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Is PDAF still more superior over CDAF in AF Tracking?


sillbeers15

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I’ve review and analysed Richard Wong’s Panasonic Lumix S1 Autofocus Test vs Sony A7III (firmware 1.2) found on the following YouTube channel below.

http://www.youtube.com/watch?v=8k3a7LNe0Mw

The following are my thoughts:

In the video, the AF tracking in video was compared between Panasonic S1 & Sony A7RIII side by side in three video modes/scenarios comparison of 4K25 on both, 1080P60 on S1 vs 4K25 on A7RIII, 1080P60 on S1 vs 4K25 on A7RIII on external recording. In the first scenario, the S1 appear to react in and out of autofocus slower than A7RIII. In the last scenario, The S1 appear faster in AF tracking. 

If it were because PDAF is a more superior and faster AF methodology, then by reducing the image processing resolution and attached to an external recording device in the third scenario will not have improved the CDAF methodology focus tracking speed employed by S1 to become faster than Sony A7RIII recording at 4K25. Furthermore, Sony A7RIII employs a hybrid AF of PDAF&CDAF with CDAF focusing on fine adjustments after PDAF has delivered the course focusing job.

 

For Panasonic and Leica digital cameras, DFD algorithm is employed to identify the focusing direction and speed up the focusing speed to match the course focusing speed offered by PDAF methodology AF sensors.

 

I read and understand the results and cause of comparison as when the video resolution reduces the required processing, especially after an external recording device is added, the S1 AF received increased processing power to reduces calculation time and improves focusing speed. My conclusion is the processing power that determines the AF tracking capability rather than the type of AF detection system. So my final thoughts are PDAF are not more superior over CDAF in maintaining AF focus tracking of cameras but rather the level of processing power provided to drive the AF engine is the significant factor of success to a reliable AF tracking.

As this is a camera gear forum, I welcome challenging and alternative thoughts for discussion.

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There is no absolute measurement for AF speed. So I do not care which camera is “best”. (There is actually no best method for all occasions).

Instead I try to understand what a camera can do well enough, and try to adapt my methods accordingly. So in most situations I know how to get from the SL what I need. And in other cases I simply use another camera (e.g. Canon 5DsR). The newer cameras are probably faster, so I am sure that S1R or SL2 are fast enough for my needs.

Often for me it makes no sense to rely only on camera technology (I use tracking AF only in special circumstances). It’s rare that I get great photos when using tracking, usually it depends all on lucky coincidences and accordingly it produces mainly garbage that I have to sort out afterwards (quite boring) .

AF speed is always a point in time. It will be faster in a few months/years. And it was slower during the longest time of my photographic life. So how could I produce photos during the last years ?  (Ironic grin)

There are many articles about the different AF types. One of the most insightful was written by Roger Cicala from lensrentals. (Already 2-3 years ago ...)

Edited by caissa
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26 minutes ago, caissa said:

There is no absolute measurement for AF speed. So I do not care which camera is “best”. (There is actually no best method for all occasions).

Instead I try to understand what a camera can do well enough, and try to adapt my methods accordingly. So in most situations I know how to get from the SL what I need. And in other cases I simply use another camera (e.g. Canon 5DsR). The newer cameras are probably faster, so I am sure that S1R or SL2 are fast enough for my needs.

Often for me it makes no sense to rely only on camera technology (I use tracking AF only in special circumstances). It’s rare that I get great photos when using tracking, usually it depends all on lucky coincidences and accordingly it produces mainly garbage that I have to sort out afterwards (quite boring) .

AF speed is always a point in time. It will be faster in a few months/years. And it was slower during the longest time of my photographic life. So how could I produce photos during the last years ?

There are many articles about the different AF types. One of the most insightful was written by Roger Cicala from lensrentals. (Already 2-3 years ago ...)

Thanks for your thoughts caissa. Looks like you did not had good AF experience in the past. Like you said, technology and know how changes each day. So what we thought we know can be different in coming days. Yes, no AF system is perfect. Half of the success/failure with AF comes from user struggle on best suitable settings. 

In my write out, I just want to hear alternative views to my thoughts. I had the motivation to put up the article cause I keep hearing general comments that CDAF is useless, if only the AF is PDAF then all focusing woes will go away.

