There will be no mirrorless camera body announced ahead of Photokina

[neuroanatomist]

Both off- and on-sensor PDAF know direction.

Water is wet.

(Just going with your idea of posting something that no one is arguing with, or is it just that your history of making outrageously false statements has finally sunk in, and you're desperate to state something that's actually correct?)

 

[neuroanatomist]

From what I am led to believe, the difference between systems is that DPAF can tell which direction you are out of focus, while the AF module in a mirrored camera can tell how far you are out of focus..... this gives two different methods for achieving focus....

With DPAF, you keep moving the lens element until you get focus, and then you stop. There may be a slight overshoot and you may have to reverse direction and return a few steps...
.

Both DPAF and dedicated PDAF are phase detect, which means both systems provide data on the out-of-focus direction (as you correctly stated) and magnitute (about which you were incorrect for DPAF).

 

[Don Haines]

The camera doesn't drive the lenses with different commands or voltage when one switches from off sensor to on sensor. A USM lens may struggle to do the back-and-forth of CDAF as readily as a STM lens, but that doesn't really play in phase detect, where the distance is known by the spacing between where rays intersect the linepair.

While the lens electronics don't change, the AF system does. Occam's razor, my man. It's obviously not a sound deductive method, but in this case the simplest solution, that on-sensor AF is different from off-sensor AF, is also predictable by the nature of the sensors used. Forget their size, spacing, etc, and just consider the filters in front of the image sensor. In order to re-construct color, every pixel has bandpass filters which only allow through a narrow band of the spectrum (reg, green, or blue). Off-sensor AF doesn't have a color filter array; they see the entire spectrum and thus have significantly more light to work with.



Both off- and on-sensor PDAF know direction.

My bad....

I should have said that one only knows the direction, while the other knows the direction and how far..... if you are (for example) 87 AF units out on a lens with 500 units of range, you move 87 units, check focus, and (if necessary) move again..... or, if you don’t know how far you have to move, you guess and it might end up looking like this... move 100, check focus, back 10, check focus, back 2, check focus, back 1, check focus

 

[neuroanatomist]

My bad....

I should have said that one only knows the direction, while the other knows the direction and how far.....

Nope. As I said above, both DPAF and dedicated PDAF know direction and magnitude. As Canon states:

The result is phase-detection autofocus, which surveys the scene and recognizes not only whether a subject is in focus or not, but in which direction (near or far), and by how much.

 

[Kit.]

According to Nikon's engineering managers' interview, Nikon could only make a combination of PDAF and CDAF work for lenses that could perform a fast "stop now" command. So, for Nikon, it was a camera-lens interface issue that did not allow them to support PDAF+CDAF combo on F-mount AF lenses (with the adapter, Nikon only supports PDAF).

Still (in my point of view), it might be possible to make a PDAF+CDAF combo working in a predictive way, maybe Nikon just had no time to finish it and will add it in later camera firmware updates.

 

[Don Haines]

Nope. As I said above, both DPAF and dedicated PDAF know direction and magnitude. As Canon states:

One of the things I like about the forum is that one is continuously learning.....

Thanks Neuro!

 

[jeffa4444]

I can’t help but feel the whole buildup for canon’s FF mirorless will be possibly even worse than Nikon. Given that Nikon are generally a lot more generous with features compared to canon (take D850 vs 5D iv/5dsr for example), canon is surely going to cripple theirs in quite a few ways compared to the ‘gold standard of specs’ Sony A7III.

In worst case scenario I’d personally predict no ibis, no full frame 4K or no dpaf in 4K (or both), no dual card slots, no on sensor adc, no eye af, no tilty or flippy screen. Sadly deep down many of us know this could in fact be the reality, even if they perfect ergonomics, menu systems and skin tones as always.

Yet, if it had a native EF Mount it would probably still manage to become the best selling ff mirorless, just because it’s canon.

Canon in the rental market are at a ratio of 4-1 to Nikon in London yet people like you would have us believe the 5DS /r is inferior to the D850, the opposite is true. Images speak not specification sheets. Oh and the Sony A7III is no where to be seen in the rental market of significance.

 

[3kramd5]

According to Nikon's engineering managers' interview, Nikon could only make a combination of PDAF and CDAF work for lenses that could perform a fast "stop now" command. So, for Nikon, it was a camera-lens interface issue that did not allow them to support PDAF+CDAF combo on F-mount AF lenses (with the adapter, Nikon only supports PDAF).

Still (in my point of view), it might be possible to make a PDAF+CDAF combo working in a predictive way, maybe Nikon just had no time to finish it and will add it in later camera firmware updates.

That’s the common condition. PDAF, since magnitude is known, invites lenses which move and stop very quickly. Those lenses typically don’t iterate (by changing direction) well, which is required for CDAF.

It is possible that canon’s DPAF systems in some situations use a CDAF step, though none of their tech papers talk to it.

 

[fullstop]

That’s the common condition. PDAF, since magnitude is known, invites lenses which move and stop very quickly. Those lenses typically don’t iterate (by changing direction) well, which is required for CDAF.

It is possible that canon’s DPAF systems in some situations use a CDAF step, though none of their tech papers talk to it.

that's why I am of the opinion that (lower) PDAF performance is (also) "an EF lens issue", not only a "camera body issue". I remain convinced that (almost all) EF lenses will not AF perform as well on future mirrorfree cameras compared to new, "designed for DP-AF" glass.

