Night shooting with the CP990
Last updated June 20, 2000. Look for future updates!
In spite of all the talk and worry about "hot pixels" and noise on long exposures, the CP990 is actually very good at low light shooting. Really, the big trick is that you will have to do a quick clean up of your shots if they are more than a few seconds long in your favorite photo program.
Lets look at a few samples. (The originals are large, but I have reduced the processed shots for more reasonable loading times)
Click the picture for the full sized version.
(warning, about 1 meg)
A 21.5 second exposure at ISO 100. This was taken about 1 hr after sunset. The sky was not that bright or colorful to the eye. You can see some CCD noise on the shot. Two of the brightest points are actually stars. I used the WC-E24 wide angle lens.
Click the picture for the full sized version.
(about 100K).
(Above) The same 21.5 second shot, "fixed" in PhotoPaint 9. I used the median noise removal filter for a quick cleanup. Since the noise is due to individual pixels, you can use the filter with radius 1 for no loss of sharpness. One nice thing is that since the real stars are larger than a single pixel, the filter left them alone. I think that this shot looks pretty good.
Click the picture for the full sized version.
(about 1 meg!)
A raw 8 second ISO 100 shot. At 8 seconds, the shot already looks pretty good, without much noise. It hardly needs any cleaning up at all. WC-E24 wide angle lens.
Click on the picture for the full sized version.
(about 100K)
The cleaned up version of the above 8 second shot. Again, I used the median noise filter in PhotoPaint 9 with a radius of 1.
Tips and observations for night shooting.
* You will see CCD noise on all of your shots over a few seconds long. You will probably want to clean this noise up in your photo program. On areas of your subject that are not totally black, the noise will hardly be visible.
* Stay at ISO 100 and make a longer exposure, rather than trying to boost the ISO. For example, a 16 second shot at ISO 100 is less noisy than a 4 second shot at ISO 400.
* Use a tripod and cable release. I am using a homemade cable release (I will publish the details later). If you don't have a cable release, you will be limited to 8 second shots. Use the self timer in that case to minimise vibrations.
* I find that the 990 is useable on very dark subjects at up to maybe 25 seconds at ISO 100. After that, no more detail is really recorded, and the noise becomes excessive.
* This may seem silly on a night shot, but watch out for overexposure! It is easy to overexpose when you are talking about such long exposures. Although it is tempting to open the shutter for 60 seconds on every shot, it is usually not necessary. 2 to 8 seconds will give very nice shots of artificial lights at night. Below is an example of a 12 second shot that was overexposed.
Overexposed at 12 seconds.
* Use manual focus. You can't trust the autofocus system in such low light, and it is really too much to expect it to work. Keep in mind if you use the Nikon Teleconverters that the manual focus settings will be wrong.
* Don't forget to turn off the flash, or you will feel dumb.
* Because the noise on the CP990 is comprised of single pixels on the CCD, you will want to use low JPEG compression to avoid having the compression routine cause a single hot pixel to bleed out into the adjacent pixels. If this happens, it is harder for your noise removal routine to remove the noise. I usually shoot in Fine mode, but you can see some slight improvement in noise removal if you can stand to use TIFF mode. Nice discrete single pixels are perfect fodder for noise removal routines.
* Reduce the sharpening. I use low sharpening or no sharpening. You can sharpen your shots later. The reason is, again, that the sharpening can blur individual noisy pixels and make the harder to remove.
* Turn off the auto contrast feature (set it to normal). Again, this is because you can get some funny results with low light shots with it on.
* White balance. Although the auto white balance may actually work quite well in most cases, you might want to set the camera to daylight white balance. The reason for this is that the auto white balance does not have a lot of light to work with on some of these shots, and you will sometimes get a funny off color (usually very red or orange) shot.
* Effect of temperature. The CCD in the camera is noisier at higher temperatures. While there isn't a whole lot that you can do to control this, one thing that I do is to only turn the camera on when you are ready to take a shot, and leave it off to cool otherwise. You can experiment with cooling your camera if you want to, but it is really not practical, and watch out for condensation!