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No, you misunderstood. Tracking AF is a solution for a problem that I do not have.   The CD vs PD discussion is quite useless because each technology has its weaknesses and strengths. If tracking AF is not crucial for your methods of working (like for me), then CDAF is more precise and often preferable.

General comments are simply too general to be useful .....    🎃

Edited by caissa
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25 minutes ago, caissa said:

No, you misunderstood. Tracking AF is a solution for a problem that I do not have.   The CD vs PD discussion is quite useless because each technology has its weaknesses and strengths. If tracking AF is not crucial for your methods of working (like for me), then CDAF is more precise and often preferable.

General comments are simply too general to be useful .....    🎃

Just out of interest, why do you attribute AF tracking failure to CD if like you said CD is more precise than PD?

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  • 2 weeks later...

I tested the SL2 once again with several moving subjects.

AF is not still not good. Lots of missed focusing. Firmware is still not final though. We should wait the 21st for definitive conclusion.
Right now it is worst than Panasonic S1R. 
No eye AF, only face detect. You have to trust the camera for choosing the closest eye. 
 

In video mode it is just usable. But AF wobble will make the clip unattractive. It is an MF only video camera. 

I am quite pessimistic. Its still AF will never come close to Sony A7R III smart phase + contrast AF. 
And its video AF is nowhere near the excellent dual pixel AF of Canon. 


DFD is a dumb tech with no future.
You will see Panasonic and Leica featuring proudly phase + contrast hybrid AF in next gen S2R and SL3 
 

 

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On 11/12/2019 at 4:09 PM, nicci78 said:

I tested the SL2 once again with several moving subjects.

AF is not still not good. Lots of missed focusing. Firmware is still not final though. We should wait the 21st for definitive conclusion.
Right now it is worst than Panasonic S1R. 
No eye AF, only face detect. You have to trust the camera for choosing the closest eye. 
 

In video mode it is just usable. But AF wobble will make the clip unattractive. It is an MF only video camera. 

I am quite pessimistic. Its still AF will never come close to Sony A7R III smart phase + contrast AF. 
And its video AF is nowhere near the excellent dual pixel AF of Canon. 


DFD is a dumb tech with no future.
You will see Panasonic and Leica featuring proudly phase + contrast hybrid AF in next gen S2R and SL3 
 

 

I suppose you picked up the SL2 for a couple of minutes to draw your conclusion? Did you set all the AF and drive settings to make comparison? 

I did similar but do not want to conclude or share cause my short experience with the SL2 performed worst than my SL in AF tracking at times while better at others. I sense that something is not adding up right.

No offence to you but your experience has no credibility ( just as mine mentioned above) unless 100 to 200 shots of AF tracking trial has been performed to draw on a conclusion.

I’m waiting to get my SL2, mount on my familiar 90-280. Make sure I set all the camera settings myself and shoot at the scenes I’ve shot hundreds of shots on my SL on the same time of the day to compare before drawing my conclusion. 

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I used it for 3 hours first time. Then 45 min last time. But I will try it again tomorrow. 

But I am absolutely sure, that it is nothing near a Sony A9. No eye AF is a big hint that SL2 is not best in class. And several test shots were not tack sharp, due to not so good face detect. 

Anyway it is quite bad in video with wobbling. Nothing like Canon dual pixel AF. Funny thing, this AF tech from Canon, makes me pause and seriously think to buy Canon R instead. RF lenses are very nice, and their size did make sense. 

 

But guess what ? We do not buy Leica for its stellar AF. It's for the lenses. And right now there are only 4 reasonable SL lenses : the APO-Summicron-SL. The other 4 are totally silly in my mind. Way too big. If it were for the zooms Canon RF makes way better sense right now, because behemoth Lumix S and Sigma DG DN art lenses did not help at all. 

So should I invest in subpar AF tech body with only 4 native lenses to choose from ? Maybe yes for M and R lenses excellent compatibility. But is it enough ? I still like my tiny CL with quite small TL lenses. 

However SL2 is indeed the best AF cameras into the whole Leica lineup. I find CL AF totally usable. SL2 will be fine too. But it is in all honesty not good enough to beat Sony, not even Nikon, nor Canon. 

