Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
02-09-2014, 09:59 AM   #1
Junior Member
PixelGeek's Avatar

Join Date: Feb 2014
Location: Ruhrgebiet, West Germany
Posts: 37
K-3 AF issue

Hi there everybody!

As you might know from my introduction, I am a new owner of a K-3 and back in the Pentax world again. I've had the camera for a little over a week now and hadn't had much time to play with it. Yesterday I went on my first real "shoot" and it was basicly the first real test the camera got. I went to a formation dancing tournament for latin dances. The trainer of one team is a close friend of mine and this seemed to be a good chance to test my new K-3.

Now I know that Pentax isn't really first choice for shooting sports. The last camera I worked with however was a Canon EOS 300D with a relatively cheese lens and that had worked fine for me. I didn't expect my K-3 to have an AF like a Nikon D4, but I did expect it to outperform the EOS 300D!

My conclusion:
Either my camera is broken or the Pentax AF seriously sucks rocks! Sorry if this is a buzz-kill!

I missed a lot of moments yesterday because the camera took too long to focus. These dancers do move quickly, but not so much in the directions that make much of a difference to the AF. And even if they move towards the camera or away from it, they are not sprinting or as challenging to focus on as a tennis ball thrown at the camera. One thing dancers do very frequently is turn around. I shot a lot of butts yesterday, which in the case of the girls usually look pretty good. But they were not what I was aiming for. What I was aiming for was the pose 2 or 3s earlier. Sure I missed moments with the Canon, but those were less by far!

Just so you can see what I mean:
I shot about 360 photos yesterday, 139 of which were not during the actual dancing, but afterwards (handing out of trophies, posing, being happy about winning). The other 220 were of the dancing. I only shot one team which danced twice for about 5 minutes each round. Of these 220 photos I threw out 41 because they were completely out of focus. 57 I threw out because of "missed moments". Of the 139 after the dancing, only a handful had issues with the focus. I had time there to wait for the focus to happen - or not.

I don't know if this is relevant, but of the 139 photos three were completely over-exposed. All were shot with a flash. When I shot portraits of couples, I shot a fair amount of redundancy. Then it happened that of three practically identical portraits one was completely over-exposed.

Now don't get me wrong! Among those remaining photos there is still a great deal of crap, like where I messed up the composition, the shots weren't to flattering or the like. But those are mistakes I made. I just don't need the camera to make mistakes for me.

My gear:
  • K-3 (obviously) with firmware v1.02
  • kit lens DA 18-135mm f/3.5-5.6 WR (and some other letters)
  • D-BG5
  • Metz 58 AF-2
The place was a gym, pretty well lit, but not enough for the kind of shutter speed I wanted. This was not the kind of light were you could run into trouble with the focus because of low light. I set the camera to X, shutter speed 1s/180 and aperture f/5.6. The flash was set to P-TTL and aimed directly forward. The dancers had a distance to me of something between 2.5m and 10m.

The whole thing smelled pretty fishy to me, so I did a completely unscientific test today. I went outside in front of the house, sat on the stairs there and tested the focus speed on both the Canon and Pentax. It was early afternoon, so there was plenty of light, which was soft because it was overcast. I first aimed at a grating, about 60cm from me and then at a barn, maybe 100 or 150m from me on the other side of the road. I went back and forth a few times. The Canon 300D was fitted with an EF 28-80 3.5-5.6 IV Ultrasonic. I tried the Pentax out with the kit lens and with a Sigma 85mm f/1.4 EX DG HSM. Both AFs were set to single shot.

Result:
The old and cheesy Canon was significantly faster! I didn't use a stop watch because the Canon was just so fast that I couldn't have pushed the button that quickly. Using my "internal timer", I'd say the Canon takes about 0.1 to 0.2 seconds to focus between the two points. The K-3 takes nearly a full second to do the same trick. I can nearly always say the German word for twenty one, which has four syllables, before the beep. From time to time, I get cut off after the third syllable - never earlier. Even if the Canon hunts (goes completely past the focus point and back again), it is still much faster than the K-3 in best time!

What I also noticed:
When focussing, the K-3 at first moves smoothly, then stops and then seems to "tick" the lens again twice or more before reaching focus. My Sigma primes show this behaviour with two or three (sometimes even 5) audible "tocks" before focus is reached.

Is this all normal or could my K-3 actually be broken?

Kind regards,
Pix

P.S. Sorry about the long text! I guess I'm a little upset because to me this camera cost a lot of money and seems to be outperformed (in terms of AF) by an entry-level DSLR that is 10 years old (and the lens is even older).

