September 18, 2014, 09:50:34 PM

Author Topic: EOS-1D X, Dual Back Button AF  (Read 5162 times)

Steve Todd

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Re: EOS-1D X, Dual Back Button AF
« Reply #15 on: March 22, 2014, 11:57:26 AM »
Thanks Viggo for helping Sanj to understand how the method I described works through your great example!  I'd hoped my original post had explained the process.  However, I guess I could have done a better job of explaining it.  That's what happens when you try to describe your thoughts on a technical subject...you know what you want to say, but your explanation doesn't adequately convey your thoughts to others.  Thanks again!  And happy shooting!
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Re: EOS-1D X, Dual Back Button AF
« Reply #15 on: March 22, 2014, 11:57:26 AM »

Northstar

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Re: EOS-1D X, Dual Back Button AF
« Reply #16 on: March 22, 2014, 12:42:39 PM »
Thanks for all the replies. The penny still fails to drop. It will one day, I hope. Currently either I do not know something or brain cells not working.
Perhaps soon I will have an 'ah ha' moment. Waiting.

sanj....you wrote "either i don't know something or"...could it be that you don't know that one shot is better(sharper)than servo for "non action" shots?   I'm sure you know this but I just thought i would point it out just in case. (i'm sure you do know because i've seen your awesome images)

the main reason for wanting the set up steve describes is to quickly and more easily switch from servo to one shot by having the buttons right next to each other.  ("af-on button" and "*" button)   (servo and one shot)
« Last Edit: March 23, 2014, 06:50:50 AM by Northstar »
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sanj

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Re: EOS-1D X, Dual Back Button AF
« Reply #17 on: March 22, 2014, 02:22:07 PM »
Thanks for all the replies. The penny still fails to drop. It will one day, I hope. Currently either I do not know something or brain cells not working.
Perhaps soon I will have an 'ah ha' moment. Waiting.

sanj....your wrote "either i don't know something or"...could it be that you don't know that one shot is better(sharper)than servo for "non action" shots?   I'm sure you know this but I just thought i would point it out just in case. (i'm sure you do know because i've seen your awesome images)

the main reason for wanting the set up steve describes is to quickly and more easily switch from servo to one shot by having the buttons right next to each other.  ("af-on button" and "*" button)   (servo and one shot)

Northstar: No I did not know that 'one shot' is sharper than servo for still objects. I thought is was about getting focus, not the way one got focus. And I believe that once I get focus and I remove the thumb from the back focus, I am as good as 'one shot'. Am I wrong?

Having said all of this, I am positive that I am missing something... I will get it one day and go 'yeyyyy'.

Northstar

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Re: EOS-1D X, Dual Back Button AF
« Reply #18 on: March 22, 2014, 05:01:57 PM »
Thanks for all the replies. The penny still fails to drop. It will one day, I hope. Currently either I do not know something or brain cells not working.
Perhaps soon I will have an 'ah ha' moment. Waiting.

sanj....your wrote "either i don't know something or"...could it be that you don't know that one shot is better(sharper)than servo for "non action" shots?   I'm sure you know this but I just thought i would point it out just in case. (i'm sure you do know because i've seen your awesome images)

the main reason for wanting the set up steve describes is to quickly and more easily switch from servo to one shot by having the buttons right next to each other.  ("af-on button" and "*" button)   (servo and one shot)

Northstar: No I did not know that 'one shot' is sharper than servo for still objects. I thought is was about getting focus, not the way one got focus. And I believe that once I get focus and I remove the thumb from the back focus, I am as good as 'one shot'. Am I wrong?

Having said all of this, I am positive that I am missing something... I will get it one day and go 'yeyyyy'.

Hi Sanj...I believe the "predictive" nature of AF servo leads to a lower hit rate on critically sharp images vs one shot...at least that's been my experience.   

Even if you acquire focus with servo and release the AF-on button like you wrote, the focus was acquired using the predictive algorithms that servo uses.  The servo system works great most of the time, but if something truly isn't moving, it's better to not have the predictive nature of servo involved.

If I'm wrong about this then someone please tell me.

