[normhead]

What Pentax camera do you own?

Your rather summary dismissal of the K-3 (in another thread) is something I find curious.

8 FPS, 23 shot (3 second buffer.) Not quite as good DR as a K-5 but still manageable.

The obvious Pentax selection would be the K-3iii.

It's odd to be looking at a 2013 camera, for action. Action is always niche, premium and always high end and is still improving with every release. In any case you are asking for "cheap premium", as if that exists.

If I were a wedding photographer I'd look at Sony, or a 1DX. For wildlife and action, if you don't need eye AF, a K-3 is pretty good.

---

Last edited by normhead; 12-15-2020 at 11:24 AM.

[CapitanXeon]

What Pentax camera do you own?

Your rather summary dismissal of the K-3 (in another thread) is something I find curious.

8 FPS, 23 shot (3 second buffer.) Not quite as good DR as a K-5 but still manageable.

The obvious Pentax selection would be the K-3iii.

It's odd to be looking at a 2013 camera, for action. Action is always niche, premium and always high end and is still improving with every release. In any case you are asking for "cheap premium", as if that exists.

If I were a wedding photographer I'd look at Sony, or a 1DX. For wildlife and action, if you don't need eye AF, a K-3 is pretty good.

I currently own a K-5 and focusing with fast lenses (2.8 or wider) will frequently result in unfocused pictures, even with the 35mm pentax, even with the 90mm Tamron, even with the 17-50 Tamron, and no amount of microadjusting can fix that, while slower lenses pretty much always work. I've also read that the K-3 has somewhat worse handling regarding shadows compared to the K-5, and as far as i know, the same focusing performance. I don't find odd looking at a 2013 camera when i'm already with a camera released on 2010 and having enough performance, except the AF system failing on the worst moments.

[BigMackCam]

I currently own a K-5 and focusing with fast lenses (2.8 or wider) will frequently result in unfocused pictures, even with the 35mm pentax, even with the 90mm Tamron, even with the 17-50 Tamron, and no amount of microadjusting can fix that, while slower lenses pretty much always work. I've also read that the K-3 has somewhat worse handling regarding shadows compared to the K-5, and as far as i know, the same focusing performance.

The following is meant constructively, so please don't think I'm being critical of you...

I still own my trusty K-5, though these days I mostly shoot a K-3 (plus K-3II backup body) and an old Samsung GX-10 (K10D clone). Additionally, I have two more GX-10s, a K10D, *ist DL and Samsung GX-1L (*ist DL2 clone). I use a wide range of K-mount AF lenses, both Pentax and third-party, prime and zoom, including some faster aperture models (f/1.4 - f/2.8). I've performed AF fine adjustment for every lens on every one of my bodies using a Datacolor SpyderLENSCAL tool in good natural light, with the camera tripod-mounted, level with the target and at a suitable distance (based on the focal length of the lens), using timed or remote shutter release. My approach is methodical and consistent.

I will say categorically that I do not have frequent AF accuracy issues on any of my K-mount bodies (even the old ones) with any of my lenses. I do get the occasional miss, as is to be expected... but it's usually due to my poor choice of AF target, or poor lighting. The majority of the time, though, my AF is dependably accurate (I'm talking here about AF.S, rather than AF.C tracking).

More specifically, a fully-working K-5 that is set up, adjusted, and used correctly is perfectly capable of accurate AF, even with fast lenses.

This leads me to suspect there's something wrong with either (a) your K-5, such as the PDAF sensor alignment being outside the range of AF fine adjustment, (b) your AF fine tuning approach, or (c) your choice of AF targets when shooting (believe it or not, you have to be quite picky in choosing AF targets). Either that, or there's something else in the way you're shooting that's affecting focus accuracy - e.g. using AF.C instead of AF.S, rocking back or forth slightly between focus acquisition and shutter release, using the wrong focus point or focus area setup for the kind of subject and shooting conditions etc.

I mention all of this because switching systems, or acquiring and maintaining additional systems, is expensive and time-consuming... and it may be that there's a much easier and cheaper solution involving your camera, AF fine tuning method, settings or shooting technique.

Incidentally, the K-3's AF is improved, and I have no concerns regarding dynamic range and shadow recovery...

