M27 - Nikon D3 v Atik Titan

[fatwoul]

Last night I put my Titan through some tests, and I thought I'd compare the results with those from my D3.

Here's M27 taken with the D3, representing about 4 hours worth of exposures (cropped to match the Titan):

Here's that image's blue channel:

And green channel:

And red channel:

And here is the Titan's effort in just 30 minutes:

Suffice to say I am more than satisfied with my new camera (in fairness, the jpg artifacts in the D3 images are from the compression for putting them online, but still, the Titan image survived this better).

The only snag I've hit is one of pixel offset. I tried to paste the Titan image into the D3's red channel, and blend them. Unfortunately, the images do no line up - due to the pixel size, they are always offset from each other in one direction or another.

I suppose I could make both images much larger, which would allow them to overlay more accurately, and then scale them back down, but that seems a little OTT at this stage.

Anyway, I'm happy.

[lukebl]

That's a good demonstration of what these these small-chip CCDs are capable of. They are great for smaller objects, as I've found with my MX716 which has a similar sized chip.

[MartinB]

The Atik has certainly passed the test!

If you are trying to use layers in PS to combine the channels and you can't match up the pixels you could try using the offset to shift the pixels in the direction you want. The minimum offset is 1 pixel in each axis so you will overshoot. However, immediately after running the offset go to the edit menu and select fade, it should come up as "fade offset" or something similar. You can now tweak with the slider to allow a sub pixel adjustment. You will probably need to do one axis at a time.

I presume this will work, I haven't got PS in front of me to double check

[lukebl]

Hope you don't mind, but I couldn't resist a little play with your images. I have used the colour from your DSLR image and merged it with your Titan image. Not easy with compressed JPEGs, though.

[Grinde]

A very interesting comparasion!

The mono ccd clearly gathers more signal, since it doesn't have to shoot through the colorfilters like bayer matrix on the dslr sensor, it'd be even more interesting to see the result if you made a LRGB image with the ccd to compare. My guess is that the ccd can get away with less exposuretime to match the noiselevel, especially with x2 binning while shooting the color subs.

Can you add a desaturated black&white version of the D3 image (instead of splitting the channels) ?

Thanks for posting, I'm really interested in those tests

[fatwoul]

MartinB - thanks I was really pleased. I'll give that a go, so cheers for the advice.

lukebl - Of course I don't mind. Your version looks brighter, but the overall colour is about the same. I'd like to try and get the Titan image blended specifically into the red channel of the colour image, and see if that helps bring out the red a little.

Grinde - Give me a sec and I'll see what I can do.

[fatwoul]

As requested...

D3 image desaturated:

Titan image:

For me, the most noticeable improvement is in the darker lobes, top and bottom - they are markedly smoother in the Titan image, without the weird edges ("weird edges"? how's that for a professional-sounding analysis?)

[AndyUK]

What a superb comparison... I'm not surprised that you're very happy with it! It certainly begins to show some of the differences between CCD vs DSLR.

As a matter of interest, what temps were the two different shots taken at? My DSLR was recording chip temps of 26C last night, which obviously can't be good (), but again, that's where the CCD will score time after time, especially at this time of year!

(I love Luke's merged image... I wonder if there's enough "dark time" for me to have a go at an RGB of this with the MN190/314 ?)

[fatwoul]

I just noticed that this thread has made it onto the FLO page for the Titan. I really should use this camera for more stuff in its own right. It really does a nice job.