02-09-2014, 10:47 AM   #2
Site Supporter
stevebrot's Avatar

Join Date: Mar 2007
Location: Vancouver (USA)
Photos: Gallery | Albums
Posts: 26,158
QuoteOriginally posted by PixelGeek Quote
P.S. Sorry about the long text! I guess I'm a little upset because to me this camera cost a lot of money and seems to be outperformed (in terms of AF) by an entry-level DSLR that is 10 years old (and the lens is even older).
I don't see that you actually compared the two cameras side-by-side or did I miss something. That being said, I think I can confidently predict the advice you will get from most of the users on this site...If the camera is not working for you, please, please, return it in exchange for one that does a better job. I would suggest the Nikon D7100 if AF performance is your goal. That camera with a comparable lens should be in about the same price range as your K-3 kit.


Steve

Last edited by stevebrot; 02-09-2014 at 12:01 PM.
02-09-2014, 10:49 AM   #3
Site Supporter
slip's Avatar

Join Date: Oct 2006
Location: 2 hours north of toronto ontario canada
Photos: Gallery | Albums
Posts: 3,515
Hi

First thing would say is that Pentax still has a way to go but is capable of good sports shots... just takes more effort and planning.
I have the K5iis which has similar auto focus settings so this info could be applied.
Unless I need to track a subject moving across the frame quickly, I use the single instead of the continuous focus mode. I find that once the camera focuses on the subject it will enable you to get a burst of shots where as in continuous mode it only manages to lock into one frame. This helps with some subjects that could be slightly blurred as you have photos to choose from.I quickly push the shutter button half way down multiple times to get a new focus then fire it when the subject is where I want it.
Prefocusing on a spot close to the subject is a must in my opinion as it shortens the focus time quite a bit.
Leave the camera in both focus priority and catch in focus.
These are not razor sharp as the ISO was really high...ISO 10,000 in most cases.
Hope this helps a bit and is not to confusing
Attached Images
         
02-09-2014, 10:57 AM   #4
Pentaxian




Join Date: Jan 2012
Location: Slovenia
Posts: 2,141
@stevebrot read the paragraph above your quote. And come on, even the K-5 can do CAF for what the OP needs. The Sigma making tons of corrections makes me think the camera might be at fault.

@OP First try updating the firmware, maybe your camera just got derped a bit during production. Second, see if you have proper AF settings dialed in. If that doesn't work, either send in for warranty or replace tge camera.

02-09-2014, 11:22 AM   #5
Veteran Member




Join Date: Jun 2010
Location: Manteca, CA
Photos: Gallery | Albums
Posts: 1,653
QuoteOriginally posted by Giklab Quote
@stevebrot read the paragraph above your quote. And come on, even the K-5 can do CAF for what the OP needs. The Sigma making tons of corrections makes me think the camera might be at fault.

@OP First try updating the firmware, maybe your camera just got derped a bit during production. Second, see if you have proper AF settings dialed in. If that doesn't work, either send in for warranty or replace tge camera.
I agree, test your camera with a focus chart. You may have an issue that is deeper than you think, worst case scenario exercise your warranty because it sounds like something is wrong with yours. I dont miss focus that much and I take pictures of my kids running around(that in itself can be compared to herding cats)
02-09-2014, 11:50 AM   #6
Site Supporter
stevebrot's Avatar

Join Date: Mar 2007
Location: Vancouver (USA)
Photos: Gallery | Albums
Posts: 26,158
QuoteOriginally posted by Giklab Quote
@stevebrot read the paragraph above your quote. And come on, even the K-5 can do CAF for what the OP needs. The Sigma making tons of corrections makes me think the camera might be at fault.
I read it before I did the post, but missed the porch step side by side comparison. Even so, I stand by my advice. The issue as I read it is time to lock, not AF accuracy. There may indeed be something wrong with the camera, but that should be easy to determine. Return for replacement might be an option, but wasting time doing so might make return for credit more difficult. I too would suggest AF-C as a possible alternative, but am not hopeful. The right tool for the job and for this job, the right tool may well not be the K-3.


Steve

Last edited by stevebrot; 02-09-2014 at 12:37 PM.
02-09-2014, 11:57 AM   #7
Pentaxian
JimmyDranox's Avatar

Join Date: Oct 2012
Location: Ploiesti, Romania
Photos: Gallery | Albums
Posts: 1,585
Some weeks ago I've tested three cameras, and three lenses. A K-5, a K-5IIs, and a K-3. What i can conclude is that K-3 is a little faster than K-5. Lenses, was a Sigma 70-200/2.8 HSM, a Tamron 70-200/2.8 with screw drive focus, and a Pentax 60-250/4 SDM, Fastest lens was Sigma, quiet snap on. Second, close enough to Sigma was Tamron, and Pentax came third , about 2-3 times slower than Sigma. Tests was done in low, artificial light, changing the lenses on every camera.

