Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
10-03-2016, 10:22 AM   #1
New Member




Join Date: Oct 2016
Posts: 4
K-3 II focus problem

Hello everyone, I would like your opinion on my problem. for a few months now, I dropped my K-50 (as it has a few issues) for a new K-3 II. however, I soon discovered a problem with it. most of my pictures are out of focus. I use most a pentax 16-85 and a sigma 17-50 2.8, but with all my lenses the results are the same. I use mostly TAV or P mode, single focus point. i took the camera for a small test when I bought it, with the 18-55 lens, the one I had with me then, and noticed that most pictures were out of focus. but I didn.t mind it that much, as I thought my 16-85 is a lot sharper, and will perform a lot better, but it didn't.
I took the camera back to the shop, and they recalibrated it. it seemed to perform somewhat better after that, but not by much, and soon, I was back where I started. same results with my sigma 17-50 2.8. It seems to me that it can't focus properly when you use the long end of the zoom, but it's quite sharp at the short end, for whatever the reason. after an hour or so, I turned off the SR and it seems that it improved the ratio of sharp pictures.
Iater on I will try to do some microadjustments with a lens cal (I've tried that before with 16-85, 18-55, and 50 1.8, but not with the sigma lens, but without any results). I really want to figure this out, as I love this camera. it takes outstanding pictures (when they are in focus...), but at this point, my K-50 is a lot sharper than my K-3 II. so, it's either the user (K-3 II is a lot less forgiving than K-50), tho I can't really belivethat I screw up almost all my pictures with every lens I got (it doesn't make sense, to me anyway), or, the camera has some problems. I don't really want to take the camera back to the store, but I will if I have to.
also, I've noticed that the shutdown it's not that fast, it takes a couple of seconds to shut down, and the top plate a second after that. and after power up, either from off, or idle, it makes this wierd scraping noise, before I can use the lens, like it has some kind of locking mechanism for the AF, when it goes idle.
any ideas? anyone else with the same problem?

Attached Images
View Picture EXIF
PENTAX K-3 II  Photo 
View Picture EXIF
PENTAX K-3 II  Photo 
View Picture EXIF
PENTAX K-3 II  Photo 
View Picture EXIF
PENTAX K-3 II  Photo 
View Picture EXIF
PENTAX K-3 II  Photo 
10-03-2016, 10:34 AM   #2
Moderator
Loyal Site Supporter
BigMackCam's Avatar

Join Date: Mar 2010
Location: North East of England
Posts: 6,308
Hello, and welcome to the forums

Looking at the EXIF data, all of your photos were taken with an aperture of f/2.8 - ie. you are using the lens "wide open". Two things to bear in mind, here. Firstly, no lens is at its sharpest wide open. Typically, you need to stop a lens down a little in order to get the best from it. This varies lens by lens, but f/5.6 - f/8 is usually where things start to get really sharp across the entire frame. Secondly, at f/2.8, there will only be a relatively shallow "depth of field" - the portion of the picture in focus between you and infinity. So, the point you focus on may be sharp, but most of what is in front of or behind the focus point will be gradually more and more blurred. To increase the depth of field, you need to stop the lens down. Landscape photography (including cityscapes) are usually shot at f/8 - f/16. At these apertures, the distance in front of and behind the focus point that remains acceptably sharp will be much greater than when you shoot at f/2.8.

There's a great article on depth of field here: Understanding Depth of Field in Photography

Hope this helps
10-03-2016, 11:29 AM   #3
Veteran Member




Join Date: May 2014
Location: Maryland
Photos: Gallery
Posts: 762
I agree that 2.8 is too wide to judge from these photos. On the other hand I was having a heck of time with my k-3, and I had just microadjusted probably 24 hours prior and they were all over the place with focus again. I looked at the af sensor, and there were 3 very tiny hairs sticking out of it. Pulled them out with tweezers and it seems to be working fine again with the adjustments I made a day ago. They looked like long pieces of fabric, not sure where they came from, but it was enough to make an issue. I am going to have a local place take a look again. I just happened to have some old dental mirrors so I was able to get in the weird angle to see it.
10-03-2016, 12:07 PM   #4
Site Supporter




Join Date: May 2016
Posts: 507
The images seems way to soft for the 2.8 aperture to be responsible, aren't they? Also they are all taken a a distance, and I would think that the depth of field would be enough even at 2.8 to make them reasonably sharp, even if the focus were off a little bit?

