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734 online
Server Time:
2024-05-16 00:55:31
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 willskith
   
Location: Boston, MA
Gender: Male
 |  |  |  | problems with long exposure light "haze" and "stars"
< on 11/5/2008 6:45 AM >
|  | | | I need some help! I dont know what to call this, but in lots of my shots where my exposures are upwards of 30 seconds there will be lots of haze and stars around bright lights. Example:
Shot at f/22 for 4 minutes. Notice the fog-like haze around the brightly lit up white building? What is the technical term for this, and how can I avoid it?
Also, the 6-point stars, most noticeable on the red lights. What can I do to avoid those?
grit your teeth in the face of fear. self repression is the true sign of a coward, toss your inhibitions to the wind. |
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briansbrains
  
Location: valbona
Gender: Male
////////////
| | | Re: problems with long exposure light "haze" and "stars"
<Reply # 1 on 11/5/2008 1:45 PM >
| | | | a polarizer filter might help some.
dunno about the spikey stars though.
www.time-zero.net |
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mANVIL
Gender: Male
| | Re: problems with long exposure light "haze" and "stars"
<Reply # 2 on 11/5/2008 2:00 PM >
| | | | I've always found the stars come when shooting at very tiny apertures (like f/22). Some people shoot like that for the intended purpose of getting the stars. Any particular reason you are shooting at f/22 ?
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Byberrian Fanman
Location: Fuck You
Gender: Male
| | Re: problems with long exposure light "haze" and "stars"
<Reply # 3 on 11/5/2008 6:05 PM >
| | | | Yes.. 'sunstars', as they're referred to, are caused by the diaphragm of the lens when stopped down to small apertures, usually between f/8 and f/22. The reason you're getting six pointed sunstars has all to do with the diaphragm of the lens itself. A lens with an even number of diaphragm blades will give you an even number of points. One with an odd number of blades however (say, seven), will double the the number of star points by the number of diaphragm blades.
Five bladed diaphragm (some older Canon and maybe others): 10 pointed sunstars
Six bladed diaphragm (Canon, others, most off-brand lenses): 6 pointed sunstars
Seven bladed diaphragm (Nikon & some Canon): 14 pointed sunstars
Eight bladed diaphragm (better Canon): 8 pointed sunstars
Nine bladed diaphragm (better Nikon & better off-brands): 18 pointed sunstars
Basically, in order to avoid creating visible sunstars, simply choose a wider aperture.
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RenegadeOfFunk
Location: Boston, MA
Gender: Male
| | | Re: problems with long exposure light "haze" and "stars"
<Reply # 4 on 11/5/2008 6:20 PM >
|  | | | Dude. It is because your shooting with a canon lens.
Actually, it may just be smog and crap from the city even though I don't have any of the haze from my night shots of Boston. I tend to shoot all my night shots at around f/4-f/5.6 to avoid the star effect on the lights. Seems to work well so far.
edit: I think that there may be haze by the lights rather than elsewhere is because the lights are illuminating fog, or haze. This doesn't appear in other parts of the photo because there is nothing there to light it.
[last edit 11/5/2008 6:26 PM by RenegadeOfFunk - edited 1 times]
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willskith
Location: Boston, MA
Gender: Male
| | | | Re: problems with long exposure light "haze" and "stars"
<Reply # 5 on 11/5/2008 7:54 PM >
| | | | Thanks for the help guys. It was actually shot with a Tokina lens, not Canon. But I try to shoot at f/22 to get the absolute sharpest detail. I'll try stopping it down and see how it goes.
grit your teeth in the face of fear. self repression is the true sign of a coward, toss your inhibitions to the wind. |
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Byberrian Fanman
Location: Fuck You
Gender: Male
| | Re: problems with long exposure light "haze" and "stars"
<Reply # 6 on 11/5/2008 8:22 PM >
| | | | Posted by willskith
But I try to shoot at f/22 to get the absolute sharpest detail. I'll try stopping it down and see how it goes.
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That's a common misconception. Stopping the lens all the way down to f/22 actually SOFTENS the image in most cases. Most lenses give their sharpest results around f/8 and f/11. Then again, this also depends on the characteristics of the lens itself. Some lenses make great, sharp images at their smallest apertures (i.e. f/22, f/32, etc.). Others make very sharp images wide open, or at large apertures (i.e. f/1.2, f/1.8, f/2.8, etc. (The Nikon 58mm f/1.2 Noct is a prime example of this)).
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willskith
Location: Boston, MA
Gender: Male
| | | | Re: problems with long exposure light "haze" and "stars"
<Reply # 7 on 11/5/2008 8:33 PM >
| | | | Posted by Byberrian Fanman
That's a common misconception. Stopping the lens all the way down to f/22 actually SOFTENS the image in most cases. Most lenses give their sharpest results around f/8 and f/11. Then again, this also depends on the characteristics of the lens itself. Some lenses make great, sharp images at their smallest apertures (i.e. f/22, f/32, etc.). Others make very sharp images wide open, or at large apertures (i.e. f/1.2, f/1.8, f/2.8, etc. (The Nikon 58mm f/1.2 Noct is a prime example of this)).
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hmmm, ill have to experiment, see where its sharpest...
grit your teeth in the face of fear. self repression is the true sign of a coward, toss your inhibitions to the wind. |
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don_corleyone
Location: F/RoX
Gender: Male
I have abandonment issues
| | Re: problems with long exposure light "haze" and "stars"
<Reply # 8 on 11/5/2008 8:39 PM >
| | | | fanman is right. the smallest aperture will give you the widest DOF (and make most of the frame "in focus") but most lenses are sharpest in the middle of the road.
EDIT: here's a good link i just found: http://www.bobatki...l/diffraction.html
[last edit 11/5/2008 8:46 PM by don_corleyone - edited 1 times]
leave the gun. take the cannoli.
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willskith
Location: Boston, MA
Gender: Male
| | | | Re: problems with long exposure light "haze" and "stars"
<Reply # 9 on 11/5/2008 9:02 PM >
| | | | that helped a lot, thanks!
grit your teeth in the face of fear. self repression is the true sign of a coward, toss your inhibitions to the wind. |
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