 

[3kramd5]

I remain convinced that (almost all) EF lenses will not AF perform as well on future mirrorfree cameras compared to new, "designed for DP-AF" glass.

I think it’s quite likely that in general new lenses will work better than old lenses with new cameras. Few if anyone would argue a contrary position.

The problem lies it trying to quantify it by using one lens and body in comparing off-sensor AF to on-sensor AF; you’re evaluating the wrong variable.

To reveal a difference associated with lens type, start by comparing two different lenses (same element mass if possible but different drive system) on one camera in one AF mode (DPAF in this case).

 

[Mikehit]

that's why I am of the opinion that (lower) PDAF performance is (also) "an EF lens issue", not only a "camera body issue". I remain convinced that (almost all) EF lenses will not AF perform as well on future mirrorfree cameras compared to new, "designed for DP-AF" glass.

A lot of lenses have had a refresh in the last 2-3 years. Others have reasonably pondered that Canon have built in as-yet-unrecognised software updates specifically to work with mirrorless capabilities.

 

[Kit.]

that's why I am of the opinion that (lower) PDAF performance is (also) "an EF lens issue", not only a "camera body issue". I remain convinced that (almost all) EF lenses will not AF perform as well on future mirrorfree cameras compared to new, "designed for DP-AF" glass.

Then, not for "DP-AF", but for "CD-AF".

Canon uses CDAF in EF bodies since 2007 (40D, then 5DII), so quite a lot of lenses must be already adapted to it, especially considering that it can be added to the lens with just a firmware update and doesn't even need a formal model refresh.

Besides, my loveliest Canon lens (17 TS-E) doesn't care about your body's autofocus.

 

[fullstop]

I think it’s quite likely that in general new lenses will work better than old lenses with new cameras. Few if anyone would argue a contrary position.

well, lots of folk here argue against me exactly on that point. When I say, EF lenses will be LEGACY on any new mirrorfree Canon camera, irrespective of mount decision, because of lower AF performance and communication-based performance compared to new native lenses. It will affect majority of EF lenses, except STM and possibly Nano USM and hopefully most recent updates. Not sure, whether many of the older ones can get suitable firmware updates.

If I look at EF Lenses like EF 50/1.4 and others that are not even able to communicate focus distance back to camera body .. those will look ... "very legacy".
EF 50/1.4 AF does not work very well AF-wise when adapted to EOS M cameras - no matter whether DP-AF or previous "Hybrid AF".

 

[rrcphoto]

@ekramd5
(almost all) EF lenses entire AF drive system - hardware and firmware/control logic is not designed/built for OS PDAF, including DP-AF (live view/mirrorfree) operation.

you're kind of wrong here.
DPAF sensors don't do CDAF, and phase detect is phase detection whether it be from the main sensor or a secondary AF sensor. Do you have ANY clue to what you are talking about? at all?

 

[3kramd5]

well, lots of folk here argue against me exactly on that point. When I say, EF lenses will be LEGACY on any new mirrorfree Canon camera, irrespective of mount decision, because of lower AF performance and communication-based performance compared to new native lenses.

I think I’ve engaged on this before, and as I recall (could be wrong) there was a context of on- versus off-sensor AF (as in this thread). I’ve argued (or intended to do so) to not conflate performance of “legacy lenses” versus “new lenses” with “legacy PDAF” versus DPAF.

It’s entirely possible and in some cases likely legacy lenses on legacy PDAF will outperform new lenses on DPAF. That’s the bit I don’t want missed in this discussion.

you're kind of wrong here.
DPAF sensors don't do CDAF

Do we know that for certain? Other image sensor-based PDAF cameras typically start with phase and finish with contrast. I’ve not seen an indication Canon does so with DPAF cameras, but also haven’t seen a conclusive source.

 

[fullstop]

Besides, my loveliest Canon lens (17 TS-E) doesn't care about your body's autofocus.

you know what: my lovely cameras don't care about your tilt-shift.

 

[fullstop]

It’s entirely possible and in some cases likely legacy lenses on legacy PDAF will outperform new lenses on DPAF. That’s the bit I don’t want missed in this discussion.

Possible yes. But I don't expect this to be the case. Mirrorfree high-fps cameras will (hopefully!) also get adequately hi-performance AF systems.In combination with new native lenses "designed to fully utilize and support this AF system" they should well exceed anything possible in terms of AF in a DSLR with detached Phase-AF. But ... we shall see. Sony A9 with native FE lenses does not seem to be much behind - if at all - in AF performance compared to Canon 1DX II with EF lenses in "detached Phase-AF" mode [viewfinder operation] ...

Whereas first reports on Nikon Z6/Z7 seem to indicate that AF performance with native z-lenses is not fully on par with Nikon F-lenses on Nikon DSLRs in viewfinder mode [detached phase-AF]. Dyed in the wool Nik-apologists are quick to point out however, that AF performance may be hampered by "half-baked, early firmware/software" and hope for improved AF performance with future firmware updates.

 

[Kit.]

you know what: my lovely cameras don't care about your tilt-shift.

And my.... oh, I've just realized that an external battery-powered HDMI monitor with focus peaking can be bought extremely cheap compared to the rest of my gear.

Thank you very much.

 

[fullstop]

And my.... oh, I've just realized that an external battery-powered HDMI monitor with focus peaking can be bought extremely cheap compared to the rest of my gear.

Thank you very much.

well, happy slapping with your nice and compact gear set then.

 

[Kit.]

well, happy slapping with your nice and compact gear set then.

I'd say as long as it fits a cabin size backpack, it's compact.