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Can't focus on stars with my 50mm 1.8... no infinity focus???

  • 20-10-2008 9:37pm
    #1
    Closed Accounts Posts: 469 ✭✭


    When I took a picture of some stars with my nifty fifty they were all out of focus. Came out exactly like this photo here: (courtesy of jraymay on flickr)

    344748505_432b84b4da.jpg?v=0

    This photo was also taken with a nifty fifty.

    Shouldn't they be pin sharp points of light? Or is there no infinity focus on the 50mm?


Comments

  • Banned (with Prison Access) Posts: 32,865 ✭✭✭✭MagicMarker


    Why not use manual focus?


  • Registered Users, Registered Users 2 Posts: 1,372 ✭✭✭silverside


    i'm no expert but i would guess that AF would have problems... try manual focussing?

    you would probably need a tripod, a long exposure, and press the shutter button gently (or use a a remote shutter release).


  • Registered Users, Registered Users 2 Posts: 287 ✭✭latchiko


    The 50mm should be able to focus on stars no problem. As long as there was no camera shake during the exposure then the stars should appear sharp. Did you use autofocus or did you focus manually?


  • Closed Accounts Posts: 469 ✭✭0utpost31


    I focused manually.... used a tripod... infinity would be at the very end of the focus wheel wouldn't it?


  • Banned (with Prison Access) Posts: 32,865 ✭✭✭✭MagicMarker


    Try autofocus:P


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  • Registered Users, Registered Users 2 Posts: 5,185 ✭✭✭nilhg


    What shutter speed? Don't forget the stars are moving, slowly I know but enough to make a difference with any sort of longish exposure.


  • Registered Users, Registered Users 2 Posts: 287 ✭✭latchiko


    0utpost31 wrote: »
    infinity would be at the very end of the focus wheel wouldn't it?

    In theory yes. In reality most lenses can focus on beyond infinity. As there is no visual indicator on the nift fifty I cannot be sure if it does but it sounds to me like this may be the problem if you moved the focus wheel all the way to the end.


  • Closed Accounts Posts: 469 ✭✭0utpost31


    Shutter speed of a few seconds. Say 15seconds max. They aren't trailing or blurred, they're simply out of fcus. I know all about moving stars, did you not see my lovely movey-star photo on the random photo thread?:pac:

    http://boards.ie/vbulletin/showpost.php?p=57623123&postcount=157

    I'll try it again in a while...


  • Registered Users, Registered Users 2 Posts: 2,259 ✭✭✭Shiny


    My experience has been that infinity is the very end of the focus wheel
    and then back about 2mm (ish).

    The extra room beyond infinity is to allow for temperature changes.


  • Registered Users, Registered Users 2 Posts: 4,699 ✭✭✭ThOnda


    And a little piece of tape prevents change of focus during manipulation with camera/lens.


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  • Closed Accounts Posts: 88 ✭✭petercox


    You'd be surprised how far the stars can move in 15 seconds!

    However, the problem here was that you were manually focusing - as has been said most lenses focus beyond infinity to allow for expansion/contraction of lens components with temperature change.

    I'd use autofocus for this, and use the center AF point in your viewfinder, as it is usually the most sensitive one. If that doesn't work, and the moon is out, try focusing on that. It makes a great infinity subject. Once you've focused on it, use AF lock or simply switch to manual focus (but don't move the focus ring yourself!). Failing that, a distant streetlight would work.

    Good luck!

    Peter


  • Registered Users, Registered Users 2 Posts: 2,357 ✭✭✭JMcL


    If your camera has live view, I'd use that for focusing manually (on the 50, make sure you turn AF off - there's no USM motor hence no manual override)


  • Closed Accounts Posts: 413 ✭✭8kvscdpglqnyr4


    silverside wrote: »
    you would probably need a tripod, a long exposure, and press the shutter button gently (or use a a remote shutter release).
    If you don't have a remote shutter, then use the timer on the camera. That way you can guarantee you don't get camera shake.


  • Closed Accounts Posts: 469 ✭✭0utpost31


    Lads, I appreciate all the suggestions about tripods & shutter releases and stars moving but I've done all that and even mirror lock. It was simply out of focus as I said.

    Next time I'll try AF on the moon or a distant streetlight and I'll post the results!


  • Registered Users, Registered Users 2 Posts: 13,381 ✭✭✭✭Paulw


    Also, don't forget that you're trying to focus through the atmosphere, and this can have an effect too.


  • Registered Users, Registered Users 2 Posts: 4,081 ✭✭✭sheesh


    0utpost31 wrote: »
    Lads, I appreciate all the suggestions about tripods & shutter releases and stars moving but I've done all that and even mirror lock. It was simply out of focus as I said.

    Next time I'll try AF on the moon or a distant streetlight and I'll post the results!

    the autofocus might not work very well with stars if you can try to autofocus on something far away if you can get a focus on that switch to manual focus before it changes and then see how you get on.


