Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
05-12-2015, 07:39 PM   #1
New Member




Join Date: Aug 2010
Location: California
Posts: 14
K20D Shutter Release Problem

On a recent vacation trip, I could not get the shutter to fire. I was using a Tamron 28-200 K-mount lens with a polarizer in bright sunlight using Autofocus. I first tried with manual mode and then in Auto (Green) mode. I was using a 32GB SDHC card and my Autofocus lever was set to AF.S. After several futile attempts followed by a message "no data storage remaining" or something like it, I sat down in the shade to locate the problem. The data card had no prior images and had been formatted in the camera prior to this trip.

I reformatted the data card thinking since I had to go though two security x-ray machines on the way to the cruise ship that had caused a problem with the data card. The only way I could get the shutter to trip was switching the Autofocus lever to manual. I took several photos using manual focus and then went back to Autofocus. I could trip the shutter now using Autofocus which continued to work for the remainder of the trip.

I had this problem before when I was in North Carolina when suddenly the shutter would not trip and disabling Autofocus fixed it then. I was using a polarizer then as well.

Anyone had an experience like this?

05-12-2015, 08:36 PM   #2
Loyal Site Supporter
UncleVanya's Avatar

Join Date: Jul 2014
Photos: Gallery | Albums
Posts: 9,832
Circular polarizer or linear?
05-12-2015, 08:44 PM   #3
Pentaxian
Not a Number's Avatar

Join Date: Mar 2012
Location: Venice, CA
Posts: 4,260
QuoteOriginally posted by UncleVanya Quote
Circular polarizer or linear?
My question exactly. Linear polarizers can through AF off.
05-13-2015, 05:03 AM   #4
New Member




Join Date: Aug 2010
Location: California
Posts: 14
Original Poster
It is a circular polarizer. I paid $52.95 at Pardee's Cameras in Sacramento.

05-13-2015, 08:23 PM   #5
Loyal Site Supporter
UncleVanya's Avatar

Join Date: Jul 2014
Photos: Gallery | Albums
Posts: 9,832
stumped
05-13-2015, 09:17 PM   #6
Pentaxian
Not a Number's Avatar

Join Date: Mar 2012
Location: Venice, CA
Posts: 4,260
Me too. Pardee's is a reputable camera shop but even they might end up with counterfeit filters.

A quick check is to look through the filter at a flat screen monitor. Rotate the filter as you would on the lens. Then flip the filter over and look through the other side. A circular polarizer will only darken from one side - the other side may show a slight color shift or no difference at all as you rotate it (depends on the quality of the filter). A linear polarizer will work the same either way.

Or you can look at the reflection of the filter in an ordinary mirror. A circular polarizer's image will look black/dark in the reflection from one side and not the other. Linear polarizers will never look black.
05-14-2015, 06:29 AM   #7
Senior Member




Join Date: Jul 2012
Posts: 152
If you had the focus mode set to AF.S, the shutter won't fire unless the camera achieves focus. See page 105 of K20D manual. And it's possible as others have mentioned that the polarizer prevented camera from reaching focus.
05-14-2015, 09:09 AM   #8
New Member




Join Date: Aug 2010
Location: California
Posts: 14
Original Poster
I knew the shutter wouldn't trip unless Autofocus had been achieved. But in this case the camera was unable to achieve autofocus. I was outdoors, trying to take a picture of an enormous cruise ship in bright sunlight and the camera was set to select autofocus, the camera mode was set to green and exposure mode was Center-Weighted. I felt autofocus should have been a snap to achieve.

As I said, the only way to shoot this picture was to turn Autofocus off. I likely could have taken the picture if I removed the polarizer, but given the brightness of the conditions, the sun near the equator and the time of day (10 AM local), I was reluctant to remove the filter while standing on a concrete dock.

05-14-2015, 11:00 AM   #9
Loyal Site Supporter
UncleVanya's Avatar

Join Date: Jul 2014
Photos: Gallery | Albums
Posts: 9,832
If the problem happens again - pull the polarizer. Try testing it as mentioned above. I have a Hoya circular polarizer and I just verified that it behaves as mentioned above - I have an older linear one I can test later - you should try what is suggested to verify that what you have is not linear. If it is linear it is known to interfere with PDAF focusing.
05-14-2015, 11:56 AM   #10
Pentaxian
Not a Number's Avatar

Join Date: Mar 2012
Location: Venice, CA
Posts: 4,260
I wonder if reflections between the front element of the lens and the rear surface of the filter could be the culprit. Cruise ships are generally white or lightly colored so there could have been a lot of light bouncing around.

How did the shots turn out? Was the contrast low or did it look ok?
05-15-2015, 03:58 AM   #11
New Member




Join Date: Aug 2010
Location: California
Posts: 14
Original Poster
I think I found the problem. It was in the handbook, I just never saw it before. And after only 6 years.

On page 58 it states, in part:

"Subjects that are Difficult to Focus On

The autofocus mechanism is not perfect. Focusing may be difficult when taking pictures under the following conditions below.

....(d) Strongly reflected light or strong backlighting (bright background)"

The most recent effort was of a white cruise ship in bright sunlight at almost midday.

Thanks for all your suggestions.
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!
autofocus, camera, card, data, dslr, k20d, k20d shutter release, lever, mode, photography, polarizer, shutter, trip
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Shutter Release Problem tjohns024 Troubleshooting and Beginner Help 2 12-21-2013 12:11 PM
K5 Shutter release problem 10speeduk Pentax K-5 4 11-28-2011 12:55 PM
Shutter release problem with my K7 Jon in SC Pentax DSLR Discussion 6 08-28-2010 12:14 PM
K20D mushy shutter release fccwpe Pentax DSLR Discussion 4 09-17-2009 04:49 PM
Remote shutter release problem slowpez Pentax Camera and Field Accessories 10 07-29-2008 07:17 AM



All times are GMT -7. The time now is 02:24 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