Disabling Shutter Release Button's Half-Press Focus

bats · 01-29-2014, 12:00 PM

I'm feeling really stupid this morning and am in a huge rush - leaving the house in 30 minutes for a photoshoot and can't find what I need in the K3 menus or manual. I need help, LOL!

I'd like to change my habits... and turn off auto-focusing with the shutter release button's half-press. I want to auto-focus ONLY when I'm using the rear AF button.

I'll be damned if I can figure out where that gets configured. I'm sure it's just me this morning. I probably need more coffee

jup · 01-29-2014, 12:08 PM - **1 Like**

Menu with camera -> section 4 -> Button Customization -> AF Button. Set that to AF2 (defaults to AF1). I use that all the time.

bats · 01-29-2014, 12:37 PM

Ah! Thank you! Exactly what I'm looking for.

**Arne Bo** · 01-29-2014, 01:07 PM

I use it as well. Very helpful and resulting in a nice keeper rate.

bats · 01-29-2014, 05:55 PM

I agree - this is going to be very useful in situations where I pre-focus and then...

a) wait for someone to enter the frame... i.e., some street shooting where I preselect the backdrop
b) or wait for fireworks to start exploding in the scene
c) or want to freeze the focus but move the camera off the selected object to recompose the framing a little

In the past, I would autofocus, then switch over to manual focus to keep the lens from moving off my target when firing. This will be much better... If I can train my brain and finger to reach for the AF button

Old habits die hard.

Thanks again, guys!

jup · 01-29-2014, 08:34 PM

Not just that:
- oftentimes I want to take second/third/fourth picture with the same focus setting and since I'd often use focus&recompose, I'd need to do the focus&recompose again.
- I still use shutter half press a lot! I use it to... Activate metering.

For example, with K-3 and top LCD I can just be walking around with the camera hanging of my neck and if I think there might be shooting opportunity half press shutter and check exposure on the LCD, maybe correct aperture and be ready to just bring camera up to my eye, AF and shoot away. I know other buttons can activate metering (AE-L I think, but it also locks), but shutter is so handy right where my finger rests...

Word of warning though - once you get used to back button auto focus (BBAF), there's no going back. These days, when somebody hands me a camera that focuses on shutter half press, it scares the hell out of me.

Also, it makes camera pretty much unusable by anybody else then you. Luckily K-3 has green mode that always defaults to shutter half press focus. With K-30 I had to have block one user mode for cases when I want to hand camera to somebody.

gosman · 01-29-2014, 10:18 PM

It is too bad that you can't do both on AF. If you use AF, it disables the shutter automatically. So then if you do use the shutter, it works too.

jup · 01-29-2014, 10:40 PM

Originally posted by gosman

It is too bad that you can't do both on AF. If you use AF, it disables the shutter automatically. So then if you do use the shutter, it works too.

Yeah, but only as long as you're holding AF. If you let go of it and then decide you don't want AF, too late. I don't want to be holding anything. I just want to have the option to choose if I want to use AF or just stare metering for every shot.

You can set AF button to cancel AF which is somehow better. The I can press it if I want to disable AF for a particular shot. So I still have the choice to disable AF for the shot whenever I decide. It's just a bit awkward and I tried. For me AF2 is the way to go. Your mileage may vary.

wpompen · 01-30-2014, 12:22 AM

I personally prefer to use AF2 but I wonder if there's a difference in the way the AF calculates.
With AF back button enabled, does the AF system keep focussing all the time, I mean uninterupted. Or does it AF finally at the moment you press the shutter full.
Does the halfway shutter method work the same?
SO is one of these methods more accurate for (fast) moving objects???

jup · 01-30-2014, 12:46 AM

Originally posted by wpompen

I personally prefer to use AF2 but I wonder if there's a difference in the way the AF calculates.
With AF back button enabled, does the AF system keep focussing all the time, I mean uninterupted. Or does it AF finally at the moment you press the shutter full.
Does the halfway shutter method work the same?
SO is one of these methods more accurate for (fast) moving objects???

For AF.S possibly. With AF1, unless you change custom settings, shutter won't release until AF focuses and if it can't focus, it won't release at all. So in theory yes, it could be a bit faster since you can just press shutter fully and camera will fire as soon as it achieves focus. With AF2 you'd have to wait for confirmation light in VF if you want to be sure it's focused and by the time you press shutter, it can be too late. That said, in situations where focus is hard, AF2 will at least allow you to fire, with AF1, if camera can't focus, you can't shoot.

Things get quite complicated when you put AF.C and continuous shooting mode into picture as there's about 4 settings that affect these and some of them are obviously irrelevant for AF2 while others might have some influence. Maybe somebody more competent can answer these, in my experience tracking and AF.C and continuous mode work pretty well with AF2 but I don't know all the ins and outs.

wpompen · 01-30-2014, 01:14 AM

Thanks! I agree they work pretty well, I'm cuious if there might be some "magical"combination. I'm using AF-C 99,9% of the time in combination with AF2, focus hold "medium".

lister6520 · 01-30-2014, 10:23 AM

Originally posted by wpompen

I personally prefer to use AF2 but I wonder if there's a difference in the way the AF calculates.
With AF back button enabled, does the AF system keep focussing all the time, I mean uninterupted. Or does it AF finally at the moment you press the shutter full.
Does the halfway shutter method work the same?
SO is one of these methods more accurate for (fast) moving objects???