In your case, I think that the camera must be checked, at a specialist, or better changed with another K-3.

Last edited by JimmyDranox; 02-09-2014 at 12:09 PM.
02-09-2014, 12:01 PM   #8
Pentaxian
Mareket's Avatar

Join Date: Jun 2011
Location: Chester
Photos: Gallery | Albums
Posts: 719
I've had similar problems, but compounded by the fact that I've been shooting roller derby which is very difficult for the AF. I think the K-3 just isn't up to the task really. I got better results when I pre-focused in manual and waited for the skaters then let off a burst of shots, but I may as well return the K-3 and go back to the K-5 if that's the best I can do. Mine either hunted and lost me a shot or just went right ahead and focused on something a couple of feet behind the focus point. Then again, this is with the 50-135, so it might just be the slow focus on that screwing things up.

And it'd be lovely to switch to a D7100 but there's the whole tied into the system thing, and I just really like using the K-5/3 and the lenses I have.

I think even with the focus system improvements in the K-3, Pentax cameras just aren't made for sports.

02-09-2014, 12:04 PM   #9
Pentaxian
Paul the Sunman's Avatar

Join Date: Aug 2011
Location: Melbourne
Photos: Gallery
Posts: 1,122
QuoteOriginally posted by PixelGeek Quote
Hi there everybody!
My gear:
  • K-3 (obviously) with firmware v1.02
  • kit lens DA 18-135mm f/3.5-5.6 WR (and some other letters)
  • D-BG5
  • Metz 58 AF-2
The place was a gym, pretty well lit, but not enough for the kind of shutter speed I wanted. This was not the kind of light were you could run into trouble with the focus because of low light. I set the camera to X, shutter speed 1s/180 and aperture f/5.6. The flash was set to P-TTL and aimed directly forward. The dancers had a distance to me of something between 2.5m and 10m.
The focus speed and accuracy on the K3 is perfect for me. No problems whatsoever. Hardly a dud shot since I got it. Your problem appears to be the much-discussed shutter delay associated with using P-TTL flash. It has nothing to do with focus. This delay of about 0.2 seconds after pushing the shutter button appears to be a software bug on the K3. I believe Pentax are aware of it and a fix should come in a firmware update soon. In the meantime, use manual flash (pretty easy) for the time being and there will be no lag.
02-09-2014, 12:07 PM   #10
Lens Buying Addict
monochrome's Avatar

Join Date: Mar 2008
Location: Kirkwood (St. Louis) MO
Photos: Gallery | Albums
Posts: 19,428
Given that to my knowledge Pentax hasn't attempted nor claimed to be a Sports/Action system, my experience with my K3 has not been at all as yours. Yet your choice of gear must be appropriate to the task - blaming the wrong gear is a falsehood.

My AF using similar conditions, similar lenses and similar settings except AF.C has been near instantaneous focus lock. I have focus-locked Bald Eagles in flight, panning, using AF.C in tracking at 300mm, though outdoors in deep overcast light.

I might not have taken the kit lens - relatively good as it might be for a kit lens - to an important indoor shoot.

I might not judge Pentax's flash exposure on a brand new camera that has updated flash logic unless you have had the Firmware for the Metz flashed by your dealer (assuming Metz has updated the FW).

If there is other gear that better meets your needs - and Sports/Action is an historical objection to Pentax, trade your gear for the other gear.

Confirmation bias is a cold mistress, though.

Last edited by monochrome; 02-09-2014 at 12:17 PM.
02-09-2014, 12:10 PM   #11
Pentaxian
JimmyDranox's Avatar

Join Date: Oct 2012
Location: Ploiesti, Romania
Photos: Gallery | Albums
Posts: 1,585
I forget to mention that both K-3 and K-5 was set to single point AF. I don't remember about K-5IIs. All lenses at maximum focal distance.

Another thing is that I have tested those lenses, Sigma and Tamron on my K-5 for fast passing cars, and both perform very good. And in my opinion, AF system on Pentax camera is fast enough for sports, but the Pentax SDM lenses, not so much.
02-09-2014, 12:15 PM   #12
Pentaxian
Paul the Sunman's Avatar

Join Date: Aug 2011
Location: Melbourne
Photos: Gallery
Posts: 1,122
QuoteOriginally posted by monochrome Quote
My experience with my K3 has not been at all as yours.

My AF using similar conditions, similar lenses and similar settings has been near instantaneous focus lock. However, I might not have taken the kit lens - relatively good as it might be for a kit lens - to an important indoor shoot.

