Imaging Source DMK 21AF04.AS
Camera review for solar system imaging
Page 5 - Resume
The DMK 21AF04.AS is great value for money and a good performer for solar system imaging. Many top planetary imagers use the cam successfully, there's no bad surprise in the camera's behaviour.
Signal processing of the device is ok - I didn't experience any noticable systematic noise like banding patterns for high gain recordings unlike the camera I used before. Personally I consider the Sony ICX098 CCDs a good trade off between sensitivity and pixel size. Pixels are small enough to obtain small FOVs per pixel even with newtonian reflectors and 5x focal length enlargement and still offer a viable noise characteristic and good sensitivity considering pixel size.
One may ask the question if a higher analog to digital conversion depth
than the camera offers can deliver better results. Basically a higher
bit depth allows fewer frames to be stacked to reach the same effective
bit depth as a result created with lower bit depth raw frames. Additionally
a higher bit depth can lead to identical results with slightly underexposed
frames compared to correct exposed frames with a lower depth - nice in
low light situations and sessions where short exposure times are required
to beat seeing. The number of frames required to obtain a certain signal
to noise ratio enhancement is not related to the bit depth, though.
The camera comes with a good and practical software package which is not too common for other cameras of this segment. The long exposure capabilities of the cam are fine to make a start into deepsky photography but the missing active cooling and only 8 bit A/D conversion don't make it a specialist for this task. The DMK 21AF04.AS is currently quite unrivaled in the price segment, some potential rivals may show up soon. The camera is highly recommended to solar system imagers looking for a solid & well known performer who don't want to invest in the range of 1000€.
Oliver Pettenpaul - July 2007