What lens to make a start on Astrophotography

Discussion in 'Canon Lenses' started by PeterGC, Feb 17, 2012.

  1. PeterGC

    PeterGC TPF Noob!

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    Hi all. I tried my hand at taking pictures of the stars last night and I was a little dissappointed with the results. I have a Canon 60d with a Canon 18mm -135mm and I am wondering if this lens is ok. I seem to have trouble focusing and my images are coming out a little blurry.
    Do I need a faster lens?


     
  2. DorkSterr

    DorkSterr No longer a newbie, moving up!

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    No sounds like you need a tripod.

    What kind of astrophotography are you trying? Stars, moon, planet?... Get a decent tripod, slow shutter speed, highest f/stop lowest ISO, manual focus, with a remote shutter release.
     
  3. PeterGC

    PeterGC TPF Noob!

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    My bad, I forgot to mention that I have and use one always at night. Don't get me wrong Ive shot a few good night scenes for a beginner I just seemed to have a few issues with focusing.
     
  4. PeterGC

    PeterGC TPF Noob!

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    I would like to try stars at first, mainly because for the next few weeks there is no full moon. and I would like a decent shot of the moon on a clear late night. You say a high f number and shoot in Manual mode.

    I've been making the mistake of shooting in a Tv mode for a long exposure. I will have a go at shooting in Manual if the skies clear tonight.
     
  5. Netskimmer

    Netskimmer No longer a newbie, moving up!

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    FWIW I prefer to shoot the moon when it is not full. I find I get much more detail in the craters.
     
  6. PeterGC

    PeterGC TPF Noob!

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    Forgive me but FWIW ?

    I will have a go at this also if you say the results are good!
     
  7. bobandcar

    bobandcar No longer a newbie, moving up!

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    For what it's worth
     
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  8. Compaq

    Compaq Been spending a lot of time on here!

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    What is it you want to accomplish with wide field astrophotography? If it's detail in the sky, then you will need a long exposure, fast lens and high ISO. Here's a picture taken with 550D and tokina 12-24mm/4.
    ISO-800
    f/4
    30 seconds

    [​IMG]

    There isn't really much detail to write home about, but I got much stars. This isn't the brightest part of the Milky way either, but not much brighter. AND, this was after post processing. Original:

    [​IMG]

    If I really bump up the ISO to 12800, then I get something like this (after pp):

    [​IMG]

    Notice the noise differences.

    As important as your equipment, is a clear, dark sky. Light pollution is bad - really bad. The more light pollution you have (that may be a city or a nearby street lamp), you get the risk of overexposing your surroundings, which you don't want. At least want a balanced exposure of the sky and the landscape.

    Your Canon 18-135mm is actually faster than my Tokina 12-24mm/4. Yours go to f/3.5 at the wide end. Some canon lenses focus past infinity, so beware of that. Experiment and find the "true" infinity mark on your lens, and mark it for future reference.

    If you want your stars to appear as "dots" and not as "lines", then another factor will affect your results: shutter speed. You can't just expose for 10 minutes, because then the stars will appear as lines on the sky. There is a rule of thumb when it comes to how long a shutter speed you can use without getting streaking stars:

    shutter speed (seconds) = 600 / effective focal length

    Your 18mm wide end is more of a 28mm (due to 1.6 crop factor). That will give you an exposure of 600 / 28 = 21 seconds.
    This is just a guideline, however. Stars move across the sky at "different speeds" (let's not be physically correct in formulations, here). Stars closer to the North star will move slower, stars farther away will move faster, so having a clue as to which part of the sky you're shooting isn't half bad either :)

    This post became long and cluttered, but I hope some good came of it!
     
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  9. Edsport

    Edsport No longer a newbie, moving up!

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    It's not so much as the lens that you use, it depends on what you're photographing. You can take the pics of the moon with any lens but a good telescopic lens will get you in much closer and using a telecoverter will magnify it even more. If you're taking photos of stars a wide lens is good for this. If you have tracking you can get some pretty decent photos with just a basic lens. These 2 photos i took using my 350D and the 75-300mm kit lens but i had tracking so i could do long exposures...

    Andromeda galaxy...
    [​IMG]

    Orion nebula...
    [​IMG]
     
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  10. PeterGC

    PeterGC TPF Noob!

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    [/QUOTE] This post became long and cluttered, but I hope some good came of it![/QUOTE]

    Cluttered it did become but to me it very useful infomation and thank you. I need to think and research a little as to what and where I will be shooting as I see all these wonderful pictures like in the post below and I think WOW. I think the moon will be good start as is big and white and very easy to spot.
    Thanks again.
     
  11. PeterGC

    PeterGC TPF Noob!

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    Now this is what I would like to do one day these are great. You mention "tracking" would this be a camera function or lens?
     
  12. Compaq

    Compaq Been spending a lot of time on here!

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    Edsport mentioned tracking, and I pretty sure he meant an equatorial mounted tripod. That means that the tripod compensates for the Earth's rotation. Normally the stars would start to streak, but when the tripod is compensation, the stars won't streak, but the ground will, if you see. The lens will be pointed at the same part of the sky during the entire exposure, as opposed to the lens following the Earth's rotation.

    I'd like one of those myself, as one is pretty limited with regard to distant objects that require longer focal lengths. I think this video is pretty motivational, as it shows that good results can be gotten with "normal" equipment. It was an eye opener for me, because I simply didn't understand that the size of the stuff in the sky is so vast, that you don't need long focal lengths to capture stuff.

     
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