[Eric Seavey]

Rent another k3iii and a more modern lens like the D FA* 85/1.4. See if that helps before making decisions.

I didn't think K3III was being rented out... so I did a search just to check... and yes, they have them on pntrs.com/t/TUJGRktHSkJHRkpISUVCRkpOSkVN?url=Lensrentals.com... Maybe I will try it out with a 50-135mm. Although, I heard about the SDM burning out...

---------- Post added 11-27-2022 at 01:21 PM ----------

Eric, the funny thing is that there are so many variables that can affect accurate focusing- the user (either technique, camera settings), the lens, the camera body, on and on. But I don't think the internet is a place that can solve this issue you're having. What I do know, is that the new AF system in the K-3 Mark III is the best AF system that Pentax has ever made in any camera to date. I've done rigorous side by side testing with it against the D500 and gave the edge overall to the camera body of the K33, despite the fact that the Nikon has a much deeper pool of lens choices. All things being equal with lenses, the K33 is a better camera than the D500- which has a stellar reputation.

I know you are (or were) frustrated, but first take a hard look at everything that you have in your control that could affect focusing. And if you still can't get the K33 to focus right, have it serviced. I was very shocked to read your reasoning for wanting to leave Pentax since the autofocusing of the K33 was about the very last thing I expected to read about.

Thanks, given the responses I have seen here, I think I will rent a K3III and compare it to mine. I understand the wealth of settings and techniques for photography, and I expected the K3III to have more reliable autofocus than the K5II, even though their focusing systems are quite different.

[Hythloday]

I mention this because my own experience is to never trust that an adjustment is correct and final.

Keep things practical. Personally I took pictures of a house (with dented bricks) and trees at the background at a distance of some 25 metres. I took them at 0, -1, -2, -3, -4 and looked which pictures looked sharpest at 100% (bricks and trees). Then I took pictures at 0, +1, +2, +3, +4 and same procedure as before. My DA20-40mm Ltd on a KP was sharpest at -2. Then I took several test pictures to see whether the pictures were really sharp at -2. They were and so this is a correct setting. My DA12-24mm needed +1 on a K-3 and my DA17-70mm needed -2 on a KP. When you are in doubt which picture is sharpest, just use 0.

But when I use my DA17-70mm on my K-3ii, no fine adjustment is needed.

Just three on my ten lenses needed some fine adjustment.

[Des]

The K-3 III auto focus system should focus on eyes through the viewfinder, if set up correctly and I haven't had too much trouble with it.

Great examples Vincent (as always). That's interesting about eye detection when using the viewfinder. The ebook for the K-3iii refers to this feature and says that it works well, but doesn't explain how to set it up. Nor does the manual. Any tip on how to set it up? (I have an interest because I have just bought a K-3iii, but this might help the OP too.)

[Rondec]

Great examples Vincent (as always). That's interesting about eye detection when using the viewfinder. The ebook for the K-3iii refers to this feature and says that it works well, but doesn't explain how to set it up. Nor does the manual. Any tip on how to set it up? (I have an interest because I have just bought a K-3iii, but this might help the OP too.)

My understanding is that eye detection requires the face detection AE to be turned on and then you have to use one of the auto modes with auto focus. If you choose your point, then it won't do that.

If your subject is far away, then you are better off using point select, as the metering segment will probably be too small to actually identify the face/eyes.

[snappyhoffy]

My understanding is that eye detection requires the face detection AE to be turned on and then you have to use one of the auto modes with auto focus. If you choose your point, then it won't do that.

If your subject is far away, then you are better off using point select, as the metering segment will probably be too small to actually identify the face/eyes.

A step by step process would be really useful to understand how to do this... maybe an addition to the eBook.

[Des]

My understanding is that eye detection requires the face detection AE to be turned on and then you have to use one of the auto modes with auto focus. If you choose your point, then it won't do that.

If your subject is far away, then you are better off using point select, as the metering segment will probably be too small to actually identify the face/eyes.

Thank you. I found another thread (Have we ALL been using the K-3 Mark III wrong? - PentaxForums.com) which says you need to have "Subject recognition" turned on (which it is by default).

So you need that turned on, and one of the auto modes, and when using the viewfinder the camera should try to recognise that you are shooting a portrait, identify the eyes, and focus on them. That's pretty sophisticated.

maybe an addition to the eBook.

Yes, something for the next edition perhaps.

