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#11
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39 megapixels vs. 4x5
Mike wrote: . . . . . . . . . . . . After you invest the $5 billion in the fab. Of course the niche players will contract out the fab. I wonder who is manufacturing the PhaseOne silicon? Kodak. Same chip being used by Imacon (Hasselblad), but with different hardware and software attached. Even if you find a fab, creating those masks is not cheap and existing manufacturing processes are geared towards economies of scale (which you correctly pointed out will not exist for MF/LF sensors). Probably never. I don't think that means these devices are frozen in high prices, since some other technology could be developed that becomes more economical to produce . . . maybe. Do you think a $3000 digital capture solution will be available in 5-8 years that can deliver 4x5 quality? I don't think so...but would value your thoughts. Scanning back? Ciao! Gordon Moat A G Studio http://www.allgstudio.com |
#12
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39 megapixels vs. 4x5
On Fri, 20 Jan 2006 21:35:58 -0500, rafe b rafebATspeakeasy.net
wrote: The mass market is already well served with image sensors of 5x7mm. For a grand, you get 15x22mm, which easily beats 35mm. For three grand, you get 24x36mm, which begins to encroach on 645 film territory Examples ? I haven't seen any digital cameras that can eaqual a well exposed TMX film yet. John |
#13
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39 megapixels vs. 4x5
On Sat, 21 Jan 2006 04:47:26 -0600, John
wrote: On Fri, 20 Jan 2006 21:35:58 -0500, rafe b rafebATspeakeasy.net wrote: The mass market is already well served with image sensors of 5x7mm. For a grand, you get 15x22mm, which easily beats 35mm. For three grand, you get 24x36mm, which begins to encroach on 645 film territory Examples ? I haven't seen any digital cameras that can eaqual a well exposed TMX film yet. Google is your friend, John. There are lots of Canon 5D captures available for download off the web. Several at Canon's website, for starters. I'm not familiar with TMX. Given a choice, I grab the slowest C41 film I can find and shoot with that. In MF, I use Reala. In LF, Portra 160. 645 scanned at 4000 dpi yields around 55-60 million pixels, so this seems like an absurd comparison, right? But if you upsample to 5D image to match the scanned-645 dimensions, it holds its own. That's only 2:1 linear upsampling, 4x in terms of pixel count. This isn't only my conclusion, of course. It's one of the reasons high-end digital is already taking a toll on MF as well. rafe b www.terrapinphoto.com |
#14
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39 megapixels vs. 4x5
Gordon Moat wrote:
Scanning back? Scanning backs can be done very inexpensively but they are very limited in what you can do with them. There are however some really large linear CCD with a lot of pixels so it would not be hard to put one together. I would say a scanning back would be pretty much limited to studio work. You could also image a hybrid scanning back, one that used an area CCD but with a very large aspect ratio. Imagine a CCD what is 8000 pixels by 1000, this is only an 8 MP sensor. But if you used this to scan instead of a linear CCD you could scan at close to 1000 times faster. By using 10 exposures you could build up an image that was 8000 x 10000 pixels. To do the same with a linear CCD would take 10000 exposures, and a lot of time. It might be possible to use TFT to somehow make a large sensor on a glass plate. The problem is that the electronics industry was willing pour billions of dollars into TFT research for displays because they know the pay off would be huge. It would be hard to get anyone to pour billions into research on making very large photo-sensor arrays. Scott |
#15
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39 megapixels vs. 4x5
On Sat, 21 Jan 2006 04:47:26 -0600, John
wrote: On Fri, 20 Jan 2006 21:35:58 -0500, rafe b rafebATspeakeasy.net wrote: The mass market is already well served with image sensors of 5x7mm. For a grand, you get 15x22mm, which easily beats 35mm. For three grand, you get 24x36mm, which begins to encroach on 645 film territory Examples ? I haven't seen any digital cameras that can eaqual a well exposed TMX film yet. I probably missed your point in my first response. If you're dedicated to shooting BW, then a Bayer- based digicam is probably not for you. As dedicated BW shooter, you're well outside of the mainstream and not really significant to the bean counters at Kodak, Fuji, Nikon, or Canon. That's not a value judgment, just a statement of fact. It's a bit ironic, of course, since there's no technological reason the same sensors couldn't work for you -- you'd just need the sensor without the Bayer filter, and of course it would need very different (actually, much simpler) post-processing. There are some high-end backs by Leaf that work that way, but again, mega $$$. rafe b |
