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Occasional Contributor
Posts: 7
Registered: ‎08-27-2018

Lens Focus Question

Hello

I'm new to this forum and have a question about an issue that I have time to time with my camera and lens I use for bird in flight photography.

Bird in flight photography is a new hobby for me since the Spring of this year and I use the Canon 100-400 version 2 lens on a Canon 40D body.

 

I have noticed a few times that when I completely lose focus on the bird while tracking it in the open sky with no obstructions, I have a hard time trying to get the camera /  lens to properly focus on the bird again.

I'm at the 400mm end of the focual length when this happens.

 

I can understand the camera and  lens having a hard time trying to refocus on a small object in the sky so, what I do is point the camera towards something on the ground like a tree or a building to try to bring things back into focus.

What I have noticed when doing this is, it takes many attempts to get the camera / lens to reacquire focus on the tree or building before I can even attempt to try and get focus on the bird again.

I'm still at the 400 end of focual range when doing this.

 

I have tried a couple of times to manually refocus the lens on the bird but, I have a hard time trying to find the bird again and I'm just not good at using this method at this point.

 

So my concern is, is this a normal issue for a situation like I've described, and if it isn't, what might possibly be the cause?

My thought is that maybe it's the AF system of the 40D.

The body is 9 years old and since BIF photography is new to me, I have no past experience that I can relate to for this kind of situation.

 

There are no AF issues at all with still objects.

 

I'm hoping that there are no issues with the lens.

I bought it brand new Sept. of last year.

 

If anyone has a possible explaination for why this happens, or how to prevent this from happening, it would be appreciated.

 

If this is of any help, my BIF settings are:

Back button focus.

AI servo mode.

High speed continuous shooting.

All focus points are active as I'm normally tracking the bird in open sky.

The lens focus range is set to 3m to infinity as the birds are always more than 3m away from me.

 

 

 

 

 

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Esteemed Contributor
Posts: 4,185
Registered: ‎02-17-2016

Re: Lens Focus Question

[ Edited ]

I think the AF system gets confused sometimes. I have the same thing happen with my T6S and 18-135 lens at 135. I can only guess that the AF system has some sort of memory and when it gets confused like this you have to fiddle with it to clear it out.

 

(You do have a valid focus point, i. e., one you are set to use, on the bird when this happens, right?

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Occasional Contributor
Posts: 7
Registered: ‎08-27-2018

Re: Lens Focus Question

The Canon 40D only has 9 AF points to choose from.

It's either individual ones or all 9.

 

I have all 9 focus points active when the conditions are a clear, unobstructed sky with nothing to pull focus off the bird.

The lost focus on the bird is usually due to my bad panning technique.

 

With all 9 AF points active, I don't understand why it takes many attempts to reacquire focus when I point the lens at a large stationary object.

I figure if all the focus points are active, it should reacquire focus pretty quickly.

 

I don't know the technical aspect of how a camera and lens work in tandem in acquiring focus but I wonder if it's because I'm in AI servo mode that is causing the delay in reacquiring focus.

Or, if it's due to an older camera's focusing system working with a newer lens technology that is causing the delay.

 

If it's a camera issue, that's fine.

I can live with that as the camera is 9 yrs old and my plan is to get a new camera.

 

If it's the lens, then that's a concern.

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Reputable Contributor
Posts: 790
Registered: ‎06-11-2013

Re: Lens Focus Question

[ Edited ]

The best way to prevent the focus from being "distracted" is to use a single point. Of course, that makes for much more work for you, keeping that AF point right on the subject, exactly where you want the camera and lens to focus.

 

Later camera models than 40D have more choice of focus patterns, such as Zone and Expansion.... which can be useful with BIF. Some models' AF you also can "tune" to help prevent them beting "distracted" by obstructions or things at a distance behind the subject.

 

Also the cameras with more AF points (80D, 77D, T7i and 6DII have 45 points... recent 5D-series and 1D-series models have 61 points.... 7D Mark II have 65 points). With more points, there's less "gap" between individual points, which makes some of the multi-point patterns more usable for subjects like BIF. (But I never use All Points/Auto... way too big coverage, too easily distracted, and once that happens focus may hunt for a while before it again finds the subject)

 

Depending on model, newer AF systems also may be color and movement sensitive, which can help when tracking fast moving subjects.

 

If I recall correctly, the 40D's AF system was very nicely improved over the 30D's (which I used a lot... I only used 40D a few times, but eventually used 50D w/same AF system a lot). But, there have been further, significant advancements since, especially noticeable with the latest DSLRs. Many are now able to focus in 2 or 3 EV lower light and even with teleconverter/lens combos that are effective f/8.

 

I use the 100-400mm II myself. It's fast, though not quitre as quick as some other lenses. As an f/4.5-5.6 lens, it just doesn't provide as much light for the AF sensors to work with.... an f/2.8 zoom or f/2, f/1.8 or f/1.4 prime can be faster . Still, on my 7DIIs the 100-400 II is plenty fast for most things.