10-03-2016, 12:13 PM   #5
Moderator
Loyal Site Supporter
BigMackCam's Avatar

Join Date: Mar 2010
Location: North East of England
Posts: 6,308
QuoteOriginally posted by leekil Quote
The images seems way to soft for the 2.8 aperture to be responsible, aren't they? Also they are all taken a a distance, and I would think that the depth of field would be enough even at 2.8 to make them reasonably sharp, even if the focus were off a little bit?
That depends on the point of focus
10-03-2016, 12:26 PM   #6
Loyal Site Supporter
Quartermaster James's Avatar

Join Date: Nov 2015
Location: Anchorage, Alaska
Posts: 609
QuoteOriginally posted by Murfy Quote
I agree that 2.8 is too wide to judge from these photos. On the other hand I was having a heck of time with my k-3, and I had just microadjusted probably 24 hours prior and they were all over the place with focus again. I looked at the af sensor, and there were 3 very tiny hairs sticking out of it. Pulled them out with tweezers and it seems to be working fine again with the adjustments I made a day ago. They looked like long pieces of fabric, not sure where they came from, but it was enough to make an issue. I am going to have a local place take a look again. I just happened to have some old dental mirrors so I was able to get in the weird angle to see it.
Oh! Dang! Now I have to locate the AF sensor and have a look at mine!
10-03-2016, 01:35 PM   #7
New Member




Join Date: Oct 2016
Posts: 4
Original Poster
thank you all for your reply, but, I know a few things about DOF. and, as leekil said, thay are way to soft and out of focus to be just that. not all the pictures uploaded are at 2.8, but the result is the same. the last one is in focus, and the one I uploaded now, are both at 2.8, and they are quite sharp. that's why I'm asking if there might be a problem with the camera (user still not excluded). you are right about stopping down a little, the failed pictures are a lot less common, than wide open. but, that's why I bought a wider lens, so I can get a more pleaseing bokeh, when I need it. also, my with my other lenses (16-85 3.5-5.6; 18-55 3.5-5.6, etc) it's behaving in the same way. and my K-50, with the same lens attached takes nice pictures. but I can't really make a comparison because my K-50 works properly only in manual mode (don't know why, but I will get it fixed)
I also found this thread
https://www.pentaxforums.com/forums/58-troubleshooting-beginner-help/329929-s...-1-4-k5ii.html
it seems to me, he's having the same problem as I am.
more than that, there are also the the other things mentioned, wich I don't know if it's something normal or not
Attached Images
View Picture EXIF
PENTAX K-3 II  Photo 
10-03-2016, 01:51 PM   #8
New Member




Join Date: Oct 2016
Posts: 4
Original Poster
I've only now noticed, that the pictures I'm uploading can't be seen at full size, so you can't propperly see how soft and out of focus actually are. where can I upload them, if anyone wants to see them? either jpg or raw

10-03-2016, 02:47 PM   #9
Administrator
Site Webmaster
Adam's Avatar

Join Date: Sep 2006
Location: Arizona
Photos: Gallery | Albums
Posts: 41,847
To me this looks like a lens problem more than a camera issue. Only the first and third shots appear mis-focused. The others are just suffering from general softness at wide-open aperture settings. The vignetting doesn't help, either

While I personally wouldn't shoot landscapes wide-open, I'm sure most if not all of these shots can be salvaged with a little bit of post-processing, such as sharpening, levels adjustment, and vignetting correction.

