I haven't been here in a while. I see interest in nightscapes, so here is a recent one.
The San Juan Mountains of Colorado are spectacular any time of day, but particularly so on a clear night with the center of the Milky Way galaxy painting the sky. The tallest mountain is Mt Sneffels at 14,158 feet (4,315 meters), just left of center. This view at midnight on June 6 shows the bright galactic center above and to the right of Mt Sneffels. The light on the landscape is all natural and from the night sky: light from stars, the galaxy, and airglow.
The bright orange star at center-right is Antares in the constellation Scorpio. The haze around Antares is light scattered by dust near Antares. The sky background appears striped red and green from airglow, molecules in the Earth's atmosphere excited by solar ultraviolet radiation. Green airglow is caused by oxygen atoms. This view was to the south, but in the north while this image was being obtained was a red aurora.
Canon 1D Mark IV, 24 mm f/1.4 lens at f/2, ISO 1600, combination of 5 exposures: three tracked 1-minute exposures mosaicked for the sky, and two 2-minute exposures fixed tripod, mosaicked for the landscape, then the sky and land combined. Tracking was by an astrotrac.
The attached image had to be compressed to jpeg level 49 to fit within the 250 kbyte limit, so there is some loss on quality.
Roger
Beautiful view of Dallas Divide. That Astrotrac is really working well. Perhaps you could put together a description and photos of your setup on your page?
You are missed on this forum BTW. Good to see you back
Don
Pretty spectacular night photo, Roger and I also am glad to see you posting again.
Since there are so few that post in Landscape on this site, you might comment on a few others....
Hi Roger, great to see you posting here again...love the image and your thorough explanation of what we are seeing in the night-time sky. Hope see more soon!
Roger, I too am so glad to see you back. The light on the landscape here is amazing, as is the detail and colors in the sky!
I just now saw this post, but earlier today I was looking at your website in an effort to improve my Milky Way shots. I'm looking for information on tracking so I can shoot at lower ISO and smaller aperture, to lower noise and increase IQ.
Can you comment on how tracking for a single longer exposure compares to stacking several shorter exposures?
I really like this.
Great color palette with wonderful textures.
I must confess I have no idea what you mean by Astrotrac and mosaiking.
Would love to see an explanation and pics to show what you do. I will check out your web page to see if you explain what you have done,
Gail
Did you know you can post to 400KB now?
Gail
Hi,
Thank you for the comments. I was not aware of the increased pixel and byte limits. The sticky at the top of the forum still says 800x1024 and 250 kb. That is from 2011. It should be updated.
I will do my usual comment on other's photos. It turned out this week was all work, 14+ hours per day. 7 days a week, so have had little time.
Originally Posted by Diane Miller
Roger, I too am so glad to see you back. The light on the landscape here is amazing, as is the detail and colors in the sky!
I just now saw this post, but earlier today I was looking at your website in an effort to improve my Milky Way shots. I'm looking for information on tracking so I can shoot at lower ISO and smaller aperture, to lower noise and increase IQ.
Can you comment on how tracking for a single longer exposure compares to stacking several shorter exposures?
Diane,
I see you are using a 5DIII. I would not recommend going below iso 1600 for night images because of fixed pattern (banding) noise at lower ISOs. If you stick to iso 1600 or 3200, then there is little difference in stacking several shorter exposures versus one longer exposure. Before I started tracking nightscapes, I was doing 8 to 10 second exposures and averaging those (of course you have to align them and that means a translation plus rotation). It is a pain. If your lens has enough geometric distortion, alignment will be difficult from corner to center to corner because as the star field rotates, the distortion changes.
The simplest device for tracking is a "barn door" mount. Here is mine: http://www.clarkvision.com/articles/...racking.mount/
It cost me about $40 to build using oak and mostly stainless steel parts (plus the ball head and arc-swiss rail). This is what I take when I want to travel light.
Here is an image of the astrotrac http://www.clarkvision.com/articles/...8829.b-768.jpg
I normally use it attached to my wimberly head. It costs about $800 but tracks very well; I have even made 1 minute exposures with my 300 f/2.8 and 1D4.
Another tracking option is a polarie star tracker (about $400).
Mosaicking is simply taking multiple frames to make an image. I use ptgui to assemble the frames https://www.ptgui.com/
One other key to night photography (and actually all photography) is aperture is the key to collecting light from the subject. People tend to use very wide angle lenses, e.g. 15 mm f/2.8, but such lenses have a small clear aperture (e.g. 5.3 mm). Whereas a 35 mm f/2.8 lens has 12.5 mm aperture so collects 5.6 times more light than a 15 mm f/2.8 lens from the same subject, whether a star or a star cloud, or a mountain top. (not to be confused to light density in the focal plane). Thus a bigger aperture diameter lens is better for night work, and you can get them in faster f/ratios for even better light gathering (e.g. 24 mm at f/2, 35 mm at f/1.4, 50 mm at f/1.2). The image in this thread was made with a 24 mm lens at f/2, so collects a lot more light than a typical 15 mm lens at f/2.8 = 5.1 times more light in the same exposure time.
I'm going to start a thread for more information over in General Photography discussion, but if it should be elsewhere, I assume the moderators will move it.
Beautiful shot. I also started with nightscape photography.
Is there any reference table about ISOs above camera electronics noise ? I'm particularly interested for the 6D and 7D.
And about White balance ? I see a lot of people using around 3800K.
Also sign me up too for an autographed copy of the book! Or e-book (better !) !