[rvandenbrink]

The Diopter should be adjusted based on your eyesight not set to zero. You adjust the diopter based on the focus and framing elements in the viewfinder to achieve clearly in focus elements when looking through the viewfinder. The only time to set the diopter to zero is if you have 20/20 vision other wise it is best to do a personal adjustment.

.. or if you shoot with your glasses on, which I do
This also makes the setting easy, if my glasses are on then the setting is zero.

[Larrymc]

.. or if you shoot with your glasses on, which I do
This also makes the setting easy, if my glasses are on then the setting is zero.

I never shoot with my glasses on and I need a right eye correction of -2.5 which is easily achievable with the K-3 Mk III viewfinder. Keeping the camera stable with my glasses up against the eyepiece is a total PITA for me, I really don't see how you do it.

[UncleVanya]

.. or if you shoot with your glasses on, which I do
This also makes the setting easy, if my glasses are on then the setting is zero.

Maybe… I find that my rites drift and what’s perfect day one isn’ta few months later. I periodically adjust the diopter to my current vision with my glasses.

---------- Post added 11-28-22 at 10:22 AM ----------

I never shoot with my glasses on and I need a right eye correction of -2.5 which is easily achievable with the K-3 Mk III viewfinder. Keeping the camera stable with my glasses up against the eyepiece is a total PITA for me, I really don't see how you do it.

-2.5… Those were the days. My best eye has a -8 or -9 with an astigmatism correction of 4 or so.

[Larrymc]

Maybe… I find that my rites drift and what’s perfect day one isn’ta few months later. I periodically adjust the diopter to my current vision with my glasses.

---------- Post added 11-28-22 at 10:22 AM ----------



-2.5… Those were the days. My best eye has a -8 or -9 with an astigmatism correction of 4 or so.

Oopsy, that was my last years prescription, this year it is -3.25 right eye and -3.00 left eye

[eric1965]

Perhaps late to the party, as you were fairly happy with the K5 II focusing.
- Clean the focusing window (under the mirror box), mirror and intermediate mirror.

- Do a reset of the camera (main reset and lens calibration reset)
- If the problem persist your K3 III could be defective and needs a factory calibration.
- If possible rent another K3 III body and check if focusing is better with your current lens setup.
With regards

[Jonathan Mac]

As much as Pentax has historically struggled with continuous AF, AF accuracy issues isn't something it's known for. In fact, Pentax cameras had better low-light focusing capabilities than Canon and Nikon for a little while

I don't think this is true at all and it certainly hasn't been my experience. I tried AF-C with my K200D and K-3 and quickly came to the conclusion that it's useless and stuck with AF-S. AF-S is generally fine for stationary subjects and gave something like a 90% in-focus hit rate in that scenario, while for moving subjects I need to rely on timing and taking several shots to get something with spot-on focus. My experience with AF-S and stationary subjects on three different mirrorless cameras is that they focus correctly, even at wide apertures, 100% of the time.

I believe that continuous AF with screw-drive lenses cannot work properly because they simply aren't capable of making the micro-adjustments needed to compensate for slight movement of a subject's eye. Lenses with built-in motors should solve this but rely on a good AF system in the camera, which newer Pentax models may have.

[Larrymc]

Perhaps late to the party, as you were fairly happy with the K5 II focusing.
- Clean the focusing window (under the mirror box), mirror and intermediate mirror.

- Do a reset of the camera (main reset and lens calibration reset)
- If the problem persist your K3 III could be defective and needs a factory calibration.
- If possible rent another K3 III body and check if focusing is better with your current lens setup.
With regards

I'm with @Eric1965. I had persistent problems with Autofocus being inconsistent with my K-3 Mk I, sometimes it would be close and other times way off and it got frustrating doing AF Fine Tune all the time. What I discovered was that I had trash on the AF Module lens that was causing the problems all along. What I did was buy some lint free Q-tips and used a drop of Isopropyl alcohol on one and carefully cleaned the lens. After initially doing the Q-Tip cleaning I try to consistently use a Rocket Blower to get the loose trash out of the mirror box and up until I retired the K-3 Mk I last year I have had no problems with AF.

You might want to use a Rocket Blower and blow out the mirror box by turning the camera lens mount down and thoroughly carefully blow out the mirror box. Then do some tests. If the Rocket Blower doesn't solve the problem then use the lint free Q-tips and isopropyl alcohol and carefully clean the AF module lens. Be very careful not to get alcohol on the sensor. If the cleaning doesn't work you probably have a defective camera and it needs returning for replacement or repair.