[Winder]

Hi everyone!

I'm looking into switching systems or maybe just have both Pentax and another one, and i'm super aware that what i need the most (excluding image quality, which one can take for granted nowadays) is a good autofocus, while a fast burst rate with a deep buffer will be largely appreciated.

I've looked into the original Sony A7 and heard people say its AF was mediocre at best, and that it has a really noticeable shutter lag. This last part would be dreadful as my needs pivot onto a pure sports use.

Is it as bad as people make it sound like?

It's contrast detection only so its pretty bad for anything that's moving and only gets worse as the light goes down. A7II is a big step up with PDAF & CDAF, but not great; It's not until the A7III that Sony puts decent AF in an A7 series body. I would not recommend the A7 or A7II for sports. A7III is serviceable.

[normhead]

More specifically, a fully-working K-5 that is set up, adjusted, and used correctly is perfectly capable of accurate AF, even with fast lenses.

The K-5 was compared to about 12 other cameras from other manufacturers and as I recall thier hit rate was up around 96%, none of the others was ver 94%, the majority were somewhere in the 80s.

Some recent K-5 BiF images....
x



The beatings Pentax gear have taken at the hands of reviewers were never justified, yet oft repeated. This taken with a DA 55-300 PLM. Faster lenses are very important on Pentax. Or sports, FDA* 70-200 2.8, DA 55-300 PLM, Pentax 70-210 4, DFA 150-450.

The Dynamic Range of the A7 was rated 14.2 the K-3 is rated at 13.4 the K-5 is rate a 14.1, the K-1 at 14.6. Feel free to make a change for more dynamic ranges, but the A7 is unlikely to be any better than your K-5. That shouldn't be a justification.

Go to Imaging Resources click on the on Camera reviews, Click on a brand, then a camera, then under basic specifications click on the "Full Specs" under "Basic specifications.' Under Dynamic Range, that's the spec your looking for. My K-1 rating was 14.6, a half stop better than a K-5 has never produced more shadow detail than our K-5. I'm guessing you need a Dynamic range of 15 or over to see even a slight difference. You're barking up the wrong tree here. There are no cameras rated 15 DR or over. The best are 14.8. Even the Sony A7RIV is only 14.8. Not enough to look better than a K-5 IMHO. The Sony A7II is only 13.6. They went backwards.

The landscape column is Dynamic Range. Depending on what your settings, more DR means more shadow detail and fewer blown highlights.
https://www.dxomark.com/Cameras/

Sorry to harp on this but you've been caught by the pop culture "FF have more dynamic range than APS-c." While possibly true generally, a K-5 has more DR than almost any Canon, FF or not. You have to go camera by camera. I'd suggest that for action and sports, DR is not the most important spec.

I hope that helps.

[fiveseven]

There's more to the IQ then just DR. There's no way a cropped sensor is going to have the same look and quality with the same lens than a full frame. Even with APSC faster lens it's a uphill task.

Even medium format 645D is lacking DR when compared to modern cropped sensor, nonetheless that cropped sensor camera will never be able to achieve DOF or "look" of MF.

Different tool for different job or desired look.

[normhead]

There's more to the IQ then just DR. There's no way a cropped sensor is going to have the same look and quality with the same lens than a full frame. Even with APSC faster lens it's a uphill task.

Even medium format 645D is lacking DR when compared to modern cropped sensor, nonetheless that cropped sensor camera will never be able to achieve DOF or "look" of MF.

Different tool for different job or desired look.

Maybe true, I haven't been able to prove it in every day shooting. I have proved for my everyday shooting people can't tell the difference APS-c or FF. While it may be possible to create different looking images it's all theoretical. In science, the theoretical is not proved until it's proven empirically.

In our comparisons, K-5 against K-1, the crop sensor has exactly the same look as the K-1. in terms of cameras that can do it all, the Nikon D850 is probably cream of thee crop, good AF, over 10 FPS, 46 MP files. It has managed to be hi res, high DR, and high FPS. As a general use camera it's pretty good at everything, except I can't match a K-1 in Pixel Shift for over all IQ and just an insignificant 1 point rating behind the 645z on the DxO test score. (A five point difference is significant.)

