• 04-01-2004, 07:03 AM
    Speed
    2 Attachment(s)
    Star Shots - What's The Difference?
    Both of these shots are of Polaris, the North Star. Both were taken on the same night, one right after the other. Both are one hour (60 minute) exposures.

    There are two things that are different in these shots. Can you spot them and figure out what caused them?

    K1000, 50mm lens, Superia Xtra 400, one hour exposures.
  • 04-01-2004, 07:07 AM
    Sean Dempsey
    nope, I have no idea what I am supposed to be seeing.
  • 04-01-2004, 09:39 AM
    darkrainfall
    I have no clue, though I am curious as to what they are.
  • 04-01-2004, 10:03 AM
    Kokopeli
    This one is tough...
    Quote:
    Originally Posted by Speed
    There are two things that are different in these shots. Can you spot them and figure out what caused them?
    First thing I noticed was the horizontal light trail in the left third of the image (#2), slightly above the tree line. That's a shooting star. (Or it's a scratch or maybe even an aircraft of some sort.)

    I'm still looking for the second difference. If I find it, I'll be sure to let you know.

    ~Brian
    Nikon Samurai #3

    ***Added after original post***

    It would also appear that the first image shows brighter trails.. I'm guessing that the f-stop was larger.. Perhaps 1.8 and that on image #2 was 5.8 or 8? The vignetting in #1 is more apparent as well...

    Am I close?
    ~B
  • 04-01-2004, 10:56 AM
    Speed
    Am I close?
    Quote:
    Originally Posted by Kokopeli
    First thing I noticed was the horizontal light trail in the left third of the image (#2), slightly above the tree line. That's a shooting star. (Or it's a scratch or maybe even an aircraft of some sort.)

    I'm still looking for the second difference. If I find it, I'll be sure to let you know.

    ~Brian
    Nikon Samurai #3

    ***Added after original post***

    It would also appear that the first image shows brighter trails.. I'm guessing that the f-stop was larger.. Perhaps 1.8 and that on image #2 was 5.8 or 8? The vignetting in #1 is more apparent as well...

    Am I close?
    ~B
    You are right on! Leave it to a Nikon Samurai to figure it out! :-)

    OK, first the line you noticed. Shooting star. Aircraft lights blink, so you get bright spots with them. Spacecraft in polar orbit would be going north/south or south/north depending on if it's our's or someone elses. And that was NOT one of the differences I was talking about. :-O


    The brighter star trails in image #1 was one of the items I was looking for. They are indeed brighter.

    The vignetting in image #1 is also more apparent, which is the second thing I was looking for.

    Both effects are caused by...a different apeture. The first image was shot with the lens at f2.0. The second image was shot with the lens at f2.8. The wider apeture gives brighter stars at the expense of more pronounced vignetting.

    It is amazing that a change of one stop can make such a big difference. Here's a link to a previous post of mine showing how big that difference can be.

    http://forums.photographyreview.com/...ead.php?t=1061

    Thanks for playing Nikon Samurai!
  • 04-01-2004, 11:22 AM
    paulnj
    too easy!!!!!!!!!!!!
    Quote:
    Originally Posted by Speed
    Both of these shots are of Polaris, the North Star. Both were taken on the same night, one right after the other. Both are one hour (60 minute) exposures.

    There are two things that are different in these shots. Can you spot them and figure out what caused them?

    K1000, 50mm lens, Superia Xtra 400, one hour exposures.
    TOP ONE HAS BIG DUST, BOTTOM HAS SMALL DUST

    TOP HAS NO HAIR, BOTTOM HAS ONE!!!

    the bottom one has more light sourse too

    OK REAL ANSWER..... SATELITES :) 2 ON TOP ONE, 1 ON THE BOTTOM
    horizontal line..got me dude!
  • 04-01-2004, 01:06 PM
    Chunk
    Just for fun, Steve, stop way down to f16 or 22 and give it a try. You can get star trails with more color in them sometimes.
  • 04-01-2004, 01:49 PM
    Speed
    Just for fun
    Quote:
    Originally Posted by Chunk
    Just for fun, Steve, stop way down to f16 or 22 and give it a try. You can get star trails with more color in them sometimes.
    "stop way down to f16 or 22 and give it a try."

    Actually, I'm dying to try some night shots at f5.6 and f8. But I need a darker site than my backyard. There's too much light pollution with Newport east of me and Havelock/Cherry Point north of me.

    My college buddies and I are planning a trip to the mountains in May. Maybe I'll get some shots then. At a minimum, I'm planning on some night landscape shots, and I've got some Provia 100 and 400 to try. Should be fun. :-)
  • 04-01-2004, 01:51 PM
    Speed
    1 Attachment(s)
    All Too Easy Indeed!!!!
    Quote:
    Originally Posted by paulnj
    TOP ONE HAS BIG DUST, BOTTOM HAS SMALL DUST

    TOP HAS NO HAIR, BOTTOM HAS ONE!!!

    the bottom one has more light sourse too

    OK REAL ANSWER..... SATELITES :) 2 ON TOP ONE, 1 ON THE BOTTOM
    horizontal line..got me dude!

    I've got to start coming up with more challenging subjects!!!

    Actually, here's a shot with a couple of polar orbiting satelites for ya!
  • 04-01-2004, 03:30 PM
    paulnj
    oh cool..............

    you caught a blackhawk in flight!

    oh wait.... dust agian :p