Is filtered imaging going to be superceded?

[gregbradley]

Sony is working on 2 types of sensors that could have uses in astrophotography.

One is an active RGB filter array that moves to do the RGB exposure and combines the 3. I imagine that would have to be done super fast or at least match 1/3rd of the shutter speed to work.

The other is a Foveon style sensor where RGB data is collected off the sensor rather than through filters in front of the sensor. Foveon works by extracting the signal at various depths in the silicone as red goes deepest green the 2nd and blue the least.

The trouble with existing Foveon sensors (Sigma Foveon cameras) is they are very noisy at higher ISOs.

But imagine a sensor that gives colour images but every pixel counts and no light sapping filter array in front of it and 4 pixels played with to make a colour image.

Greg.

[glend (Glen)]

Is this the Active Pixel Colour Sampling sensor that obtains colour data for every pixel. The IMX189 CMOS single layer sensor is rumoured to be the first to use this approach.
Here is a diagram of how it works:

http://www.sonyalpharumors.com/sr4-d...mpling-sensor/

I have not seen any detail on how long bulb exposures would work, unless perhaps you have to set the exposure on the camera controls and it then moves the filter matrix to build the sub. So a 300 sec sub would be exposed for 3 x 300 seconds to build a RGB 300 second sub which would take at least 900 seconds to generate in theory.

[Bassnut (Fred)]

Its all smoke and mirrors, granted the Foveon sensors allows much higher res, but it slams QE, useless for astro. Sony sensors and Nikon are spawns of the devil, designed to destroy civilisation as we know it, over proper KAF sensors and Canon. Beware.

[gregbradley]

Very funny Fred.

What do you see as the strength of a Canon CMOS DSLR sensor over the Sony?

Sony has considerably higher dynamic range - 14.5 stops versus Canon's best at around 12.5-13. Push the shadows on the Sony and the image comes up, do that with a Canon you get heavy noise and fixed pattern noise.

Canon are good at proper RAW (or at least they used to be) good for time lapse (or used to be). Not so sure about Canon white balance. Sony's and Fuji's are top notch.

Greg.

[rally]

Links Greg ?

[gregbradley]

Originally Posted by rally

Links Greg ?

This area is pretty well documented and often discussed on DPReview.com

Here is one link:

http://www.bobatkins.com/photography...mic_range.html

The Nikon D800 is the Sony 36mp Exmor sensor. Its the same story with the 6mp Exmor sensor which is used in several branded cameras from Nikon D7000 to Fuji X and Pentax K. The results are the same.

The Exmor achieves this by having the analogue to digital conversion done on the sensor at each pixel site. The Canon does this off sensor and the longer the path to the ADC the higher the noise.

Its one of Sony's marketing strengths for their sensors. Sony is the largest manufacturer of CMOS sensors with 42% of the global market.

The 4 main sensors in digital cameras that Sony make are the 16mp an 24mp APSc Exmor (the 16 is bit long in the tooth now) and the 24 and 36mp full frame. A rumoured near 50mp Exmor is coming as competition to the Canon 50mp sensor. It won't even be close (the Canon that is).

Sony's mill goes down to 15 microns and Canons aging facility is more like 300. So that is another factor. Canon though still make awesome cameras and their sensors are still sensational, simply that the Sony is better.

However that does not necessarily translate to better for astrophotography. Sony for example hot pixel filter their RAWs which can clip dim stars like Nikon used to do. Naughty Sony.
Sony also only output a compressed lossy RAW to make smaller files.
But a Sony sensor in a Nikon does not do this but may have other issues for astro.

Canon as far as I know are still most suitable for astro. Modded 6Ds seem awesome. We don't really need that extra dynamic range so much although it might be handy when bringing up dust areas in an image that you can boost it without colliding with a ton of noise.

Greg.