As for "the look", I'm not sure its real. I always think I have something until I do a blind test. It's more about extra pixels for printing big as far as I can tell. And even then the differences are minimal.

What you want for sports is what DxO calls sports, which is actually ISO. They give you the highest ISO that can be used to produce a clean 8MP image from the file. The best for this might be the Sony A7Riii at 3730 ISO tops. 42 MP,10 FPS. That's going to let you use a nice high ISO for faster shutter speeds, 10 FPS which is adequate for all but the most demanding shooting, and B&H has it on sale right now for $2000. Honestly if you can't afford that, you're never going to be an action shooter. But mind you, adapted lenses are crap for action shots, you're going to pay a bundle for your lenses. It's less FPS than a K-3iii but apart from that it looks pretty useful for just about anything. And it's DR is near the that 14.7. Really, on paper it's a technological wonder. However, it's rating is more than 5 points below a K-1, which mean it's images will be noticeably inferior in some instances. And that's without using the K-1 in Pixel Shift.

Seriously, it sounds to me like the O.P. isn't getting the most out of his K-5. He might want to ask on the forum or search for articles on K-5 action shooting technique. It could get the O.P the improvement he wants.

---

Last edited by normhead; 12-15-2020 at 07:15 PM.

[CapitanXeon]

Sorry to harp on this but you've been caught by the pop culture "FF have more dynamic range than APS-c." .

I haven't implied this and i hope i didn't sound like it, but i thought that recovering shadows was much harder from a K-3 than from a K-5, that's all. I don't want to go back to my K-m /K-2000 days.

I haven't looked specifically into FF because i wanted a FF or because the pop culture, in fact i bought a Canon 7D Mark II (Crop sensor that seemed to have everything i needed) and had to return it to the shop because the battery was so toast it wouldn't charge.

I just want to make the right decision, and currently i find that a Canon with two L series lenses, or some equivalent on another brand, has the potential to stop bugging me, and with less money as well. I've not been able to find any second hand fast lenses on shops in my country that could be part of a pack like i want to do with Canon, or some equivalent on another brand, for a reasonable price, until the point i could snag a body, a battery grip, a genuine battery and a lens for the Canon for the price of a second hand 70-200 f/2.8.

For the reviews, i consistently don't care of what a single review says when my K-m, my K-5 and my already sold brand new K-70 can't focus properly at random with different lenses that all they have in common is a fast aperture.

As you should be able to understand, i don't want to spend that kind of money on a system that consistently shows me that is unable to focus properly at those apertures, and i'd rather have two systems or switch altogether.


And i hate this feeling, because all i know about photography, is because of those three Pentax cameras, of which the K-5 has already 70.000+ shots.


---------- Post added 12-15-20 at 07:13 PM ----------

The following is meant constructively, so please don't think I'm being critical of you...

I still own my trusty K-5, though these days I mostly shoot a K-3 (plus K-3II backup body) and an old Samsung GX-10 (K10D clone). Additionally, I have two more GX-10s, a K10D, *ist DL and Samsung GX-1L (*ist DL2 clone). I use a wide range of K-mount AF lenses, both Pentax and third-party, prime and zoom, including some faster aperture models (f/1.4 - f/2.8). I've performed AF fine adjustment for every lens on every one of my bodies using a Datacolor SpyderLENSCAL tool in good natural light, with the camera tripod-mounted, level with the target and at a suitable distance (based on the focal length of the lens), using timed or remote shutter release. My approach is methodical and consistent.

I will say categorically that I do not have frequent AF accuracy issues on any of my K-mount bodies (even the old ones) with any of my lenses. I do get the occasional miss, as is to be expected... but it's usually due to my poor choice of AF target, or poor lighting. The majority of the time, though, my AF is dependably accurate (I'm talking here about AF.S, rather than AF.C tracking).

More specifically, a fully-working K-5 that is set up, adjusted, and used correctly is perfectly capable of accurate AF, even with fast lenses.

