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02-16-2008, 12:37 PM   #16
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QuoteOriginally posted by jeffkrol Quote
Well maybe you are being a bit extreme:
Here's 2 images
One at 200, pushed 3 stops (per RSE)
One at 1600 "normal". Small -ev adj just to make things a bit more equal looking..
To be completely honest, the 1600 looked a little better because the sensor (which was swapped out) on my D now has some horiz. pattern noise. The 1600 image came out much flatter than the way underexposed 200 onr though.....
The 1600 image has FAR less detail than the 200...

02-16-2008, 01:04 PM   #17
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QuoteOriginally posted by AVANT Quote
The 1600 image has FAR less detail than the 200...
Yes, thanks for bringing that up. Not sure where the 1600 is getting smoothed out.. Tried Pentax software on a new image, same smoothing (err.. noise reduction): I'm pretty sure with a little PP noise reduction I can make the 2 identical w/ a slight edge to the 200 (at 3 ev boost).
02-17-2008, 03:06 AM   #18
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Some additional information:

QuoteQuote:
Intensified CCD with fiber-optic coupling
An image intensifier helps to increase the sensitivity of a camera by amplifying the input light signal before relaying it to the CCD/CMOS sensor of a camera. There are in principal two ways to relay the output image from an image intensifier to a CCD/CMOS sensor. The first is by means of a relay lens. A lens coupling is flexible, but the downside is that a lens coupling has a relatively low efficiency caused by the limited aperture of a lens. A more efficient way is to use a fibre-optic window to transfer the image from the intensifier to the CCD. Such a fibre-optic window contains a large number of small (6-10 micron) individual fibres and is acting as an image guide. By using a tapered fiber optic window a magnification or demagnification can be accomplished. Generally a de-magnification factor is chosen that will best match the CCD/CMOS sensor size to the output diameter of the intensifier.

Source: CCD camera sensitivity - by cooling or by coupling to an image intensifier - Lambert Instruments
My understanding is that most CCD/CMOS cameras today use this intensifier method. Light is physically amplified BEFORE being absorbed by the CCD.
02-17-2008, 03:13 AM   #19
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QuoteOriginally posted by AVANT Quote
Some additional information:



My understanding is that most CCD/CMOS cameras today use this intensifier method. Light is physically amplified BEFORE being absorbed by the CCD.
Most modern conventional camera image sensors have a micro-lens array integrated into the array, that's the only form of focusing or intensification.

Tutorials - Digital Camera Sensors

02-17-2008, 04:47 AM   #20
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QuoteOriginally posted by distudio Quote
Most modern conventional camera image sensors have a micro-lens array integrated into the array, that's the only form of focusing or intensification.

Tutorials - Digital Camera Sensors
The purpose of Microlens is to increase the efficiency of the senor by gathering light that would have previously been lost. It is not the layer that creates the intensification.

QuoteQuote:
Single microlenses are used to couple light to optical fibres while microlens arrays are often used to increase the light collection efficiency of CCD arrays. They collect and focus light that would have otherwise fallen on to the non-sensitive areas of the CCD.

Source: Microlens - Wikipedia, the free encyclopedia
02-17-2008, 05:08 AM   #21
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Source: How Intensified CCD Cameras (ICCD) operate

They aren't in the digital camera CCD market, but the design idea is still there.

Notice the separate layer where electricity is passed through. That's where light is being intensified (amplified). This is all before the CCD actually gets a chance to capture the light.

Cameras like the D300 can "boost" to 6400 ISO, but can operate at 200-3200 ISO without "boost". Because to get 6400 ISO, it is using the processor method of underexposing and bringing the exposure back up, but the 200-3200 is through physical amplification of the light signal.

I've had to do a bit of research since I only knew the basics of it before, very interesting reads.
02-17-2008, 09:44 AM   #22
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this thread is soo cool.
02-17-2008, 12:04 PM   #23
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Don't know if anyone's mentioned this but take a read of this flickr discussion. Same topic (more or less) with Nikon D50\70. Click Here.

Thanks

02-17-2008, 12:22 PM   #24
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QuoteOriginally posted by AVANT Quote
Light is physically amplified BEFORE being absorbed by the CCD.
Interesting thought!

One should be aware of the fact that light cannot easily be amplified. Light amplification means to transform one photon into many which isn't possible by a first order process.

What light amplifiers typically do is create an electron from a photon and then create many photons from there on. This does not make much sense if one is interested in electrons only. It's possible too to amplify by chemical processes but I'm unaware that this is used in the optical industry at all.

A quote from TechTalk ... Single Photon Detectors:
QuoteQuote:
Photon Counting CCD - charge coupled devices offer excellent quantum efficiencies comparable to that of good photo-diodes. Recently, a CCD with additional ionisation based charge amplifier at the output stage was release which was claimed to allow photon counting, at least if strongly cooled. Still, two major problems appear, the size of the single CCD spot, which is a few µm diameter only (larger areas would not allow photon counting anymore) and the very low readout time. The same spot on a CCD usually is read out not faster than 30 ...60 times a second, which makes this detector unusable for 99.95% of all photon correlation experiments. Unfortunately, there is little hope, the frame readout time will ever be as fast as 10 .. 20 ns, not even 1 µs.
So, if the CCD signal really must be amplified, it is done by electron-physical effects (like the avalon effect, I assume).

EDIT:
Note how disappointed the original poster was that 1,000,000 fps may be hard to achieve
02-17-2008, 01:42 PM   #25
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QuoteOriginally posted by AVANT Quote
The purpose of Microlens is to increase the efficiency of the senor by gathering light that would have previously been lost. It is not the layer that creates the intensification.
You said "My understanding is that most CCD/CMOS cameras today use this intensifier method."
I said "they don't", and as impressive as the technology is I'm pretty sure that we aren't going to have multi-stage Peltier/water cooled ICCD in regular digital cameras ever.
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