Problem acquiring focus

Hi..  I have been getting some really great shots with my new lens (100-400mm II plus 1.4x III) (See most recent entries in my photostream at flickr)..

But often when the light is glaring or there are moving bushes etc... the autofocus just won't latch on.

Yesterday it was with a hummer way up in the glare, today a red-wing BlkBrd on a tree branch that swayed and behind that was open water and trees across the water.  The autofocus wanted the trees in the background. I tried everything and gave up

I am using evaluative metering and 9 point AF.. 9 Point AF seems to be more reliable than single point.

I don't take off the teleconverter.  I assume that the AF would probably work much better if I did, but I need the distance.

Any tips?

Thanks

CD

I don't know how far away your birds were, but perhaps you don't need the focus limit switch set to full.

cdmazoff wrote:

But often when the light is glaring or there are moving bushes etc... the autofocus just won't latch on.

AF usually chooses the subject with most contrast. Moving bushes in front of the sky or some bright object are very contrasty.

I am using evaluative metering and 9 point AF.. 9 Point AF seems to be more reliable than single point.

In such occasions I would use 1 point AF. Have you tried it?

jp4 wrote:

I don't know how far away your birds were, but perhaps you don't need the focus limit switch set to full.

Thanks for the reply jp4.. I moslty shoot at the full range so I have my focus limit set to full, and this time it was definitely at the long end.

Pepege wrote:

cdmazoff wrote:

But often when the light is glaring or there are moving bushes etc... the autofocus just won't latch on.

AF usually chooses the subject with most contrast. Moving bushes in front of the sky or some bright object are very contrasty.

I am using evaluative metering and 9 point AF.. 9 Point AF seems to be more reliable than single point.

In such occasions I would use 1 point AF. Have you tried it?

Yes, I switched back to 1 point AF .  Didn't help. .. I also had trouble with the manual ring in AF mode.. I might try flipping the switch to MF   but by then the bird has flown! 

cdmazoff wrote:

jp4 wrote:

I don't know how far away your birds were, but perhaps you don't need the focus limit switch set to full.

Thanks for the reply jp4.. I moslty shoot at the full range so I have my focus limit set to full, and this time it was definitely at the long end.

If I think my subjects will be beyond 3m, which they usually are, I set the lens switch to the 3m-infininty mark, the autofocus is better.

Also, I almost always use one point AF. Pump the focus button if it locks onto something other than your subject.

I also use BBF.

cdmazoff wrote:

Hi.. I have been getting some really great shots with my new lens (100-400mm II plus 1.4x III) (See most recent entries in my photostream at flickr)..

But often when the light is glaring or there are moving bushes etc... the autofocus just won't latch on.

Yesterday it was with a hummer way up in the glare, today a red-wing BlkBrd on a tree branch that swayed and behind that was open water and trees across the water. The autofocus wanted the trees in the background. I tried everything and gave up

I am using evaluative metering and 9 point AF.. 9 Point AF seems to be more reliable than single point.

I don't take off the teleconverter. I assume that the AF would probably work much better if I did, but I need the distance.

Any tips?

Thanks

CD

I can think of a couple of issues. One is that you are riding at the edge of the f/8 autofocus limit by combining  the 1.4X with your 100-400 II. It should still work under good light, but that brings us to the second issue. When you shoot against glare or haze or low light the autofocus has a harder time locking focus.

About the only suggestions I can make are:

1. remove any filters

2. try a single point focus

3. use a lens hood

4. you might need to switch over to manual focus under rotten light.

Good luck!

hotdog321 wrote:

cdmazoff wrote:

Hi.. I have been getting some really great shots with my new lens (100-400mm II plus 1.4x III) (See most recent entries in my photostream at flickr)..

But often when the light is glaring or there are moving bushes etc... the autofocus just won't latch on.

Yesterday it was with a hummer way up in the glare, today a red-wing BlkBrd on a tree branch that swayed and behind that was open water and trees across the water. The autofocus wanted the trees in the background. I tried everything and gave up

I am using evaluative metering and 9 point AF.. 9 Point AF seems to be more reliable than single point.

I don't take off the teleconverter. I assume that the AF would probably work much better if I did, but I need the distance.

Any tips?

Thanks

CD

I can think of a couple of issues. One is that you are riding at the edge of the f/8 autofocus limit by combining the 1.4X with your 100-400 II. It should still work under good light, but that brings us to the second issue. When you shoot against glare or haze or low light the autofocus has a harder time locking focus.

About the only suggestions I can make are:

1. remove any filters

2. try a single point focus

3. use a lens hood

4. you might need to switch over to manual focus under rotten light.

Good luck!

