460EX or 428EX or 314+L requiring less exposure?

[donboysail]

Using the exact same scope settings, which model unbinned 428EX or 314+L  or 460EX 2x2 binned would require less exposure time to produce the same image of a DSO target?   

Don

[topboxman]

Yes binning reduces exposure. Binned 2x2 simply sums the adjacent four pixels squares. But binning 2x2 reduces resolution by a factor of 4.

For LRGB imaging, it's recommended not to bin Luminance but okay to bin each RGB filters. You will lose too much color information if you bin with Luminance filter.

Peter

[donboysail]

Yes 2x2 binning of a 460EX will yield a capture size of 1375x1100.  I assume then that the 460EX 2x2 binned camera would require less exposure than the 428EX unbinned.

Of course the FOV of the 460EX is 50% larger than the other two cameras and if one used less focal reduction to match the image size then maybe there wouldn't be any difference in exposure length of the binned 460EX over the 428EX or 314+L. 

And where does that leave the 314+L.  So the question remains then between the 428EX and 314+L about which one would require less exposure for the same target.

Don

[topboxman]

That's kind of difficult to answer. I think the best answer is to experiment with different cameras and binning of same object and evaluate the images.

Personally, I prefer to not to use binning mainly because of reduced resolution. 428EX, 460EX and 314L use same Sony Exeview CCD so the exposure should be about the same for same binning. Even though 428EX/460EX pixel sizes are a little smaller than 314L, 428EX/460EX are little more sensitive.

Bottom line, I believe you will not notice much difference using same exposure for same binning for all three cameras especially for deep space imaging because all three cameras share the same Exeview CCD technology.

I am not exactly sure what your goal is but it seems that you are trying to save time by exposing less using binning. I would look for quality images even it may take a little more time. It's rewarding to get great images if you work a little harder.

Peter

[donboysail]

What I'm after is the ability to capture images in the shortest time using one of these color cameras. I am not interested in LRGB imaging.  So I was hoping that someone would know which one of these cameras would fit the bill.  I assume the 460EX is a bigger chip version of the 428EX and that is why I suggested a 2x2 binning with the 460EX would still keep me in the same resolution range.   

Don

[topboxman]

If you bin color CCD camera, it will no longer be color. You cannot bin color CCD camera to retain color images. Binning color CCD will ruin the Bayer Matrix.

Peter

[Konihlav]

the problem is that your question can't be answered the way you put it :-) even same scope settings, as you say, can't guarantee the same DSO image (as you want) because the cameras have different pixel sizes and that binned one would render image twice smaller (but with larger FOV due to bigger chip surface). The binned image being smaller means it shows less details, but due to increased SNR it will look smoother (if you care about noise - compare images by noise level vs. time needed to get the same, nice looking image - pretty pictures work)...

to put it simple, 428EX and 460EX have the same ExView HAD II technology with much reasonably higher QE (good for LRGB) then the 314L+ but they have a bit higher RN (readout noise) which may sound (it usually is that case, but this time there's an exception) it is worse for narrow band, but I calculated that the notably higher QE can compensate the 5e- vs 3.9e- readout noise increment in the new HAD II chips...

sorry I can't tell more details, I am too tired today, my eyes can't see any LCD screen any more after spending many hours at work last few days... one day I hope to find the strength and mood to write a large case study (article) for my blog on cameras...

in short, if you care about narrow band, any of these cameras you mention is the best thing you can purchase based on what's today on the market available. I personally fully advice to get 460EXM (I own one of these babys too ;-) )

[Konihlav]

if you want to purchase an OSC (color version of camera, like 314LC+ or 428EXC or 460EXC (notice EXC is color and EXM is mono)) then the only difference between 428 and 460 is the chip size, i.e. FOV you get. Everything else is the same (except of price). 314LC+ is nice, but I would not buy it today when you can have 428EXC the 428 has much smaller pixels which is good for OSC color cameras.

[donboysail]

Thanks Peter and Konihlav for your replies.  I learned alot, for one I didn't know that binning in a color camera doesn't retain color cause the Bayer matrix gets messed up.  We're still in the investigating stage and there is more to check out.

Don

[bwa]

Not to totally confuse issues here BUT some color CCD's do offer binned color.  Kodak's KAI-10100 color sensor does color binning on-chip to offer color at 2x2 and 4x4 binning.  It is used in Celestron's Nightscape color CCD.

I don't believe any of ATIK's CCD's offer this option?

bwa

[topboxman]

That's true. SXVR-M26C also has color binning. But I have read the results aren't very good and it requires software to handle this. For SXVR-M26C, I believe only Nebulosity can bin color but the reports I've read is not so good.

So for binning 2x2 or greater, you are better off to get mono camera plus filters.

Peter