[camyum]

...I never found a technique that helped me feel comfortable using two buttons instead of one...

thats a good point.

[FantasticMrFox]

thats a good point.

It's not like we have five fingers per hand, including an opposable thumb, and when holding a DSLR at the grip the thumb is pretty much resting on or right next to the AF button anyway

[normhead]

It's not like we have five fingers per hand, including an opposable thumb, and when holding a DSLR at the grip the thumb is pretty much resting on or right next to the AF button anyway

Way too often I am manually focusing with the right hand and holding the camera with the other. I'm totally used to my thumb bearing the weight of the camera as part of my grip. Trying to make it control focus while doing that would be difficult. Especially with my 6 pound Tammy 300 2.8.

@Normhead With back-button AF you can use AF-C 100% of the time.

Since AF.c slows your frame rate and initial focus lock, how would that be an advantage?

But give me an exact modus operandi and I'll try it out.

Did you guys read the part on IR where it mention using tracking slows your initial focus lock to .25s with a 1sx, much slower on most camera as opposed to a K-1's .9, less than 1/10 of a second? For many shots AF.s is simply faster than AF.c unless you are actually shooting a bird in flight. Then even Pentax tracking is a the way to go. If you do that a lot, you should probably shoot something other than Pentax. I've done it twice this year, am one of those to demonstrate to someone how it worked.

The absolute first considered point of reference for me, is eliminating shutter lag. Pentax AF.s is pretty much top notch for that, and when I say that I'm including all brands' AF.c with tracking enabled in the mix.

[biz-engineer]

I have no idea why, it just never felt right.

Same for me, unless training to get used to it, back button AF requires additional attention, I just prefer to have AF done via the shutter button.

Since AF.c slows your frame rate and initial focus lock, how would that be an advantage?

I think, the back button AF is not only for AF.c, also works with AF.s. Using the back button AF allow to disconnect AF from shutter release, which means, for example in low light, you can focus with the back button AF and even if it is too dark for AFs lock, you can still take the shot by pressing the shutter button and your shot will be in focus. You can use the back button AF to prefocus, than you don't need to keep your finger on the shutter button, and when you press the shutter button the lens is already prefocused where you want it to be (lag = 0). You can also use the AF back button to inhibit focusing of the shutter button. Using AF.s with the shutter button, the lag is very short (as you say), but if you program the back button AF for focusing, then the lag for shooting bursts is even shorter, it's immediate. Typically, I used that for photographing a kingfisher; this guy either does not stops or he lands on a perch above water, but he only stay for a very short time, he may take off immediately. So, I use the back button AF to prefocus on the perch, and when the kingfisher lands on the perch, I fire a burst to catch the moment.

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Last edited by biz-engineer; 05-21-2017 at 11:32 AM.

[normhead]

Same for me, unless training to get used to it, back button AF requires additional attention, I just prefer to have AF done via the shutter button.


I think, the back button AF is not only for AF.c, also works with AF.s. Using the back button AF allow to disconnect AF from shutter release, which means, for example in low light, you can focus with the back button AF and even if it is too dark for AFs lock, you can still take the shot by pressing the shutter button and your shot will be in focus. You can use the back button AF to prefocus, than you don't need to keep your finger on the shutter button, and when you press the shutter button the lens is already prefocused where you want it to be (lag = 0). You can also use the AF back button to inhibit focusing of the shutter button. Using AF.s with the shutter button, the lag is very short (as you say), but if you program the back button AF for focusing, then the lag for shooting bursts is even shorter, it's immediate. Typically, I used that for photographing a kingfisher; this guy either does not stops or he lands on a perch above water, but he only stay for a very short time, he may take off immediately. So, I use the back button AF to prefocus on the perch, and when the kingfisher lands on the perch, I fire a burst to catch the moment.

And my method is to focus on the branch, lift my wings off the button with the camera set to first frame focus priority. Without trying it, just by the numbers, my method would be faster.

[biz-engineer]

Without trying it, just by the numbers, my method would be faster.

No, because when you'll press the shutter button again, even if the lens is already prefocused, you'll still need to have AF lock done in AFS because the camera release the shutter. When using back AF only mode, when you press the shutter the camera takes the shot.

[normhead]

No, because when you'll press the shutter button again, even if the lens is already prefocused, you'll still need to have AF lock done in AFS because the camera release the shutter. When using back AF only mode, when you press the shutter the camera takes the shot.

I assume that with a prefocus imaged Pentax AF is fastest, that's what the IR results say, at least in my interpretation. Prefocus and press the shutter release and Pentax is fastest. After all, it is a test of AF, not of how fast the shutter can fire.

[BrianR]

I assume that with a prefocus imaged Pentax AF is fastest, that's what the IR results say, at least in my interpretation.

None of them directly apply to Back Button Focus in any AF mode that I can see, so I don't see how you can compare. I'd take a guess that the shutter lag you'd get would close to the lag for MF. Just a guess, but it doesn't seem to me that it activates the AF routine if you are setup for BBF but keep your finger off the AF button when you hit the shutter (this is how I usually prefocus, and probably pretty standard for BBF users).

