Sunday, January 03, 2010

Moon over Vegas Valley

Steve W said:
The other day TC(Girl) and you talked about making images of a moon lit field and I decided to give it a go. We don't have any fields here in the Las Vegas valley, so I hope desert will suffice.
[Click for big pic.]


Spent about 1-1/2 hours out there and got 3 exposures. The long exposure NR [The camera takes an extra, black, exposure, to get the noise level and deduct it from the exposure] doubled the time for each 8 min exposure. From the histogram I probably should have done 16's + LENR but I was running out of dark (sounds odd doesn't it).

The tops of the peaks look to be brought up by the lights of Las Vegas and the sky was backlit by the Pahrump valley which is about 25 miles behind the peaks. The moon was almost directly overhead, so there isn't a lot of shadows. From what I have read, exposures longer than about 2 min start to soften the shadow detail and not totally blocked
.
[I had trouble getting that sentence, so Steve clarified:] You had mentioned that under moonlight the shadows would have no detail (blocked). The moon moves in the sky about it's diameter every 2 minutes, so the shadow's edge begins to soften. Given enough time and the open-ness of the desert bushes, there is slight detail in the shadows of them.
I hope I am using the right terms in using 'blocked' for when the sensor records no data or in other words falls off the left side of the histogram. The highlights on the right that fall off are 'Blown'.

Canon 5D MI set to Bulb, EF 24-105 f/4L IS set to Infinity focus, Canon TC-80N3 Timer Controller, all mounted on a very Slik tripod and ball head.
480 sec @ f/8 and ISO100
PP= Luminance, -30 Blue, +25 Orange, +15 Red. A touch of Clarity and Vib. Levels= +.08 center slider. NR= +1 on the Blue channel. Dust spot removed from the sky. Black border and burned the bottom corners.

Thanks to Steve, this is great.

Me, I would have tried with 400 ISO, probably the image quality would not have suffered much.
And perhaps I could have used F:4.0, if it would have had the depth-of-field to make the foreground sharp (which depends on the lens and the distances).

Steve comments:
The Aperture was decided for DOF. I have done enough up there in the daylight to know f/8 is about min if you want the foreground in focus. I wasn't sure about the noise, so I used ISO 100. As it was, I did get a bit of noise show up in the sky. Higher ISO with faster exposure might have about the same noise, I would just have to test that [very long exposures tend to increase noise. - E]. I was also interested in seeing how long the star trails would be at the 8 min exposure. Doing the math, I could have used the 35 f/1.4 @1.4, ISO 400 and the exposure time would have been 7 stops faster, or 4 sec. It is all tied together.
-

4 comments:

TC [Girl] said...

Steve W. said...
" We don't have any fields here in the Las Vegas valley, so I hope desert will suffice."

Are you kidding me?! This picture is...WOW!! :-D Thanks for shooting it and sharing it w/us! It's VERY COOL!! :-) Probably a LOT more interesting than the field I am wanting to shoot! :-) What time of the night did you shoot it?

Anonymous said...

It was written to the camera at 4:27 AM. I decided on an early morning shoot as the moon was in the better position.

Glad you enjoyed it and you really should give it a go. Not hard to do with a steady rest. I think one could practice in a dark room with a little light coming through a window.

TC [Girl] said...

Well...if you were out there 1 1/2 hours, then you must also be keeping w/the reputation of your area: "...that never sleeps" just to get this shot, Steve! lol! Thanks for sharing the very cool results. :-)

Funny you should mention the latter. I've been thinking of trying that w/some light that comes in. I think I will "give it a go"! Thanks! :-)

TC [Girl] said...

Hi, Steve...

Just bumped into this blog, looking for another. Sure enjoy that picture, still! :-)

I had the opportunity to try a Fujifilm X10, recently, and took a panorama of the field that I am wanting to do the night shot of. That was a lot of fun! Wish I had had the chance to try the night thing but, truthfully, I don't know where to start on that whole thing! I don't think that I could do a panorama, because of the movement, of course. And...I have a remote timer but haven't figured out how to use that thing, yet, either! :-/ Every year, I keep saying that I'm going to find a photography class to join! :-/