Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
10-30-2009, 01:09 PM   #1
Pentaxian
dosdan's Avatar

Join Date: Dec 2007
Location: Brisbane, Australia
Photos: Gallery | Albums
Posts: 1,699
Star points on lights in night shots

The star-effect depends on the number of leaves/blades that form the lens aperture circle. With an even number of leaves, its the same name of star points as the number of leaves. While an odd number of leaves doubles the number of points.


Taken with a Pentax-DA 16-45/F4 - 8 leaves - 8 points



Taken with a Pentax-M 50/F1.7 - 6 leaves - 6 points



Can someone show an image taken with an odd number of leaves?

Dan.


Last edited by dosdan; 10-30-2009 at 01:17 PM.
10-30-2009, 01:33 PM   #2
Veteran Member




Join Date: Oct 2007
Photos: Gallery
Posts: 418


Taken with a Sigma 17-70mm F2.8-4.5 DC, 7 blade diaphram. Looks like 14 star points.
10-30-2009, 01:50 PM   #3
Ash
Community Manager
Loyal Site Supporter
Ash's Avatar

Join Date: Mar 2007
Location: Toowoomba, Queensland
Photos: Gallery | Albums
Posts: 22,695
Hadn't considered the phenomenon until you mentioned it.
One with the 16-50 - 9 blades, so indeed 18 pointed stars...

[IMG][/IMG]
10-30-2009, 01:52 PM   #4
Veteran Member
Eruditass's Avatar

Join Date: Jul 2009
Location: Pittsburgh, PA
Photos: Gallery | Albums
Posts: 2,206
Very cool, I always wondered about that!

10-30-2009, 02:02 PM   #5
Pentaxian
Lowell Goudge's Avatar

Join Date: Jan 2007
Location: Toronto
Photos: Gallery | Albums
Posts: 15,400
actually you always get 2 points per blade, or more appropriately a line.

the reason it looks like double the points on an odd number of blades is because the lines don't fall symetrically on top of each other.

look for a lens where the aperture does not close down symmetrically with an even number of blades and I'll bet you can see the double lines again
10-30-2009, 02:03 PM   #6
Damn Brit
Guest




Moved to Lens forum.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
k-mount, pentax lens, slr lens, star
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Night star picture questions mr tibbs Photographic Technique 85 11-17-2010 01:42 AM
Landscape Star Trails (night exposure) Marc Langille Post Your Photos! 42 01-07-2010 03:58 AM
night lights ltdstar Post Your Photos! 1 12-23-2008 08:54 PM
night Lights artifax1 Post Your Photos! 10 11-27-2008 06:02 AM
How to pan for trailing lights in Night photos hinman Post Your Photos! 6 09-25-2007 02:09 PM



All times are GMT -7. The time now is 12:17 PM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top