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01/31/2006 01:57:21 AM · #1 |
I am using Canon S1 IS, which is having a maximum shutter speed of 15 seconds. It does not have a B-setting. I want to shoot stars, and at 15 seconds, although the stars are registered, the sky comes out totally black (whereas I would like it to be dark blue).
Help please.
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01/31/2006 02:01:04 AM · #2 |
Originally posted by kbhatia1967:
I am using Canon S1 IS, which is having a maximum shutter speed of 15 seconds. It does not have a B-setting. I want to shoot stars, and at 15 seconds, although the stars are registered, the sky comes out totally black (whereas I would like it to be dark blue).
Help please. |
Have you tried increasing the ISO? |
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01/31/2006 02:02:49 AM · #3 |
| Yes. I have used ISO 400, but this leads to a lot of noise, and does not help either. |
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01/31/2006 02:09:45 AM · #4 |
Originally posted by kbhatia1967:
I am using Canon S1 IS, which is having a maximum shutter speed of 15 seconds. It does not have a B-setting. I want to shoot stars, and at 15 seconds, although the stars are registered, the sky comes out totally black (whereas I would like it to be dark blue).
Help please. |
don't shoot when the skies are dark? |
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01/31/2006 02:53:43 AM · #5 |
Originally posted by zerocusa:
Originally posted by kbhatia1967:
I am using Canon S1 IS, which is having a maximum shutter speed of 15 seconds. It does not have a B-setting. I want to shoot stars, and at 15 seconds, although the stars are registered, the sky comes out totally black (whereas I would like it to be dark blue).
Help please. |
don't shoot when the skies are dark? |
But then the stars will not register at all! |
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01/31/2006 04:01:51 AM · #6 |
I suspect you're trying to achieve a result that your equipment won't let you achieve - so the best way is to borrow or hire a camera that does have a bulb setting.
On the other hand, if this is something you're going to start doing regularly, then it might be a good excuse to buy another camera. :)
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01/31/2006 05:22:04 AM · #7 |
Originally posted by kbhatia1967:
the sky comes out totally black (whereas I would like it to be dark blue). |
But if you're shooting at night, after sunset, the sky will come out black. It's the sun that gives it the blue colour. Space is black. :) |
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01/31/2006 05:34:44 AM · #8 |
Or you could take a shot every 15 seconds and then stack the exposures.
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01/31/2006 05:53:52 AM · #9 |
I think that when you see dark night shots of stars where the sky is more blue than black, they may have been taken in RAW and adjusted.
--jrjr |
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01/31/2006 06:05:51 AM · #10 |
In the period between "nautical twilight" and "astronomical twilight" the sky will be a very deep blue if it is a clear sky and properly exposed.
"Civil twilight is defined to begin in the morning, and to end in the evening when the center of the Sun is geometrically 6 degrees below the horizon. This is the limit at which twilight illumination is sufficient, under good weather conditions, for terrestrial objects to be clearly distinguished; at the beginning of morning civil twilight, or end of evening civil twilight, the horizon is clearly defined and the brightest stars are visible under good atmospheric conditions in the absence of moonlight or other illumination. In the morning before the beginning of civil twilight and in the evening after the end of civil twilight, artificial illumination is normally required to carry on ordinary outdoor activities. Complete darkness, however, ends sometime prior to the beginning of morning civil twilight and begins sometime after the end of evening civil twilight.
"Nautical twilight is defined to begin in the morning, and to end in the evening, when the center of the sun is geometrically 12 degrees below the horizon. At the beginning or end of nautical twilight, under good atmospheric conditions and in the absence of other illumination, general outlines of ground objects may be distinguishable, but detailed outdoor operations are not possible, and the horizon is indistinct.
"Astronomical twilight is defined to begin in the morning, and to end in the evening when the center of the Sun is geometrically 18 degrees below the horizon. Before the beginning of astronomical twilight in the morning and after the end of astronomical twilight in the evening the Sun does not contribute to sky illumination; for a considerable interval after the beginning of morning twilight and before the end of evening twilight, sky illumination is so faint that it is practically imperceptible."
R.
Edit to add: quoted info comes from the U.S. Naval Observatory website.
Message edited by author 2006-01-31 06:45:42. |
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01/31/2006 06:39:47 AM · #11 |
| Bear, where do you get this stuff? |
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01/31/2006 06:44:32 AM · #12 |
Originally posted by wsteyn:
Bear, where do you get this stuff? |
My general information? I read. A lot. 5-7 books a week, all my life. The specific knowledge of dark blue in sky comes from years of architectural photography, however, in the pre-photoshop days, when we had to know when and how to get proper night shots without glaring black skies.
The quoted definitions in my earlier post come from googling up the United States Naval Observatory.
R.
Message edited by author 2006-01-31 06:46:25. |
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01/31/2006 06:47:17 AM · #13 |
| I must be reading the wrong books, won't find that in Terry Pratchet, then again... |
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01/31/2006 06:55:23 AM · #14 |
You can get a LOT of good, solid scientific information by reading good science fiction; Arthur C. Clarke, for example. David Brin. Larry Niven. Jerry Pournelle. Many others. These people are fanatics about building on a foundation of real science to make their extrapolations. And there are popular science writers (Stephen J. Gould comes to mind) who do fantastic essays on all sorts of strange and mysterious stuff.
Ditto for history; there are any number of skilled practitioners of historical fiction who research exhaustively, and it's an entertaining and painless way of getting a background in some of the esoteria of history. For example, Erica Jong wrote a beautiful novel of the Venetian Republic, "Serenissima", that tells you stuff you never even imagined.
This is presuming you (or whoever reads this) tend to bog down when reading straight history, biography, science, and the like, and prefer to read for entertainment. Myself, I read pretty much across all categories, at least when I look at the aggregate of 50+ years of reading :-)
R. |
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01/31/2006 07:31:59 AM · #15 |
I did my first ever star photos last night. The exposures were 50 seconds at F2.8 and ISO400. I'm not at home at the moment to post an image, but the best photo and a record of the shoot can be found on my PAD for yesterday (link in my sig).
The image isn't very good but the experience was valuable.
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01/31/2006 07:46:07 AM · #16 |
I tried to shoot stars, but there is one problem:
stars MOVE. so even 10 seconds of exposure shows stars not like dots, but like sticks. there is only one star still: polar star. all other stars move around it. so you have to shoot at high ISO (but not with your camera) or just try to shoot stars near the moon, so the light from moon could make the sky blue. |
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01/31/2006 07:53:01 AM · #17 |
Coupla points...
- What Bear posted is exactly correct, very late evening (or extremely early morning!) is the best time to get a field of stars with a deep blue background.
- Use a very wide angle to minimize trailing, unless that's what you're after. Using a 15mm fisheye on a 1.6-crop cam, 15-30 seconds is about the max.
- The longer the focal length, the shorter time you will have before trailing is visible
- If you plan carefully, you CAN stack exposures to get better rendition of the stars and reduce noise. Each exposure will need to be rotated slightly to register with the others.
Bottom line, night star/landscapes are very challenging, but surely possible. They are, however extremely difficult to pull off with a small-sensor cam, since they will be very noisy.
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01/31/2006 07:53:27 AM · #18 |
You need to put your camera on a telescope that tracks so you can cancel the effects of the earth's rotation. You also need a camera that can do a good job with noise control on long exposures. Most DSLR's can do this well, as can a very few point&shoots:
  
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