Quote:
Originally Posted by Peter Ward
The reason I made the exposures all 30 seconds was based on the following logic....
Object rains down say 900 photons in 30 seconds...and to simplify the argument, evenly spread in R, G and B
Multi-spectral camera gets all 900 photons shining on the sensor.
Mono Camera with R G or B filter in front gets only 300 photons. To get an equivalent "full spectrum dose" three exposures need to be made to get the equivalent 900 photons to the sensor.
Also I could only trip the 5D for a maximum of 30 seconds using a USB cable, and didn't feel like guiding any of the exposures  |
This is not so..
Mono camera gets 300 photons with each filter... which is 900 for RGB picture (three frames times 300 photons, right?)
But DSLR has 1/3 number of sensors for each colour. So the sensor gets 300 photons for the whole frame... this is 1/3 sensitivity compared with CCD mono.
Not fair comparison,