Chill with the attitude man. What's up with that? Once you get all snarky, no one is going to listen. We both know that all too well.
Sorry, these responses from people who clearly haven't compared the systems side-by-side is just intolerable. At least I can engage in a conversation with you... (well, except that one time years ago
Now, you claim that Canon cameras cannot track in the "Z" axis (which I can only assume means within the depth of the scene, towards or away from the photographer), or track in Z while also tracking in X/Y (vertically and horizontally within the frame).
No no no I don't claim that at all. I would never
say the 5D3 isn't good at tracking in the Z-axis; in fact, it's phenomenal at it
. You got my statement priorities completely backwards in your statement. I'm talking about the 5D3's ability to automatically move the AF point in the X-Y planes to stick with your initial subject as you recompose
or the subject moves quickly & erratically in the X, Y, and Z planes
I disagree that it's literally impossible to do accurately with Canon. It may not be as good. I don't know exactly how good Nikon's 3D AF unit is, I haven't had enough time with a Nikon camera in specific use case scenarios to fully test it out. I am not denying it could be better.
It's not literally impossible. I never said that; at least I hope I didn't. And if I did, I meant that it's so inaccurate compared to what's available in the 1D X and Nikon pro-bodies that - to me - it's almost incapable in comparison
. My sincere apologies
if I implied it's literally
incapable. But I do believe I've said on many occasions that the 5D3 does have a mode that attempts
to do this; it just doesn't do it well.
Please, please do yourself a favor and go to a camera store & plop on a 24/1.4 or 35/1.4 and try 3D tracking on the D810. Initiate focus using the center (or whichever) point on the camera salesman's eye (yes, get up that close to him), and then move the camera around wildly recomposing. The camera will 'stick' to the eye so well you'll wonder if there's some trickery going on whereby the camera is using the accelerometer to figure out how to move the focus point (this is obviously not the case).
It'll be so good that your entire perspective on distance + 2D AF tracking across the frame will completely change, and then you might understand why I feel that the 5D3's 'ability' is so poor next to the competition in this regard that you may as well call it 'incapable' in this respect
. And that it literally doesn't have the hardware necessary to track as accurately as what the other systems offer. The 1D X will do this sort of tracking as well, but is more prone to losing the subject in all my tests than the system Nikon's honed for years and years. And that, of course, shouldn't be surprising as it's 1st-generation tech for Canon.
That's not to say the 5D3's AF system is bad. I started this conversation b/c someone made a blanket comment that the 5D3 clearly has a superior AF system to the D800. And for certain types of shooting, that's just demonstrably wrong. Why that's so hard for people here to believe is astounding.
And one of the reasons I'm being rather passionate about this discussion is b/c I kept my 5D3 for years b/c I also believed that there wasn't a camera capable of better AF out there. Part of that belief was being mislead by people making erroneous claims just like the one above about Canon AF undoubtedly being better. You might say I'm just allergic to this sort of misinformation.
It's more complicated than what some would lead you to believe. I pointed out where the 5D3 is better (cross-type AF, high sensitivity wider-baseline AF points in the center) and where it's worse (3D AF/iTR). And boom
that was it. B/c of that one thing that I claimed that Nikon can do better (as well as the 1D X, just not quite as well), I was attacked for obviously being wrong, should RTFM, etc. etc. uninformed opinion, etc. etc. BS from people who - even up until now - haven't even once answered my question 'Have you used
iTR or 3D AF tracking, ever, to so authoritatively claim I'm wrong?' Or, for that matter, tried subject tracking on a mirrorless ILC (not overall focus performance, just the ability for that on-screen box to move around & stick to your original subject)?
Because obviously there's no way any of these guys might have missed something all these years having shot Canon, right? I mean all of us here know everything, right? RIGHT??
Which is why I say that confirmation bias
runs rampant on these forms.
I am specifically disputing your claim that Canon cameras (with the exception of the 1D X, although you allude even it cannot do it, despite iTR metering) "literally doesn't have the hardware to accurately follow subjects *around the frame* accurately."
No, I never
said the 1D X can't do it, despite iTR metering. I said it doesn't do it as well as Nikon's system, which should be no surprise as Nikon has iterated this system through many generations over years and years, and this is 1st generation tech for Canon. And by that I mean the 1D X is more prone to losing the subject or getting confused. It's still very good compared to the 5D3, which itself has iterated its algorithms over years and years to use depth information to stick to a subject as it moves across the frame.
But how good can that possibly be? Think about it: the center point of the AF system detects a subject 10ft away, then you recompose, then the camera notices a subject 10ft away is now over the left-most AF point, and meanwhile there's now nothing at 10ft away at the center point. Therefore, the camera decides your subject has moved (or you've recomposed such that the subject is now at) the left-most AF point. But what if your subject moved to 9ft away during this time as well? Well, with some clever algorithms you could analyze all the focus points and see if there was some progression of a subject like this (I've assigned letters to specific focus points for ease of discussion):
- Subject in center point (C) 10ft away
- Center point C no longer detects anything at 10ft, but the point just to its right (D) has a subject at 9.8ft
- Point D no longer detects a subject at 9.8ft, but the point to its right (E) detects a subject at 9.5ft.
