[jpzk]

DPReview reviewed the K-1?

... Blah !
Not really worth reading.

[rawr]

Pix pls.

[reh321]

.... These questions may seem simplistic but the problem is simple - the continuous autofocus does not work properly and reliably. Can we K-1 owners expect Pentax to fix this function in the K-1 or must we just except it as is? If the later, then Pentax should at least explain why and not advertise the capability (for example, claiming next generation autofocus hardware).

Other than this continuous autofocus issue, I think Pentax has created a wonderful and outstanding camera.

If you look at the special features crammed into this very reasonably priced FF, such as pixel shifting, I believe it is primarily aimed at landscape photographers. Locking onto moving targets tends to be more of an "event" thing, so I wouldn't expect Pentax to have put extra effort into that for the K-1. If they do improve AF, I would expect it to show up in the K-3ii replacement.
{BTW - as a retired engineer, I never expect the people who write advertising to get it right

[GUB]

DPReview just posted a very negative review of the K-1 continuous autofocus. I have owned a (full frame) K-1 for 2 weeks and have owned various Pentax DSLRs over the years (also currently own K-3). I have always used single (not continuous) autofocus and generally get good focus results. In order to protest the DPR review, I just tested continuous autofocus on my K-1 as follows: Pentax 300mm f4 DA* lens with aperture set at F/4 (for shallow depth of field). K-1 in autofocus continuous mode, sel 9 (red grid), continuously shooting shutter at medium speed. The focus hold setting was set to low. First frame action was set to focus priority. Action in AF.C Cont. set to focus priority. The ISO was set at 800 and the shutter speed (aperture priority exposure) was about 1/2000 sec. Like the DPR test, I had a person ride a bike towards me at relatively low speed. I focused the grid on the rider's head, depressed the shutter button and held it down for about 20 frames as the rider moved towards me and I maintained the focus grid pointed at the rider's head. I repeated this test several times. I was shocked and disappointed to find that the rider's head was in focus in only 30% of the frames. Therefore, apparently the negative DPR autofocus test results are valid. Of course, using an aperture like F/8 would substantially increase the percentage of in-focus frames. However, that would just mask the basic functional problem.

I am very concerned about the poor performance of this important camera function and fear that it will limit the K-1 market share. I'd like to ask the following questions:

1) Does anyone have success with continuous autofocus on the K-1 or K-3? Is there some trick to making it work reliably (other than slow apertures)?

2) Does anyone know why technically the Pentax continuous autofocus performance is so poor and inferior to, say, Nikon D750? Is it due to less powerful (and less expensive) computational hardware in the K-1 compared to the D750? Is it due to inferior tracking algorithms? Is it due to the lack of some other proprietary hardware?

3) Is there anything that can be done to make the Pentax K-1 continuous autofocus more accurate and competitive?

These questions may seem simplistic but the problem is simple - the continuous autofocus does not work properly and reliably. Can we K-1 owners expect Pentax to fix this function in the K-1 or must we just except it as is? If the later, then Pentax should at least explain why and not advertise the capability (for example, claiming next generation autofocus hardware).

Other than this continuous autofocus issue, I think Pentax has created a wonderful and outstanding camera.

Just curious but did you have Image stabilization on ? I wonder if it could create AF issues. I am not in the habit of doing this type of action photography but I learnt the hard way to turn it off for waterfalls. The IS could be stabilizing the background at the expense of the cyclist.

[biz-engineer]

The focus hold setting was set to low.

The focus hold setting should be set to OFF when subject are moving in the Z direction, otherwise K1 AF tracks better across the frame but slows down in the Z direction, that's to prevent the camera to refocus on objects that come into the focus plane of the subject. That matches what Adam wrote.

Pentax 300mm f4 DA* lens with aperture set at F/4 (for shallow depth of field)

The DA300 is not very good for tracking, especially when the subject comes near the camera, the SDM AF of the DA300 is too slow to catch up at near focus distances. DFA150-450 works way better for AF tracking.

There, for sure, can be cameras with better AF tracking, D5 or 1Dx. Regarding camera such as 5DIII, 5Dsr, D750,D610,6D.... the difference of AF may not be much to justify switching systems, especially for getting a successful bike test. For the occasional shooting of races, aircrafts, and bird inflight, I get good results from my K3 and K1, and I'm not going to switch to Nikon or Canon for a bike test (although I'm rather impressed by the keeper rate I get on a "bike test").

