[Larrymc]

Modern camera, modern lens makes a hell of a difference.

KP and DFA150-450



The DFA28-105 can even make flightless birds fly

Excellent captures, Sandy!! Good to see the KP showing its stuff.

[c.a.m]

This thread highlights a challenge in comparing autofocus performance of different equipment and brands – a scarcity of credible quantitative tests and objective reports.

Anecdotes and hyperbole. In many reviews and discussions here and elsewhere, most comments on AF tend to be qualitative and anecdotal, whether positive or negative. We read statements along the lines of “the other guy got more in-focus keepers; my Pentax AF couldn’t compete,” “Brand X sweeps the floor with Brand Y,” and “Camera X has faster AF; I made a quick test.” While such sweeping statements probably reflect the users’ subjective impressions, which shouldn’t be discounted, I would suggest that they shouldn’t serve as a basis for others to draw definitive conclusions.

Methodical quantitative tests and analyses are rare. The online reviews that purport to present credible tests typically fail to account for key parameters; they don’t describe all of their pertinent test conditions; or they don’t report meaningful data. Nor is it obvious that the tests have been performed with optimal camera settings or that comparable lenses have been used.

The Wobbly Bike. One of the more prominent series of AF tests conducted by DP Review – the so-called ‘wobbly bicycle’ test – should be noted at least for DPR's effort to include it as a common reference point in their camera reviews. However, even this test has been conducted in various settings under uncontrolled lighting conditions, different riders wearing different clothing, and different motion dynamics, amongst other variations. DPR’s reports typically omit information that would allow the tests to be repeated; hence the tests are not entirely credible.

The scarcity of credible AF tests should not be surprising – these are difficult to set up and time consuming to conduct. Several key performance measures need to be considered, including time to achieve AF lock, accuracy, precision, tracking ability against several relative target motions, and distances to the target. These issues have been discussed frequently in other PF threads, and summarized succinctly by member @beholder3 here at post #6: Accurate AF Lenses? - PentaxForums.com

What about the Real World? Another gap is that anecdotes and tests are usually not extrapolated credibly to real-world in-field situations. For example, it might be claimed that Camera X’s AF is tens of milliseconds faster than Camera Y, or it achieves a few more in-focus shots in a long burst. The crucial question is how the performance measures translate to real-world situations – for example, are tens of milliseconds really critical, or do nine in-focus shots in a burst produce a better end outcome than seven?

A recent thread pointed to an AF test conducted by a reputable German magazine (also posted by @beholder3: One of very, very few repeatable AF.C autofocus tracking tests - PentaxForums.com). Although the test was relatively narrow in scope, it showed how AF performance can be quite variable across brands and camera models depending on the conditions. The test could also serve to challenge those sweeping subjective claims that we hear frequently.

While we often hear the recurring theme that Pentax AF is inferior to other brands, one might wonder whether such sentiment is well founded, or based on limited personal experience, or simply a regurgitation of a popular myth that has not been updated to reflect contemporary camera systems.

- Craig

[Sandy Hancock]

@Sandy Hancock; Great examples. I think that you're quite correct -- modern gear performs better. Would you say these shots are typical of your experience with that camera/lens combo?

First, a disclaimer - I'm no birder. I have no experience with other brands, so I don't know what I'm missing

That said, once I got an AF lock on the bird the AF points danced around in the viewfinder and tracked it very well. I keep my thumb on the back AF button and shoot deliberate short bursts of two or three shots rather than spray and pray. Most shots in a sequence were sharp. Keepers were selected by pose and framing more than focussing errors.

[Sandy Hancock]

While we often hear the recurring theme that Pentax AF is inferior to other brands, one might wonder whether such sentiment is well founded, or based on personal experience, or simply a regurgitation of a popular myth that has not been updated to contemporary camera systems.

I wonder whether the opinions of most reviewers is at least partly due to unfamiliarity with Pentax gear. And bias of course

[c.a.m]

I wonder whether the opinions of most reviewers is at least partly due to unfamiliarity with Pentax gear.

Possibly. However, I find that the 'Pentax AF is sub-par' perspective is also parroted here at PF, albeit rarely in an offensive manner. Perhaps some folks are basing their view on older Pentax gear.

[Des]

Amen to all that Craig.

The other thing I'd add is that it takes time to get the best AF results out of any camera/lens combination. [Edit: After posting I saw Sandy made the same point.] You have to learn what works best. Even within the same system there is a learning curve - I'm still getting to know the KP even though it has essentially the same AF system as the K-3, partly because the ergonomics are different. I wouldn't assume that I could pick up a camera/lens that I'm unfamiliar with and instantly get the best results. This must make it hard for even conscientious testers.

