[rvandenbrink]

No sharpness problems here, my lenses are mostly new/PLM though. I shoot a KP, so I’d expect a k3iii to be as good, or better for subjects in motion
If everything is out of focus I’d suspect those (very high) lens adjustments, but they’re not
Try a new PLM lens with no adjustments? Even a standard zoom like an 18-135 should give you good results a f8-ish.

---------- Post added 11-26-22 at 04:33 PM ----------

just had a thought - verify that your viewfinder diopter adjustment is at zero?

[JPT]

I don't know about Canon or Nikon AF, or whether it makes sense for you to change to a mirrorless system, but I can say that your experience moving from the K-5 II to the K-3 III does not match mine. I went from the K-5 IIs to a K-3 III and the AF is a big improvement in all regards. This is with a mix of screwdrive, DC and PLM lenses - nothing expensive or fancy. In fact, the K-3 III required less AF adjustment than any Pentax I've owned - basically none.

So I can only imagine you have been unlucky and got a bad unit. Or perhaps some kind of mix-up with settings. In any case, I can't imagine a fully functioning K-3 III would have trouble with the kind of photography you describe.

Also, I heard some people had focus calibration issues improve after a firmware update. The current version is 1.60 and 1.70 should be coming in a few weeks.

K-3 III firmware is available here.
Latest PENTAX K-3 Mark III Firmware Update : Software Downloads | RICOH IMAGING

[LukaszWro]

Nearly all my dog shots are with the DA 18-135, and I've never did any fine focus adjustment on any lens.

Lucky You. I had to make fine adjustment for my DFA* 50 with K1II. Something about -5, don’t remember exactly but now it’s perfectly spot on. Quick and accurate.

[Larrymc]

just had a thought - verify that your viewfinder diopter adjustment is at zero?

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.

[Larrymc]

The current version is 1.60 and 1.70 should be coming in a few weeks.

Is this inside information??

[eddaytona]

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.

I set diopter so that read-out info in viewfinder is in focus. Imo better than the view of the "elements" you are seeing through the finder.

---------- Post added 11-26-22 at 10:15 PM ----------

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.

I set diopter so that read-out info in viewfinder is in focus. Imo better than the view of the "elements" you are seeing through the finder.

[UncleVanya]

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

[K2 to K50]

There are far too many examples, spread throughout this forum, of superbly accurate images achieved by a variety of owners using a variety of lenses with their K3iii to say that the K3iii's autofocus is not up to scratch. I am one of those lucky owners who has never had to to do any fine adjustment with either my KP or my K3iii for any of my lenses and find it amazing that someone has had to do this with ALL their lenses.
I cannot imagine trying to even guess if I have a subject in focus without the diopter being set correctly.


I would try ruling out my own eyesight playing tricks with me by asking someone competent to take a few shots with my camera and a couple of the lenses and see what results they get. Maybe even get someone else to test the fine adjustment settings on your lenses?

Maybe you just got unlucky and ended up with a faulty K3iii body?

[beholder3]

Now, for portrait photography with faster lenses, the phase detect autofocus is near useless, and it is mostly a miss, especially when the subject is wearing red.

That is a pretty weird claim. The color only comes into effect when the color is being focused on. "wearing red" would suggest a full body portrait and that certainly isnt challenging to any Pentax camera of the last few years, regardless of fast lenses. It even more weird that you focus on the clothes and not the face.

not getting precise focusing

Sounds like you have some dirt on the AF system lens in the body that is throwing everything off.

I would like to try out another K3III just to see if all cameras have the same problem. *Anyone in the Los Angeles area?

You really should do a side by side shoot with some other Pentaxian. If he nets better results the equipment type is not the reason.

SMC Pentax-DA 70mm F2.4 Limited, Pentax DA 50mm f1.8 lens, Pentax 100mm f/2.8 WR D FA smc Macro Lens

As has been stated before, screw drive is fast, but it is not the most precise option.
Probably all three lenses you mention are not exactly top notch candidates.

[Hythloday]

I am one of those lucky owners who has never had to to do any fine adjustment with either my KP or my K3iii for any of my lenses

You are really very lucky indeed.

Four years ago I bought a DA20-40mm Ltd and it was really a sharp lens when I used it on a Pentax K3. Last year I used it on a Pentax KP and it was less sharp, especially at the borders. So I checked for front focus/back focus. At -2 it is really sharp again. But I also checked the other lenses I have. The result: DA12-24mm +1, DA17-70mm -2. The rest is ok.

When you should fine adjust ALL your lenses at extreme values, the camera may be faulty.

[pschlute]

When you should fine adjust ALL your lenses at extreme values, the camera may be faulty

The AF/FA menu allows you to adjust for manufacturing tolerances in the PDAF system itself. Having to make a big adjustment like -/+ 10 does not mean the camera is faulty. Only if you have lenses that would require more than a 10 adjustment should you send it back to Pentax for re-calibration, which will be done free under warranty.

My old K-1 required between -6/-10 adjustment for various lenses. Having set them 6 years ago they do not require change over time.

[Rondec]

I guess the question I have is whether the focus accuracy seems better with live view. If so, then maybe doing some focus adjustment on the lenses is all it would take. Portraiture is not typically a hard thing for cameras to deal with -- this isn't any birds in flight scenario.

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.


On the Slide (DA *16-50mm PLM at 50mm and f2.8)



Elise (DFA *70-200mm at 200mm and f2.8)

[Larrymc]

I set diopter so that read-out info in viewfinder is in focus. Imo better than the view of the "elements" you are seeing through the finder.

---------- Post added 11-26-22 at 10:15 PM ----------



I set diopter so that read-out info in viewfinder is in focus. Imo better than the view of the "elements" you are seeing through the finder.

The Read Outs and the elements are essentially on the same plane so they should be both in focus. The elements of the framing and focus points are the thinnest parts of what you see in the viewfinder so having them in focus, the readouts will be in focus too.

[StigVidar]

albeit all my lenses need -4 to -8 fine focus adjustment.

Are you sure of this? I have adjusted my own lenses and I see that finding the correct value can be very difficult. Sometimes when I think I have it right, it can often be that it focus wrong at infinity and I have to readjust. And a value like N can create some "nervous" focusing while N+1 or N-1 creates a focusing with less variance. (sorry, it is difficult to explain.......)

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

[Rush2112]

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.