This leads me to suspect there's something wrong with either (a) your K-5, such as the PDAF sensor alignment being outside the range of AF fine adjustment, (b) your AF fine tuning approach, or (c) your choice of AF targets when shooting (believe it or not, you have to be quite picky in choosing AF targets). Either that, or there's something else in the way you're shooting that's affecting focus accuracy - e.g. using AF.C instead of AF.S, rocking back or forth slightly between focus acquisition and shutter release, using the wrong focus point or focus area setup for the kind of subject and shooting conditions etc.

I mention all of this because switching systems, or acquiring and maintaining additional systems, is expensive and time-consuming... and it may be that there's a much easier and cheaper solution involving your camera, AF fine tuning method, settings or shooting technique.

Incidentally, the K-3's AF is improved, and I have no concerns regarding dynamic range and shadow recovery...

I don't know, might be a me issue, but a piece of equipment that, when combined body and lens, was +2000€ on its day, should NOT come with this kind of "yeah you won't be able to focus forever because the this is misaligned beyond user ability to fix it" when specifically using expensive equipment. As said, slower lenses will focus perfectly, and i have had a great time with my 18-135, but i've yet to have any f/2.8 lens that can focus reliably on any of my three cameras, even when set to AF.S on a tripod when taking the pictures to sell the K-70.

I love Pentax unique features like quick shift, but time passes and to me starts to look as a workaround like "yeah you'll need this A LOT". And i get it, i've had my ocasional miss as well with the 18-135, but one thing is that, and another is consistent misses when shooting a product that go away if i completely defocus the thing and start over. I could assume i haven't tuned the thing properly, but this behavior says otherwise, because it will snap in focus when it feels like it.

Whatever it is, and as i said, despite what reviews say, i take my own experience with my own equipment as the most truthful representation of my own experience with the system, and today it is that i can't rely on AF with fast lenses. Portraits will fail, product photography will fail, and overall, make for a bad time.

[fiveseven]

Maybe true, I haven't been able to prove it in every day shooting. I have proved for my everyday shooting people can't tell the difference APS-c or FF. While it may be possible to create different looking images it's all theoretical. In science, the theoretical is not proved until it's proven empirically.

In our comparisons, K-5 against K-1, the crop sensor has exactly the same look as the K-1. in terms of cameras that can do it all, the Nikon D850 is probably cream of thee crop, good AF, over 10 FPS, 46 MP files. It has managed to be hi res, high DR, and high FPS. As a general use camera it's pretty good at everything, except I can't match a K-1 in Pixel Shift for over all IQ and just an insignificant 1 point rating behind the 645z on the DxO test score. (A five point difference is significant.)

As for "the look", I'm not sure its real. I always think I have something until I do a blind test. It's more about extra pixels for printing big as far as I can tell. And even then the differences are minimal.

What you want for sports is what DxO calls sports, which is actually ISO. They give you the highest ISO that can be used to produce a clean 8MP image from the file. The best for this might be the Sony A7Riii at 3730 ISO tops. 42 MP,10 FPS. That's going to let you use a nice high ISO for faster shutter speeds, 10 FPS which is adequate for all but the most demanding shooting, and B&H has it on sale right now for $2000. Honestly if you can't afford that, you're never going to be an action shooter. But mind you, adapted lenses are crap for action shots, you're going to pay a bundle for your lenses. It's less FPS than a K-3iii but apart from that it looks pretty useful for just about anything. And it's DR is near the that 14.7. Really, on paper it's a technological wonder. However, it's rating is more than 5 points below a K-1, which mean it's images will be noticeably inferior in some instances. And that's without using the K-1 in Pixel Shift.

Seriously, it sounds to me like the O.P. isn't getting the most out of his K-5. He might want to ask on the forum or search for articles on K-5 action shooting technique. It could get the O.P the improvement he wants.

Test and comparisons and stuff you read online....... I'm referring from personal experience and this is not meant as another debate of crop vs FF, I own 18 cameras, six are FF and for portrait work I'd never pick APSC over FF, a completely different animal and I compare it to real life experience not what's popular, hip, or what others debate about. Have been shooting for years with a cropped cameras, once I tried FF I was sold.

