Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
07-02-2015, 11:14 AM   #1
Pentaxian




Join Date: Jul 2011
Location: Eastern Oregon
Posts: 615
So does the K-3 AFC tracking work at all?

This is not an area of photography I really have any experience with so I am asking because I am probably doing something wrong, maybe...


I was at the dog park with Chloe the Yellow Labrador model and she ran at me a few times from say 150 feet away and all the photos seem to have focused about 4-6 feet behind her.


My settings were AFC, 9 point group focus, continuous advance - medium. I think I tried one pass at single point spot but with the same results. Lens was the 70mm DA LTD and the camera was set to program exposure in bright sunlight so shutter speed was 1/500th (the grass is sharp 4-6 feet behind her in every photo.)


Any suggestions? Or is this just not something the Pentax's do?


Thanks!

07-02-2015, 11:32 AM - 4 Likes   #2
Site Supporter
stevebrot's Avatar

Join Date: Mar 2007
Location: Vancouver (USA)
Photos: Gallery | Albums
Posts: 27,474
All Pentax cameras have an undocumented feature where the AF selectively switches off when dogs or small children are detected in the frame. The K-3 and K-3II are particularly good at this due to the presence of the advanced high density RGB meter used in conjunction with the PDAF system. The reputed purpose is to promote battery life.

Canon, Sony, and Olympus have made good progress in this area whereas Nikon fairs far worse. The AF system on a Nikon will track a buzzing fly or bee for as long as it takes resulting in extreme battery drain. Major fail, Nikon.


Steve
07-02-2015, 12:11 PM   #3
Veteran Member
crewl1's Avatar

Join Date: Jul 2010
Location: Los Angeles, CA
Photos: Gallery | Albums
Posts: 9,797
I have not tried dog parks and I don't own a dog so will have to make an extra effort to replicate your situation.
I have had good success with approaching bike riders using AF-c, shutter in high speed continuous, with center spot or selected focus point.
I found that if I used the auto select for neighboring focus points the camera would find a more contrasts object to focus on.
So I stick with single point.
For air shows it is ok to use the auto select as the camera prefers an airplane to a featureless sky.
Turn off AF Hold setting if so the camera can readjust on approaching objects.

It is possible that approaching dogs are much faster than jets or bikes so the camera just can't keep up.

Check out this thread for some testing and settings info.https://www.pentaxforums.com/forums/172-pentax-k-3/274284-another-k-3-af-c-test.html

Last edited by crewl1; 07-02-2015 at 12:29 PM.
07-02-2015, 12:23 PM   #4
Pentaxian
JinDesu's Avatar

Join Date: Jun 2011
Location: New York City
Photos: Gallery
Posts: 5,626
QuoteOriginally posted by stevebrot Quote
All Pentax cameras have an undocumented feature where the AF selectively switches off when dogs or small children are detected in the frame. The K-3 and K-3II are particularly good at this due to the presence of the advanced high density RGB meter used in conjunction with the PDAF system. The reputed purpose is to promote battery life.

Canon, Sony, and Olympus have made good progress in this area whereas Nikon fairs far worse. The AF system on a Nikon will track a buzzing fly or bee for as long as it takes resulting in extreme battery drain. Major fail, Nikon.


Steve
I had to double check my calender to make sure it wasn't April.

07-02-2015, 01:18 PM   #5
Pentaxian
johnmflores's Avatar

Join Date: Apr 2009
Location: Somerville, NJ
Photos: Gallery | Albums
Posts: 5,185
While Pentax AF may not be up to Nikon or Canon standards, it can be used to capture action. It requires some practice though; you can't just set it and expect it do all of the work. You're settings seem good. Is AF achieved with a half press of the shutter or via the button on back? I use back button AF, and sometimes I use AF.S instead of AF.C and work on anticipating and capturing the action.



Here's a sequence of shots.



