RAW shots of stars converted to Jpg in DPP lose colour. Can this be avoided?

[ScottHolder]

I took a RAW shot of Jupiter with my EOS T3i, and background stars appear in red and blue, as well as white. However, when converted to JPG in Digital Photo Professional, the stars lose their color and all are white. Is there a way to convert to JPG without this colour loss?

Also, Photoshop CS2 will not read the .CR2 files. Is there a workaround? If not, is there another photo editor I can use?

[cicopo]

You should be able to convert the CR2's to DNG's which can then be processed in CS2.

[ScottHolder]

I've tried Adobe's DNG converter, but it doesn't see the .CR2 files.

[TCampbell]

Are you sure that's not sensor noise?

When we refer to stars as "red" or "blue" they are really mostly white with a very pale tint of blue or pale tint of red (unless you are looking a star named "Hind's Crimson Star" in the constellation Lepus (below Orion) -- that star *is* red -- there's nothing subtle about it. )

When you convert an image to JPEG, the JPEG algorithm may apply some image smoothing as a byproduct of it's compression. If you do not want any image quality loss, convert the image to TIFF (TIFF is a "non-lossy" format... JPEG Is a "lossy" format by definition.)

Are you taking the photo of Jupiter through a telescope?

There is a technique whereby you take many images (actually people often use video to record a couple thousand frames) and then use a program called "Registax" which performs image stacking. The stacking improves the look of the planet, reduces sensor noise, and can correct for chromatic aberration caused not by the lens... but by the atmosphere (the atmosphere behaves like a lens... you'll notice opposite ends of the planet have a blue fringe vs. a red fringe.)

[ScottHolder]

I'm not entirely convinced that the stars are sensor noise. They are sharp dots against a black background, appearing just like a starfield. If I increase the brightness to the maximum, noise does appear, but looks very different from the points of light that I believe are stars. When I convert to TIFF, the points remain, but the colour is gone. I'm not using a telescope. I'm using a telephoto lens at 250mm.

[hsbn]

then can you put up some sample photo? If it's sharp dot, it's more like noise because at 250mm, in order to capture a star as a sharp dot, you'll need exposure time of 1.25 second or shorter. Anything longer will make your stars blurry. Also I assume your lens will not be wide (F2.8 or larger), so there is no way you can capture it as a sharp dot unless you're using tracking device of some sort.

[cicopo]

If I remember correctly Tim & at least one other member here are heavily involved in astro photography so I'd be inclined to think it's noise or hot pixels etc vs colored stars.

[hsbn]

The red/blue sounds more like noise than stars. It's either noise or hot pixel which will be remove upon converting to JPG.

[ebiggs1]

I would like to know your detailed set-up.

If you have a T3i with the 55-250mm f4-5.6, I am surprised you got anything. You could be seeing some CA. That lens at full zoom (250mm) is not real good.

Also what settings in the camera did you use.

[ebiggs1]

"Also, Photoshop CS2 will not read the .CR2 files. Is there a workaround? If not, is there another photo editor I can use?"

Yes,  update you Photoshop. What version do you have? PS is the software of choice. 

Need way more info from you.