Back Buton Focusing - Help Rqd Please.

snoop69

snoop69

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Name
Paul
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Recently i have noticed that a lot of my portraits have been out of focus.

Now either one of three things is happening (or both) since.................

1. Purchasing a couple of used Sigma lenses or
2. Using back button focusing.
3. My technique has gone to pot.

I had some pretty sharp shots football 'action' shots using BBF but when
trying to focus on a models eyes for example & then re-composing,the shots
have been OOF which is cheesing me off.

For portrait shots should i be either...............

1. BBF on the models eyes then release the * button,re-compose the shoot or
2. Turn off BBF,lock onto the eyes then shoot? or
3. Check my lenses for sharpness?

Help please as i have a wedding next month (not official tog) so i would like
to get this sorted.

Also,im in Dover if anyone wants to pop round for a cuppa & give me some
hands on advice :thumbs:
 
Anybody any suggestions :shrug:
 
Don't have bbf I don't think on mine so don't know what it is but I just select the central focus point, focus on the eyes then with the shutter half pressed recompose the shot, or change the focus point to a one that I can place over the eyes to get the shot I need
 
Creed said:
Don't have bbf I don't think on mine so don't know what it is but I just select the central focus point, focus on the eyes then with the shutter half pressed recompose the shot, or change the focus point to a one that I can place over the eyes to get the shot I need
Click to expand...

Thanks Creed, im thinking maybe i should release the back button once focused,recompose
& then get the shot. I think by holding the * the focus point is changing at
the same time.
 
Surely if you are holding down the * the camera will continue to focus? When you do the focus and recompose, you should release the * button when recomposing
 
grumpybadger said:
Surely if you are holding down the * the camera will continue to focus? When you do the focus and recompose, you should release the * button when recomposing
Click to expand...

I thought that was the case but im used to holding the button for sports photography.
I just needed it confirmed that what i was doing wrong was something silly &
hopefully not my lenses as ive heard they can be OOF.

If i use regular focusing,does the focus not change or does it remain locked
all the while the shutter is half pressed?
 
snoop69 said:
Thanks Creed, im thinking maybe i should release the back button once focused,recompose
& then get the shot. I think by holding the * the focus point is changing at
the same time.
Click to expand...

Spot on - great for sports since you can track the action & release if anything gets in the way which might get focussed on... You do need to release the * to lock focus if you're shooting models.
A lot of people only use BBF for action shots and normal half-press for static.
 
Thanks guys - im going to have a play & try & learn not to keep the button
pressed (sports mode).

I had a feeling my brain was in 'donut' mode - just needed it confirming :lol:
 
snoop69 said:
Thanks guys - im going to have a play & try & learn not to keep the button
pressed (sports mode).

I had a feeling my brain was in 'donut' mode - just needed it confirming :lol:
Click to expand...


If you do this and move slightly (forward or back) or the model moves, won't this throw the focus out?
 
Are you using AI-Servo mode? That would explain why the AF continues when you recompose. If you're in single shot AF then it should stay locked so keeping the button pressed or releasing should have no effect on the focus.

More likely the problem is movement either from rotating the camera when you recompose or forward/backward movement. Either will be more likely if you're shooting at f/2.8 or wider head & shoulders (or closer) shot.
 
grumpybadger said:
Surely if you are holding down the * the camera will continue to focus? When you do the focus and recompose, you should release the * button when recomposing
Click to expand...

I thought that one press of the * was an exposure lock not anything to do with focus no need to hold it.
 
pxl8 said:
Are you using AI-Servo mode? That would explain why the AF continues when you recompose. If you're in single shot AF then it should stay locked so keeping the button pressed or releasing should have no effect on the focus.

More likely the problem is movement either from rotating the camera when you recompose or forward/backward movement. Either will be more likely if you're shooting at f/2.8 or wider head & shoulders (or closer) shot.
Click to expand...

That was the bit I was about to type. 1 shot all the way for this stuff...
 
snoop69 said:
I thought that was the case but im used to holding the button for sports photography.
I just needed it confirmed that what i was doing wrong was something silly &
hopefully not my lenses as ive heard they can be OOF.

If i use regular focusing,does the focus not change or does it remain locked
all the while the shutter is half pressed?
Click to expand...

If you have single shot on it will not re -focus but with rapid shot on then it will, is what I found
 
It moves AF control away from the shutter release, useful in lots of situations, not just fast action.
 
So pressing the * will focus for you... so u dont have to hold the shutter halfway down... and u can take repeated shots with the same focus point?
Or it just switches it to manual.
 
Trev Rich said:
So pressing the * will focus for you... so u dont have to hold the shutter halfway down... and u can take repeated shots with the same focus point?
Or it just switches it to manual.
Click to expand...

You can set it up a few different ways, I think there are about 4 options in the custom function.

The way I use: pressing * focuses. Pressing the shutter halfway activates the meter.

I use AI Servo focusing all the time, so holding * will give continuous focusing and I just release to stop. So effectively you get AI and one-shot focus at the same time.

And I can shoot whenever I want without waiting for focus. It allows manual focussing because you can just release the * to stop the AF motor. Whereas if focus is on the shutter button the AF will fight your manual focussing when you go to shoot.
 
Trev Rich said:
So pressing the * will focus for you... so u dont have to hold the shutter halfway down... and u can take repeated shots with the same focus point?
Or it just switches it to manual.
Click to expand...

Best use ive found is for tracking a footy player for instance. You can focus
on a chap running towards you or down the line & the focus will stay with
him. When you anticipate him passing the ball or shooting, you press the shutter.
Holding the * button feels a lot more comfortable/natural than
using your index finger which can get very tired after shooting 80 teams at
a sporting event twice a week.
 
Jayst84 said:
You can set it up a few different ways, I think there are about 4 options in the custom function.

The way I use: pressing * focuses. Pressing the shutter halfway activates the meter.

I use AI Servo focusing all the time, so holding * will give continuous focusing and I just release to stop. So effectively you get AI and one-shot focus at the same time.

And I can shoot whenever I want without waiting for focus. It allows manual focussing because you can just release the * to stop the AF motor. Whereas if focus is on the shutter button the AF will fight your manual focussing when you go to shoot.
Click to expand...

snoop69 said:
Best use ive found is for tracking a footy player for instance. You can focus
on a chap running towards you or down the line & the focus will stay with
him. When you anticipate him passing the ball or shooting, you press the shutter.
Holding the * button feels a lot more comfortable/natural than
using your index finger which can get very tired after shooting 80 teams at
a sporting event twice a week.
Click to expand...


Thanks guys.
Will have a play later.
Thanks for taking the time to give advice :thumbs:
 
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