If you look closely you can see that the camera lost focus a couple of times but recovered pretty quickly. It was my first time shooting youth football.
07-02-2015, 01:38 PM   #6
Site Supporter
stevebrot's Avatar

Join Date: Mar 2007
Location: Vancouver (USA)
Photos: Gallery | Albums
Posts: 27,474
QuoteOriginally posted by Qwntm Quote
I was at the dog park with Chloe the Yellow Labrador model
QuoteOriginally posted by stevebrot Quote
All Pentax cameras have an undocumented feature where the AF selectively switches off when dogs or small children are detected in the frame.
Sorry about the "tongue-in-cheek" response. Your question was quite honestly put, but the common "Pentax AF Sucks" rant generally begins with some statement about dogs in the yard or active small children. Also typical is that Nikon (any model) has no difficulty tracking their dogs and/or kids.

The usual response to Pentax shortcomings (menus, behavioral quirks, missing features, etc.) on this site is to claim that such is an advantage or an undocumented feature of some sort. My comment was in the spirit of that tradition.


Steve
07-02-2015, 04:27 PM   #7
Pentaxian




Join Date: Jul 2011
Location: Eastern Oregon
Posts: 615
Original Poster
QuoteOriginally posted by stevebrot Quote
Sorry about the "tongue-in-cheek" response. Your question was quite honestly put, but the common "Pentax AF Sucks" rant generally begins with some statement about dogs in the yard or active small children. Also typical is that Nikon (any model) has no difficulty tracking their dogs and/or kids.

The usual response to Pentax shortcomings (menus, behavioral quirks, missing features, etc.) on this site is to claim that such is an advantage or an undocumented feature of some sort. My comment was in the spirit of that tradition.


Steve


No worries. I totally understand. Every brand has it's shortcomings. Perception is everything. Pentax has a camera in the K-3 that is in a lot of ways far more professional than a Canon EOS 7DII but most people think it's not even as professional as a Fuji XT-1. And I think the Fuji's are all glorifies P&S's. (JMHO.)


Ricoh is making improvements and we will get to a point where it's not a shortcoming of the technology but in our abilities to understand and use it. This happened to Canon when they upgraded the 5DM2 to the 3. The AF went from basic to so sophisticated overnight and no one knew how to make it work...


So that was kinda my question on the K-3, does it work and I'm doing it wrong, or are we just not there yet.


The dog is kinda fast. She's 1 1/2 years old and is probably moving at least 20mph towards me and at a distance of 20 feet that's probably pretty quick. Maybe not a good model for sports after all? The camera worked fine as she zipped by me 15 feet away, so from the side it tracks just fine. It's directly towards me that nothing was in focus except the grass consistently 5 feet behind her.
07-02-2015, 05:20 PM   #8
Loyal Site Supporter
clackers's Avatar

Join Date: Jul 2013
Location: Melbourne
Photos: Albums
Posts: 9,024
QuoteOriginally posted by Qwntm Quote


Any suggestions? Or is this just not something the Pentax's do?

As Steve was hinting, that's about the toughest auto focus situation in the playbook, for any photographer, with any camera.

A sports pro will be shooting athletes with focal lengths of 300mm or more - the subjects are actually some distance away.

I've shot cyclists moving at me faster than 50kmh, but at 200mm or more. Once they fill the frame, I stop shooting as the small DoF makes any subsequent shots unusable.

One thing you can do without purchasing anything else is to pre-focus on the area where you get the dream shot of Chloe returning to you (the grass is fine) and fire away at the K-3's high framerate after calling her.

You have an advantage over the old film togs who did this around a tennis baseline or basketball ring in that you can trade off ISO for depth of field if you like.

07-02-2015, 05:49 PM   #9
Site Supporter
slip's Avatar

Join Date: Oct 2006
Location: 2 hours north of toronto ontario canada
Photos: Gallery | Albums
Posts: 3,533
Although not as astenically (spelling) pleasing, using f stops like f8 would likely help as you will have greater depth of field

Randy
07-02-2015, 06:09 PM   #10
Site Supporter
Sandy Hancock's Avatar

Join Date: Feb 2012
Location: Adelaide Hills, South Australia
Photos: Gallery | Albums
Posts: 5,725
AF-C, single point, high burst, and perhaps most importantly, a lens with fast AF.
It works for me
07-02-2015, 07:01 PM   #11
Site Supporter




Join Date: Mar 2009
Location: Gladys, Virginia
Photos: Gallery
Posts: 16,250
I guess the question to me is whether your first frame is in focus. If it is, then I find the camera does track decently. If the camera doesn't lock accurate focus on the first frame, then all bets are off as to what will be in focus after that.
07-02-2015, 07:21 PM   #12
Pentaxian




Join Date: Jun 2009
Location: GMT +10
Photos: Albums
Posts: 10,844
QuoteOriginally posted by Qwntm Quote
does it work and I'm doing it wrong,
Yes, K-3 AF-C tracking takes practice, that's all.
Sometimes it takes the first hour of a event for me to figure out the settings that work best for the action type there - alongside with my other settings (aperture, shutter speed, ISO etc).