#16
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39 megapixels vs. 4x5
"rafe b" rafebATspeakeasy.net wrote
[...] If you're dedicated to shooting BW, then a Bayer- based digicam is probably not for you. [...] you'd just need the sensor without the Bayer filter, and of course it would need very different (actually, much simpler) post-processing. At the moment I have to wonder if that's true. What is the naked spectral sensitivity of a sensor without a Bayer filter? Is it not dead straight, and extending much farther into UV and IR than film? If it is, then I think B&W photographers would be very unhappy with a nonfiltered sensor. B&W is, truly, color without hue; that is, B&W photographers always have to deal with the modulation of colors by the film. |
#17
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39 megapixels vs. 4x5
On Sat, 21 Jan 2006 11:44:25 -0600, "AH2"
wrote: "rafe b" rafebATspeakeasy.net wrote [...] If you're dedicated to shooting BW, then a Bayer- based digicam is probably not for you. [...] you'd just need the sensor without the Bayer filter, and of course it would need very different (actually, much simpler) post-processing. At the moment I have to wonder if that's true. What is the naked spectral sensitivity of a sensor without a Bayer filter? Is it not dead straight, and extending much farther into UV and IR than film? Not sure about UV response, but yes, most CCDs respond readily to IR, and in fact require IR filtration for "normal" applications. IIRC, glass attenuates UV (unless it's quartz) so UV isn't going to get through the taking lens in any case. If it is, then I think B&W photographers would be very unhappy with a nonfiltered sensor. B&W is, truly, color without hue; that is, B&W photographers always have to deal with the modulation of colors by the film. The point is that the sensels for a BW imaging chip would not want the standard Bayer filtration, but a something that's the uniform over all sensels. Such sensors and filters certainly exist, but have no role in the consumer/prosumer market. This cuts both ways. It's not just the manufacturers unwilling to serve the BW market. It's that the BW market (such as it is) is unreceptive to digital capture in the first place. You can't serve high-tech to Luddites. There's a comparable issue with digital printing. Those desiring to print in monochrome with inkjets are pretty much ignored by the mass market, and left to fend for themselves. The market niche there has been picked up by expensive RIPs and share- ware products like Roy Harrington's QuadTone RIP. rafe b www.terrapinphoto.com |
#18
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39 megapixels vs. 4x5
AH2 wrote:
"rafe b" rafebATspeakeasy.net wrote [...] If you're dedicated to shooting BW, then a Bayer- based digicam is probably not for you. [...] you'd just need the sensor without the Bayer filter, and of course it would need very different (actually, much simpler) post-processing. At the moment I have to wonder if that's true. What is the naked spectral sensitivity of a sensor without a Bayer filter? Is it not dead straight, and extending much farther into UV and IR than film? The sensors extend way out in the IR but not very far into the UV at all. To get a BW CCD camera to work well you need to use a filter somewhere, this can either be in front of the sensor or in front of the lens. These filters are fairly simple and don't stop much of the visible light. To get the effect you want the use of color filter on the lens would work about the same as with a panchromatic film. The only thing stopping digital cameras from going to BW is there is little market for BW. Scott |
#19
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39 megapixels vs. 4x5
"rafe b" rafebATspeakeasy.net wrote in message
... The point is that the sensels for a BW imaging chip would not want the standard Bayer filtration, but a something that's the uniform over all sensels. Sorry I am having such a hard time wrapping my little mind around the idea that it is desirable to produce a flat luminal response to all colors; I am so accustomed to conventional film's relatively similar curves, and modulating outcomes using filters. This cuts both ways. It's not just the manufacturers unwilling to serve the BW market. It's that the BW market (such as it is) is unreceptive to digital capture in the first place. You can't serve high-tech to Luddites. Are you saying that B&W photographers are Luddites? I find them more inclinded to some complex metrics - in particular, translating colors as they wish to. B&W is color photography. There's a comparable issue with digital printing. Those desiring to print in monochrome with inkjets are pretty much ignored by the mass market, and left to fend for themselves. Well, so-called B&W printing is far better on most consumer ink-jet printers than it was only four years ago, but Yes, to get very good grey-tones one has to resort so some spendy media and the public isn't interested. |