Sorry for the late response--I've been in the mountains doing night photography of fall colors.
Regarding what iso to use to minimize banding, look at the images here for the 7D: http://www.clarkvision.com/articles/...tion-canon-7d/
To test for yourself, simply take some exposures (any shutter speed will do, e.g. 1 second) with your lens cap on in a dim room and do all ISOs (e.g. 100, 200, 400, 800, 1600...). Convert to 16-bit tiffs then stretch each one and see where the fixed pattern noise is very small. For reference, I use my 7D with night imaging at ISO 1600. At that iso, the banding noise is not visible in my images, even when stretched hard.
Many people force the color of the night sky to be blue. If the moon is not out, and the sun is well below the horizon, the night sky is rarely blue (and pretty much never now that we are near solar maximum). The night sky is red, green, yellow or orange, often banded colors. So to force a color temperature to make the sky blue is unnatural, kind of like making a sunset 500K to make the sky blue even if it was a red sunset.
The last few days, I saw yellow,red, green, and orange skies. Even magenta for a brief time, and banded red and green at others. This is due to airglow.
Roger, a very compelling photo and well shot/executed/processed!
I am one of those who just personally like the look of a colder/blue night sky in the photos. I think there's some place left for artistic licence with nocturnal landscapes (as with any form of landscape photography), so each to his own. I will try and use auto WB end of the year when I am in Etosha and the Kalahari again to see how the skies come out "naturally" (I normally shoot on fluorescent WB for these).
As an aside, the posting limit is now 400kb so if you intend to grace us with more of your stunning nocturnal work, it would be good to increase your file size for better quality.
Hello Roger, thank you for the test suggestion.
But now I'm more confused than I thought it would be possible !
I used an EF 50/1.8 II and exposed for 1 second at f/2.8 with the lens cap on, for each ISO including the 1/3 ISOs (125,160, 320, 500, etc).
I did the test for Canon 7D and 6D both with the latest firmware. RAW files.
I converted the files to TIFF 16 bits using Canon DPP latest version
Then I imported them into Lightroom 4.4.
I am not sure if I did stretch the images the right way.
I stretched the histogram moving all the exposure sliders (Highlights, Shadows, Whites, Blacks) to their maximum (+100).
Now comes the interesting part.
Canon 6D
Some noise and FPN at ISO, 50,100,125.
ISO 160,200,250,320,400. Almost no noise. No FPN.
ISO 500. Some noise.
ISO 640,800,1000,1250,1600,2500,3200. Some noise where the image looks like a starry sky.
ISO 4000 Starry Sky.
ISO 5000,6400, - FPN visible.
ISO 10000 - FPN is better than previous ISO.
ISO 25600 and above - abstract art.
Canon 7D
Stretching the files the same way, it's noise everywhere !
I must be doing something wrong or there is something I didn't understand.
The only conclusion that I can think of is that Canon is cooking some RAW at some ISOs.
Hello Roger, thank you for the test suggestion.
But now I'm more confused than I thought it would be possible !
I used an EF 50/1.8 II and exposed for 1 second at f/2.8 with the lens cap on, for each ISO including the 1/3 ISOs (125,160, 320, 500, etc).
I did the test for Canon 7D and 6D both with the latest firmware. RAW files.
I converted the files to TIFF 16 bits using Canon DPP latest version
Then I imported them into Lightroom 4.4.
I am not sure if I did stretch the images the right way.
I stretched the histogram moving all the exposure sliders (Highlights, Shadows, Whites, Blacks) to their maximum (+100).
Now comes the interesting part.
Canon 6D
Some noise and FPN at ISO, 50,100,125.
ISO 160,200,250,320,400. Almost no noise. No FPN.
ISO 500. Some noise.
ISO 640,800,1000,1250,1600,2500,3200. Some noise where the image looks like a starry sky.
ISO 4000 Starry Sky.
ISO 5000,6400, - FPN visible.
ISO 10000 - FPN is better than previous ISO.
ISO 25600 and above - abstract art.
Canon 7D
Stretching the files the same way, it's noise everywhere !
I must be doing something wrong or there is something I didn't understand.
The only conclusion that I can think of is that Canon is cooking some RAW at some ISOs.
Thank you.
Hi Fabio,
Sorry for the late response. I've been out the last couple of weeks on a photo tour of fall colors, working mainly at night. Perhaps we should take this discussion off list (email would be best for me) to resolve the issues. Not sure about DPP, as I have not used it in a while, but is there a black point adjustment? if so, you should set it to zero. In CS5 ACR, the black point defaults to 5 and that truncates some low level data. This may be what you are seeing. For the images in my sensor analyses, I use DCRAW with no interpolation, so the data is as in the raw data file, just reformatted for viewing. But I can see the same effects in ACR by setting the black point to zero. If you want to send me a couple of 6D raw files, I can check them out for you. Canon raw data typically have an offset of around 2048 out of 16383, so no data goes below zero. Most (all?) Nikons do not have an offset, so about half the dark pixels are truncated to zero.
Let's talk by email.
I'd be interested in the conclusions here, after the details are worked out.
ACR used to set the Black Point at 5, but with CRAW 7 the new Process 2012 (which has much better ability to pull out tonal detail) the sliders work differently, from a centered 0 point. Not sure how that translates to checking dark frames and truncated pixels...
San Juan Mountains, Colorado Nightscape
Reply With Quote
Originally Posted by Diane Miller
