Re: Bayer filter removal
- From: David Dyer-Bennet <dd-b@xxxxxxxx>
- Date: Fri, 13 Apr 2007 17:08:12 -0500
cgiorgio wrote:
"David Dyer-Bennet" <dd-b@xxxxxxxx> schrieb im Newsbeitrag news:461fb9b6$0$952$8046368a@xxxxxxxxxxxxxxxxxxxxxxxxxIs any company offering removal of the Bayer filter from a Nikon-mount DSLR? Particularly the D40? (I suspect it may not be feasible due to the stacking order and how the microlenses, AA, IR cut, and Bayer are combined, and other issues, and I haven't been able to Google up much, but I thought asking might still turn something up.) I'm interested in a high-sensitivity B&W camera for low-light situations.
Certainly nobody will do that, Also you could easily buy a couple of D1 MK 3 's plus assorted lenses for the cost of doing that.
I can't tell if you know more than me on this topic, or less. I don't believe that the Bayer filter is fabricated directly on the sensor as part of the manufacturing process in most cases, but I don't have a good specific source to point to, either.
I do know that a number of places offer cameras with the IR-block filters removed, and there are instructions floating around for how to do that yourself in various models. The cost for the commercial versions is modest.
It would be a more realistic approach to cool the sensor with liquid nitrogen (and float the camera with dry nitrogen to keep water out) to achieve a higher signal / noise ratio. A full frame sensor camera or a larger than full frame camera (like Mamyia) would be the easiest solution for achieving improved signal to noise ratio.
I very much doubt that LN cooling is feasible today for a camera I could use to take photos at dimly-lit music parties.
A larger-sensor camera would have lower noise, but it would use much slower lenses; this is why photojournalism and especially street photography migrated to 35mm in the first place.
In production multiple sensors are processed on a wafer (4", 6" or 200 mm) and only separated after they have run through all the processing steps (except for bonding).
Even if a pin compatible black and white version of the original sensor would exist, it would need custom developed image processing (ASIC's and firmware) because processing black and white pixels can not use the same weighting used as for processing the signals from a Bayer matrix sensor. Recording in RAW and using a customized external converter program to obtain an image from that would be slightly easier - but probably not for any *.nef files, as these are not true RAW but store pre processed data. The camera display would also be pretty useless, but I did not have that on my film cameras and could still take pictures.
Digital IR photos are frequently taken by using a visible-light-blocking filter. This greatly reduces the sensitivity, but usable IR photos can be taken with most digital cameras this way. I believe the dyes in the Bayer filter are mostly transparent in the infrared (or at least all the colors are about the same density in the infrared). With P&S cameras, the preview is reasonably accurate, and looks mostly monochrome, as does the captured image. So I'm not at all sure that a rework of the firmware (or external processing using a true raw file) would be necessary to achieve usable B&W results. (I've shot infrared with an Epson 850Z and a Fuji S2 using the Hoya r72 visible-light-blocking filter). (A rework of the firmware or external RAW processing with a special B&W version of the software might give some real increase in resolution, though.)
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- References:
- Bayer filter removal
- From: David Dyer-Bennet
- Re: Bayer filter removal
- From: cgiorgio
- Bayer filter removal
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