Quote:
Originally Posted by Ryderscope
Very nice work Joe. An artistic rendition that captures the imagination.
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Hi Rodney,
Thank you for your kind comments.
Quote:
Originally Posted by Leo.G
Beautiful image Joe!
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Thank you Leo
Quote:
Originally Posted by leon
Hey Joe, that is really a beautiful image the things we can do with just a tripod and a lens, and I suppose a clear night helps, well done. 
By the way what Lens did you actually use and was it a combination of many exposures or just a single exposure, would you mind
sharing the details, thank you.
Leon |
Hi Leon,
Thanks for your comments.
Even in the Bortle 2 skies out there in the Boorowa Region, you can't do a single long exposure. One of my students had a Canon 200D camera. It doesn't have the extended shutter speed range like the Pentax so we set the intervalometer to do 2 min exposures in B mode. In B mode, the sequential exposure triggers were ignored and the 200D kept the shutter open for the full 1hr 7m ISO ISO800 17mm f2.8. Unfortunately, we didn't notice what was happening. The field trip across three locations spread over 35km, started with location scouting at 400pm and finished with Milky Way setting at 200am and so I scheduled the hour from 10pm-11pm while the star trails were being captured as free time when people, especially me, could have a much needed rest in their cars during the 10 hr marathon. So his camera captured one long exposure while we were resting and talking to the police
We have yet to work out how or why this happened but the intervalometer was one of mine that I loaned him. I programmed it and hence I know it was correctly programmed and working. Nonetheless, the result of the single long exposure is informative. Any such long exposure would need to be captured at minimum ISO and small aperture and doesn't present much advantage other than not having to stack the final results which is pretty easy. Noise can really build up over such a long exposure. Determining the optimum parameters of such a long exposure would not be easy. The single long exposure and attached to this reply.
Capture details:
Samyang 14mm f2.8 lens
Pentax K1, ISO 400, shutter speed set to 2m40s
I used an external intervalometer with a 1s shutter press and a delay time of 2m 42s between exposures for 25 exposures, so about 1hr 5mins in total.
The ambient light on the landscape in the area is really dark. I determined 2m 40s @ISO 400 and f2.8 was enough. The ISO 400 maintains sufficient
Photographic Dynamic Range ( PDR ) to capture a range of star colours and not blow out the sky. The compressed PDR at high ISO turns all the star trails white and it can make the sky turn pretty white. So there is no magic setting. It really depends upon your local conditions. I have also included one of my subs with histogram to illustrate the sort of appearance I'm looking for when I shoot.
You don't need a high end full frame camera. This technique works well with any camera. I have included with permission, the star trail of one of the other participants, Min Lush. Min used a 14 year old Pentax k5, APSc camera and the low ISO technique, ISO 800, 25 x 2 min exposures, f4.