I might not judge Pentax's flash exposure on a brand new camera that has updated flash logic unless you have had the Firmware for the Metz flashed by your dealer.
The Metz firmware can be updated by the user via USB. I reiterate though that the shutter delay when using P-TTL on the K3 is a Pentax issue, and has nothing to do with Metz. The delay occurs with all brands of flash.

Last edited by Paul the Sunman; 02-09-2014 at 12:23 PM.
02-09-2014, 12:24 PM   #13
Pentaxian
Mareket's Avatar

Join Date: Jun 2011
Location: Chester
Photos: Gallery | Albums
Posts: 719
QuoteOriginally posted by JimmyDranox Quote
Another thing is that I have tested those lenses, Sigma and Tamron on my K-5 for fast passing cars, and both perform very good. And in my opinion, AF system on Pentax camera is fast enough for sports, but the Pentax SDM lenses, not so much.
I tried shooting some stuff with the 50/1.4 and that was a god awful experience. Though when it did work it was beautiful.

QuoteOriginally posted by monochrome Quote
If there is other gear that better meets your needs - and Sports/Action is an historical objection to Pentax, trade your gear for the other gear.
I might, I just really like my gear. It just seems a shame that the K-3 has such a good AF system yet it doesn't seem to be working for me in CAF. Does anyone have suggestions of things to try in case it's just user error? I was shooting with low tracking and single point expansion (the 9-point selection mode thing) with the first and subsequent frames set to focus confirm. I tried loads of different settings but those seemed the most consistent, but still didn't seem to keep up with the action.

There was one particular shot I missed completely because try as I might I couldn't get the 50/1.4 to actually focus on the thing I wanted, despite using centre point only and the subject easily covering the spot.

Maybe I should go get it checked out...
02-09-2014, 12:48 PM   #14
Loyal Site Supporter
AquaDome's Avatar

Join Date: Jan 2014
Location: New Carlisle, IN
Photos: Gallery | Albums
Posts: 1,397
If you don't think you will grow into the K-3, by all means switch. Life is too short to be saddled with an incompatible camera.

I shot over 1200 pictures at the Chinese New Year parade last weekend. Mostly autofocus. Partly cloudy, so lighting conditions were all over the place. K-3, DA 18-135. There were a few "lost shots" due to autofocus not locking quickly. Often because there was lots of confetti in the air. This was the first "major workout" for my K-3. In comparison, my Canon EO-S 70D is slightly better in the AF department (fewer focus-hunts, just as accurate when it locks), but far less fun to shoot. My Nikon D7000 is equal in AF speed and accuracy, but only in well-lit conditions. While indoors with tungsten lighting, calling AF on the D7000 a "mixed bag" would be generous.

Also, letting the K-3 do the metering in TAv mode proved more accurate than me reading the meter and adjusting manually. I seem to do better in Manual mode on the Nikon D7000. Its metering/sensitivity seem to be more like shooting film.

Mostly, I shoot with my K-50. Its functional sweet-spot is right where my creativity is these days. They're all different with different abilities. They're all capable of far greater work than I put them through. The more I weed through all the bells & whistles (and turn them all off), the more I find that the biggest limiting factor is me.
02-09-2014, 12:55 PM   #15
Lens Buying Addict
monochrome's Avatar

Join Date: Mar 2008
Location: Kirkwood (St. Louis) MO
Photos: Gallery | Albums
Posts: 19,428
OI have an FA50/1.4 but I don't use it much any more. I do know I just got an FA50/2.8 Macro that can run lock and back to focus if it picks the wrong direction. My experience with DA55~300, DA40/2.8 and FA35/2 has been exceptional. I use back button AF enabled and AF.C center point most of the time unless I am tracking moving subjects. I've found using the back button helps me catch such things as moving vehicles and moving dancers and shooting 3-shot bursts. My index finger isn't fast enough to anticipate and catch what I want. Using AF.C allows me time to focus on the subject before the immediate moment, I guess, as in shooting lacrosse.

I really don't shoot much action though - street,landscape, people. Not for money.
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, camera, canon, dslr, firmware, flash, focus, k-3, lens, lenses, op, pentax, pentax help, photos, pix, saturday, settings, shot, sigma, tamron, test, time, try
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
K-3 Power-on issue rskura Pentax K-3 141 05-17-2016 04:10 AM
K-3 USB connectivity issue peterjcb Pentax K-3 8 03-20-2014 08:12 PM
K-3 flash issue konraDarnok Pentax K-3 68 03-13-2014 06:07 AM
How good is the K-3's AF-C tracking AF? Jeff Charles Pentax K-3 6 12-09-2013 03:41 PM
K-5 AF Issue stormtech Pentax K-5 44 05-30-2012 03:53 AM



All times are GMT -7. The time now is 07:35 AM. | See also: NikonForums.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