Analysis of Rishi Sanyals claims on competence and scientific approach for the K-1 AF test

Started Jul 6, 2016 | Discussions thread
LightBug Senior Member • Posts: 2,396
Re: AFC test was redone!

Rishi Sanyal wrote:

LightBug wrote:

Tatouzou wrote:

joergensmi wrote:

...

It can be clearly seen that the central AF-point has been selected and none of the upper ones.

For me it is clear now that this test fails due to faults by dpreview.

http://www.dpreview.com/reviews/pentax-k-1/6

There has been an update of the exiftools by Phil Harvey The version is 10.22 dated 07.07.2016 12:26 7.226.089 exiftool.exe

The result is now
Focus Mode : AF-C (Focus-priority)
AF Point Selected : Center; Single Point

I wonder why Rishi Sanyal didnt reply this post about the AF point he used: these are facts, and they show incoherences in his assessments of how he conducted the review.

First of all, I didn't write this review. Do you see my name on the author list?

There was a miscommunication about which set of images the author ended up including in the rollover we published (we had 20+ runs), which was ultimately irrelevant to the conclusions of these tests, because the center point was still over the bike, and the bike/cyclist were still out of focus in most of the shots, with focus far behind the entire bike (playing catch up).

All you've managed to do is nitpick something that has absolutely no relevance or bearing to the conclusion or review. But, out of respect for our audience, we redid it today again, to get the same exact result.

DPR obliged and re-did the straight-line AFC test. Results look much better than before, I could count 4-5 frames in focus, while previously I remember only 1 or 2 was in focus.

There is literally no difference in the results. We're publishing the rollovers side-by-side just for you. Why would the results be any different to begin with? As I'd noted before, Richard's face was within the DOF of what the AF points were focusing on (the bike in the last rollover prior to today), so the only reason we re-did the test was simply to avoid the nitpicking criticisms that we already knew had nothing to do with the end result. There is no change in the results.

-Rishi
-------------------------
Rishi Sanyal, Ph.D
Deputy Editor, Technical Editor | Digital Photography Review
dpreview.com (work) | rishi.photography (personal)

Rishi,

I have to disagree with your statement above that redoing this test makes no difference. I do see a increase in hit rate from first test to second test.

Here are crops from the first straight-line AFC test:

http://www.dpreview.com/galleries/0725780996/photos/3477783/imgp2504?inalbum=dpr-k-1-afc-test-1-crops

From the first set, I would consider IMGP2504, IMGP2513 in focus. That's 2 out of 14 when the focus point was not set on the face.

Here are crops from the second straight-line AFC test that was redone:

http://www.dpreview.com/galleries/0725780996/albums/dpr-k-1-afc-test-2-crops

From the second set, I would consider IMGP2813, IMGP2814, IMGP2819, IMGP2821, IMGP2822 in focus. That's 5 out of 14 when we give K-1 a chance to actually focus on the face.

So I think the redo was worthwhile, don't you think?

Joey

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