[idontstairs]

You don't want a modern DFA* like the 50mm F1.4 for sure if you are having autofocus problems. That lens is big and slow. Plus on crop it is like a 75mm. My dog can run to me faster than the DFA^ 50mm lens can focus. I tried getting shots of my running dog with the DFA* 50mm on 3 or 4 separate occasions and gave up.


I've had auto focus issues since day 1 with mine. It's about 20% accurate. Through all the firmware updates. And two 15mm limited lenses were so bad it was like they were decentered. -10 to +10 adjustments didn't help. With the wide angle lens the camera is locked in to the center 5x5 grid and it still didn't know what to focus on 2 out of 10 times. There just wasn't an autofocus point selected. The other 8 times the auto focus point was never in the same place either.

I took my K-3iii out the week before Halloween to do night shots with the 50mm F1.4 and the black focus point at night made it a whole lot worse. I had to switch to af.s center point with auto focus assist and even with the red conformation that the camera had acquired focus I ended up with 2 keepers out of over 700 shots. About 2 in 10 were in focus on something in the image. In contrast my friend took his Nikon Z6ii and I set it up for him so he just had to touch the rear LCD screen where he wanted the camera to focus and it took a photo. In focus. I had more keepers setting his camera up and taking practice photos then I did the whole two hours shooting with my K-3iii.

In past years I had used my KP with a 77mm limited to shoot the Halloween event and had much much better results. Hundreds if not thousands of keepers over the years I used my KP.


Since I've purchased my K-3iii I have also bought a Nikon Z6 and two Fuji mirrorless cameras. I will probably never buy a Pentax again or at least I won't preorder a new release camera at full price.

Is my autofocus module defective? I've seen a few people complain about faulty autofocus on their K-3iii.

I spent $2,400+ on mine. I've had offers of about 33% what I paid. At this point in time I would rather blow my K-3iii up with tannerite, video it, and hope the youtube video paid me back the 33% over time. It's not even about the money at this point in time either. My K30 crapped out with the aperture block failure. I still bought a K-5II, K3, and a KP. The sheer disappoint with my K-3iii in on a whole different level.

[UncleVanya]

You don't want a modern DFA* like the 50mm F1.4 for sure if you are having autofocus problems. That lens is big and slow. Plus on crop it is like a 75mm. My dog can run to me faster than the DFA^ 50mm lens can focus. I tried getting shots of my running dog with the DFA* 50mm on 3 or 4 separate occasions and gave up.


I've had auto focus issues since day 1 with mine. It's about 20% accurate. Through all the firmware updates. And two 15mm limited lenses were so bad it was like they were decentered. -10 to +10 adjustments didn't help. With the wide angle lens the camera is locked in to the center 5x5 grid and it still didn't know what to focus on 2 out of 10 times. There just wasn't an autofocus point selected. The other 8 times the auto focus point was never in the same place either.

I took my K-3iii out the week before Halloween to do night shots with the 50mm F1.4 and the black focus point at night made it a whole lot worse. I had to switch to af.s center point with auto focus assist and even with the red conformation that the camera had acquired focus I ended up with 2 keepers out of over 700 shots. About 2 in 10 were in focus on something in the image. In contrast my friend took his Nikon Z6ii and I set it up for him so he just had to touch the rear LCD screen where he wanted the camera to focus and it took a photo. In focus. I had more keepers setting his camera up and taking practice photos then I did the whole two hours shooting with my K-3iii.

In past years I had used my KP with a 77mm limited to shoot the Halloween event and had much much better results. Hundreds if not thousands of keepers over the years I used my KP.


Since I've purchased my K-3iii I have also bought a Nikon Z6 and two Fuji mirrorless cameras. I will probably never buy a Pentax again or at least I won't preorder a new release camera at full price.

Is my autofocus module defective? I've seen a few people complain about faulty autofocus on their K-3iii.

I spent $2,400+ on mine. I've had offers of about 33% what I paid. At this point in time I would rather blow my K-3iii up with tannerite, video it, and hope the youtube video paid me back the 33% over time. It's not even about the money at this point in time either. My K30 crapped out with the aperture block failure. I still bought a K-5II, K3, and a KP. The sheer disappoint with my K-3iii in on a whole different level.

This sounds like an awful experience. In a thread on the da 15 issues I saw another user who sent their lens to Pentax Japan had similar issues with the lens until it was repaired. The end result was very satisfactory.

BTW, I don’t see that you created threads and posted images trying to get help to resolve these issues (you certainly aren’t required to) so I can’t comment in detail on these issues. But I feel your pain. I am sorry you’ve had such an experience.