Shooting moon, stars etc with digital camera?

[MidKnight]

Ive heard that theres some problems trying to use a digital camera trying to take photos of the moon and stars etc, that something happens and its burns something on the photo. ??

anyone know anything about this?

ive just taken a couple of photos with a 300D using a few differant settings with some very interesting results, that for a start the moon is nothing but a white cycle, BUT!, the moon apears a second time in the photo with its detail in it, but a off colour.

anyway im looking for any info about this.

thanks

[nosquare2003]

Never heard any problems of using a DSLR to shoot the moon.

A white circle was the result of over-exposure that its details were lost (since you intended to shoot the moon).

[MidKnight]

that doesn't explain the mirroring of the moon in the photo.

heres one example, as you'll see the moon is mirrored to the left,bottom of the photo. this one isn't really a good example, and unfortuanly i deleted the others and its raining now, so i can't get anymore atm

http://www.midknight.com.au/photos/moon/IMG_3712.jpg

[nosquare2003]

I thought that you shot the moon only.

From the picture, my guess is lens flare - the reflection of light between different glasses in the lens.

[MidKnight]

i had some of just the moon only too, i will take more and post them hopefully tomorrow is weather is good. but in every shot ive done theres been that mirror effect.

[sparty314]

The second image of the Moon is a dead giveaway that your photo is overexposed. All the black sky around the moon fools the camera's metering. Remember, the moon is in full sun, so you can use the sunny f/16 rule (approximately)!

Here is a 100% crop of a photo I took of the Moon a few days ago:
http://mywebpages.comcast.net/bearss/moon.jpg

[sparty314]

Additionally, I think you'll find that you can't get both the moon and the forground exposed properly at the same time. You'll need some type of digital equivalent to a double exposure--a composite image, perhaps.

[PaulB]

Definitly lens flare.
You need to expose for the moon only to get detail on it. The setting you used was trying to get a 'correct' exposure for the whole scene and overexposed the Moon but underexposed the landscape.
Try metering in manual mode just the Moon only and you might get something like a couple of stops less than a 'normal' daylight exposure.
However without a much longer lens you aren't going to get a large image of the Moon anyway.

What lens/settings etc did you use for the pic. you posted?

[sparty314]

My Moon pic:

Taken with:
10D
M, f/8.0, 1/125, ISO 200
Sigma 50-500mm EX

[FotoPhreak]

Definitly lens flare.
Try metering in manual mode

How exactly do you do this?

I know what your talking about, but having only just received my first DSLR, even SLR, I am a qualified reader but underqualified user!

[sparty314]

I would suggest that, since you're using a digital camera (no film and developing costs), you just experiment in manual (M) mode by setting both the aperture (f/stop) and shutter speed. For example, for the picture I posted, I manually set the camera to f/8.0, 1/125, and ISO 200. I didn't pay any attention to the camera's warning that the shot would be underexposed.

I have found that the camera "wants" to drastically overexpose the scene regardless if I'm using a telephoto lens or even a wide angle lens. For example, if you are taking a landscape shot at night with the Moon, the camera exposes for a properly lit daytime scene. This is a weird effect!

In your original post, you mention taking pictures of stars. That can be really easy as well. Just set your camera on a tripod with a wide/medium lens, set the aperature to a relatively large value (f/2.8 or something), and open the shutter for a long time. Unfortunately, you'll need some type of remote shutter in order to do bulb photography (shutter speeds longer than 30 s). For the Digital Rebel/300D, you can by the Canon RC-1 infrared remote (http://www.bhphotovideo.com/bnh/controller/home?O=productlist&A=details&Q=&sku=12935&is=REG) for only about $25. I know for a fact that this remote *will* work with the 300D (despite how it may be advertised). Or, you can rig a wired one up yourself for about $5 with parts from radioshack. With long exposures, you'll be able to capture star trails and colors in deep sky objects.

Good luck!

