Live Stack – Online and Offline suggestions
Posted: Fri Nov 12, 2021 6:51 am
Live Stacking is a great feature. Using it more and more, especially when I realized that I could skip some of the real-time tests (e.g. FWHM, Brightness) to save setup time and do them later carefully “offline” replaying the frames using the “Folder Camera”. Now I capture using Live Stack, saving stacked frames only, with Alignment and Guiding/dithering active (using PHD2) and enjoy the show made easy with the main histogram controls (including log X axis) coupled with the small histogram. Ideally, I should avoid the latter and leave it ‘reset’, as the “save as seen” option reduces to 8 bit PNG. But there is one problem that forces that sometimes (see below). This experience leads me to make a couple of suggestions …
Online Live Sack
I love the Live Stack histogram controls, especially with the log X axis and the real-time responsiveness to changes even with a 12M pixel camera. I capture without any colour balance in the camera controls and set the balance in the Live Stack histogram. There is just one minor issue:
Zero “black” on a log scale?
If I am tempted to nudge the black level on the main histogram, I can change it, but not set it back again. This is no doubt because the bottom of the X axis in log mode is not zero. I need to clear Log mode, drag the middle marker out of the way, set the black level marker down and then return to log mode and set the middle marker again. Or reset it all and drag the middle marker again (but reset of curves now resets the colour balance too – is this new? It really shouldn’t). It would be nice if the very bottom of the X scale was faked to transition to zero, so that the black level marker dragged all the way goes to zero.
Perhaps not Earth shattering as issues go. Because of all this, I tend to leave the Black level where the Auto set it and use the small histogram to nudge the Black level. I’d prefer not to touch the small histogram at all and “Save with adjustments” as 16 bit PNG. Still, not much work post-processing from the 16 bit PNG to fix the black level later.
Autofocus using assistant
One small change to the focussing assistants would make them much easier to use for a quick focus check before Live Stacking. When “OUT” is selected, it would be nice if it racked the focus IN by half the scan range (plus backlash) and then started the OUT scan across the previous focus position. No need to manually enter an offset focus position with cold fingers and a slow brain at 2am. I guess I could use the sequence editor to do just this, as auto focus there appears to have this behaviour. But why not here?
Offline Live Stack
Reprocessing using the “Folder Camera” permits some time spent tweaking quality filters such as FWHM and Brightness. It’s nice to watch the statistics improve and noise fade during playback. And with playback at about 1 frame per 1-2s the 60s subs go past pretty quickly. But there are one minor issue.
PNG via Folder Camera
As is common, it’s hard to recognize a RAW colour frame saved as a 16 bit mono PNG file. A checkbox declaring the mono frame as RAW colour, and perhaps a Debayer order droplist, would help greatly. Alternatively, the Colour Space droplist could include RAW16 and interpret the data as colour. Not a big issue, as I have switched to saving stills in FITS format to allow easier playback without needing to convert RAW PNG to colour FITS in PIPP.
All in all, using Live Stack is a very satisfying experience both online and offline.
Cheers, Chris.
Online Live Sack
I love the Live Stack histogram controls, especially with the log X axis and the real-time responsiveness to changes even with a 12M pixel camera. I capture without any colour balance in the camera controls and set the balance in the Live Stack histogram. There is just one minor issue:
Zero “black” on a log scale?
If I am tempted to nudge the black level on the main histogram, I can change it, but not set it back again. This is no doubt because the bottom of the X axis in log mode is not zero. I need to clear Log mode, drag the middle marker out of the way, set the black level marker down and then return to log mode and set the middle marker again. Or reset it all and drag the middle marker again (but reset of curves now resets the colour balance too – is this new? It really shouldn’t). It would be nice if the very bottom of the X scale was faked to transition to zero, so that the black level marker dragged all the way goes to zero.
Perhaps not Earth shattering as issues go. Because of all this, I tend to leave the Black level where the Auto set it and use the small histogram to nudge the Black level. I’d prefer not to touch the small histogram at all and “Save with adjustments” as 16 bit PNG. Still, not much work post-processing from the 16 bit PNG to fix the black level later.
Autofocus using assistant
One small change to the focussing assistants would make them much easier to use for a quick focus check before Live Stacking. When “OUT” is selected, it would be nice if it racked the focus IN by half the scan range (plus backlash) and then started the OUT scan across the previous focus position. No need to manually enter an offset focus position with cold fingers and a slow brain at 2am. I guess I could use the sequence editor to do just this, as auto focus there appears to have this behaviour. But why not here?
Offline Live Stack
Reprocessing using the “Folder Camera” permits some time spent tweaking quality filters such as FWHM and Brightness. It’s nice to watch the statistics improve and noise fade during playback. And with playback at about 1 frame per 1-2s the 60s subs go past pretty quickly. But there are one minor issue.
PNG via Folder Camera
As is common, it’s hard to recognize a RAW colour frame saved as a 16 bit mono PNG file. A checkbox declaring the mono frame as RAW colour, and perhaps a Debayer order droplist, would help greatly. Alternatively, the Colour Space droplist could include RAW16 and interpret the data as colour. Not a big issue, as I have switched to saving stills in FITS format to allow easier playback without needing to convert RAW PNG to colour FITS in PIPP.
All in all, using Live Stack is a very satisfying experience both online and offline.
Cheers, Chris.