[normhead]

Test and comparisons and stuff you read online....... I'm referring from personal experience and this is not meant as another debate of crop vs FF, I own 18 cameras, six are FF and for portrait work I'd never pick APSC over FF, a completely different animal and I compare it to real life experience not what's popular, hip, or what others debate about. Have been shooting for years with a cropped cameras, once I tried FF I was sold.

And I own 9 different cameras in 6 different formats, (1:2.3, 1 inch, APS-c, 645 film, 120 film, Digital FF, Film FF. As well I've shot with 8x10 film, 4x5 film. So I have my own experience, 1 year in Ryerson Politech Photo Arts and 15 years teaching photography. If that's in anyway important. Unlike you, I'll shoot APS-c for a lot of different reasons. My point is, you may be just as compromised as anyone else when it comes to confirmation bias. The only way you can prove otherwise is to do a blind test, and prove you can tell the difference from similar MP images.

[fiveseven]

And I own 9 different cameras in 6 different formats, (1:2.3, 1 inch, APS-c, 645 film, 120 film, Digital FF, Film FF. As well I've shot with 8x10 film, 4x5 film. So I have my own experience, 1 year in Ryerson Politech Photo Arts and 15 years teaching photography. If that's in anyway important. Unlike you, I'll shoot APS-c for a lot of different reasons. My point is, you may be just as compromised as anyone else when it comes to confirmation bias. The only way you can prove otherwise is to do a blind test, and prove you can tell the difference from similar MP images.

How am I compromised since I own more APSC's then FF's?
My blind test is pretty straight forward. I like what I see in a ff output better.

Here's a video, a comparison of 24mp - pretty much the same sensor (except mp density and obviously size). APSC gives more noise and less detail.

You Tube

You Tube

[BigMackCam]

I don't know, might be a me issue, but a piece of equipment that, when combined body and lens, was +2000€ on its day, should NOT come with this kind of "yeah you won't be able to focus forever because the this is misaligned beyond user ability to fix it" when specifically using expensive equipment.

If it's a mis-alignment problem with the camera, then all I can tell you is that manufacturing issues occur with every brand of camera (and lens, and accessory), whether it costs 500€ or 5000€. That's why you see manufacturer refurbished examples of almost every model available on eBay and from retail suppliers from time-to-time. It's why we have warranties on new equipment, and why it's important to fully test any product whether you buy it new or used, so you can return it if there's a problem. Most complex, specialised, expensive equipment isn't designed to be user serviceable or adjustable (beyond some minor tweaks in menus) these days... It's just too complex. Do you think the rangefinder in a 6500€ Leica M10 is meant to be user-aligned? No... you have to send it back to Leica for service - and this happens, believe me (Google it if you don't).

As said, slower lenses will focus perfectly, and i have had a great time with my 18-135, but i've yet to have any f/2.8 lens that can focus reliably on any of my three cameras, even when set to AF.S on a tripod when taking the pictures to sell the K-70.

If slower lenses focus OK but fast lenses don't, it's likely that the slower lenses only appear to focus properly due to the increased depth of field.

More interesting to me is that you've not had reliable focusing from an f/2.8 lens on any of your three cameras (all Pentax?). Was this always with the same lens, or several different ones? If it's just one lens, then it's quite possible it is misaligned. I've had several Tamrons with such issues. If it's happening with multiple lenses on three cameras - and if you've carried out AF fine adjustment for all combinations - then there is something wrong with your AF assessment and fine adjustment procedure, your technique and/or camera settings that's affecting AF accuracy.

I love Pentax unique features like quick shift, but time passes and to me starts to look as a workaround like "yeah you'll need this A LOT". And i get it, i've had my ocasional miss as well with the 18-135, but one thing is that, and another is consistent misses when shooting a product that go away if i completely defocus the thing and start over. I could assume i haven't tuned the thing properly, but this behavior says otherwise, because it will snap in focus when it feels like it.

What focus point(s) are you using? Single centre, single off-centre, multi-point... ? Which focus mode - AF.S, AF.C? PDAF or Live View with contrast detect? What aspect of a product or subject are you focusing on when it misses - is there sufficient detail and contrast for the autofocus to distinguish it? AF is clever, but it can't work magic... it requires some degree of involvement from the user. You have to meet it half way. I have numerous lenses with Quick Shift, and I very rarely have to use it. My AF is generally accurate... on all of my cameras and lenses.