- Point E no longer detects a subject at 9.5ft, but a point 6 points to the left (F) now detects a subject at 9.2ft.
... and so on and so forth.
Are you starting to see how incredibly complex this can get, and how prone to failure this might be if the subject is moving like this in 3-axes and/or the movement is convoluted with you recomposing? Or another subject entering the frame at a similar depth?
Are you starting to see how using an image sensor (Sony SLT, or all mirrorless ILCs really), or a color sensor with some finite resolution to recognize color patterns (enough to detect a face, which we know RGB sensors can do given their face-detection ability) that communicates with the PDAF sensor might have the potential to perform significantly
Canon cameras ARE capable of tracking in Z, or tracking in Z while the subject is also moving around in the frame. That's what I'm saying, that's what everyone else is saying, and it's been possible since at least the 7D, since I've tracked rather erratic birds flying directly at me (i.e. in the z-axis) with the 7D.
Funny, b/c that's what I've been saying too. Of course it can track in the Z-axis well; that's the whole point of phase detection! At the risk of sounding like a broken record, the 5D3/7D just can't accurately track that subject in the X-Y plane of your frame as well as a camera with an accessory color/image sensor that has the ability to recognize a subject based on an actual, albeit low-resolution, RGB image.
Now, you have re-qualified you statements to specifically refer to close subjects with wide angle lenses.
I only said that b/c there can be a lot of focus plane shift from recomposing using wide-angle lenses, and subjects can drastically change distance and fall out of the acceptable DOF zone. Combine this with movement across the X-Y plane and you're really, really stressing an AF system that can only track subjects based off of analyzing distance information from 61 (or worse, 19) AF points.
Let me try to explain with some numbers:
Your DOF at 35/1.4 for a subject 1m away is 6.4cm. At 2m it's 26cm. Either way, it's small. Your DOF at 200/2.8 for a football player running towards you from 30m away is nearly 4 meters. Now do my thought experiment above for each of those cases. For one, you have more tolerance for error in tracking b/c your football player is not going to fall out of your DOF zone in a fraction of a second. Second, if others enter the frame near this runner - as is typically the case with sports - even if this subject confuses the AF system, it's quite likely it won't affect the perceived focus (b/c they'll both be in a similar plane within the tolerable DOF).
Because using AF tracking to allow the camera to automatically select the AF point to stick to my moving subjects at 24/1.4 or 35/1.4 or even 85/1.2 was so unreliable in practice - in critical scenarios like weddings where you can't afford to have the camera wildly missing focus during the action - I'd resort to selecting my AF point, and then allowing the camera to track (AI servo) along the Z-depth axis only - which it does/did remarkably well. But that constrained me to keep the subject under the selected AF point during the action, which constrained my composition.
My point is that with iTR and 3D AF, you can often actually trust the camera to use the correct AF point after you've initially identified the subject - which allows you to decouple the composition & subject movement from focus.
I honestly don't think messing around with a camera in a store is going to prove the case either...however renting a D810 would be sufficient to let me explore their 3D AF in totality.
It's actually so obvious that I bet you a nickel a trip to the camera store is all you need to get an initial idea of what I'm talking about.
On the other hand, full tracking of subjects at longer focal lengths, including those moving at you in the z-axis (as has often been seen with basketball and soccer photos...where the player with the ball is moving down the field, dodging oncoming opponents), has been done quite frequently. And before the 1D X...I remember there being a lot of talk about how much that improved with the 1D IV, and I remember reading a couple of articles comparing the 1D IV to Nikon cameras in exactly that use case scenario (I can go digging for them, but that was a number of years ago now...) Neither camera performed poorly...although I remember the reviewers having specific complaints about BOTH AF systems in those use cases.
I KNOW that Canon does gather enough information to perform the necessary z-axis tracking analysis.
Again, you have no argument from me here on this. You seem to have completely misinterpreted what I've been writing!
I don't think a full RGB metering sensor is essential for z-axis tracking, even of erratic subjects. It's probably BETTER, Canon clearly states that iTR enhances the tracking abilities of the 1D X AF system.
Er, which is essentially what I've been trying to say all this time. I really wish people actually read and digested what others right, rather than just seeing 'Nikon' and being like 'SQUIRREL!' and jumping behind their barracks ready to assume the defensive apologist attitude and the offensive RTFM/user-error/you-can't-possibly-be-right-b/c-that'd-mean-I've-been-wrong-all-this-time attitude.
And for the record...I always want better. I am very interested in seeing what Canon does when they link their full sized image sensor into the AF system. That could give them the ability to gather pre-frame information via the iTR, as well as full-frame information during the following exposure via DPAF...THAT has me rather intrigued.
Yes, I firmly believe DPAF might revolutionize AF. For reasons that are too lengthy to go into here/now.