North
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neuroanatomist

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Re: EOS-1D X, Dual Back Button AF
« Reply #19 on: March 22, 2014, 05:07:55 PM »
Thanks for all the replies. The penny still fails to drop. It will one day, I hope. Currently either I do not know something or brain cells not working.
Perhaps soon I will have an 'ah ha' moment. Waiting.

sanj....your wrote "either i don't know something or"...could it be that you don't know that one shot is better(sharper)than servo for "non action" shots?   I'm sure you know this but I just thought i would point it out just in case. (i'm sure you do know because i've seen your awesome images)

the main reason for wanting the set up steve describes is to quickly and more easily switch from servo to one shot by having the buttons right next to each other.  ("af-on button" and "*" button)   (servo and one shot)

Northstar: No I did not know that 'one shot' is sharper than servo for still objects. I thought is was about getting focus, not the way one got focus. And I believe that once I get focus and I remove the thumb from the back focus, I am as good as 'one shot'. Am I wrong?

Having said all of this, I am positive that I am missing something... I will get it one day and go 'yeyyyy'.

There was another thread about using AI servo and back button AF instead of one shot.  The theoretical issue I have with that method is that even with fast lenses, AI servo uses data from the less accurate f/5.6 sensor lines because they are faster.  Practically, I don't know how much difference that actually makes in real world shooting.

As Northstar points out, the algorithm is different as well, AI servo is optimized for moving subjects.
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Viggo

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Re: EOS-1D X, Dual Back Button AF
« Reply #20 on: March 22, 2014, 05:21:24 PM »
My personal experience has been, through testing on all sorts of subjects in all sorts of light, that One Shot is only better when light is VERY poor and it misses just as much or as little as Ai servo if you take 20 shots of the same subject in normal light. This is true for the 1dX, but not the 1d3, 1d4, 5dc, 5d2 and 5d3. IF you miss more still subjects with the 1dx using Ai Servo, try changing the case to Case 1 or 2. Using Case 6 for a non moving subject will give a lower hit rate for sure. I have also used 4 point expansion for still subjects with great results. 1.2, 2.8 or f4 has nothing to do with the hit rate.
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eml58

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Re: EOS-1D X, Dual Back Button AF
« Reply #21 on: March 22, 2014, 06:55:24 PM »

Northstar: No I did not know that 'one shot' is sharper than servo for still objects. I thought is was about getting focus, not the way one got focus. And I believe that once I get focus and I remove the thumb from the back focus, I am as good as 'one shot'. Am I wrong?

Having said all of this, I am positive that I am missing something... I will get it one day and go 'yeyyyy'.

Hi Sanj, having seen your impressive Images & the things you like to Photograph, this might help to understand what is being suggested (I have certainly set my own Bodies up for this method).

Before the Firmware update Back Button could only be programmed for either AI Servo OR single shot.

That's still the same, but now we can set up the Back Button Focus Button for say AI Servo (Those Cheetahs at 80KPH)

And we can at the same time set up AE Lock Button for Single Shot Focus (Those lovely Bollywood stars I've seen you Photograph)

Under "normal" conditions your in the Bush Photographing a Cheetah @ 80KPH in the Serengeti, so AI Servo works best, but suddenly the most Beautiful Bollywood star on the Planet suddenly appears standing under a Tree 10 metres away (all thoughts of the Cheetah are now completely superfluous at this point), your AI Servo isn't the best way to capture this situation in all it's Glory, single shot is, gives you much better Focus Lock, you can focus on the eyes (or where ever you desire) and be a lot more confident you have excellent focus.

Prior to the firmware update you would have had to go into your menu system & change your Back Button Focus Button to single shot from AI Servo and that takes time, time to allow that Bollywood Star to become skittish and make a break for the tall grass, so now we can programme one button for AI Servo, the other button for single shot, and that Bollywood star is dead in the Serengeti.

Hope that helps, now........ all we need to do is get a Cheetah & a Bollywood Star into the same area......

I'll work on the Cheetah, I'll leave the Bollywood Star to you.
« Last Edit: March 22, 2014, 07:01:39 PM by eml58 »
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Re: EOS-1D X, Dual Back Button AF
« Reply #21 on: March 22, 2014, 06:55:24 PM »

expatinasia

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Re: EOS-1D X, Dual Back Button AF
« Reply #22 on: March 22, 2014, 09:14:57 PM »
I think eml58 and others explained it very clearly, but if you are in AI Servo mode you use the AF ON button to focus as you normally do, but if you want to switch to One Shot mode you now simply need to press the * button and it automatically shifts to One Shot and focuses under that system. Some will find it easier than using one of the front buttons to switch.