Whatever it is, and as i said, despite what reviews say, i take my own experience with my own equipment as the most truthful representation of my own experience with the system, and today it is that i can't rely on AF with fast lenses. Portraits will fail, product photography will fail, and overall, make for a bad time.

I'll say again, I do not have AF accuracy issues with any of my Pentax cameras - K-3II, K-3, K-5, K10D, *ist DL, plus Samsung-branded GX-10 (three of them) and GX-1L. That's NINE cameras. Every one of them required some AF fine adjustment to focus accurately with the many lenses I own (such is the nature of PDAF sensors in DSLRs of any brand). Using a dedicated AF adjustment target and proper, controlled conditions and procedures, I've carried out those adjustments for all nine cameras with all of my lenses, and the result is dependably accurate AF with every camera / lens combo. In a few instances, my AF fine tuning procedures have led me to conclude that a particular lens is mis-aligned such that accurate AF can't be achieved within the +/- limits of the camera's AF fine adjustment, and I returned those lenses or had them serviced under warranty.

I don't doubt what you've experienced, and I feel for you... I know it's frustrating; but if you're having these problems with three cameras and multiple lenses, and I'm not - with NINE cameras and many lenses - then, with respect, you're doing something differently than me.

We can solve this if you have any desire to do so... and it's probably something pretty simple, we just need to find out what it is. There are many members here who'll be willing to help if you ask, and I'm one of them. Feel free to PM me if you wish.

It sounds, though, as if you've made your mind up that Pentax AF is unreliable or doesn't work properly. That's categorically incorrect, as thousands of members here can attest... but, if you're sure we can't assist and convince you otherwise, you're probably better off switching to a different system... in which case, whatever you do, choose a mirrorless platform with on-sensor PDAF - that way, you won't have to worry about AF fine adjustment in future.

[normhead]

How am I compromised since I own more APSC's then FF's?
My blind test is pretty straight forward. I like what I see in a ff output better.

Here's a video, a comparison of 24mp - pretty much the same sensor (except mp density and obviously size). APSC gives more noise and less detail.

Sony A7iii vs Sony A6500: 4K Video + Photo Comparison - YouTube

I can prove almost anything in a video. Thats still confirmation bias. You ignore the evidence against, you pick the evidence that proves what you think. You don't learn a thing. You're basing your defence on click bait.

APSC gives more noise and less detail.

Except when I'm using my 300 2.8 and cropping, when APS_c puts 24 MP into 1 16 MP segment of FF sensor, and APS-c gives you more detail, and if you can shoot at 100 ISO, pretty much the same noise. How is it possible the guys in your posted video neglected to mention that minor detail? They aren't really addressing the whole issue. Just one part it. They were engaged in confirmation bias, not education. If those guys are so smart how did they miss that? Or more to the point, if you're so smart, how did you miss that? Blinkers?

I never said there are no differences or that one format can't be shown to be different than others. Your video shows the negative (to APS-c) and emphasizes the positives for FF. There are times when every format I use is selected because it gives me the best chance of the picture I'm hoping to take that day. FF is the best at what FF is the best at. (For me landscape.) APS-c is the best at what it's good for, for me, birding.) My 1 inch sensor ZS100 is the best for low light mushroom photography on the fly under the forest canopy. It has great DoF at ƒ2.8.. My k-1 is best if I have the time to set up a tripod and shoot long exposure Pixels shift images for mushrooms (at F22.). All the other formats have their benefits as well. Saying FF is always the best is just an internet marketing scam. It's so sad to see people sucked in like this.

Believe what you like, no sweat off my back.

[BigMackCam]

Just to show that the K-5's AF is reliable with a fast lens, I started from scratch with adjustments for my FA50/1.4...

I set up my SpyderLENSCAL and camera as below:



This is a pretty poor setup, really... Typically, I would mount the camera on a proper, sturdy tripod, but just wanted to do this quick and dirty test for the OP's benefit.

