First light - Canon 6D with Canon 135mm f2 L series.
yahoo,
The clouds have finally gone after six weeks here in the centre of Australia. Absolutely frustrating but since rebuilding my dead computer last night my SBIG STT 8300m would not talk to my laptop so strapped the camera canon 6D unmodified with the new 135mm lens on and did 1h 40m on Orion with darks and flats applied.
I have no idea how I see similar images with perfect background sky using ISO 1600, f4, and 4 minute exposure times? Is there something I am doing wrong as my first picture is really just a smash out process to see the uneven and circular background through out the image. I have then cropped the central section but processed the hell out of this just to even be a little bit happy with it.
Should the set up I have tracking on an Astrophysics mount (was not guiding during this only tracking) give me these flat images??? I do have an expensive UV filter on front to protect my lens. Advice would be wonderful..
Those look like nice orion tests seems the lens is working well how many subs did you use?
I use the Olympus OMD EM1 with Zuiko 150mm F2.0 and performance is great as long as I stack more than 20 minutes worth of 0.5-1 minute subs with enough darks.
Hi Mark, that lens looks very nice. What aperture was it set at?
For an hours worth of data stretched properly you should easily pick up Bernard's loop. What processing are you doing after staciking?
Cheers,
Andrew.
Hi Andrew. I use photoshop cc and just do levels curves and again but I think I can sort of see it but I would have thought more of it would be obvious. Lens was f4.
Looking good & natural Mark
4 min subs are ok too, tho 8 mins will show more Loop and depth over the entire field, you have covered a large area and the dust in the 'outfield' is rather faint, so, longer subs will help. And some peeps really know how to process the data for all its worth
Nice going so far ...
Thankyou Bob. Now all I need is fine weather. I'll have a crack at 8 minute subs and see what comes in. What ISO would you suggest for this from very dark site. Ayers Rock = Yahoo.
Thankyou Bob. Now all I need is fine weather. I'll have a crack at 8 minute subs and see what comes in. What ISO would you suggest for this from very dark site. Ayers Rock = Yahoo.
Mark
Ayers Rock hey, your in astro heaven I'd expect !! I gotta see that rock one day ?
Re Subs, seeing you have been using iso 1600, id suggest to keep on 1600, as know the higher iso the more noise, particularly in summer months, tho if you drop to iso 800 then you'll need to add to even longer subs to gather the same light signal, - problem - the trade off is the longer the sub time the more noise again
So, iso 1600 and plenty of them - say atleast 15 - 20.
Are you doing "in-camera-darks" what a slow painstaking caper that is, valuable imaging time ticking away, if you wish to add Darks, then can do them on a cloudy night .
Hi Mark - if you're not already then I'd honestly reccomend you look into doing calibrations, as in flats. The amount of vignetting in the lens means that the background brightness varies a lot across the image so it's almost impossible to pull the fine detail out of the shadows.
Levels and curves should be 99% of what you need to do to squeeze out the features you're looking for.
Cheers,
Andrew.
Hi Mark - I think it would be worth trying the lens at f2.8. The Canon 135L, by most accounts, is a very good lens. Good calibration with flats will become more important at these wider apertures, but twice as many photons would be captured.
From my experience with the 6D, unless the ambient temp is down to 10 deg C, dark frame noise with start hammering your subs at 8min length. Still worth a try to compare.
Another thing up your sleave is bumping the ISO to 3200, which the 6D can handle ok, but you do loose a stop of DR in highlights. M42 does get blown out when you start chasing the fainter regions anyway, so some shorter exposures always help.
For my 6D (modded) + Zeiss 135 f2.0, this is my typical settings:
f2.5, ISO3200, 4x3s, 4x8s, 4x30s, and 8x90s depending on sky darkness. With an unmodded 6D, I would go 4x3s, 4x8s, 4x30s, 12(or more)x120s, f2.5, ISO3200. Without modification, the 6D picks up about 25% of the Ha reds, so does take more to pick up the Barnard's Loop and Horsehead.
Hope this helps.
