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10-23-2015, 07:08 PM   #1
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Autofocus and the future. A theoretical discussion.

I read a LOT of threads here at pf, and while I don't chime in on most (I prefer lurking), I do notice that some topics just keep coming up. One of these is the mention of af points and af speed. I know that canon and nikon offer quite a few cross-type AF points, and yes I would agree that Pentax can be a little lacking on that. Pentax also gets mentioned for having slow AF compared to its competitors quite a bit. Given the sheer number of years that cameras have been around and the ever evolving and quickening rate of technological advancements, certain thoughts come to mind that it's about time for some changes to appear. Let us speculate a bit, even if nothing ever comes to pass, it can still be a bit fun to imagine the future.

Topics for discussion:

1.) Cross type AF points: It might just be time for a company to start coming out with something better. What do you think this could be (please try to be semi-detailed in examples and reasoning)? Would a new type bring more benefit? etc...

2.) Autofocus technology: Methods of weight reduction, friction reduction of moving parts, better motor/propulsion methods, etc...

First and foremost the goal is to have fun, but try to be realistic... like say things that could be done in the next 5 years or so. Second is to try to keep the conversations/posts limited within the scope of the presented topical points. Again, have fun, but don't stray too far. That being said, I'll start off with my projections below.

Projections:

1.) Cross AF points might be replaced with asterisk af points for even more accuracy and speed. Basically combining standard cross type af points with diagonal cross af points. The technology to do this should exist, but it is most likely cost prohibitive to implement. The question of whether it would have benefit or merit could be explored further.

2.)AF Technology could be advanced (and generally is) by materials research, making things like lens elements lighter. I think it would be possible to decrease af response time by floating certain components in a magnetic levitation field, however two downsides would be increased lens weight and potential cost. Another detractor to this method might also be decreased accuracy due to fluctuations in positioning DUE to the magnetic field flotation. A bit of a double edged sword but I believe successful experimentation/research could yield results within a year or so.

Please post your speculations. I look forward to reading them.

10-23-2015, 08:08 PM   #2
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There's really nothing special about Canon and Nikon's AF over Pentax. The differences are twofold:
1) The competitors offer better AF-C mode, Nikon especially.
2) The competitors have more focus points

Pre-K3, the focus points are quite large and this makes for some focus issues. My K-5 Mark IIs will miss my desired spot by a bit despite my putting the focus point right where I want--I suspect it's finding something nearby it likes better. That's one reason why the K3 is so much better--the focus points are smaller. If you listen to Canon users, they frequently complain about AF issues. Most of these users are with the entry level cameras with few focus points.
10-23-2015, 08:52 PM - 1 Like   #3
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Here is a link to a recent Ricoh patent which might be a pretty revolutionary development I think. ??SR????? ???????????????? - ?????? ????? ?? ???? ??. The translation to English leaves a lot to be desired, but it allows one to get a rough idea. A quote from the site (again, the translation isn't all that great, but provides some idea of what's involved):

"Ricoh's new patented concept is very easy way out, allowing the sensor to a position deviation obtained said before "projection data in different locations." In other words, the whole image sensors have become the focus when the phase difference AF sensor. In addition, the technology also significantly expand the area of ​​focus, in theory, almost the entire imaging area can be realized retardation focus."

Hoping (almost expecting) to see something revolutionary with the new full frame.

Daryl

Edit: Strangely, I see a bunch of question marks in the link, but the link still works (anyway on my machine).
10-24-2015, 02:46 AM   #4
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Some Nikon camera reviews/comparation affirm that when the same af module (i.e: MultiCam 4800 used in d7000 and d600) is mounted in APSC and FF , it works better with FF (in terms of accuracy and fastness). If true, This could be due to more light disposable in FF for sensor , so.. Perhaps we'll find a great improvement in AF performance in the new coming Pentax FF.

10-24-2015, 02:47 AM   #5
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An argument that is often made is that it's not the camera body, it's the lenses that most affect AF speed. And while I think that's true, I don't really think this lets Pentax of the hook. I mean, DSLRs are about the system, not the body, right? Pentax is at a disadvantage there already, because 3rd party lens makers don't make as many lenses for Pentax as they do for Canon/Nikon. So you have less choice in fast AF glass there too (in case of Tamron, the newest USD lenses are often not made for Pentax while older and slower lenses are). Pentax itself doesn't really offer many alternatives. There is the DA* line, which is the top of the line, so you would expect fast AF, but thanks to the SDM micromotors, that's really not the case. Even the screw-driven 55-300 focuses faster than the 60-250 on a modern body. Now there's DC, which is good for consumer lenses like the 18-135. But they put that into the 70-200 as well. The Canon/Nikon equivalents are just as expensive, but they have ring-type motors AND built-in stabilization.

So even if the latest Pentax DSLRs have fast AF algorithms, good sensors, etc etc etc it still won't make much of a difference. In fact, Pentax could already be there, and most of us won't notice.

Btw the Pentax K-3 has 25 cross-type AF points, which is better than e.g. a D7200. The Canon 7D II beats that, but not many other APS-C cameras do. So I can't see how Pentax is "behind" in that area. In fact, I'd say that if there's one area of autofocus where Pentax is not lacking, it's the number of cross-type AF-points. The K20D already had 9 of those, similar to the EOS 50D. Meanwhile, the Nikon D90 had only 1. Only with later models did they fall behind a bit (e.g. 9 on the K-5 II versus 15 on the D7100). But even that's no longer the case.

Last edited by starbase218; 10-24-2015 at 04:46 AM.
10-24-2015, 08:27 AM   #6
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This is not the kind of thread like "Pentax AF is a mess". We're just arguing what FF could bring us in this matter. I have quite good expectations. Consider that my camera is k5 and if FF will arrive soon at a reasonable price, I'll prefer upgrading to it than to k3.
10-24-2015, 12:16 PM   #7
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QuoteOriginally posted by bm75 Quote
Some Nikon camera reviews/comparation affirm that when the same af module (i.e: MultiCam 4800 used in d7000 and d600) is mounted in APSC and FF , it works better with FF (in terms of accuracy and fastness). If true, This could be due to more light disposable in FF for sensor , so.. Perhaps we'll find a great improvement in AF performance in the new coming Pentax FF.
The AF sensors are separate and never touch the sensor itself unless you're in live view.
10-24-2015, 01:19 PM   #8
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You're completely right. I know that . It's my fault in communication. I was just arguing if it's true that more light could involve a better AF performance (referred better performance of the same AF module on different Nikon bodies - APSC and FF). Could it be?

10-25-2015, 11:21 AM   #9
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Improving their lenses with DC motors would likely go a long way to catching Nikon and Canon.

Randy
10-30-2015, 05:06 AM   #10
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QuoteOriginally posted by Auzzie-Phoenix Quote
I know that canon and nikon offer quite a few cross-type AF points, and yes I would agree that Pentax can be a little lacking on that.
Except on high-end FF bodies, Pentax cameras often have more cross-type AF points. The K-3 has 25, the Nikon D7100 15. Both are excellent.

Nikon has the edge on tracking, and that's a software issue. The AF systems on modern Pentax cameras have no problem moving fast enough, just test the 16-85 (or even the new 18-50 RE) and you'll see
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