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Old 27-08-2013, 01:53 PM
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graham.hobart (Graham stevens)
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SX colour camera question

On the SX website- with the new cameras it is reporting the same QE for both mono and colour cameras. Is this taken before a bayer matrix is applied or after the rgb film is on?
SX 814 and SX 814C Trius = 77%QE
? Any thoughts

Graz.
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Old 27-08-2013, 02:40 PM
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There would be no way the colour has the same QE.

A good one shot colour QE is 35%. Perhaps this is better at a guess
it might be 45-55%.

Greg.
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Old 27-08-2013, 02:43 PM
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multiweb (Marc)
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Here's a cool chart.
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Click for full-size image (QE_PBernhard.jpg)
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Old 27-08-2013, 03:15 PM
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graham.hobart (Graham stevens)
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sx colour

it's an ICX 814 Sony sensor-maybe they are just reporting the lab data before the rgb as the colour and mono data sets are the same on the AEC link to the SX website.
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Old 27-08-2013, 04:40 PM
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Quote:
Originally Posted by multiweb View Post
Here's a cool chart.
Excellent chart. It's funny, the older the chip, the higher the QE (at Ha)
. So much for advancing technology
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Old 28-08-2013, 07:23 AM
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Originally Posted by Bassnut View Post
Excellent chart. It's funny, the older the chip, the higher the QE (at Ha)
. So much for advancing technology
Yes I thought the same thing. Why did Kodak abandon whatever they did on the KAF3200 chip? Was it in response to the false diffraction spikes that chip sometimes had I wonder.

It seems they dropped something out that was successful, at least for our use anyway. I guess not too many customers wanted Ha response they were more after RGB response.

Greg.
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Old 28-08-2013, 09:22 AM
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Graz. Based on other Sony chips, colour QE is probably somewhere round .55 - .6, likely to be something like that shown in figure 8 of: http://www.ptgrey.com/support/downlo...for_ICX445.pdf

note that colour QE only applies in the transmission bands of the Bayer filters - you actually end up with less than about 1/3 of the photons getting through the filters, so the effective QE compared to broadband is likely to be a bit less than 0.2 for a high performance OSC.
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Old 28-08-2013, 11:06 AM
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Kind of misleading their quoting such high QE numbers. It needs to be an apples to apples comparison. So a mono QE figure obviously is what the sensor actually does.

A colour sensor is way less as its got a bayer or other array on top and that weakens QE a lot as you point out. So 35% is more likely a figure.

True Sense Kodak colour arrays are likely to be higher because they have some clear filters in there just like LRGB imaging uses.

One of the DSLR manufacturers also has that technology. I forget which one now.

If someone is planning to get one shot colour then realise it will be a fraction of the sensitivity of the mono. Probably something like 1/2 or less sensitive. Due to the maths used to calculate the values of surrounding pixels it isn't 1/4 or less as it may seem but its a big hit to sensitivity.

Greg.
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