  • Registered Users, Registered Users 2 Posts: 25 Lionsden


    Paulw wrote: »
    Also, don't forget that you're trying to focus through the atmosphere, and this can have an effect too.

    The above is most probably the issue you are having. There are a number of factors here that can, and do, have a an effect on your photo, Dust in the atmosphere, moisture in the air etc, etc. The best nights for doing this are nights wth a good hard frost!!! Just not so nice being out in them...;)


  • Closed Accounts Posts: 469 ✭✭0utpost31


    It's nothing to do with dust, moisture, air, atmosphere, rain, hail sleet or snow or goblins or UFOs etc... as I said it was simply a focus issue with the 50mm lens. I was turning the focus wheel past infinity.

    I took pics of the stars with other lenses with no focus/atmospheric problems at all...

    2962578450_e62f9e1bb8.jpg

    With the 50mm lens I simply misfocused it.


  • Closed Accounts Posts: 88 ✭✭petercox


    Next step: get an equatorial mount and do some layering of multiple exposures =)

    Peter


  • Moderators, Society & Culture Moderators Posts: 25,558 Mod ✭✭✭✭Dades


    0utpost31 wrote: »
    I took pics of the stars with other lenses with no focus/atmospheric problems at all...
    Was that taken on the same night, though?

    'Twas frosty out last night to be sure.

    (Great shot btw - like to see it bigger)


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  • Closed Accounts Posts: 469 ✭✭0utpost31


    Yes it was taken on the same night in the same place. Bigger version here, it's fairly noisy though...


  • Closed Accounts Posts: 469 ✭✭0utpost31


    Shiny wrote: »
    My experience has been that infinity is the very end of the focus wheel
    and then back about 2mm (ish).

    Thanks Shiny I did as you said and voila the stars were in focus. If you look closely I think I might have gotten 2 faint shooting stars. Now all I need is a sky that isn't polluted with orange light. I fiddled the white balance to get rid of the orange cast.


    2977204069_871ab324ca.jpg


  • Registered Users, Registered Users 2 Posts: 16,624 ✭✭✭✭Fajitas!


    Are you in Kilsheelan or Clonmel?

    Up the mountains with you, either ways.


  • Moderators, Technology & Internet Moderators, Regional South East Moderators Posts: 28,536 Mod ✭✭✭✭Cabaal


    petercox wrote: »
    Next step: get an equatorial mount and do some layering of multiple exposures =)

    Peter

    A lad I work with has this setup, he's taken some fantastic shots
    heres one http://flickr.com/photos/steveroche/2930195220/


  • Closed Accounts Posts: 469 ✭✭0utpost31


    Fajitas! wrote: »
    Are you in Kilsheelan or Clonmel?

    Up the mountains with you, either ways.

    Cill Siolan. I'm not going up those mountains, have you heard about the panther that roams the comeraghs?:eek:

    Kiddin... Yeah the comeraghs are good enough for clear skies, I never have enough time though. Every single night I've tried to take pics of stars, clouds eventually came in and ruined everything. If I know it's going to be an exceptionally clear night well then I'll go out of my way to find a good spot.


  • Registered Users, Registered Users 2 Posts: 16,624 ✭✭✭✭Fajitas!


    Ah I think that panther's gone further up to Tipp by now... Easier prey :p

    Keep an eye on the clouds and head up the mountains, or at least, far away from lights... It just means less work afterwards, which is always a good thing!


  • Moderators, Arts Moderators Posts: 10,520 Mod ✭✭✭✭5uspect


    Must get t-adapter for new Adli scope!


  • Closed Accounts Posts: 469 ✭✭0utpost31


    Cabaal wrote: »
    A lad I work with has this setup, he's taken some fantastic shots
    heres one http://flickr.com/photos/steveroche/2930195220/

    Wow some brilliant photos there. The first one of andromeda is cool, especially when you see that he took it with a 350d and a sigma 70-300.... how the feck?!


  • Registered Users, Registered Users 2 Posts: 79 ✭✭lukeod


    0utpost31 wrote: »
    Wow some brilliant photos there. The first one of andromeda is cool, especially when you see that he took it with a 350d and a sigma 70-300.... how the feck?!

    How the feck indeed?!?!


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  • Registered Users, Registered Users 2 Posts: 16,624 ✭✭✭✭Fajitas!


    The head means that the camera can follow the stars.... Handy piece of kit :)


  • Closed Accounts Posts: 469 ✭✭0utpost31


    So I finally got a decent clear night. Went out with my 70-300mm, couldn't believe I could get this with it:

    2982474641_4defe9137f.jpg

    I didn't have a shutter release with me so there's a teeny bit of shake, but I've found it and am heading back out right now. It's fffffeckin' fffffreezin'.


  • Registered Users, Registered Users 2 Posts: 2,259 ✭✭✭Shiny


    Is the above an individual photo or a stack ?


  • Closed Accounts Posts: 469 ✭✭0utpost31


    It's one individual photo. 8seconds, is1600, f5.6.


    Here's another one although the orion nebula is a tad messier in it.

    2983451750_3a96fc5a0e.jpg


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