#1  
Old 27-08-2013, 01:53 PM
graham.hobart's Avatar
graham.hobart (Graham stevens)
DeepSkySlacker

graham.hobart is online now
 
Join Date: Nov 2008
Location: hobart, tasmania
Posts: 1,992
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.
Reply With Quote
  #2  
Old 27-08-2013, 02:40 PM
gregbradley's Avatar
gregbradley
Registered User

gregbradley is offline
 
Join Date: Feb 2006
Location: Sydney
Posts: 15,452
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.
Reply With Quote
  #3  
Old 27-08-2013, 02:43 PM
multiweb's Avatar
multiweb (Marc)
ze frogginator

multiweb is offline
 
Join Date: Oct 2007
Location: Hinchinbrook
Posts: 18,185
Here's a cool chart.
Attached Thumbnails
Click for full-size image (QE_PBernhard.jpg)
178.5 KB64 views
Reply With Quote
  #4  
Old 27-08-2013, 03:15 PM
graham.hobart's Avatar
graham.hobart (Graham stevens)
DeepSkySlacker

graham.hobart is online now
 
Join Date: Nov 2008
Location: hobart, tasmania
Posts: 1,992
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.
Reply With Quote
  #5  
Old 27-08-2013, 04:40 PM
Bassnut's Avatar
Bassnut (Fred)
Narrowfield rules!

Bassnut is offline
 
Join Date: Nov 2006
Location: Sydney
Posts: 4,772
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
Reply With Quote
  #6  
Old 28-08-2013, 07:23 AM
gregbradley's Avatar
gregbradley
Registered User

gregbradley is offline
 
Join Date: Feb 2006
Location: Sydney
Posts: 15,452
Quote:
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.
Reply With Quote
  #7  
Old 28-08-2013, 09:22 AM
Shiraz's Avatar
Shiraz (Ray)
Registered User

Shiraz is offline
 
Join Date: Apr 2010
Location: ardrossan south australia
Posts: 4,787
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.
Reply With Quote
  #8  
Old 28-08-2013, 11:06 AM
gregbradley's Avatar
gregbradley
Registered User

gregbradley is offline
 
Join Date: Feb 2006
Location: Sydney
Posts: 15,452
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.
Reply With Quote
Reply

Bookmarks

Thread Tools
Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +10. The time is now 05:37 PM.

Powered by vBulletin Version 3.8.7 | Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
Advertisement
SkyWatcher Australia
Advertisement
Lunatico Astronomical
Advertisement
Bintel
Advertisement
NexDome Observatories
Advertisement
Celestron Australia
Advertisement
Meade Australia
Advertisement
OzScopes Authorised Dealer
Advertisement
Astronomy and Electronics Centre
Advertisement