IBM Computer tethered to the scanback is a Pentium III 800MHZ with 768 megs of ram. One can watch a avi movie on this machine that is sourced across the LAN from another machine; while a 50 megapixel scan is being done.</p>

<p>The IR filter is just taped to the Orange stapler on the 4x5 speed Graphics bed. The taking lens is a 135mm F5.6 Componon working at F11.</p>

<p>The lights were purposely set at different distances to compensate for the uneven fading of the original.</p>

<p>The lights are not Alien Bees; but just 9 buck Harbor Freight Halogens. There is a Kodak color reference and Kodak grey scale on the copy board; it is behind the close lamp and cannot be seen.</p>

<p>The old CRT is sitting on the 17 foot long box rail of the old obsolete process camera. Normally the 4x5 speed is bolted to the process camera and the Tiltall tripod is not used. This p38 original was so huge I had to move the platen.copy board way away; and not use the process cameras front. There are some file cabinets that limit the copy boards range that I really need to move if I did much of this. The Process camera shoots a 24x36" negative and is built into the building, A 3 x enlargement makes a 6x9 foot print. The breaker to the process camera is 230 volt at 60 amps</p>

<p>It is about the norm if I mention that I use a 50 megapixel scan back that folks think you need a wazoo speed computer; when any used Pentium computer at the thrift store for 25 bucks will work fine.</p>

<p>.<br /> <img src="Email & IM Direct Link" alt="" /><img src="http://i4.photobucket.com/albums/y148/ektar/scanback/P5180051SCANBACK.jpg" alt="" /></p>

<p><img src="http://i4.photobucket.com/albums/y148/ektar/scanback/P5180050BIGCAMERAMAY2010.jpg" alt="" /></p>

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<p>Also some people says at the motion picture industri at Kodak that 35 film is able to give between 8K up to 10K and the modern most advanced DI are on 4K. How do you comment on that? Also there is some article on that in the Variety.<br /> Here is the link<br /> http://www.variety.com/article/VR1118006119.html?categoryid=2525&cs=1</p>
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<p>We are getting OT here, but, oh, why not--from the linked article:<br /> <br /><em>One is that it simply can't pass along all the information contained on a 35mm film frame. . . . [E]ven those done in the more detailed 4K format may not do full justice to the image on a camera negative. "A 35mm film negative can contain a resolved image equivalent to up to 8K," says d.p. John Bailey . . . .</em><br /> <br />Well let's see: 4k means 4096 x 1714 for 2.39:1 or 3996 x 2160 for 1.85:1 (<a href="http://en.wikipedia.org/wiki/4K_resolution">http://en.wikipedia.org/wiki/4K_resolution</a>). The image area on 35mm motion picture film is usually about 22 x 16 mm (the widescreen stuff is "anamorphic"--special lenses squeese it down on the long side). So for 35mm motion picture film to even equal <strong><em>4k</em></strong>, it would have to deliver (that is, capture with sufficient MTF and then be scanned in a way that reproducess) anywhere from 54 to 93 lp/mm, depending on the aspect ratio and whether you mean horizontal or vertical. (Details: for 2.4:1, you'd need 93 lp/mm horizontal and 54 lp/mm vertical, and for 1.85:1, you'd need 91 lp/mm for horizontal and 68 lp/mm for vertical.) While I don't doubt that the ordinary motion picture color films can give decent response at 54 lp/mm, I seriously doubt they give much response at 93 lp/mm.<br /> <br />So basically, I strongly suspect the guy, whatever his credentials, is just wrong on this technical point. My strong suspicion is that, at best, effectively, regular 35mm motion picture film effectively equals 4k resolution in real-world situations, and cannot approach 8k. But of course there are people on photo.net who think that drum-scanning Velvia 50 at 8000 ppi is reasonably likely to yield substantially higher resolution than does drum scanning it at 4000 ppi--despite Fuji's own data sheet showing that (presumably at real-world subject contrast), the film is down to 50% MTF response at about 45 lp/mm (about 2300 ppi) and they do not even show any curve plotted past about 60 lp/mm (about 3000 ppi), at which point the MTF response is down to about 35%.<br /> <br />Caveat: I do not know whether the digital motion picture cameras have anti-alias filters in front of those 4k sensors. I would suspect not, just like medium format digital backs don't have them. But if they do have anti-alias filters, that might mean he's got a point.</p>
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  • 3 months later...

Hey Kelly, you seem to know a lot. Can you tell me why I can shoot a high quality image with a tiny little sensor? I

mean if a tiny little sensor less than 1/5 the size of a typical Nikon or Canon DSLR can capture 10 or 12 megapixel

images good enough to print at 16x20, then why couldn't a 50 megapixel APS-C or 100 megapixel full-frame DSLR be

made, and consequently a 200 megapixel medium format camera with new, super-hi-def lenses? If so, why not 400 or

500 megapixel single-chip backs for LF? Eventually, as super-HD becomes more popular , such equipment will

become more than just a dream, no? Look what has happened to HD video. Today video cameras are available for a

reasonable price ($2,000) that would have been worth $100,000 just five or ten years ago. Similar things have

happened in the digital SLR world, with a 16 megapixel camera shooting faster and costing less than a quarter of what

a 4 megapixel camera cost just 8 or 10 years ago. Sensors are getting bigger, and as they do, last year's sensors are

being sold for half price or less. Isn't it reasonable to assume that in a few years a 60 megapixel sensor at 40x50mm

will be just a few grand? Isn't it likely that some boutique chip maker like Foveon was might make a 4x5 sensor for

$50,000 each? . . . in a few years from now? Just 20 sensors would bring a million bucks! Imagine 2,000 sensor

sales?

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