On Nikon too, I can confirm, AF-C tracking isn't bullet-proof or point-and-shoot, even with lenses with fast AF.
07-02-2015, 08:35 PM   #13
Senior Member




Join Date: Feb 2014
Posts: 241
I think on AF-C the K3 defaults to just firing away even if not in focus. BUt you can also set the camera so AF-C will put focus as a priority over keeping the frame rate going. I've only had my K3 for a few weeks and have only been able to try the focus priority on a single hawk. It did seem to work a lot better than on my K50 and it did pause between some shots, shooting off a few quick ones and then pausing ( I presume to recapture focus) before firing the shutter again.

So you might try setting it to give priority to focus before firing instead of priority on keeping the frame rate going even if the camera thinks the focus is off. I'd be interested to know the results.
07-02-2015, 09:03 PM   #14
Pentaxian




Join Date: Jul 2011
Location: Eastern Oregon
Posts: 615
Original Poster
QuoteOriginally posted by Sandy Hancock Quote
AF-C, single point, high burst, and perhaps most importantly, a lens with fast AF.
It works for me


Hey, how did you get my dog for your photo shoot???




---------- Post added 07-02-15 at 10:05 PM ----------

QuoteOriginally posted by clackers Quote
As Steve was hinting, that's about the toughest auto focus situation in the playbook, for any photographer, with any camera.

A sports pro will be shooting athletes with focal lengths of 300mm or more - the subjects are actually some distance away.

I've shot cyclists moving at me faster than 50kmh, but at 200mm or more. Once they fill the frame, I stop shooting as the small DoF makes any subsequent shots unusable.

One thing you can do without purchasing anything else is to pre-focus on the area where you get the dream shot of Chloe returning to you (the grass is fine) and fire away at the K-3's high framerate after calling her.

You have an advantage over the old film togs who did this around a tennis baseline or basketball ring in that you can trade off ISO for depth of field if you like.


I have been a photographer for long enough to see your point. There is a HUGE difference between tracking a subject at 300 feet away with a 200mm lens than tracking a subject 30 feet away with a 70mm lens. Very possible that the "dog test" is exceeding the parameters of the system. I need to try again with my 70-200 at 200mm and see what happens.
07-03-2015, 12:24 PM   #15
Pentaxian
Mike.P's Avatar

Join Date: Mar 2008
Location: South Coast .. UK
Photos: Gallery
Posts: 1,758
QuoteOriginally posted by stevebrot Quote
All Pentax cameras have an undocumented feature where the AF selectively switches off when dogs or small children are detected in the frame. The K-3 and K-3II are particularly good at this due to the presence of the advanced high density RGB meter used in conjunction with the PDAF system. The reputed purpose is to promote battery life.

Canon, Sony, and Olympus have made good progress in this area whereas Nikon fairs far worse. The AF system on a Nikon will track a buzzing fly or bee for as long as it takes resulting in extreme battery drain. Major fail, Nikon.


Steve
Genius
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!
200mm, afc, camera, dof, dslr, feet, focus, k-3, k-3 afc, k3, lens, pentax, pentax k-3, photo, photographer, shot, shots, subject, tamron, test
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
How much better is the AF tracking on the K-3 II? bwDraco Pentax K-3 50 06-29-2015 12:55 PM
K-3 AFC 27 points real life test biz-engineer Pentax K-3 12 05-03-2015 01:33 AM
So does the K01 not work with Sigma APO EX DG HSMII? OnTheWeb Pentax K-01 13 05-10-2014 06:20 AM
Transcend Wifi SDHC Card in K-3, does it work? cofra Pentax K-3 5 04-30-2014 12:12 AM
K-3 HDR. Does it work? skyer Pentax K-3 12 12-11-2013 05:51 AM



All times are GMT -7. The time now is 01:44 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