Thanks to all of you for your advice.  Craig, :

1. I don't use any filters,

2. I am trying single point when 9 point won't work,

3. I ALWAYS use a lens hood,

4. and I'm now going to go out and experiment with the AF switch and single shot. I'm always shooting AI Servo because I do birds and they twitch

cdmazoff wrote:

4. and I'm now going to go out and experiment with the AF switch and single shot. I'm always shooting AI Servo because I do birds and they twitch

You could try back-button focusing as well. It never worked for me, though.

cdmazoff wrote:

hotdog321 wrote:

cdmazoff wrote:

Hi.. I have been getting some really great shots with my new lens (100-400mm II plus 1.4x III) (See most recent entries in my photostream at flickr)..

But often when the light is glaring or there are moving bushes etc... the autofocus just won't latch on.

Yesterday it was with a hummer way up in the glare, today a red-wing BlkBrd on a tree branch that swayed and behind that was open water and trees across the water. The autofocus wanted the trees in the background. I tried everything and gave up

I am using evaluative metering and 9 point AF.. 9 Point AF seems to be more reliable than single point.

I don't take off the teleconverter. I assume that the AF would probably work much better if I did, but I need the distance.

Any tips?

Thanks

CD

I can think of a couple of issues. One is that you are riding at the edge of the f/8 autofocus limit by combining the 1.4X with your 100-400 II. It should still work under good light, but that brings us to the second issue. When you shoot against glare or haze or low light the autofocus has a harder time locking focus.

About the only suggestions I can make are:

1. remove any filters

2. try a single point focus

3. use a lens hood

4. you might need to switch over to manual focus under rotten light.

Good luck!

Thanks to all of you for your advice. Craig, :

1. I don't use any filters,

2. I am trying single point when 9 point won't work,

3. I ALWAYS use a lens hood,

4. and I'm now going to go out and experiment with the AF switch and single shot. I'm always shooting AI Servo because I do birds and they twitch

Sounds like you really know what you are doing. I think you may need to go "old school" manual focus if it still acts up. Happy "hunting!"

Pepege wrote:

cdmazoff wrote:

4. and I'm now going to go out and experiment with the AF switch and single shot. I'm always shooting AI Servo because I do birds and they twitch

You could try back-button focusing as well. It never worked for me, though.

Hi Pepege: I tried BBF and almost had a stroke!!!  I think I'm BBF challenged; sort of almost like camera-dyslexic 

jp4 wrote:

cdmazoff wrote:

jp4 wrote:

I don't know how far away your birds were, but perhaps you don't need the focus limit switch set to full.

Thanks for the reply jp4.. I moslty shoot at the full range so I have my focus limit set to full, and this time it was definitely at the long end.

If I think my subjects will be beyond 3m, which they usually are, I set the lens switch to the 3m-infininty mark, the autofocus is better.

Also, I almost always use one point AF. Pump the focus button if it locks onto something other than your subject.

I also use BBF.

Yes, if it's slow focusing and your subject is more than 3m away, switch the focusing limiter on.  That's what it's there for, the focusing will be faster.  Particularly with the extender attached, which does slow the focusing.

cdmazoff wrote:

Hi Pepege: I tried BBF and almost had a stroke!!! I think I'm BBF challenged; sort of almost like camera-dyslexic

I have not gone to BBF myself, but I find the hitting the AF-ON button will show me if the camera is focusing  on the bird and usually gives me the shot that I want.  The birdfeeders in my yard have an embankment of brush on them and it is very tricky getting the focus on the bird and not the background.  But with care (and multiple attempts) I usually get the shot I want with a 100-400L II (but without a 1.4x.)

CameraCarl wrote:

I think you are simply exceeding the capability of the Canon AF system. Your description of subjects makes it seem that the subject is hard to locate and focus on. Best bird photos are typically made with the sun at your back.

Thanks to all of you for your replies. Here are some shots where the AF worked quickly enough for me to get them.. So it will give you an idea of the ability of my setup when it's working!! Problem is it doesn't always work. I'm wondering whether the next step is to upgrade to a Canon camera that autofocuses more quickly.. I never understood that the chip in the camera makes a lot of difference as well. I'm actually a beginner at all of this (going beyond the more or less point and shoot I did with the SX50). Just got the 800D at the end of Feb 2018 and started BIF, and got the Canon 100-400 etc 2 weeks ago.

Yes.. I do tend to shoot at the wrong time of day!!! Here's a snap I got this week, near the end of the day with the sun more or less at my back. It could be crisper.. It is a shot of flying Western Sandpipers. Boy are they difficult. You just see this blur and you pan and pray!!! I do find that some of my shots are on the fuzzy side (at full zoom) and some are totally beyond crisp at full zoom. Must be the light. BTW I do use bump focus.

Handheld, near sunset

Handheld...