As for less conscientious ones .... have a look at the Northrup review of the K-1 in which he pans the tracking performance. Hmmm. (It's just before he explains that the K-1 isn't really the best value FF on the market because a Canon with second hand lenses is cheaper that a K-1 with new ones. )

The 55-300 PLM is so quick that if I miss focus I can only say it's operator error.

[Larrymc]

Amen to all that Craig.

The other thing I'd add is that it takes time to get the best AF results out of any camera/lens combination. You have to learn what works best. Even within the same system there is a learning curve - I'm still getting to know the KP even though it has essentially the same AF system as the K-3, partly because the ergonomics are different. I wouldn't assume that I could pick up a camera/lens that I'm unfamiliar with and instantly get the best results. This must make it hard for even conscientious testers.

As for less conscientious ones .... have a look at the Northrup review of the K-1 in which he pans the tracking performance. Hmmm. (It's just before he explains that the K-1 isn't really the best value FF on the market because a Canon with second hand lenses is cheaper that a K-1 with new ones. )

The 55-300 PLM is so quick that if I miss focus I can only say it's operator error.

Excellent captures, Des. Most of my misses with the PLM are very much my fault. BTW, I know you are a DXO, user have you found a workable user lens profile you like with the PLM since they haven't published a lens profile for the PLM yet? I can't seem to find a lot of fault with the PLM as far as distortion of any type.

[Des]

I know you are a DXO, user have you found a workable user lens profile you like with the PLM since they haven't published a lens profile for the PLM yet? I can't seem to find a lot of fault with the PLM as far as distortion of any type.

Frustratingly no, Larry. I tend to leave in-camera corrections turned on for that lens - I agree that there isn't much distortion anyway. The main issue in PP is its vignetting. I use my own preset to adjust that, but a DxO one would be better.

[clackers]

OK, don't bother...I'll tell you now. FUJIFILM AF eats Pentax AF for breakfast lunch and dinner.

We all know that endless hype … for example, Fuji claimed that the XT-1 had the world's fastest AF, etc, and you've absolutely believed it, Surfar, just lapped it up.

But see the numbers here …

How good is Pentax AF tracking? - PentaxForums.com

[surfar]

But see the numbers here …

Yes,I'm subscribed to his stuff...seen it.

I'm on the K-1(version one), are you?

[Rondec]

We all know that endless hype … for example, Fuji claimed that the XT-1 had the world's fastest AF, etc, and you've absolutely believed it, Surfar, just lapped it up.

But see the numbers here …

How good is Pentax AF tracking? - PentaxForums.com

I found it interesting that the amazing XT-3 in beholder3's thread about AF-C only achieved about 40 percent "ok" series in which the majority of photos in the series were sharp and there were no complete fails. I don't think the message is particularly to gloat about how terrible Fuji's cameras are or to say that Pentax is better, but just to say that there is no replacement for skill on the part of the photographer and that auto focus modules, even in top end mirrorless cameras, still have a ways to go.

[totsmuyco]

I've tried a friends D7200 with his Tamron lenses and I agree, the AF.C licks my K-3II and k-5II. But that's not the end of the world. It took me quite a while to find the k-3II usable for AF.C mode. It was after some tips from the guys in this forum that I finally understood how to use the camera for action shots. From about 60%-70% success rate, I ended up to about 90% success rate. It's not perfect but, I don't think it's that bad.

[beholder3]

Three years ago there was another good test:
Results from a really repeatable AF.C test (no Pentax inlcuded) as reference - PentaxForums.com

[ErikRuss]

New to this forum and new to Pentax digital. I bought a used K-5 (very low shutter count) with a Tamron 18-200mm lens. It had the original firmware and spent time "hunting" in overcast. Checked and download latest firmware and installed. This seemed to sharpen the focus and make acquisition quicker (shooting same subject in same light). My Nikon D7000 also seems to "hunt" in overcast, and I was impressed by the K-5's results.

[clackers]

I've tried a friends D7200 with his Tamron lenses and I agree, the AF.C licks my K-3II and k-5II.

Except it doesn't. Showing that skill and technique comes into it, which you showed by raising your own rate to 90% as you said, Tosmuyco.

Proof is here, both the D7200 and K3-II are specifically measured and reported:

How does Pentax AF-C compare to other brands? - PentaxForums.com