Results 1 to 14 of 14

Thread: long exposure

  1. #1
    Member
    Join Date
    Jan 2006
    Location
    Johor Bahru, Malaysia
    Posts
    830

    Default long exposure

    have anyone try be4 use BULB more than 30 mins??
    will harm body or no?? want to try for star trail.. but worry will harm my camera body.. anyone kind n tell me?? thx!!

  2. #2

    Default Re: long exposure

    It shouldn't harm your camera body. I have seen star trail photos that have an exposure time of 6 hrs + and can't imagine pros would do this if it was going to damage the camera.

  3. #3

    Default Re: long exposure

    nor reason why an extended bulb exposure should damage your camera unless you did it in bright sunlight.

    if you're using digital, you might want to charge your batteries fully otherwise it might switch off during the exposure
    Work: PicasaWeb | Play: Animus3 | Mobile: Tumblr

  4. #4
    Member
    Join Date
    Jan 2006
    Location
    Johor Bahru, Malaysia
    Posts
    830

    Default Re: long exposure

    thx!! BRO, will try later...

  5. #5
    Member
    Join Date
    Jan 2006
    Location
    Johor Bahru, Malaysia
    Posts
    830

    Default Re: long exposure

    i only know somebody use hundre pics for merging to get star trail...

  6. #6
    Member
    Join Date
    Apr 2007
    Location
    Hougang, Singapore
    Posts
    361

    Default Re: long exposure

    I'm not sure, but i read somewhere that long exposure introduces some noise ( it seems CCD produces random noise as a result of long exposure).

    Not sure how effective is the inbuilt noise cancellation function
    Canon 5D mk II /50 f/1.8, 24-105 f/4 IS L, 70-200 f4 IS L, 580EX II
    My Flickr

  7. #7
    Senior Member
    Join Date
    Dec 2005
    Location
    Clementi, Singapore
    Posts
    2,836

    Default Re: long exposure

    Quote Originally Posted by gumnaam View Post
    I'm not sure, but i read somewhere that long exposure introduces some noise ( it seems CCD produces random noise as a result of long exposure).

    Not sure how effective is the inbuilt noise cancellation function
    Dont use the inbuilt noise reduction - its useless and will take about an hour to process your picture after you have taken it.

    Noise builds up due to the sensor getting hot. Longer the exposure, the warmer the sensor gets.

  8. #8
    Member
    Join Date
    Apr 2007
    Location
    Hougang, Singapore
    Posts
    361

    Default Re: long exposure

    Quote Originally Posted by wildstallion View Post
    Dont use the inbuilt noise reduction - its useless and will take about an hour to process your picture after you have taken it.

    Noise builds up due to the sensor getting hot. Longer the exposure, the warmer the sensor gets.
    The inbuilt function work as following

    After the shutter closes, it clears the charges on sensor, and exposes it for same time ( with shutter closed), so as to get the noise floor, and does some processing based on that data........ but yes....... as per my experience it gives good results
    Canon 5D mk II /50 f/1.8, 24-105 f/4 IS L, 70-200 f4 IS L, 580EX II
    My Flickr

  9. #9
    Senior Member
    Join Date
    Dec 2005
    Location
    Clementi, Singapore
    Posts
    2,836

    Default Re: long exposure

    Quote Originally Posted by gumnaam View Post
    The inbuilt function work as following

    After the shutter closes, it clears the charges on sensor, and exposes it for same time ( with shutter closed), so as to get the noise floor, and does some processing based on that data........ but yes....... as per my experience it gives good results
    In my experience it gives no result, and after a long exposure of 30 minutes plus i do not want to sit around waiting for another 30 minutes for it to clean the photo when about 30 seconds in PS will do the trick.

    Sorry, its a useless function and i stand by that....

  10. #10

    Default Re: long exposure

    Actually if u search e net, how they remove noise due to e long exposure of the sensor is to expose it using e same exposure time n then do a PP fm there. Most of e noise wud be remove, tink they call tis e hot pixel noise. The other form of noise fm e pic will still be there tho. Need further PP for tat.

    Google it n u'l find e answer n tat's e best method i noe of removing those super long exposure noise. Of course wud be better if u do e noise cancellation at home cuz normally i do my star trail super late at nite n ur batt wud not have enuff juice to do e same exposure again.

  11. #11
    Senior Member
    Join Date
    Aug 2005
    Location
    Tanjong Katong
    Posts
    3,710

    Default Re: long exposure

    Use film camera. That's the best for long exposure. Especially those fully mechanic one (that not required any battery to operate).

    Knowing your gear limitation is a must.

    Regards,
    Arto.

  12. #12

    Default Re: long exposure

    Quote Originally Posted by Artosoft View Post
    Use film camera. That's the best for long exposure. Especially those fully mechanic one (that not required any battery to operate).

    Knowing your gear limitation is a must.

    Regards,
    Arto.
    but you would then have to account for reciprocity failure for long exposures with film...

  13. #13
    Senior Member
    Join Date
    Aug 2005
    Location
    Tanjong Katong
    Posts
    3,710

    Default Re: long exposure

    Quote Originally Posted by theRBK View Post
    but you would then have to account for reciprocity failure for long exposures with film...
    With digital camera no need?

    Regards,
    Arto.

  14. #14

    Default Re: long exposure

    Quote Originally Posted by Artosoft View Post
    With digital camera no need?

    Regards,
    Arto.
    within the limits of photography, CCD and CMOS seems to be able to hold reciprocity well enough... I'm sure there are limits to it (isn't there always) but not for how we would normally use digital cameras... noise is of course a different story, especially when taking really long exposures where heat from the sensor itself can build up... but current sensors should be able to take it, especially with darkframe subtraction to reduce such noise, and there is always noise reduction software...

    although I must note that with dark frame subtraction, we might actually be taking the same amount of time as if we are taking into account reciprocity failure in film, but on the other hand, this is a more systematic and reliable increase in time than taking into account reciprocity failure in film as there is no guess work to be done... the dark frame exposure is the same length of time as the exposure itself...

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •