Here are 2 comparison shots of Copernicus, one a crop of a 350D image ( LEFT ) the other a full frame webcam image ( RIGHT ). The central image shows the larger 350D image, rotated to match webcam shot, which is also a crop of a full frame which I had compressed to 1600x1600 pixels for emailing so is still not original resolution.
Webcam image was processed with Registax 4, multi point aligning, from 300 frames.
Both were similar phase of moon as can be seen by shadow details.
I have my opinion as to which I prefer but what do you think ?
PLEASE NOTE : Images are not from same photo session .... if that affects your opinion, please don't vote !
Last edited by bluescope; 01-05-2007 at 06:02 PM.
Reason: clarification
Steve - if these were both presented at the same luminosity, I still think that the 350D image is far more descriptive. The ejecta around the crater rim is well defined, whereas it's not in the webcam image.
Good to know it's not too far behind though! Well done on the comparo
Not sure Eric, probably several months without hunting through all my files, I have a large library of lunar images over the past 18 months or so .... so this is not a same session comparison .... it's a resolution question I suppose comparing single exposure versus stacking.
Quote:
Originally Posted by erick
Taken how far apart in time, please Steve? (I'm looking at the shadows in the craters)
Agreed Chris, considering the webcam costs around one tenth the price of the 350D and has a much smaller chip !
Quote:
Originally Posted by Omaroo
Steve - if these were both presented at the same luminosity, I still think that the 350D image is far more descriptive. The ejecta around the crater rim is well defined, whereas it's not in the webcam image.
Good to know it's not too far behind though! Well done on the comparo
.........BUT, what was the Trans, Seeing, etc like in each one. Can't really compare without having matching observing conditions....
That is where I was headed. Though I have no direct experience, I would expect that different transparencies and seeing conditions would be important to image quality. Secondly, I reckon that even a small difference in the incident sunlight angle could lead to big differences in definition of the surface objects. From the shadows in the craters, the incident sunlight angle seemed somewhat different between the two images.
ps. I voted for the 350D image. However, I could happily cope with both framed on my wall .
While I appreciate the attempted comparison, I don't think it can be used as a true comparison.
As others have said, it really needs to be done on the same night, same illumination, same conditions.
The webcam image is overexposed in some areas, and looks like it was taken in worse seeing and/or not processed to the best it could be. It looks a bit too smooth.
For a larger format image, the 350D will be great it would be possible to take a few using burst mode to stack, but the results will be limited and will still end up quite noisy if you take a crop.
The resolution of the webcam is limited at 640x480, but at longer focal length it will always out-do a DSLR (in my opinion) due to its ability to take many frames (over 1800+) and capture the seeing. That is, taking so many frames will allow you to find the sharp ones as the seeing fluctuates, and stacking the best few hundred will reduce noise and enhance detail (through processing).
You would have to be quite lucky to get a very sharp image across the whole field with a DSLR, as you need to capture that image when the seeing is good.
DSLR's are great for "whole moon" type shots where you want the large format and wide field of view. Assembling mosaics from small webcam images is very time consuming.
I look forward to more comparisons as it's a very worthwhile exercise! Well done!
Thanks for participating in the pole so far. I don't think anyone should take this too seriously, it's just a bit of fun after all and not a controlled scientific experiment ! All of your opinions are appreciated.
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