I had that same doubt when I first 'discovered' disabling the half press focus so I spent some time playing around with it to understand it better, As far as I can tell it works exactly the same as the shutter half press. In AF.S it will stop focusing either when focus is achieved or when you let go of the button. In AF.C it will keep focusing as long as you keep the button pressed.

The big difference is that in AF.C you can stop focusing by releasing the button before releasing the shutter, so effectively you don;t ever need to set the camera to AF.S when you use the rear button.

derekkite · 01-30-2014, 10:14 PM

Originally posted by jup

Yeah, but only as long as you're holding AF. If you let go of it and then decide you don't want AF, too late. I don't want to be holding anything. I just want to have the option to choose if I want to use AF or just stare metering for every shot.

You can set AF button to cancel AF which is somehow better. The I can press it if I want to disable AF for a particular shot. So I still have the choice to disable AF for the shot whenever I decide. It's just a bit awkward and I tried. For me AF2 is the way to go. Your mileage may vary.

This takes away focus in movie mode during the shoot.

Bonobo · 01-31-2014, 08:33 AM

Here's a question for you guys, how many of you use AF2 and have the grip? I've been playing around with it and it is quite awkward since there's no AF button on the grip and you then can't use shutter half press to (re)focus once you turn the camera to portrait. I'd love to hear how someone manages to use both at the same time.

souless · 01-31-2014, 09:00 AM

There is one AF button on the grip according to the above image?!
right beside the green button.

01-29-2014, 12:00 PM	#1
bats Senior Member Join Date: Sep 2010 Location: San Francisco Photos: Gallery Posts: 102	Disabling Shutter Release Button's Half-Press Focus I'm feeling really stupid this morning and am in a huge rush - leaving the house in 30 minutes for a photoshoot and can't find what I need in the K3 menus or manual. I need help, LOL! I'd like to change my habits... and turn off auto-focusing with the shutter release button's half-press. I want to auto-focus ONLY when I'm using the rear AF button. I'll be damned if I can figure out where that gets configured. I'm sure it's just me this morning. I probably need more coffee

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01-29-2014, 12:08 PM - 1 Like	#2
jup Senior Member Join Date: Nov 2009 Location: San Jose, CA Posts: 103	Menu with camera -> section 4 -> Button Customization -> AF Button. Set that to AF2 (defaults to AF1). I use that all the time.

01-29-2014, 12:37 PM	#3
bats Senior Member Join Date: Sep 2010 Location: San Francisco Photos: Gallery Posts: 102 Original Poster	Ah! Thank you! Exactly what I'm looking for.

01-29-2014, 01:07 PM	#4
Arne Bo Site Supporter Join Date: Nov 2013 Location: Hamburg Photos: Albums Posts: 123	I use it as well. Very helpful and resulting in a nice keeper rate.

01-29-2014, 05:55 PM	#5
bats Senior Member Join Date: Sep 2010 Location: San Francisco Photos: Gallery Posts: 102 Original Poster	I agree - this is going to be very useful in situations where I pre-focus and then... a) wait for someone to enter the frame... i.e., some street shooting where I preselect the backdrop b) or wait for fireworks to start exploding in the scene c) or want to freeze the focus but move the camera off the selected object to recompose the framing a little In the past, I would autofocus, then switch over to manual focus to keep the lens from moving off my target when firing. This will be much better... If I can train my brain and finger to reach for the AF button Old habits die hard. Thanks again, guys!

01-29-2014, 08:34 PM	#6
jup Senior Member Join Date: Nov 2009 Location: San Jose, CA Posts: 103	Not just that: - oftentimes I want to take second/third/fourth picture with the same focus setting and since I'd often use focus&recompose, I'd need to do the focus&recompose again. - I still use shutter half press a lot! I use it to... Activate metering. For example, with K-3 and top LCD I can just be walking around with the camera hanging of my neck and if I think there might be shooting opportunity half press shutter and check exposure on the LCD, maybe correct aperture and be ready to just bring camera up to my eye, AF and shoot away. I know other buttons can activate metering (AE-L I think, but it also locks), but shutter is so handy right where my finger rests... Word of warning though - once you get used to back button auto focus (BBAF), there's no going back. These days, when somebody hands me a camera that focuses on shutter half press, it scares the hell out of me. Also, it makes camera pretty much unusable by anybody else then you. Luckily K-3 has green mode that always defaults to shutter half press focus. With K-30 I had to have block one user mode for cases when I want to hand camera to somebody.