Adam
PentaxForums.com Webmaster (Site Usage Guide | Site Help | My Photography)



PentaxForums.com's high server and development costs are user-supported. You can help cover those costs by donating. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

10-03-2016, 04:12 PM   #10
Pentaxian




Join Date: Sep 2012
Location: NY
Photos: Gallery
Posts: 2,263
I have a Pentax 16-85 that I use, and I have no problems with AF or image output. I usually do not shoot landscape with less than F11/F13 aperture. I like to use F14 or above if I want to assure measurable depth in my output. If a user shoots landscape and wants depth of field and detail in an image, the user should utilize an aperture that will provide it. Shooting at lower shutter speeds while doing landscape commonly allows the use of the smaller apertures (higher F stop numerals). I have a K-3II and have never had a problem with the AF system.

Last edited by C_Jones; 10-03-2016 at 04:20 PM.
10-04-2016, 04:59 AM - 1 Like   #11
Veteran Member




Join Date: May 2014
Location: Maryland
Photos: Gallery
Posts: 762
QuoteOriginally posted by Quartermaster James Quote
Oh! Dang! Now I have to locate the AF sensor and have a look at mine!
It's in the front inside below the
Lens mount, a little clear thing tthat sticks out slightly.
10-04-2016, 07:08 AM   #12
Loyal Site Supporter
Quartermaster James's Avatar

Join Date: Nov 2015
Location: Anchorage, Alaska
Posts: 609
QuoteOriginally posted by Murfy Quote
It's in the front inside below the
Lens mount, a little clear thing tthat sticks out slightly.
Thanks!
10-08-2016, 02:46 PM   #13
New Member




Join Date: Oct 2016
Posts: 4
Original Poster
UPDATE: because i'm quite busy right now, I took some test shots inside the house, late in the evening, with my flash on. to my surprise, all my pictures were very sharp, both with my pentax 16-85 and sigma 17-50, from wide open to constant 5.6 where applicable, and the whole zoom lenght. the only thing I did, was to blow some air, very softly, on the AF sensor (at least I think it's the AF sensor, according to Murphy, above), as much as I could see inside (not that much). I also noticed that, if I check, my sensor will, most of the times, show that it has dust on it, all over the place (even tho I have the sensor cleaning option on, both for start up and shut down).
I really hope that it's just some dust that it's causing me grief, and not the camera, as i don't want to to take it back to the shop again. maybe just for a sensor cleaning. I should mention that the body that I bought, was the one exposed in the shop, because it was the last K3 II they had, and I really wanted it .
I love my k-50, I took some beautiful shots with it (and my old lenses), and I was expecting from my K-3 at least a level up in image quality, not problems. will check it out on my next days off

to Adam: I'm sure there's not that much you can salvage form those shots, they are much worse than what you can see in those tiny pictures (I'll send you the raw files, if you want). and yes, I should turn on the vigneting and chromatic aberation options in the menu. I usually keep them off, as it slows the camera a bit (if you shoot in bursts), and they are easy to remove in post processing. but thank you anyway

Last edited by ionnut; 10-08-2016 at 02:57 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!
camera, dslr, focus, ii, k-3, k3, lens, lot, pentax k-3, pictures, results, sigma
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Some questions about using manual focus lenses on K-3 II sarge Pentax SLR Lens Discussion 7 08-31-2016 01:34 PM
K-3 II power off problem kirk Troubleshooting and Beginner Help 22 01-14-2016 02:38 PM
K-3 II focus problem Jeremychou Pentax K-3 3 11-20-2015 05:07 AM
AF Focus Problem on K-3 jakey217350 Pentax K-3 2 10-24-2015 02:32 PM
K-3, auto focus problem ladybug36 Troubleshooting and Beginner Help 9 12-05-2014 07:31 PM



All times are GMT -7. The time now is 09:58 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