The only thing is, and maybe this is something I have misunderstood, is you need to keep the * button down because as soon as you release it, your camera switches back to what it was on before - most likely AI Servo.

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Re: EOS-1D X, Dual Back Button AF
« Reply #23 on: March 22, 2014, 09:36:33 PM »
The only thing is, and maybe this is something I have misunderstood, is you need to keep the * button down because as soon as you release it, your camera switches back to what it was on before - most likely AI Servo.

If you're using back button AF, when you release the button the camera simply stops focusing...which is the point of back button AF.  So, with that setup, you press one back button to focus with AI Servo or the other back button to focus with One Shot.

The issue that I have with the setup is that I usually want single point selection with One Shot, but with Servo I want 61-pt auto (for people) or 8-pt expansion (for birds).  The dual back button approach won't change the point selection mode, AFAIK.
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expatinasia

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Re: EOS-1D X, Dual Back Button AF
« Reply #24 on: March 22, 2014, 09:47:09 PM »
The issue that I have with the setup is that I usually want single point selection with One Shot, but with Servo I want 61-pt auto (for people) or 8-pt expansion (for birds).  The dual back button approach won't change the point selection mode, AFAIK.

I think you are right, you can choose the AF point but not the setting. Mind you it only takes a second or two to toggle between those three settings and you do not need to remove your eye from the VF to do so. I think mine toggles between single small point, single point, 8-pt expansion and 61-pt auto.
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Re: EOS-1D X, Dual Back Button AF
« Reply #25 on: March 22, 2014, 10:18:24 PM »
The issue that I have with the setup is that I usually want single point selection with One Shot, but with Servo I want 61-pt auto (for people) or 8-pt expansion (for birds).  The dual back button approach won't change the point selection mode, AFAIK.

I think you are right, you can choose the AF point but not the setting. Mind you it only takes a second or two to toggle between those three settings and you do not need to remove your eye from the VF to do so. I think mine toggles between single small point, single point, 8-pt expansion and 61-pt auto.

I have C2 set to One Shot and single point, C3 set to Servo and 61-pt, and the M.Fn button set to change modes – so it's one button press to go to Servo, two to go back (C1 is restricted).
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sanj

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Re: EOS-1D X, Dual Back Button AF
« Reply #26 on: March 23, 2014, 12:51:30 AM »
Now I understand. Clearly understand. Thx much ALL!!!

However I am very surprised that servo will not focus on still objects. Everyone is saying that. But that has not been my experience so far. Or perhaps I have not noticed it. Hmmm.

Eml: You not only photograph beautifully but write beautifully as well.

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Re: EOS-1D X, Dual Back Button AF
« Reply #27 on: March 23, 2014, 12:57:17 AM »
And yes, if one did feel the need to have one shot, this is a great firmware update. Very thoughtful of Canon.
I am telling myself: If Canon thought there was a need to do this, then one shot must be 'sharper'.

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Re: EOS-1D X, Dual Back Button AF
« Reply #27 on: March 23, 2014, 12:57:17 AM »

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Re: EOS-1D X, Dual Back Button AF
« Reply #28 on: March 23, 2014, 06:29:13 AM »
This is my favourite new feature of the new FW.  I had been fairly happy using AI Servo all the time and just releasing it for static or focus/recompose shots. However the one shot algorithms are more accurate and I recently was photographing perched birds in very low rainforest light and sometimes really needed that more accurate One shot focus with the confirmation beep and flash combined with spot focus mode to get accurate focus. I think in good even average light using the aiservo is fine but it was helpful in f 5.6, 1/60, ISO 20000 type light.
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Re: EOS-1D X, Dual Back Button AF
« Reply #29 on: March 23, 2014, 10:20:49 AM »
Since I don't own a 1DX, I think I'll just heckle those more fortunate than myself!   8)

This thread is a true camera geek thread!!   :P

A bunch of uber-camera geeks sitting around discussing the various methods, techniques and strategies of which button method they use to focus with on their fancy expensive cameras!  And even going so far as to consider the f-stop and speed of the focus points together with which algorithm is used for the different focus modes!  Wow!

Truly, it's an enlightening thread but I just had to step back and joke with you a minute on how truly geeky it is!!   ;D
Yes, but what would  surapon  say ??  :D

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Re: EOS-1D X, Dual Back Button AF
« Reply #29 on: March 23, 2014, 10:20:49 AM »