01-29-2014, 10:18 PM	#7
gosman Senior Member Join Date: Jan 2014 Location: Texas Posts: 263	It is too bad that you can't do both on AF. If you use AF, it disables the shutter automatically. So then if you do use the shutter, it works too.

01-29-2014, 10:40 PM	#8
jup Senior Member Join Date: Nov 2009 Location: San Jose, CA Posts: 103	Originally posted by gosman It is too bad that you can't do both on AF. If you use AF, it disables the shutter automatically. So then if you do use the shutter, it works too. Yeah, but only as long as you're holding AF. If you let go of it and then decide you don't want AF, too late. I don't want to be holding anything. I just want to have the option to choose if I want to use AF or just stare metering for every shot. You can set AF button to cancel AF which is somehow better. The I can press it if I want to disable AF for a particular shot. So I still have the choice to disable AF for the shot whenever I decide. It's just a bit awkward and I tried. For me AF2 is the way to go. Your mileage may vary.

01-30-2014, 12:22 AM	#9
wpompen Forum Member Join Date: Mar 2013 Posts: 64	I personally prefer to use AF2 but I wonder if there's a difference in the way the AF calculates. With AF back button enabled, does the AF system keep focussing all the time, I mean uninterupted. Or does it AF finally at the moment you press the shutter full. Does the halfway shutter method work the same? SO is one of these methods more accurate for (fast) moving objects???

01-30-2014, 12:46 AM	#10
jup Senior Member Join Date: Nov 2009 Location: San Jose, CA Posts: 103	Originally posted by wpompen I personally prefer to use AF2 but I wonder if there's a difference in the way the AF calculates. With AF back button enabled, does the AF system keep focussing all the time, I mean uninterupted. Or does it AF finally at the moment you press the shutter full. Does the halfway shutter method work the same? SO is one of these methods more accurate for (fast) moving objects??? For AF.S possibly. With AF1, unless you change custom settings, shutter won't release until AF focuses and if it can't focus, it won't release at all. So in theory yes, it could be a bit faster since you can just press shutter fully and camera will fire as soon as it achieves focus. With AF2 you'd have to wait for confirmation light in VF if you want to be sure it's focused and by the time you press shutter, it can be too late. That said, in situations where focus is hard, AF2 will at least allow you to fire, with AF1, if camera can't focus, you can't shoot. Things get quite complicated when you put AF.C and continuous shooting mode into picture as there's about 4 settings that affect these and some of them are obviously irrelevant for AF2 while others might have some influence. Maybe somebody more competent can answer these, in my experience tracking and AF.C and continuous mode work pretty well with AF2 but I don't know all the ins and outs.

01-30-2014, 01:14 AM	#11
wpompen Forum Member Join Date: Mar 2013 Posts: 64	Thanks! I agree they work pretty well, I'm cuious if there might be some "magical"combination. I'm using AF-C 99,9% of the time in combination with AF2, focus hold "medium".

01-30-2014, 10:23 AM	#12
lister6520 Veteran Member Join Date: May 2012 Posts: 733	Originally posted by wpompen I personally prefer to use AF2 but I wonder if there's a difference in the way the AF calculates. With AF back button enabled, does the AF system keep focussing all the time, I mean uninterupted. Or does it AF finally at the moment you press the shutter full. Does the halfway shutter method work the same? SO is one of these methods more accurate for (fast) moving objects??? I had that same doubt when I first 'discovered' disabling the half press focus so I spent some time playing around with it to understand it better, As far as I can tell it works exactly the same as the shutter half press. In AF.S it will stop focusing either when focus is achieved or when you let go of the button. In AF.C it will keep focusing as long as you keep the button pressed. The big difference is that in AF.C you can stop focusing by releasing the button before releasing the shutter, so effectively you don;t ever need to set the camera to AF.S when you use the rear button.

01-30-2014, 10:14 PM	#13
derekkite Pentaxian Join Date: Sep 2011 Location: Nelson B.C. Posts: 3,782	Originally posted by jup Yeah, but only as long as you're holding AF. If you let go of it and then decide you don't want AF, too late. I don't want to be holding anything. I just want to have the option to choose if I want to use AF or just stare metering for every shot. You can set AF button to cancel AF which is somehow better. The I can press it if I want to disable AF for a particular shot. So I still have the choice to disable AF for the shot whenever I decide. It's just a bit awkward and I tried. For me AF2 is the way to go. Your mileage may vary. This takes away focus in movie mode during the shoot.

01-31-2014, 08:33 AM	#14
Bonobo Senior Member Join Date: Feb 2010 Location: Miami Posts: 226	Here's a question for you guys, how many of you use AF2 and have the grip? I've been playing around with it and it is quite awkward since there's no AF button on the grip and you then can't use shutter half press to (re)focus once you turn the camera to portrait. I'd love to hear how someone manages to use both at the same time.

01-31-2014, 09:00 AM	#15
souless Senior Member Join Date: Feb 2010 Location: Taipei Posts: 110	There is one AF button on the grip according to the above image?! right beside the green button.