I’ve been using my ZWO 1600 mono for a couple of years now and there’s no going back
but once my rig has been setup and is imaging away, it requires very little attention (usually!).
This leaves me with not a lot to do on those nights out at a dark site. As a result, I’ve been experimenting with a couple of entry-level cameras I have to hand.
Of course, this led my mind down a bit of a rabbit hole when it comes to the data I get from my cameras...
Canon 1100D - this is a classic IMO, inexpensive and no frills, and I’ve astro modded it as from the factory (almost?) all consumer cameras are weak outside the visual wavelengths of light, including the valuable Ha band. This camera has the ancient Digic 4 chip (most recent Canon camera have the Digic 8), and saves its data in the CR2 RAW format that is well supported in most astro software.
Fujifilm X-A3 - I bought this as a point and shoot mostly for daytime, but the curiosity got the better of me of course
This camera has much more recent Sony sensor with the standard Bayer array, unlike the rest of the X-series cameras. Regardless, the Fujifilm RAF RAW format is much less well supported, although support exists in DCRAW and Adobe Camera RAW. Interestingly, this camera seems to have a much less aggressive near-IR cut-off, and Ha emission targets show up reasonably well, for an unmodded camera.
Both cameras have been superseded by more recent models (many times, in the case of the 1100D!), with updated sensors and/or on-camera processing engines. The 1100D is always used with long exposure noise reduction off, and the X-A3 with Noise Reduction set to -2, which is the lowest value, there is no option for off.
Which leads me to question...when is RAW, RAW?
While I appreciate these are black boxes, and we’ll never truly know, advancements in sensor and on-camera processors don’t always give better results.
Take Sony and Nikon cameras for example. Both appear to feature spatial filtering algorithms to remove stray pixels before the data is written to the RAW files, examples being the infamous Sony “star eater”, although from reading Cloudy Nights, even some Nikon’s (including the D5300, with a similar sensor to my X-A3) appear to do some funky things to the stars.
Similarly we can question the uniquitous Canon processing, after all, skeptics might say they are likely to be employing comparable techniques to remain competitive. With the later and later revisions of the Digic processors, perhaps there is a case that the algorithms Canon are using are becoming more sophisticated, but just not as intrusive as the Sony and Nikon?
I’ll post a few example images shortly, but if anyone has any insights or would like to share some raw data or analysis, by all means post or get in touch.
I’m also curious about the spectral response of these cameras, but that’s another ball game...