Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
04-26-2016, 11:24 PM   #16
Pentaxian




Join Date: Feb 2015
Photos: Gallery
Posts: 12,171
QuoteOriginally posted by clackers Quote
Low contrast behaviour is another thing - have you seen a focus chart like those used to determine those ratings? That's made up of very distinct black and white shapes.
Yes, I agree regarding focus charts and -ev ratings.

Now, when I look at the photo posted here (the one with the guy and the two dogs), the fence is in focus and the person+dogs aren't in focus. K3 AF firmware behavior (as I just checked on my K-3): if the camera does not find a focus, it turn the focus ring up to nearest focus, that's the default behavior of Pentax AF (that's also the default behavior of Canon cameras, at least): the camera AF tries to focus on the object under the selected focus point, closest to the camera.

If the fence is in focus, and the person's not in focus, I bet multi 27 points AF Auto was used, and if this is the case, the camera AF focuses on whatever looks more contrasty since there is no other condition for the camera to know what to focus on. For portraiture, AFS single point select should be used, eventually 9 points Auto, but never 27 points Auto. If any AF mode is selected, that's not really a problem of the camera, that's a problem of knowing what focus mode should be use for each case. Unfortunately, the documentation of the K3 AF is not very explicit, which may also lead to customers thinking the AF is worse on the K3 compared to previous cameras, the truth being that at least the AF of the K3 is more complicated.

04-26-2016, 11:30 PM   #17
Otis Memorial Pentaxian
Otis FanOtis FanOtis FanOtis FanOtis FanOtis Fan
Loyal Site Supporter
clackers's Avatar

Join Date: Jul 2013
Location: Melbourne
Photos: Albums
Posts: 16,394
QuoteOriginally posted by biz-engineer Quote

If the fence is in focus, and the person's not in focus, I bet multi 27 points AF Auto was used, and if this is the case, the camera AF focuses on whatever looks more contrasty since there is no other condition for the camera to know what to focus on. For portraiture, AFS single point select should be used, eventually 9 points Auto, but never 27 points Auto.
Exactly. People talk about more than 100 AF points but I want just one on my target, not something closer, not something more contrasty.

Like you, I bet a nice little green square lit up in the viewfinder on the fence. And then the shutter button was depressed.
04-27-2016, 03:06 AM   #18
Loyal Site Supporter
Loyal Site Supporter




Join Date: Mar 2009
Location: Gladys, Virginia
Photos: Gallery
Posts: 27,601
QuoteOriginally posted by harrisonww Quote
I had the pentax ist dl and the pentax kr before i purchased the k3.. The speed of the k3 put the other two cameras to shame however i hit focus with the ist dl at twice the rate that i did with the k3. This is a typical shot i was getting; i would have everything set for another person to simply frame the middle of the shot and click the shutter. group points, single points it didnt seem to matter the cameras keeper rate was just terrible. Having said that it didnt perform in many different scenarios, sports i can understand i used to shoot skateboarding and snowboarding and you need fast lenses and a fast tracking system I do not come to expect this from a pentax camera. I used the k3 for landscape shots and infinity focus shots and it was out of focus half of the time as well. What got me to sell the camera is the focus points would lock in for lets say a group shot of people standing still and it would be out at f4.0-5.6, fast shutter speed and decent lighting.... shooting anything faster would make the photos completely useless..There is room for the argument that I as a photographer dont utilize the k3 properly or I dont use the autofocus system properly? But i hit shots in manual focus or used the back button AF with single point to try to get a better accuracy rate. I gave this camera a lot of extra time to figure it out.. my friends canon 5d mark II autofocus points light up nice and bright with autofocus conformation and that may be a great feature in the k1. Lets just hope the points it lights up are actually in focus.

This photo was 400, f8.0. 1/80. Sigma 50mm hsm used. I had same problems with 5 lenses including the pentax 35mm 2.4

I handed the camera to my sister she took 10 shots i told her move the centre focus point around to get it to focus to the back fence and back on me so it would readjust. It hit focus 4/10 times (I would have manual focused but its hard to see in the viewfinder for anyone not used to the k3 and i wasnt taking the picture)... THE SUBJECTS ARENT MOVING! How can it possibly miss this badly. Anyways before everyone destroys me for ripping on the k3 I dont feel bad I finally separated from the k3 and I will await the k1 reviews hoping for a hands on and perhaps a happy purchase. I love the brand and the kr and the ist dl I wouldnt change for the world, best cameras I have owned.. The k3 took great photos but DAMN the focus was a major problem for me.
I choose my auto focus (seldom use the center point) and I haven't had much trouble. Older cameras struggled a little more, mainly because the auto focus points were so big that you could easily focus on someone's shirt rather than their eyes, but K3 is better in that respect. Tracking still isn't perfect.

I do think putting subjects right in front of a contrasty wall is a situation that is hard on an auto focus system, as well.

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, autofocus, k3, k5, photography, solutions, thanks, time, vs
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Adapted telephoto M42 Lenses - PF/CA Problems..Solutions? cahudson42 Pentax Q 16 03-20-2014 02:48 PM
Start up and Card Read Problems:Some Solutions tommen Troubleshooting and Beginner Help 3 09-23-2012 09:22 PM
Let's hear your stories about solving lighting problems in the field (non-studio) philbaum Flashes, Lighting, and Studio 5 08-25-2011 08:54 AM
K7 common problems? crewl1 Pentax DSLR Discussion 6 02-19-2011 12:12 PM
Need help with exposure problems and snow photography problems, urgent please respond montezuma Photographic Technique 7 02-24-2008 05:43 PM



All times are GMT -7. The time now is 02:33 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