Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
05-16-2012, 03:27 PM   #1
Junior Member




Join Date: Aug 2011
Posts: 30
Aperture not fully adjustable?

I realized something quite annoying, with my kit DA 18-55 lens and K-x set on Av, depending on where I am focusing the aperture is not fully adjustable to the max and min stops that I know the lens is capable of. Sometimes it stops as low as f40, other times at f32, same thing with max. sometimes it is f4 others times only f5.6. Any explanation or way to make it fully adjustable?

05-16-2012, 03:31 PM   #2
Pentaxian




Join Date: Oct 2011
Location: Savannah, GA
Posts: 4,988
That's why it is listed as 3.5-5.6. The max aperture changes with the zoom -- at 18mm you can open to f/3.5, but at 55mm you can only go to f/5.6. In the middle, you get the middle range. This is normal for most zoom lenses, except for "fixed aperture" zooms, which are generally higher quality and more expensive.
05-16-2012, 03:35 PM - 1 Like   #3
Veteran Member
RioRico's Avatar

Join Date: Jun 2008
Location: Limbo, California
Posts: 11,264
The DA18-55/3.5-5.6 has different aperture limits at different focal lengths. At 18mm the range is f/3.5-22. At 55mm the range is f/5.6-40. An f-stop is a ratio of the aperture diameter to the focal length. As the focal length changes, the ratio changes. Does this make sense?
05-16-2012, 04:14 PM   #4
Junior Member




Join Date: Aug 2011
Posts: 30
Original Poster
aaahhh, ok that makes sense. I was wondering why it was listed like that. Thanks guys!

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!
aperture, camera, dslr, lens, max, photography, times
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Fader ND Adjustable Filter - Anyone Have Experience? Tamia Pentax Camera and Field Accessories 4 01-18-2012 04:54 AM
K-x aperture problem: always fully stopped down on DA lenses amrocha Troubleshooting and Beginner Help 4 11-03-2011 03:47 PM
Optio A36 Fully powers up, then fully powers down. PicturePlant Pentax Compact Cameras 6 08-11-2011 11:45 AM
Adjustable settings on K-X briankabat Pentax DSLR Discussion 7 03-06-2011 01:09 AM
K200 blurry & not adjustable danielac Pentax DSLR Discussion 3 10-30-2010 05:28 PM



All times are GMT -7. The time now is 12:19 AM. | See also: NikonForums.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