3CCD CAMERA FOR SALE

I've been using a Philips SPC900nc webcam for the better part of a year to do my lunar and planetary imaging with and decided to upgrade to a DMK21AU04.AS (Monochrome). Here is a controlled comparison between the two cameras.

This test was done indoors with controlled lighting where I targeted a dim object at 25fps which is a typical planetary situation with my f10 scope and a 2.5x barlow.

My assesment is that for ~$50 the SPC is a great place to start and to develop your skills. However, the DMK is clearly in a different class than the webcam. You can run it at any framrate/exposure with spectacular image quality (no hot pixels, no banding, very sharp resolution, with no muddled areas like webcams produce). Also dropped frames just don't happen - at any framerate/exposure! The SPC would drop about 5% of frames at 25fps and at other framerates it would drasticly increase to around 10% to 25%! **edit: turns out that when the frame rate drops below 1/25th of a sec, the SPC sends blank frames so it can continue to send 25fps to the computer even though only say, 10 frames per second are being recorded - thus it's doing exactly what your asking it to, but it appears as if it's dropping frames** Also, the SPC has terrible banding at all framerates which requires constant darkframes to be taken and used in processing. With the DMK, Noise is greatly reduced from that experienced with the SPC and more importantly, it's perfectly uniform across the image which makes darkframe subtraction, for the most part, unnecessary.

I found the SPC limited my range of exposures and thus made it virtually impossible to get a good contasted image. This is very important for obtaining focused, sharp images with good detail. The DMK will definately allow me to get the right exposure w/o having to comprimise the image quality.

**Added**: I have started to use both cameras together to obtain LRGB planetary images which has worked quite nicely! I also found that using 5fps or 10fps with the SPC makes for uncompressed frames (higher quality) where-as using 25fps gives me compressed frames which resulted in the "muddled" appearance mentioned above. Another added benifet of using the 2 cameras together (over 4 color filtered images combined - true LRGB - is that you can get nearly the same information in 1/2 the time which is very important with the fast ration of Jupiter and Saturn. Oh - and the $50 SPC is much cheaper than $250 for even a cheap RGB filter set and manual filter wheel! This makes a pretty good combination!

This was the sunset on Saturday when super moon was coming. As most of the people went to see and shoot the super moon, I was wandering in Terra Nova watching the sunset.

I forgot to bring my ND filter and so my Nikon was strling to capture the high contrast in the scene.

I am always lazy and careless in making sure of high technical quality in the pictures. I don’t think much details in highlight and shadow are recorded and this is of course a flawed image.

Many photographers including amateur and professional care a lot about technical quality in pictures.

I always give myself the excuse and argument to escape from this. When you put a lot of effort in getting the best technical quality, you may be putting less effort in aesthetic quality at the same time.

With the advance of technology, the technical quality in the pictures will be surpassed in 10 or 20 years the most. But the great aesthetic beauty in Atget’s Paris pictures or works by Henri Cartier-Bresson will last 100 years or 1,000 years even when the modern cameras and lenses can produce better quality than the ones used by Atget or Bresson.

So I remain lazy in learning the high dynamic range in Photoshop and all the sophisticated techniques in digital world. I am still shooting JPEG and using cheap glasses. I am not interested to analyze the test results of all the gears and optics. I wonder if Van Gogh will bother to choose the brushes and paint before he draws the sunflowers and self portraits.

Happy Monday and great week ahead!