Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
03-08-2014, 07:55 AM   #1
Senior Member




Join Date: Feb 2014
Location: Western Australia
Photos: Albums
Posts: 173
AF Assist light

How dark must it be to trigger the AF assist light on the K5IIs?

This evening I was trying to take a photo of a broken down engine with the DA 18-135 under conditions so dark that I couldn't see anything without a torch. The camera would try to focus but fail, but it never activated the AF assist light (and yes, I do have it enabled in the menu).

I tried TAv, Av and a user mode but no luck. The camera did focus under torchlight and I was able to take a flash photo but it would have been much easier if the light worked. My K-r in comparison will readily use the AF assist light.

03-08-2014, 09:29 AM - 1 Like   #2
Veteran Member




Join Date: Jul 2009
Location: London
Posts: 889
Only operates in AF.S. Worth checking focus mode setting.
03-08-2014, 10:18 AM   #3
Senior Member




Join Date: Feb 2014
Location: Western Australia
Photos: Albums
Posts: 173
Original Poster
QuoteOriginally posted by JohnX Quote
Only operates in AF.S. Worth checking focus mode setting.
Ahhh! Thank you JohnX!

I was using the back button AF technique as described here so I was in AF-C.
03-08-2014, 01:09 PM   #4
Veteran Member




Join Date: Jul 2009
Location: London
Posts: 889
Interesting thread. I get where the OP is coming from but surely what he describes would only really be an issue if you were set up with a lens aperture that was giving incredibly narrow dof or subjects moving directly towards or away from you?

Have you tried 'catch in focus'? P134 of the K5 manual. Although designed for use with manual lenses it is possible to 'fool' the camera and use AF lenses in manual.

I would have thought that camera movement/shake was much more likely to be a problem than focus though.

If you want seriously odd combinations of settings by the way try using a Fuji camera!


Last edited by JohnX; 03-08-2014 at 01:15 PM.
03-08-2014, 04:59 PM   #5
Senior Member
zekewhipper's Avatar

Join Date: Dec 2010
Photos: Albums
Posts: 298
QuoteOriginally posted by Dieseler Quote
Ahhh! Thank you JohnX!

I was using the back button AF technique as described here so I was in AF-C.
You can use back button focusing for AF-S too if you didn't know.
03-08-2014, 09:46 PM   #6
Pentaxian
MadMathMind's Avatar

Join Date: Dec 2013
Location: Houston, TX
Photos: Gallery
Posts: 1,641
It has to be really dark for it to come on but not so dark that it can't even identify an AF target without the light. If you try to take a photo in a cave (with no lights), for instance, focus won't have a clue what to do and the light won't come on. It's pretty random when it is and is not needed, but the camera has to think it will get the focus with a bit more light.
03-09-2014, 12:28 AM   #7
Senior Member




Join Date: Feb 2014
Location: Western Australia
Photos: Albums
Posts: 173
Original Poster
QuoteOriginally posted by JohnX Quote
Have you tried 'catch in focus'? P134 of the K5 manual. Although designed for use with manual lenses it is possible to 'fool' the camera and use AF lenses in manual.
I have tried 'catch in focus' with my K-r but could never get it to work as I don't have a MF lens or one with an AF/MF switch. I have not tried it with the K5IIs. How do you 'fool' the camera?

---------- Post added 9th Mar 2014 at 04:35 PM ----------

QuoteOriginally posted by zekewhipper Quote
You can use back button focusing for AF-S too if you didn't know.
I thought that should be possible too, but I could see the reasoning behind Wired using AF-C so I tried that. The main issue was that I did not realise the AF assist light would not work in AF-C, I have a lot to learn about this new camera! For that matter, the AF light on the K-r probably doesn't work in AF-C either, but I rarely used AF-C on that camera.

---------- Post added 9th Mar 2014 at 04:42 PM ----------

QuoteOriginally posted by MadMathMind Quote
It has to be really dark for it to come on but not so dark that it can't even identify an AF target without the light. If you try to take a photo in a cave (with no lights), for instance, focus won't have a clue what to do and the light won't come on. It's pretty random when it is and is not needed, but the camera has to think it will get the focus with a bit more light.
So below a certain light threshold, the camera does not even try to use the AF light or try to focus? I know the specs say -3EV, but I can't visualise how dark that is.
03-09-2014, 07:37 AM   #8
Pentaxian
MadMathMind's Avatar

Join Date: Dec 2013
Location: Houston, TX
Photos: Gallery
Posts: 1,641
QuoteOriginally posted by Dieseler Quote
So below a certain light threshold, the camera does not even try to use the AF light or try to focus? I know the specs say -3EV, but I can't visualise how dark that is.
I've had a mixed experience with the AF light as well. It doesn't always come on when I think it should. That said, I just took my camera into a totally dark room (no windows or light at all) and the AF light DID come on this time. No idea when it does or doesn't come on. I've had it come on when I though it wouldn't be necessary and not come on when it should.

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!
af, af-c, camera, dslr, focus, k-5, k-5 ii, k-5 iis, k-r, k5, lenses, light, pentax k-5, photo
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
AF assist light only works in green mode robheath Pentax K-3 11 10-01-2017 10:33 AM
MX-1 and AF assist light Mooey Pentax Compact Cameras 10 05-20-2014 02:45 PM
Flash Af assist light Dionisis_K Pentax Camera and Field Accessories 5 11-21-2012 04:56 AM
AF assist light HSV Pentax DSLR Discussion 7 09-10-2012 07:03 PM
K7 AF assist light faulty? Spock Pentax DSLR Discussion 7 08-19-2009 01:48 AM



All times are GMT -7. The time now is 07:14 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