In any case, it's worth pointing out that the canon 1dx user who couples the focusing with the shutter button can hold the half press after prefocusing and eliminate the shutter release lag penalty compared to the k1. Also kinda interesting is that pre-focused in liveview (holding shutter half-pressed), the 1dx wallops the k1. The pre-focused liveview 1dx is even faster (by an amount that's probably irrelevant to most uses) than the pre-focused optical viewfinder k1. Kinda impressive, and I think this would make LiveView less annoying (only applies to pre-focused, the lag for either AF mode would still be annoying).

[normhead]

None of them directly apply to Back Button Focus in any AF mode that I can see, so I don't see how you can compare. I'd take a guess that the shutter lag you'd get would close to the lag for MF. Just a guess, but it doesn't seem to me that it activates the AF routine if you are setup for BBF but keep your finger off the AF button when you hit the shutter (this is how I usually prefocus, and probably pretty standard for BBF users).

In any case, it's worth pointing out that the canon 1dx user who couples the focusing with the shutter button can hold the half press after prefocusing and eliminate the shutter release lag penalty compared to the k1. Also kinda interesting is that pre-focused in liveview (holding shutter half-pressed), the 1dx wallops the k1. The pre-focused liveview 1dx is even faster (by an amount that's probably irrelevant to most uses) than the pre-focused optical viewfinder k1. Kinda impressive, and I think this would make LiveView less annoying (only applies to pre-focused, the lag for either AF mode would still be annoying).

Do you have even a shred of evidence to support what you're saying? Keep in mind, I shoot beside guys with 1Dxs quite often. Don't be trying to BS me here. What I'm saying is, quite often, if i'm prefocused, my burst starts first. In real life, out in the field. What you might be talking about I have no idea. If there is some 1DX advantage, it's not enough to make up for a fast trigger finger, IMHO.

[BrianR]

Do you have even a shred of evidence to support what you're saying?

What I've said about the 1dx is straight from the Imaging Resources test you keep going on about:

Canon 1DX Review: Initial Test - Performance

See the "prefocused" line. See also the Live View section.

For reference, the K-1 page is here:

Pentax K-1 Review - Performance

It's not that complicated.


What I've said about the lag time with BBF was a guess, I was clear about that. The lag is pretty much non-detectable to me shooting with BBF and my k5iis. So even if it fell under the worst case of the IR tests for the k5iis, I'm confident that it's by far not the slowest piece of the puzzle (that would be me and my finger).

[normhead]

See the "prefocused" line. See also the Live View section.

We've been through this before.

The image may be prefocused, but with AF.s the camera is going to check the focus before it fires the shutter. That's why the test is called the AF test. It's a test of the AF system that doesn't rely on lens speed. Just how fast the AF system can check focus and release the shutter. You can continue to believe there is n test of the AF system involved, and I will continue to disagree.

I prefocus all the time. All I care about is how fast I get my shot off after I press the shutter release, because I am often responding to a specific situation.
So that's my routine, prefocus, shoot when appropriate. I just don't understand how you can continue say this test doesn't accurately portray what I do. IN fact if tests exactly what I do, and Pentax in AF.s is faster than anyone using a tracking algorithm and AF.c .

You can think what you want, but that's my take, and my experience in the field. I don't rely on semantical arguments or possibly misunderstood test interpretations to make up my mind on these things. As I said in my post. After noticing multiple times that I often fired the first shot in a volley of shots taken by a group of photographers, I started looking for something that would explain that. If you have some different experience and can explain that some other way, have at her. I am younger than a lot older than most of these guys, my reflexes are probably a lot slower, so that's pretty much one explanation eliminated. What do you have?

From the Article you posted

Full Autofocus
Single Point (center) AF 0.129 second - Time from fully pressing shutter button to image capture. All AF timing measured with Sigma 70mm f/2.8 Macro lens.

They are measuring AF timing.

1Dx Full Autofocus 61-point Auto Selection AF - 0.221 second -

K-3II
Full AutofocusSingle Area AF (Center AF point)- 0.140 second - Time from fully pressing shutter button to image capture. (All AF timing measured with Pentax 35mm f/2.8 Limited lens).

IR says they are testing AF, you say they aren't.

When talking my method of taking the images beside a 1Dx shooter using the 61 point array and tracking, my K-3 will outperform the 1Dx.

You can argue all you want about this not being a test of AF, but you should seriously consider the possibility you might be wrong.

This is clearly not a test of MF or Prefocussed there are other tests for those categories, this is a test of the AF system, where it doesn't have to move the lens, taking out the variable presented by different ways of powering the AF motor. This is a pure test of how fast the camera's AF system can confirm focus and shoot.

By far the most interesting point to me its that all these 1Dx shooters could be faster than me by shooting single point AF.s but none of them seems to have figured that out. They re so enamoured with their tracking system they cripple their camera.

[BrianR]

You can continue to believe there is n test of the AF system involved, and I will continue to disagree.

