Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
04-13-2012, 12:42 PM   #16
Veteran Member
Anvh's Avatar

Join Date: Sep 2011
Posts: 4,616
QuoteOriginally posted by Lowell Goudge Quote
Think about this from the field of view

The FOV is much narrower at 55mm as opposed to 18 mm. Therefore the hood can only cover the shortest focal length to avoid vignetting
Well yes but the flare protecyion is the same at 18mm as with 55m, they way you wrote it down it looked liked the hood did nothing at all at 55mm or was even worse then at 18mm but that isn't true.

04-13-2012, 12:44 PM   #17
Veteran Member
Anvh's Avatar

Join Date: Sep 2011
Posts: 4,616
Pentax DA18-250 flare.
04-15-2012, 05:29 PM   #18
Site Supporter
stevebrot's Avatar

Join Date: Mar 2007
Location: Vancouver (USA)
Photos: Gallery | Albums
Posts: 27,483
The "UFO" is not flare and is not related to the quality of lens coating per se. It is a form of spherical aberration referred to as "coma" and is a matter of lens design. That being said, a high flare situation can make coma more dramatic.

Here is a real cool video showing how it works:



Generally, coma can be reduced by use of a smaller aperture.


Steve

Last edited by stevebrot; 04-15-2012 at 05:34 PM.
04-15-2012, 06:56 PM   #19
Inactive Account




Join Date: Dec 2008
Location: Ames, Iowa, USA
Photos: Albums
Posts: 2,965
Steve, coma is what I was referring to in my earlier post. A small, bright, source like the sun is needed to observe such a figure.

I think the source of the figure in the photo is the sun, positioned just outside the sensor's field of view, but inside the lens' surface field of view.

Look at Sagitta's (OP's) photo again:

The coma figure is in line with the sun (upper left corner) through the center of the photo. I'll bet this is no coincidence.

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!
flare, flickr, pentax help
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
BBC: What really caused the eurozone crisis? jolepp General Talk 4 12-27-2011 09:51 AM
What caused my pictures to look like this? sdilecce Pentax Film SLR Discussion 12 02-06-2011 03:39 PM
Japanese food + strange flare o_O Zav Post Your Photos! 6 02-15-2009 01:49 PM
Very strange lens flare Eastern Shore Charlie Post Your Photos! 10 10-18-2008 09:58 AM
Strange lens flare NaClH2O Post Your Photos! 14 01-31-2007 12:17 AM



All times are GMT -7. The time now is 03:29 AM. | 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