[mattchase]

Hey MidKnight,

I think what you refer to as "something burns into the photo" is hotpixels (sometimes also called noise). These are a side effect of doing long exposures with a digital camera, and are created from the sensor getting hot. The longer the sensor is active (as in exposing), the hotter it gets, and eventually some of the individual pixels on the sensor will reach a point where they leak their charge and will appear to expose the image, whether there was really anything to be exposed or not. They will show up as the color of that pixel (RGB), or as a shade of that color depending on how much energy leakage there is. Some digital cameras will show hotpixels after just 1 or 2 seconds, others can go 20 or 30 seconds before they show up. I don't know about the 300D, but the D60 and 10D were both very good at supressing hotpixels, with only a couple showing up at ISO 100 and 30 seconds (see here for my test results http://www.matthewchase.com/digitaldingus/canon/index.html ).

Hotpixels will also show up based on the air temperture. A 1 minute exposure in 95* air will show more hot pixels than a 1 minute exposure in 65* air, which would show more than the same exposure in 25* air. This is why many astrophotographers will bear the cold of the winter months to do a lot of their shooting, or find a high elevation with cooler summer tempertures. The really serious guys will even cool their equipment while they are shooting, to keep the sensor from becoming too hot internally.

If the 300D is similar to the 10D, then you probably won't need to worry too much about hotpixels, even at exposures into the 1-3 minute range. Also do a search for hotpixel software, as there are a few good programs out there that will help eleminate them when they do occur. There is also a technique for removing them yourself, called dark frame subtraction. This is done by first taking the picture you want (say a 1 minute exposure of the stars), followed by a 2nd exposure of the same exact time (1 minute), but with the lens cap on the camera. The 2nd image will record a completely black image, except for where the hotpixels are located, which should match exactly where the hotpixels are in the first (real) exposure. In Photoshop, you would combine these two images using the Subtract method (I believe that is it...), and wherever the hotpixels line up in both images, they will be removed.

But anyway, enough techie talk. To sum it up, here are two shots. The first is what you will be getting to start, star trails. This was shot with my D60 at ISO 100, F2.8, and about 9 minutes 20 seconds. Below the resized image is a link to the full size image (2.4mb), straight from the camera, so you can see the hotpixels in it. If I did a dark frame for this shot, most of the hotpixels would go away, though at anything less than 5x7 they aren't that noticable anyways.
http://www.matthewchase.com/digitaldingus/stars/img_5289.jpg
Click here for full size image (http://www.matthewchase.com/digitaldingus/stars/img_5289full.jpg)

This second shot is of the Milky Way with my D60, at ISO 400, F2.8, and just under 8.5 minutes. The difference here is that I used my telescope to track the stars.
http://www.matthewchase.com/astrophotos/2_22_03/img_4563_std.jpg

[CyberDyneSystems]

that doesn't explain the mirroring of the moon in the photo.

heres one example, as you'll see the moon is mirrored to the left,bottom of the photo. this one isn't really a good example, and unfortuanly i deleted the others and its raining now, so i can't get anymore atm

http://www.midknight.com.au/photos/moon/IMG_3712.jpg

Don't lie to us,. clearly you were on Jupiter when this shot was taken,. and the sky had jsut twoo of it's moons visible in the shot! :mrgreen:

[scottbergerphoto]

Definitly lens flare.
Try metering in manual mode

How exactly do you do this?

I know what your talking about, but having only just received my first DSLR, even SLR, I am a qualified reader but underqualified user!

Set the camera to "Manual" or M mode. Using a hand held spot meter or a zoom lens that allows you to fill the viewfinder with the moon and the camera set to partial or center weighted metering, take a reading (shutter and aperture). If you used the zoom technique, zoom out and recompose your picture. Set the camera to one of the many acceptable shutter/aperture combinations and take the picture. Use the histogram to judge the need for exposure compensation.
The following pictures were taken using a 10D in M mode, 100-400 IS L and metered with a Sekonic L358 light meter with 1 degree spot attachment:
http://www.pbase.com/scottbergerphoto/lunar_eclipse_11082003
BTW, Sparty314, that's a great picture! What lens were you using?
Scott

[sparty314]

Scott,

Thanks for the compliment. I know it's not great, but it is the best I have taken so far. It's with my "new" Simga 50-500m EX. I feel kind of cheap including it here, because I already used it in another thread where I announced the purchase of the lens. (But it did seem apropriate...) I only wish I had the lens during the eclipe last Fall!

[Ballen Photo]

My Moon pic:

Taken with:
10D
M, f/8.0, 1/125, ISO 200
Sigma 50-500mm EX
Sparty, Great shot of the Moon. I like the detail.
........Bruce