The real dealbreaker for me is still the weight and size of body and lenses. Way too high. 

 

 

 

 

Edited by nicci78
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7 hours ago, nicci78 said:

I used it for 3 hours first time. Then 45 min last time. But I will try it again tomorrow. 

But I am absolutely sure, that it is nothing near a Sony A9. No eye AF is a big hint that SL2 is not best in class. And several test shots were not tack sharp, due to not so good face detect. 

Anyway it is quite bad in video with wobbling. Nothing like Canon dual pixel AF. Funny thing, this AF tech from Canon, makes me pause and seriously think to buy Canon R instead. RF lenses are very nice, and their size did make sense. 

 

But guess what ? We do not buy Leica for its stellar AF. It's for the lenses. And right now there are only 4 reasonable SL lenses : the APO-Summicron-SL. The other 4 are totally silly in my mind. Way too big. If it were for the zooms Canon RF makes way better sense right now, because behemoth Lumix S and Sigma DG DN art lenses did not help at all. 

So should I invest in subpar AF tech body with only 4 native lenses to choose from ? Maybe yes for M and R lenses excellent compatibility. But is it enough ? I still like my tiny CL with quite small TL lenses. 

However SL2 is indeed the best AF cameras into the whole Leica lineup. I find CL AF totally usable. SL2 will be fine too. But it is in all honesty not good enough to beat Sony, not even Nikon, nor Canon. 

The real dealbreaker for me is still the weight and size of body and lenses. Way too high. 

 

 

 

 

I agree that the Sony A9II is the best in class in AF capability.

None of us have expectations that the SL2 AF beat or stay on par with A9II. 

We did not buy or were interested in the class leading AF capability.

What I am interested in is how well the AF tracking of the SL2 has improved over the SL now that there is a more powerful processor and more AF selection in sub menu plus four years of firmware development on AF since launch of SL. I am pretty certain things have improved on AF but question is ‘how much’ and ‘how reliable’. I always attribute half of the AF poor performance to the user. Either the settings are not optimised or just having too high expectations. Cause even on a 100% AF capability, the camera cannot read our mind like our eyes do.

Just try to reduce the drive speed if the AF tracking is not producing good hit rate. That will tell us if the AF calculation for tracking is too slow ( processor related) or the AF looses the target.

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Just wait for final firmware and final camera. 

Only prototypes with beta firmware are available for testing. Have to wait Thursday for real production models. But I am pretty sure, not to buy SL2 and stick with APS-C. Zoom lenses size are crazy and I am not ready to go this route. 

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It's funny (to me) that this "A9 is the best" thread came-out on the same day as this:

(The video uses humour to get a point across. This technique does not sit well with some people. Just think of it in the thousand+ year tradition of the court jester, the only person allowed to tell the truth to the monarch...)

 

So yes, A9 is "the best," as long as you only value speed, and you don't compare it to the EOS 1Dx or Nikon D5 (or the mid-tier SLRs from either brand). Unfortunately, that speed comes at the expense of ergonomics, colour, IQ, native lens quality, features, etc.

Ultimately, your choice will come down to personal requirements (real or perceived), and budget. There is no perfect camera, and you will always be able to find a feature that a camera doesn't have. Additionally, having "all the features," like the S1, doesn't necesarilly make a camera user-friendly.

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On 11/21/2019 at 11:03 PM, BernardC said:

It's funny (to me) that this "A9 is the best" thread came-out on the same day as this:

(The video uses humour to get a point across. This technique does not sit well with some people. Just think of it in the thousand+ year tradition of the court jester, the only person allowed to tell the truth to the monarch...)

 

So yes, A9 is "the best," as long as you only value speed, and you don't compare it to the EOS 1Dx or Nikon D5 (or the mid-tier SLRs from either brand). Unfortunately, that speed comes at the expense of ergonomics, colour, IQ, native lens quality, features, etc.

Ultimately, your choice will come down to personal requirements (real or perceived), and budget. There is no perfect camera, and you will always be able to find a feature that a camera doesn't have. Additionally, having "all the features," like the S1, doesn't necesarilly make a camera user-friendly.

+1. There isn’t and will never be a perfect camera as nothing can read and replace one’s eye + mind.

Edited by sillbeers15
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