I did the bike test to try to comply with DPR, but... this was the first time in my life I have to shot bikes coming at me up to a few meters away. I previously shot race bikes but I would stand so close to get hit by a bike for the sake of being able to do the "DPR AF test".

How to say it? Are tests that you never use in your shooting any relevant for the choice of a camera system???
The DPR test is more about building a bad reputation than it is actually useful in the field. The proof is written by yourself: before the DPR test you where happy with the camera, and now that you did the DPR test you're not happy anymore. What it says: the camera is fine for you, but DPR review make you discontent of the system you were satisfied with. In the meantime, DPReview makes money out of the clicks they record from their website, and users like you may spend more money to switch to another system that you actually did not need.

[Ptitboul]

1) Does anyone have success with continuous autofocus on the K-1 or K-3? Is there some trick to making it work reliably (other than slow apertures)?

I don't have the K-3. And I don't think that the AF-C tracking of my K-1 is much better than my K-5 II.
However, tracking is not the only thing that may be required in AF-C.
And I have good success in using continuous autofocus on subjects that are not coming towards the camera.

2) Does anyone know why technically the Pentax continuous autofocus performance is so poor and inferior to, say, Nikon D750? Is it due to less powerful (and less expensive) computational hardware in the K-1 compared to the D750? Is it due to inferior tracking algorithms? Is it due to the lack of some other proprietary hardware?

I don't know, but I have hypothesis, and it comes down to software.

I don't think that Pentax AF does subject tracking. The "Group AF" modes use simultaneously many AF sensors, and apparently recognise that the subject has moved when there is another sensor that is in focus. It is very efficient when following a subject that is moving laterally, because it may be difficult to be sure that the same AF sensor is always on the subject. I have been able to take pictures of swallows in flight using this technique. And the K-1 is better than the K-5 II because it has more AF sensors. However, some other bodies (e.g. D750, but not 6D) do subject tracking: they use the metering sensor to recognise the shape and color of the subject, and decide which AF sensors to use, knowing where the subject is. The K-3 or K-1 have a metering sensor with enough pixels to be able to do the same, therefore I think that the issue is inferior software.

I don't think either that Pentax AF does predictive AF. It doesn't seem to compute the distance of the subject, to predict what is the subject speed in the z axis, and to focus where the subject will be. Therefore, on subject moving quickly towards the photographer, the AF is always a bit late, because when it computes focus confirmation and decides to take the picture, the subject has already moved a bit. This is partly a software issue, and partly a hardware issue: fast focusing lens are a hardware improvement, and lenses that report precisely the focusing distance are another improvement. I know that old Pentax lenses report the focusing distance, but in a very imprecise manner. I don't know if recent lenses report it more precisely. Nikon is more explicit on that subject, they tell which lenses are compatible with predictive focus tracking, and they say that they take into account the "release time lag". Cf. Nikon | Technology | Predictive Focus Tracking System

3) Is there anything that can be done to make the Pentax K-1 continuous autofocus more accurate and competitive?

Improving the software can improve it a lot.

[Kunzite]

Starting with the K-3, Pentax has subject tracking: "Supported by the PENTAX Real-time Scene Analysis System, the K-1’s Auto Tracking function accurately detects the subject’s motion based on various factors including color, then keeps pinpoint focus on the subject throughout the imaging process by automatically shifting the in-focus point."
Features5 | PENTAX K-1 | RICOH IMAGING
However, the K-3 had the first version - and that was a mere 3 years ago. I'm not sure if the K-1 version was improved; but even if it has, that would make it generation 1 1/2 or something. Hard time competing with the well established Canikons.

[biz-engineer]

And I have good success in using continuous autofocus on subjects that are not coming towards the camera.

What I've noticed is that the Z AF tracking depends a lot of the speed of the target:
- If the target is slow moving the camera update the focus in large jumps
- if the target is too fast for the lens focus actuation to catch up, the camera lose focus
- if the target is fast but speed is below what the lens motor can do, then the camera AF tracking is excellent

[Nicolas06]

There lot of truth in the following statement by biz-engineer. While DPR may very well have a valid point of AFC performance and while you may be better of with some other camera if AFC performance, you don't have such requirement.

before the DPR test you where happy with the camera, and now that you did the DPR test you're not happy anymore. What it says: the camera is fine for you, but DPR review make you discontent of the system you were satisfied with. In the meantime, DPReview makes money out of the clicks they record from their website, and users like you may spend more money to switch to another system that you actually did not need.