No, I never said ANYTHING of the sort (quick edit- on a second read, I don't know what you're trying to say, some typos in there that I might have misread), in fact I said the complete opposite from the first time you brought this test up:

Slow Pentax AF.... ha, eat my shorts - PentaxForums.com

I just don't understand how you can continue say this test doesn't accurately portray what I do.

I also never said this AT ALL. I've said what you do is odd, and not the normal method of prefocusing as I've ever read it explained, which would involve focusing on the thing, then holding the half-press (i.e. the "Prefocused" line of your IR tests), or switching to manual focus. Under these conditions, the K-1 is not faster than the 1Dx. And an edit - to be clear, under the corner case that you live in, yes, the K-1 responds faster than the 1Dx, I've NEVER disputed that line of the IR tests.

I don't rely on semantical arguments or misunderstood test interpretations to make up my mind on these things. As I said in my post. After noticing multiple times that I often fired the first shot in a volley of shots taken by a group of photographers, I started looking for something that would explain that. If you have some different experience and can explain that some other way, have at her. I am younger than a lot older than most of these guys, my reflexes are probably a lot slower, so that's pretty much one explanation eliminated. What do you have?

Dunno, they aren't ready? You're better at predicting the action? You're firing your burst before the action peaks? They aren't using their cameras in an optimal way? All sorts of variables that are utterly out of control if you hope this to be a comparison of two camera systems.

---------- Post added 05-21-17 at 09:22 PM ----------

This is clearly not a test of MF or Prefocussed,

They have a "Manual Focus" line:

"For most cameras, shutter lag is less in manual focus than autofocus, but usually not as fast as when the camera is "prefocused"."

and a "Prefocused" line:

"Time to capture, after half-pressing and holding shutter button."

So yes, it is included.

...this is a test of the AF system, where it doesn't have to move the lens, taking out the variable presented by different ways of powering the AF motor. This is a pure test of how fast the camera's AF system can confirm focus and shoot.

And again, I was one of the people who pointed this out to you:

Slow Pentax AF.... ha, eat my shorts - PentaxForums.com

[normhead]

I also never said this AT ALL. I've said what you do is odd, and not the normal method of prefocusing as I've ever read it explained, which would involve focusing on the thing, then holding the half-press (i.e. the "Prefocused" line of your IR tests), or switching to manual focus. Under these conditions, the K-1 is not faster than the 1Dx. And an edit - to be clear, under the corner case that you live in, yes, the K-1 responds faster than the 1Dx, I've NEVER disputed that line of the IR tests.

BrainR, your personal that my shooting style may be "odd'" is completely aggressive, and uncalled for, judgemental and undocumented and inappropriate to the thread. You've essentially dismissed my point by using an intellectual mis-direct. Please, don't do that again.

And again, I was one of the people who pointed this out to you:

Absolutely incorrect. That was my take from the beginning. Unless you imply that somehow you pointed out what I already knew. It amazes me how often this happens to you. You think you've told me something new and continue to believe it until as now, I'm forced to tell you how it really was. I can understand telling me something you understood and thought was special, but your assumption you're telling me something i don't already know is way off base. I knew you didn't understand that in the referred to discussion. I chose to let it go.

It basically astounds me how many times I refer to article, and people assume I have read or have misinterpreted the article. And they are always so sure I am mis-enterpretting things, not themselves. Such is life.

I explain it, post images, explain myself as thoroughly as I can, and you always seem to think I've missed something. So let's just get it out of the way. There is nothing "odd" about not using the AF button, or locking focus, then lifting your finger and waiting for the perfect moment. Lots of people do it. What's odd is your labelling of such a practice as odd. Just because you don't do it, doesn't make it odd.

[BrianR]

BrainR, your personal take on how appropriate my shooting style may be "odd'" is completely aggressive, and uncalled for, judgemental and undocumented and inappropriate to the thread. You've essentially dismissed my point by using an intellectual mis-direct. Please, don't do that again.

My apologies if you took this in an offensive way, it was not my intent. I don't generally mean 'odd' to mean a bad thing, eg. I typically equate 'odd people' with 'interesting people'. Call it "different" or "unique" if you prefer.

What you've described is not how anyone I know shoots when prefocusing, and I have filed it away as something to keep in mind if I ever come up for a use case for it.

Absolutely incorrect. That was my take from the beginning. Unless you imply that somehow you pointed out what I already knew. It amazes me how often this happens to you. You think you've told me something new and continue to believe it until as now, I'm forced to tell you how it really was. I can understand telling me something you understood and thought was special, but your assumption you're telling me something i don't already know is way off base. I knew you didn't understand that in the referred to discussion. I chose to let it go..

That thread speaks for itself.

I'm done in this one, have a good night.

[normhead]

My apologies if you took this in an offensive way, it was not my intent. I don't generally mean 'odd' to mean a bad thing, eg. I typically equate 'odd people' with 'interesting people'. Call it "different" or "unique" if you prefer.

What you've described is not how anyone I know shoots when prefocusing, and I have filed it away as something to keep in mind if I ever come up for a use case for it.



That thread speaks for itself.

Exactly, it just doesn't say what you think it does. Thanks for offering your interpretation.