Quote:
Originally Posted by Peter Ward
So, getting back to the original post. Yep, it is pretty obvious given the same flux, a dedicated medium QE CCD astrocam shows higher dynamic range, better QE, lower noise etc than on off the shelf Premium DSLR
|
Hello Peter
So what then was the purpose of the test other than comparing apples to oranges.
My reason for using the term subjective still holds as you obviously feel that comparing a CCD to a off the shelf DSLR is valid.
The test would be objective if you leveled the playing field.
For example you say you optimised the shot noise for both cameras by applying a software algorithm. Correct if i am wrong but shot noise or Poisson noise relates to the random variation in the incoming photon flux. That was on a par for both cameras to start with.
If you discount the IR cut off filter in the dlsr, the different QE's, the non linearities of QE/wavelength, the differences in gain or conversion factor, the differences in dark current, the differences in readout noise, the differences in bias current and then present 2 pictures one showing more red than the other then i fail to see objectivity. Your test was subject to vast differences in camera specification and then to illustrate something that should be obvious.
The high ISO or gain on the DLSR also adds extra noise and narrows the dynamic range of the DLSR to say nothing of the 16bit ADC vs the 12bit ADCf the DLSR.
So imo apples and oranges, hyundais and SLK,CCD and CMOS makes for an unfair and biased comparison which is not objective.
What the test illustrated for me is that the canon 5d produces a good image although a few tweaks would certainly narrow the gap substantially.
The current range of CCD's are certainly superior but this may not always be the case given that the CCD technology is in effect old technology and the CMOS technology is newer with a better future potential.
Regards
Steve
Just my opinion