#20
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39 megapixels vs. 4x5
rafe b wrote: On Sat, 21 Jan 2006 04:47:26 -0600, John wrote: On Fri, 20 Jan 2006 21:35:58 -0500, rafe b rafebATspeakeasy.net wrote: The mass market is already well served with image sensors of 5x7mm. For a grand, you get 15x22mm, which easily beats 35mm. For three grand, you get 24x36mm, which begins to encroach on 645 film territory Examples ? I haven't seen any digital cameras that can eaqual a well exposed TMX film yet. Google is your friend, John. There are lots of Canon 5D captures available for download off the web. Several at Canon's website, for starters. I'm not familiar with TMX. Given a choice, I grab the slowest C41 film I can find and shoot with that. In MF, I use Reala. In LF, Portra 160. TMX commonly refers to Kodak TMax 100, which is a B/W film. Kodak Technical Document F-32 has information on all TMax films, including developing options. Probably one of the best choices for getting the maximum resolution from large format lenses. 645 scanned at 4000 dpi yields around 55-60 million pixels, so this seems like an absurd comparison, right? Actually, if we just use the 39 MP Kodak CCD, and look past PhaseOne to Imacon, we can find that the Imacon has a micro step mode that moves the entire CCD a small amount. While some would claim the resolution increases, what actually happens is that edge definition becomes more accurate. The maximum file would then be 8000 by 10000 pixels, which is more like an 80 MP digital back. The slightly smaller than 645 area remains the same. To match the file size with 4x5 in a scan would only need a 2000 dpi scan. With a very good high end scanner, even a perfect 2000 dpi scan only means about 40 lp/mm maximum. Some large format lenses are capable of closer to 60 lp/mm, though to get that would mean a 3000 dpi or greater scan, meaning a much larger file size. In reality, the PhaseOne and Imacon backs should be expected to be close to 40 to 45 lp/mm, based upon similar technologies (cell site sizes on other CCDs). A Canon 5D is actually higher resolution in real tests, a Canon 1Ds Mark II is slightly better, and a Nikon D2X has even greater real resolution capability. Kodak TMax 100 is actually beyond the (resolution) capability of most large format lenses at common working apertures, so the lens is the greatest limit in large format film usage. When the film area increases, a greater scan is needed to capture all the information. This implies overscanning beyond needs to capture as much as possible from the film. Then when it comes to printing, as in commercial printing or wide format inkjet systems, the only advantage of such a large scan, and the only advantage of that much resolution over that area is the ability (potential) to make a really large print. Those considering optical prints might be better thinking in terms of contact printing. If 4x5 film is contact printed, the resolution is extremely high. In fact, it is beyond the ability of the average person to even see the limits of that resolution. If we take 5 to 6 lp/mm as the common limits of eyesight, and a best capability of 60 lp/mm as a common capability of large format, then we would need more than 10x optical enlargement before we could see the limits of resolution from 4x5 film . . . that would be a print near 40" by 50". Obviously, some really good optics on the camera and enlarger would be necessary, and these would be very expensive items needing a great deal of skills to operate. So far, the colour prints of Edward Burtynsky are the closest I have seen to that. But if you upsample to 5D image to match the scanned-645 dimensions, it holds its own. That's only 2:1 linear upsampling, 4x in terms of pixel count. This isn't only my conclusion, of course. It's one of the reasons high-end digital is already taking a toll on MF as well. I think it is more a matter of the skills and time needed to get the most out of medium format or large format. Many of us have seen some really nice prints from medium format and large format. When the need for scanning to create that print comes up, then the scanner requirements are very high. When the need to get the best optical enlargements from those films arises, then the very top quality of enlarger, lenses, and techniques is needed. To put this in plain language, some photographers are finding it substantially easier to use direct digital and a computer, and many of those people are quite happy with the results. Ciao! Gordon Moat A G Studio http://www.allgstudio.com |
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