I reset the AF fine adjustment number to zero, set the camera in Live View, and adjusted the position of it until it was pointing at the dead centre of the black and white checkerboard. I then cycled AF, looked at the distance readout of the lens, and kept adjusting the position of the camera and recycling AF until the distance showed 1 metre every time:



Next, I switched off Live View, set the camera to use a single centre AF point, put my hand in front of the lens and cycled AF so it would be out of focus (this lens doesn't have Quick Shift ), took my hand away and cycled AF once more, all without moving the camera. Initially, the distance readout on the lens was slightly to one side of the 1 metre mark, so I made AF fine adjustments and repeated the process until I got a 1 metre readout every time (sorry for the shaky handheld phone shot ):



With that completed, PDAF and Live View (CDAF) should match. [Actually, this is a nice, quick and easy way to carry out AF fine adjustment for any camera with Live View, as it negates the need to actually take photos and therefore doesn't increase shutter count ]

Finally, I went outside to take some test shots. It's very dull out today, and I was shooting handheld, braced against the wall of my home. The first shot was taken in Live View, and this is a 100% crop:



For the second shot, I switched to PDAF, focused on a distant object (to ensure the camera and lens would need to refocus), then cycled AF and took the shot. Again, this is a 100% crop:



These shots are both in acceptable focus, considering the screw-drive AF mechanism. Actually, the PDAF shot is ever-so-slightly more accurately focused here, but a tiny difference like this can be attributed to the screw-drive mechanism or even the smallest back or forth movement of the photographer. This was quite a challenging test, since the padlock was less than a meter from the camera, and the 50mm lens was set to f/1.4, so depth of field was very shallow indeed.

Through numerous iterations of PDAF and Live View shots, focus accuracy was within the variance shown above, with Live View sometimes being that bit more precise and on other occasions, PDAF being the winner (just). This is in line with reasonable expectations; after all, AF is good... but not perfect

[normhead]

Just to show that the K-5's AF is reliable with a fast lens, I started from scratch with adjustments for my FA50/1.4...

I set up my SpyderLENSCAL and camera as below:



This is a pretty poor setup, really... Typically, I would mount the camera on a proper, sturdy tripod, but just wanted to do this quick and dirty test for the OP's benefit.

I reset the AF fine adjustment number to zero, set the camera in Live View, and adjusted the position of it until it was pointing at the dead centre of the black and white checkerboard. I then cycled AF, looked at the distance readout of the lens, and kept adjusting the position of the camera and recycling AF until the distance showed 1 metre every time:



Next, I switched off Live View, set the camera to use a single centre AF point, put my hand in front of the lens and cycled AF so it would be out of focus (this lens doesn't have Quick Shift ), took my hand away and cycled AF once more, all without moving the camera. Initially, the distance readout on the lens was slightly to one side of the 1 metre mark, so I made AF fine adjustments and repeated the process until I got a 1 metre readout every time (sorry for the shaky handheld phone shot ):



With that completed, PDAF and Live View (CDAF) should match. [Actually, this is a nice, quick and easy way to carry out AF fine adjustment for any camera with Live View, as it negates the need to actually take photos and therefore doesn't increase shutter count ]

Finally, I went outside to take some test shots. It's very dull out today, and I was shooting handheld, braced against the wall of my home. The first shot was taken in Live View, and this is a 100% crop:



For the second shot, I switched to PDAF, focused on a distant object (to ensure the camera and lens would need to refocus), then cycled AF and took the shot. Again, this is a 100% crop:



These shots are both in accurate focus. Actually, the PDAF shot is ever-so-slightly more accurately focused, but a tiny difference like this can be attributed to the screw-drive mechanism, or even the smallest back or forth movement of the photographer. This was quite a challenging test, since the padlock was less than a meter from the camera, and the 50mm lens was set to f/1.4, so depth of field was very shallow indeed.

Through numerous iterations of PDAF and Live View shots, focus accuracy was consistent with the results above...

Aren't you just getting to be quite the little investigator? Myself, I always find, if you really want to know, investigate yourself. Your cameras, your lenses, your workflow. Knowing what someone else found using their camera and their lenses and a different work flow may or may not be relevant. Not to mention that you learn a lot more than just your published results. The process itself is informative. You can't be credible if you haven't done the work yourself. Thanks for your effort.