Question about shooting the moon......

Discussion in 'Digital Discussion & Q&A' started by oldnavy170, Oct 26, 2006.

  1. oldnavy170

    oldnavy170 TPF Noob!

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    Ok, as most of you know I bought a new camera. Now, my question is.....I have been trying to take a picture of the moon since I have a 12x optical zoom and I can't seem to get a real close shot. Now maybe I don't know how much zoom I need but when I bought the camera one of the "sample" photos was that of a close up of the moon.

    I am also having issues with the camera shaking (it's my hands that can't keep still) which is causing alot of blurring. I have noticed that the blur is mostly when I use the zoom.

    Is this normal to have alot of blur when zoom is used? Now for those who didn't know I bought a new camera, I am talking about a Canon S2 IS.

    Thanks.
     
  2. astrostu

    astrostu Guest

    It looks like your camera has an equivalent optical zoom of 108 mm. This provides a field of view of around 20° across (horizontal). The full moon is 1/2° in diameter, meaning it will cover 1/40th of your horizontal field, which is 65 pixels, or about 0.9 inches at 72 dpi (normal screen resolution).

    The extra zoom - 4x digital - does not actually change the optics, rather, it digitally zooms in on the image, extrapolating the image (effectively blowing it up as you would on Photoshop). So it doesn't actually make for a better zoom, which is why I usually avoid digital zooms.

    But, assuming that the zoom were actually all optical, you'd get a 432 mm lens at about 5° horizontal, so 1/10 of your field of view would be the moon. 259 pixels, or about 3.6" across on your screen.

    So ... on the subject of blur, you would expect it to be larger when a higher zoom is used. If you, for example, have an effective blur of 0.1 degrees but your field of view is at its largest (36 mm), that's only a 0.2% effect. But at your 12x, it's a 2% effect, so it will appear 10x more blurry.

    So you have two things working against you. First, you're using a digital zoom that's effectively changing a 0.9" image into a 3.6" image in simple software. Second, your increased zoom is increasing the blur. Is there an image of the sample photo somewhere online? I couldn't find one on Canon's site.
     
  3. iflynething

    iflynething TPF Noob!

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    ...
     
  4. oldnavy170

    oldnavy170 TPF Noob!

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    Yes, here is the sample moon that I looked at:

    [ame="http://www.amazon.com/gp/product/customer-images/B0009GZSSO/ref=cm_ciu_pdp_images_1/002-6790920-8673623?ie=UTF8&s=photo&index=1#gallery"]http://www.amazon.com/gp/product/customer-images/B0009GZSSO/ref=cm_ciu_pdp_images_1/002-6790920-8673623?ie=UTF8&s=photo&index=1#gallery[/ame]


    I zoomed in as much as I could and I wasn't that close. Here is a sample of what I got: (I know that it wasn't a full moon but I still would of thought I could get closer)

    [​IMG]
     
  5. W.Smith

    W.Smith TPF Noob!

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    This, of course, is the realm of the tripod and the beanbag. You didn't mention you used either one, OldNavy?
     
  6. oldnavy170

    oldnavy170 TPF Noob!

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    No, I don't use a tripod but I am looking into buying one. Humm, beanbag? What do you do with that?
     
  7. astrostu

    astrostu Guest

    Well, one issue with your image is that the exposure time is way too long. You need to custom set the exposure time. A moon like that would probably be around 1/120 sec, but play with it.

    The Amazon image looks highly pixelated and sharpened with some smoothing applied so the blow-up doesn't look as obvious.

    You need to: (1) Wait for darker skies. (2) Take a shorter exposure, unless you're trying to get Eartshine. (3) Get a tripod (a $40 one will do the job).
     
  8. hobbes28

    hobbes28 Incredible Supporting Member

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    You use a bean bag to hold your camera still so you can set it on the ground/car/porch/grill/etc. and it will remain still while the shutter is open. (Usually best used with the timer so you don't have to touch the camera while it's shooting, thus reducing shake).

    I'd put the camera on it's manual mode, put it at around an f8 and mess with your shutter speeds to bring down your exposure until you have a black sky and can catch the details in the moon. That way, too, you can bracket the speeds to get your desired result without having to check on the computer after every shot.
     
  9. fmw

    fmw No longer a newbie, moving up!

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    When shooting the moon, don't use your in-camera meter. It will try to expose the night sky to 18% gray as you saw in your image. Instead set 1/ISO setting as a shutter speed manually, set f8 for aperture and bracket from there manually. On a clear night, the moon should take about the same exposure as a normal subject on a sunny day. It is brightly lit by the sun, after all.
     

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