The K1 is 1800$ for 36MP. The D810 is 2800$. The K1 has pixel shift, an astrotracer, in body SR that work on all lenses, and quite advanced ergonomics thanks to a fully articulated back screen and more control wheels.

It could be argued that you could have spent less money on another system to get what you needed. It could be argued that for people that put AF performance first K1 is not the best choice. We do not all agree on this but this is a valid, understandable point.

But if you brought the K1 for the right reasons, for its strengths, it is fantastic value and actually better than what the competition provide at the same price point.

If you had brought D750 instead you would have other, different limitations.

[Not a Number]

Yup, I'm not sure about all the negativity.

There appears to be a trend that any criticism of the K-1 (or even Pentax in general) is met with attacks on the messenger. I guess PF is going to turn to the DPReview norm of behavior.

[monochrome]

Use single point center focus and track with the rear AF button. When you press the shutter, it's ready. And if you have enough light for a high shutter speed, say 1/320 or higher and ISO 3200, turn off SR. Turn off all the stuff you don't need. because you're shooting DNGs.

SR has zero effect on Z-axis tracking. IBIS is not ILIS.

You would disable SR if the camera was on a tripod - which I believe was the case in the DPR test. I'm not defending the K-1. It failed the test and it always will - but that test isn't relevant for the K-1 use profile and their inferences (not suitable for shooting small, active children) are not supported. Who puts a dSLR on a tripod to burst-photograph little kids?

The K-1 is not suitable for shooting a weaving bicyclist riding at you while the camera is mounted on a tripod.

Done and done.

[vonBaloney]

Just curious but did you have Image stabilization on ? I wonder if it could create AF issues. I am not in the habit of doing this type of action photography but I learnt the hard way to turn it off for waterfalls. The IS could be stabilizing the background at the expense of the cyclist.

Pentax shake reduction does not evaluate anything about the image in order to work -- it stabilizes the sensor based on camera movement/rotation. So it doesn't matter if it is a waterfall or a cyclist or even if the lens cap is on, works the same. I'm not aware of any IS system trying to stabilize based on the subject in-frame -- is that even a thing?

[UncleVanya]

I think their is some concern about some people posting with an ulterior motive. That perceived lack of integrity may be what brings the pile on. In this case the op sends quite genuine and is interested in the responses and has good points to make.

[monochrome]

There appears to be a trend that any criticism of the K-1 (or even Pentax in general) is met with attacks on the messenger. I guess PF is going to turn to the DPReview norm of behavior.

Negativity is as negativity does. Overall the review was fair and complimentary. 84 is an OK score, though some people question the weight placed on AF. Silver is probably right - K-1 is at the end of the IMX094 generation and is average in fps, buffer size and speed, mass, below average video (in its class) - but a fabulous field camera and value generalist camera.

If the review had said that in non-charged words, explained the tracking AF test and why it scored a fail (AF points are grouped in the crop frame), not rated the ENTIRE AF poor, not made unsupported conclusions such as unsuitable for shooting active small children (based on the bicycle test) and avoided snarky corporate overlord references (bring an Amazon Kindle to read while waiting for AF to lock) - no one would have had a valid complaint.

When they title the review 'Special K?' they're inviting acrimonious responses. If they don't know that they're living in a Nikon bubble.

What we know for certain is, if your use case is putting a 36mp FF camera and f/2.8 70~200 zoom on a tripod to burst shoot a weaving bicyclist coming down a hill at you . . . . don't buy a K-1.

[Adam]

There appears to be a trend that any criticism of the K-1 (or even Pentax in general) is met with attacks on the messenger. I guess PF is going to turn to the DPReview norm of behavior.

I'd like to urge fellow members to approach criticism with a level-headed attitude. Every camera has its flaws and while DPR may have exaggerated its negativity regarding the K-1's AF, it's probably fair to say that there are other cameras out there that can do better.

One could speculate that DPR might simply not have the experience with Pentax equipment needed to obtain ideal tracking results. In any case, their findings certainly don't discredit the fact that the K-1 is an amazing value and a compelling FF camera to more than just current Pentax owners.