[bass3587]

For the life of me I can't find it now but Ricoh announced they've improved the auto focus performance on the new model K1 Mark II. Saw the post on Instagram. If anyone can find it. Post a link for everyone to read. It is very interesting.

[pete-tarmigan]

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[alpheios]

Ricoh Imaging on Instagram: ?Pentax K-1 MKII Auto Focus Improvements Reviewed Motion Tracking Algorithm in XY Direction: The accuracy of motion tracking was improved??
here you go

[6BQ5]

Hmm! There is mention of improvement in the X-Y plane. I never had too many problems with X-Y. Is there any improvement in the Z axis? How well will the K-1 mk II focus and track oncoming subjects like people running toward the photographer?

[stevebrot]

Is there any improvement in the Z axis? How well will the K-1 mk II focus and track oncoming subjects like people running toward the photographer?

Z-axis tracking is really sort of a misnomer. At base, it is just plain AF.C with possible provision for predictive focus point. Both precision and accuracy are related to the sensitivity to OOF in AF.C and the mechanical speed and accuracy of the focus mechanism to provide near-real-time updates with high accuracy. Even with predictive algorithms (detection of linear trend of focus change), any lag will make acceptable focus in burst of an approaching target is difficult and even harder for a single exposure where a trend may not have registered with the system.

Since Pentax did not mention improvement to AF.C or Z-axis predictive focus, it is safe to assume that no intended improvements have been made. (That would not mean that such will not be found in anecdotal reports or fan-site testing.)


Steve

[richandfleur]

Hmm! There is mention of improvement in the X-Y plane. I never had too many problems with X-Y. Is there any improvement in the Z axis? How well will the K-1 mk II focus and track oncoming subjects like people running toward the photographer?

That is the big question!

AF wise you typically don’t need to change the Focus much at all, if the subject is moving but staying the same distance from the lens.

Where I want/need it, is where my kids are in a running/cycling race, and moving towards the camera.

[monochrome]

That is the big question!

AF wise you typically don’t need to change the Focus much at all, if the subject is moving but staying the same distance from the lens.

Where I want/need it, is where my kids are in a running/cycling race, and moving towards the camera.

YEP. The only AF.C failure I’ve had on both K-1 and KP (understanding the very real design limitations of K-1) was of my 1-year-old grandson very hesitantly walking toward me. Lenses were 24-70 on K-1 and 20-40 on KP and light was good.

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Last edited by monochrome; 04-12-2018 at 02:40 PM.

[derelict]

Will this algorithm come with to those with a MK1 that have it upgraded?

[stevebrot]

Where I want/need it, is where my kids are in a running/cycling race, and moving towards the camera.

I you want to get the shot, use full manual focus technique, i.e. pre-focus on the spot where they are coming out of a curve (usually provides a clear view) and do a short burst at f/8 while panning. I shoot crits with the FA 77/1.8 (no, not a sports lens) and get at least one keeper per short burst.


Steve

[richandfleur]

I you want to get the shot, use full manual focus technique, i.e. pre-focus on the spot where they are coming out of a curve (usually provides a clear view) and do a short burst at f/8 while panning. I shoot crits with the FA 77/1.8 (no, not a sports lens) and get at least one keeper per short burst.


Steve

Agree, just saying it’s 2018 and the non Pentax world has the ability to achieve this and more (eg eye tracking AF) now.

[pete-tarmigan]

Will this algorithm come with to those with a MK1 that have it upgraded?

Yes. See:
K-1 Hardware Upgrade: Pentax Loves You, Too - Pentax Announcements | PentaxForums.com

[stevebrot]

Agree, just saying it’s 2018 and the non Pentax world has the ability to achieve this and more (eg eye tracking AF) now.

D500 and the Nikon dSLR line in general is the best example for PDAF (Canon being the distant second), though eye tracking is limited to an eye that had previously been acquired by point selection. The key of Nikon's success is proprietary (and patented) predictive focus, meaning that the focus goes to where the subject will be (X, Y, and Z axes) in anticipation of it actually being there. Depending on burst rate and subject path, this may or may not be successful. Fortunately Newton's first law still applies and the subject is usually where the prediction placed it. As long as the AF motor is faster than the frame rate and the AF point density is high, this works quite well, most of the time (see DPReview's assessment of the D850).

I am sure there must be a good answer (the truth is out there) for why Pentax is not able to acquire/maintain Z-axis focus on approaching subjects on a par with competitors (poor IBIS performance at longer focal lengths?).

(FWIW, I have generally had good luck at moderate subject distance hand-held with the Sigma 17-70 (C) on my K-3.)


Steve

[derelict]

Yes. See:
K-1 Hardware Upgrade: Pentax Loves You, Too - Pentax Announcements | PentaxForums.com

Great. I am really thinking about picking up a K1. Getting one on the used market and then getting it upgraded to II status will be cheaper than just buying a II.

[pete-tarmigan]

Great. I am really thinking about picking up a K1. Getting one on the used market and then getting it upgraded to II status will be cheaper than just buying a II.

Just make sure you buy it and get it to Precision before the end of August.