Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
07-02-2015, 03:08 PM   #1
Site Supporter
slip's Avatar

Join Date: Oct 2006
Location: 2 hours north of toronto ontario canada
Photos: Gallery | Albums
Posts: 3,533
K3 metering

Does the type of metering (for example spot) effect autofocus on the K3?

Thanks

Randy

07-02-2015, 04:13 PM   #2
Site Supporter
stevebrot's Avatar

Join Date: Mar 2007
Location: Vancouver (USA)
Photos: Gallery | Albums
Posts: 27,474
No, I don't think so. While it is rumored that the high resolution RGB detector used in the K-3's meter is leveraged by the focus system for target tracking, the meter mode (spot, center averaging, matrix) does not play into the AF behavior*. The most likely scenario would be both systems drawing from the same data source, but for different purposes. The difference between the three meter modes is probably not based on a physical mask or by turning off portions of the sensor. Instead, it is more likely based on selective sampling from available meter sensor data. There may be some additional clues available by looking for information on the similar system used in the Nikon D7100 and D7200.


Steve

* I have not experienced any cross-talk issues on my K-3, but would welcome any comments indicating else wise.
07-02-2015, 07:37 PM   #3
Pentaxian




Join Date: Jun 2009
Location: GMT +10
Photos: Albums
Posts: 10,843
QuoteOriginally posted by slip Quote
Does the type of metering (for example spot) effect autofocus on the K3?
The two systems (AF and metering) are very closely linked. They talk to each other a lot. Pic related:



And something like spot metering might directly effect your AF if, for example, you decide to link your metering to your AF point, as you can choose to do [Menu > C1 > 5. Link AE and AF point].
07-03-2015, 12:56 PM   #4
Site Supporter
stevebrot's Avatar

Join Date: Mar 2007
Location: Vancouver (USA)
Photos: Gallery | Albums
Posts: 27,474
QuoteOriginally posted by rawr Quote
And something like spot metering might directly effect your AF if, for example, you decide to link your metering to your AF point, as you can choose to do [Menu > C1 > 5. Link AE and AF point].
I don't use that feature, but thought that was exactly how it works...spot metering at the point of focus.

Nice graphic, BTW.


Steve

07-03-2015, 01:06 PM   #5
Site Supporter
stevebrot's Avatar

Join Date: Mar 2007
Location: Vancouver (USA)
Photos: Gallery | Albums
Posts: 27,474
QuoteOriginally posted by stevebrot Quote
I don't use that feature, but thought that was exactly how it works...spot metering at the point of focus.
I just gave the feature a test drive and with exposure set to the AF point and spot meter selected, the location of the "spot" is very narrow and located at the point of focus rather than the frame center (very cool). Changing to center average and matrix results in a less pronounced effect.


Steve
07-03-2015, 01:09 PM   #6
Site Supporter
stevebrot's Avatar

Join Date: Mar 2007
Location: Vancouver (USA)
Photos: Gallery | Albums
Posts: 27,474
QuoteOriginally posted by rawr Quote
And something like spot metering might directly effect your AF if, for example, you decide to link your metering to your AF point, as you can choose to do [Menu > C1 > 5. Link AE and AF point].
QuoteOriginally posted by stevebrot Quote
I just gave the feature a test drive and with exposure set to the AF point and spot meter selected, the location of the "spot" is very narrow and located at the point of focus rather than the frame center (very cool).
Turns out in works the other way around for the case where AE and AF are linked. The AF point drives the bias of the metering. I would strongly doubt that with the menu setting on default (no linkage), that spot metering would affect focus point selection* or focus tracking behavior.

Steve

* I was able to test this with focus is set to A-27 and meter to spot using AF-S. The focus point selection was the same in my test scene regardless of the meter was in spot, center-weight, or matrix. Likewise, metering was identical regardless of the focus point.

Last edited by stevebrot; 07-03-2015 at 01:25 PM.
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!
dslr, k-3, k3, pentax k-3
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Why is metering with manual lenses unreliable? iDon Pentax K-3 9 01-19-2015 11:26 AM
K3 metering--Assistance please alamo5000 Troubleshooting and Beginner Help 6 12-27-2014 06:50 PM
K3 spot metering coliver80 Pentax K-3 16 12-15-2014 07:27 AM
K3 new metering system -tend to underexpose? Sleepy Pentax K-3 21 10-09-2014 02:27 PM
Metering the K and M lenses on the K3 NaClH2O Pentax K-3 21 05-28-2014 05:06 PM



All times are GMT -7. The time now is 09:52 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