[Echo Eric]

I am posting this in the K3- DSLR specific forum as I would like to get input from K3ii users.

I have recently purchased a K3ii and some new lenses to upgrade from the K20D I have been using with several manual lenses from my K1000 35mm. One area I wanted to venture into more was sports photography, with both people and animals.

One subject I have been focusing on for practice is dogs. The area I am getting hung up on is trying to consistently get clear focused pictures. In general I tend to find my camera back focusing for moving subjects, both laterally and head on. I should mention that the focus is consistently perfect for stationary and closer subjects. I was hoping for some pentax specific advice from pentax users. Since I mostly shoot with canon 7D users who's cameras "just focus", other than some basic techniques, I have not gotten anything terribly helpful.


The two lenses I primarily use are a Pentax HD DA 16-85mm and a Tamron 70-200mm f/2.8 DI LD (IF) Macro
For my camera settings, currently I am using:

• The AF button on the back of the camera, not the half press focus
• AF.C - Continuous focus
• The center 9 points for focus tracking, making the center point my starting focus
• Action in AF.C focus is set to Focus priority, not shutter priority
• High priority (4) - for Hold AF status

I have attached three photos: on the first, my focus point was on the lead dog (not the best lighting or contrast), on the second I had my focus point on the dog with the black collar, the third shows the focus for general stationary photos.

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[quh86]

hey there,

i only shoot k-5 but to me it seems that there is back-focusing even in the stationary picture. of course at 16mm mostly anything will be in focus but to me it seems that the tree is sharper than the girl.

try adjusting your focus for 50mm or above, where sharpness is most critical.

hope that helps

[mikeSF]

all three look back focused. Have you run a test chart to fine adjust the lens/camera?
Also, with tricky moving objects, being nearly wide open does not help you either.

[Craig66]

Try changing your setup and see if you get similar results.


Go to focusing area spot , shutter release half press focus with AFC focus set to Focus priority. With subjects coming straight at you a higher f setting may also help you out.


If your still getting back focus problems. You may need to try the AF fine adjustments.


But you said you get clear shots with stationary subjects. So I'd be doing a focus test with tripod and stationary subjects at F2.8 to see if you do have a back focus problem before changing AF fine adjustments.

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Last edited by Craig66; 01-19-2016 at 11:05 PM.

[asp1880]

For my camera settings, currently I am using:

• The AF button on the back of the camera, not the half press focus
• AF.C - Continuous focus
• The center 9 points for focus tracking, making the center point my starting focus
• Action in AF.C focus is set to Focus priority, not shutter priority
• High priority (4) - for Hold AF status

Try "SEL 1" (one AF point) instead of "SEL 2" (9 points). I've also experimented with dogs galloping straight at me and I could not
get "SEL 2" to work for me - it was too drawn to the background clutter. "SEL 1" was best for me, but you need to keep that
point perfectly on the dog or the sequence will be spoiled by lots of OOF shots.


Even with perfect tracking technique, don't expect better than 30-50% sharp shots. That's what I could achieve anyway. I have a K-3 BTW.


Regards,
--Anders.

[Echo Eric]

Everyone, thank you for the advice.

- For the focus testing chart, I have not ran this yet, but I will try and at different focal lengths for each lens.
- While I typically try to use a smaller aperture, when I am limited by light, I tend choose shutter speed over sharpness otherwise the dogs are a blur. I realize this isn't best, but it seems to have slightly better results then using a higher ISO; at least when I get the focus. I'll have to keep playing with this.

[blueheron90]

The two lenses I primarily use are a Pentax HD DA 16-85mm and a Tamron 70-200mm f/2.8 DI LD (IF) Macro
For my camera settings, currently I am using:

• The AF button on the back of the camera, not the half press focus
• AF.C - Continuous focus
• The center 9 points for focus tracking, making the center point my starting focus
• Action in AF.C focus is set to Focus priority, not shutter priority
• High priority (4) - for Hold AF status

I recently got the da* 60-250 f4, and I have been losing my mind over the same back focusing issues. After trying nearly every combination of auto focus setting and AF fine tune adjustments, I think I finally have the correct formula for shooting figure skating with my K-3 II.

First of all, I stop the lens down to f5.6 to give the focal plane a bit more wiggle room. I can't wait for the Pentax 70-200 2.8 to come out so I can gain that extra stop of aperture, but until then, I use around ISO 1600 which seems to produce a negligible amount of noise that is easily removable in ACR.

Next, af.c is fairly decent on this lens/body combination. Using 9 point focus will very often find the contrast in the background before the actual subject I am trying to shoot, so I have learned to use only the center point which has produced many more usable in-focus shots. I have my AF button on the back of the camera set to disable AF when pressed, thus I am able to center the subject to gain focus, then press the AF button and move the subject anywhere in the frame and still retain focus. I strongly recommend this method, in conjunction with the half-pressed shutter button for AF to quickly take shots as soon as the subject is moved to proper position.

I also have high priority af turned on, though I am really not sure how much this actually helps when using the single spot focusing.

This may or may not be relevant to you, but I have +4 AF fine tuning on just this lens. It seems to help with fast motion, but I think it may just be my copy of this lens.

I hope any of this helps you, I know how frustrating it is to find faults in either the expensive gear or the technique, but keep practicing and experimenting and most importantly - learning! Here are some pictures - the exif data should help better clarify some things I mentioned

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[Echo Eric]

I did test the focus on all of my lenses using a DIY target (I ordered one that is taking a bit to come in the mail) and found that almost all my lenses required a AF adjustment. Surprisingly all my pentax lenses were all over, while my third party lenses were closer to 0 offset. I have yet to test the results for action shots, however for close portraits this made a big difference.

pic-nic, I have noticed a difference in focus speed/accuracy when there is a high contrast background, but as I have been reminded many times for Pentax users and users of other brands, Pentax autofocus tracking is very far behind the competativators.

Here are two samples from my SMC Pentax-FA 31mm F1.8 AL Limited after the AF fine adjustment.

[IchabodCrane]

I did test the focus on all of my lenses using a DIY target (I ordered one that is taking a bit to come in the mail) and found that almost all my lenses required a AF adjustment. Surprisingly all my pentax lenses were all over, while my third party lenses were closer to 0 offset. I have yet to test the results for action shots, however for close portraits this made a big difference.

pic-nic, I have noticed a difference in focus speed/accuracy when there is a high contrast background, but as I have been reminded many times for Pentax users and users of other brands, Pentax autofocus tracking is very far behind the competativators.

Here are two samples from my SMC Pentax-FA 31mm F1.8 AL Limited after the AF fine adjustment.

Nice shots! As for focus tracking on Pentax, the camera itself is often quite good. It's the lenses that often are the problem as many of them were designed when long focus throws were the norm.