Go back and read the manual again?

[SyrBrian]

I'm a relative newbie and I need some guidance with autofocus -

I am using a Canon EOS 70D with  Tamron 150-600 telephoto using a tripod -

shooting a bird feeder in my yard , I've focused on the feeder and when birds arrive I depress

the shutter halfway and the camera appears to try and re-focus the shot (into a complete blur) ...

thanks for any input !

Brian M

[Waddizzle]

---

@SyrBrian wrote:

I'm a relative newbie and I need some guidance with autofocus -

I am using a Canon EOS 70D with  Tamron 150-600 telephoto using a tripod -

shooting a bird feeder in my yard , I've focused on the feeder and when birds arrive I depress

the shutter halfway and the camera appears to try and re-focus the shot (into a complete blur) ...

thanks for any input !

Brian M

---

Yes, reviewing the manual is always a good thing.

Using a super telephoto means relearning a few things.  That lens has a long MFD, minimum focusing distance, so make sure the bird feeder is at least 25 feet away from you.  The lens should have a focusing range range switch, so learn to use it.

For best results, I suggest a fast shutter speed, 1/1000 or faster, and an f/8 aperture setting.  Since you are on a tripod, focused on fixed object, then pre-focusing on the feeder and switching the lens to MF might be a good thing.  This will allow you to experiment with that exposure settings you need to capture small birds, without having to worry about focusing.

[SyrBrian]

Wadizzle -

thank you for your suggestions - I will try each of them - much appreciated!

brian

[Waddizzle]

---

@SyrBrian wrote:

Wadizzle -

thank you for your suggestions - I will try each of them - much appreciated!

brian

---

Oh, yeah.  If you are on a tripod, then you might want to try turning off any Optical Stabilization in the lens.  You do not need it on a tripod.  With some lenses the OS and AF can get into a tug-of-war with each other.  Yours might be one of them.

[kvbarkley]

Or, using it the way you are now, as soon as it focuses where you want it on the bird feeder, switch the lens to manual focus. This will lock the focus and prevent re-focus. But I second the sugggestion to set only the middle point (or area) for focus.

[Waddizzle]

---

@kvbarkley wrote:

Or, using it the way you are now, as soon as it focuses where you want it on the bird feeder, switch the lens to manual focus. This will lock the focus and prevent re-focus. But I second the sugggestion to set only the middle point (or area) for focus.

---

I have a custom shooting mode, which almost does exactly that.  It switches to Single AF point, One Shot focusing, Single Shot shooting, and BBF focusing so that the shutter does not refocus when I press the shutter.  I call this my “bird sitting on a branch, in a tree” mode.  I would use this for the feeder, so that I do not need to switch the lens back to AF mode if I suddenly need AF.

My other custom shooting mode does the exact opposite.  It switches to all AF points active, AI Servo focusing, Continuous shooting.  The shutter activates focusig, and what was the BBF button now disables focusing.  This is my regular “action shooting mode”.

[TCampbell]

If you let the camera use any auto-focus point it wants, it will tend to pick the auto-focus point which can focus on the *nearest* thing.  This can result in “something” behind in focus... just not what you intended.  If you want to force the camera to focus on only your intended target, select single-point focus and make sure the focus point is on your intended target.

Also, make sure you know the difference between “One Shot” vs “AI Servo” focus modes (The former is for subjects where the focus distance isn’t changing.  The latter is for subjects where the focus distance is changing such as action photography).

One other important difference... in “One Shot” focus mode, the camera uses “focus priority” which means if you fully press the shutter button, it wont take the shot unless/until an AF point has achieved focus on something.  This is great for non-action photography (portraits, landscapes, candies, etc.).  In “AI Servo” mode, it will take a photo as soon as you fully press the shutter button whether it had time to focus or not (this is called “release priority”).   This is heavily used for action-photography where you’re tracking a subject.   So if you do decide to try AI Servo, make sure you half-press until you’re happy with focus ... you can track the subject as long as you want while half-pressing the shutter... and when you fully press the shutter it WILL take the shot.  If you fully press the shutter too soon, it will still take the shot... but it may not be focused.  The idea behind “release priority” is it helps the photographer capture the “decisive moment” in an action event.   

It would seem mysterious if you did not know the camera was intentionally designed to behave that way.   Canon is basically doing this in response to top photographers telling them how the camera should behave.

[ebiggs1 · Accepted solution]

"I've focused on the feeder and when birds arrive I depress

the shutter halfway ...."

It sounds like you are trying to do it the easy way.  That almost will never work.  You need to select a single center focus point and you need to focus on the bird each time one arrives. Use One Shot not AI-Servo. Leave OS/IS/VC, etc. on or tun it off, I don't see any difference on mine.

If you have multiple focus points active who knows what it focused on?  Use just one.