 

BIF are particularly challenging, though. Any camera and lens might struggle with them due to their speed, rapid changes in direction, etc. I think it's fair to say all shooters have some missed focus shots with BIF, regardless how capable their gear might be. OTOH, sometimes we just get lucky! Following was done with a 5D Mark II (which has a pretty pokey AF system, nowhere near as quick or good trackng movement as 50D, 7D, etc., in my experience):

 

Red tail hawk fly by

 

Lens was Canon's EF 300mm f/4L IS USM, which I've used a lot handheld when shooting sports. I had a whole bunch of missed focus and poorly composed shots of that hawk, trying to shoot it with the 5DII. But the bird was cooperative and kept zooming past, circling and hunting right around me for about 45 minutes.... and the 5DII was the camera I had on hand, so it was what I used. (I brought the full frame to take some scenic shots, wasn't expecting to shoot BIF! I know I could have done better with my 50Ds, which were what I was using along with the full frame camera at the time.)

 

I use pretty much the same settings as you, except I never use All Points. When I had cameras which only offered Single Point as an alternative, that was what I used. Now with other cameras I sometimes use Zone or Expansion, but still generally avoid All Points. That just leaves too much up to chance, for my liking.

 

Finally, I have to say, autofocus with these cameras and lenses is faster and more accurate than I ever was shooting with manual focus gear.... And I was actually quite good, shooting sports with my film cameras "back in the day".

 

It''s probably the limitations of your camera's AF system.... unlikely the  lens which is a very good performer in reasonably good lighting conditions (I switch to f/4 or faster lenses in more challenging light). Practice will help too, I'm sure (and perhaps some patience). Try Single Point, but expect to need to do more work with it. If and when you upgrade to a new camera you'll very likely be getting a higher performance AF system in it, which will bring out the best of that lens.

 

***********


Alan Myers
San Jose, Calif., USA
"Walk softly and carry a big lens."
GEAR: 5DII, 7DII (x2), 7D(x2) some other cameras, various lenses & accessories
FLICKR & ZENFOLIO 

 

 

 

 

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VIP
Posts: 13,017
Registered: ‎12-07-2012

Re: Lens Focus Question

"I have all 9 focus points active ..."

With your camera, I would use just the center point.  You know you still have MF. You can help the lens when it is struggling to obtain focus. If it is a small bird flying fast, it may be very difficult.

EOS 1DX and 1D Mk IV and several lenses!
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VIP
Posts: 10,378
Registered: ‎08-13-2015

Re: Lens Focus Question

“I'm new to this forum and have a question about an issue that I have time to time with my camera and lens I use for bird in flight photography.

Bird in flight photography is a new hobby for me since the Spring of this year and I use the Canon 100-400 version 2 lens on a Canon 40D body.”

 

——————————————————-

 

Sometimes lenses need a nudge on the focusing ring when you make a significant change your focus distance.

 

The lens has a focus range adjustment switch.  Set it for long range focusing.  For capturing BIF, I would use AI Servo focusing mode, with all AF points active.  The camera will want to focus on the nearest subject, so keep the subject within the area in the viewfinder covered by AF points.  This is where YOUR skill at tracking a moving subject come into play.  

 

This was taken with a 6D, which only has 11 AF points, and a Sigma 150-600mm “C” lens..

 

DF4E01CE-6722-4867-8532-F0ED9814F527.jpeg

 

I am not familiar with the features of that camera body, but check to see if it has an Image Priority adjustment.  There would be two settings: First Image and Second Image.  These settings only kick in when you are in AI Servo and Continuous Shooting modes.  I suggest setting them both to full tilt Focus Priority, which will force the camera to lock focus before it activates the shutter.

----------------------------------------------------------------------------------------------------------------------------------------------------------

"Doctor told me to get out and walk, so I bought a Canon."
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Occasional Contributor
Posts: 7
Registered: ‎08-27-2018

Re: Lens Focus Question

[ Edited ]

Thank you for your informative reply amfoto1.

Thank you to the others that replied as well.

 

My concern about the lens possibly being part of the focus issue has been alleviated.

I discovered yesterday that I simply have to lessen the lens focal length to reacquire focus much quicker than what had been happening.

Probably similar to what is suggested in Waddizzle's post.

 

Regarding using a single AF point for BIF, the common technique from what I've read is to use the centre AF point only.

My understanding for this is that the centre AF point is more accurate / better focus, at least for the Canon 40D.

I've tried this and haven't had a lot of success and I need to practice it more.

 

Unfortunately, my time for BIF photography is very limited for the most part.

So, I use all AF points being active to increase my chances of getting some in focus shots.

I only use all AF points when the bird is an open sky setting..usually a clear blue sky.. with nothing to pull focus off the bird.

If the bird is flying among trees or buildings, then I use the centre AF point only, with little success.

I know I would have zero chance of getting a flying small bird in focus just using the centre AF point.

 

Other than more practice, the other thing that I hope will help me, is a newer camera with an updated focus system.

I'm hoping that the rumored Canon 7D Mark III does get released sometime between now and next Spring.

Thought about getting the current Mark II but, I can wait until next Spring to see if there is going to be a Mark III.

 

This Osprey picture was taken recently using all AF points active.

Other than cropping, there were very little Lightroom adjustments to this image if i remember correctly. It's almost "straight out of the camera".

Not sure how this will appear regarding size and resolution on this site but, it looks good on my desktop screen.

Osprey, eagles and hawks are my main BIF attempts.

Again, thanks for all the replies.

IMG_0836.jpg

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VIP
Posts: 13,017
Registered: ‎12-07-2012

Re: Lens Focus Question

"It's almost "straight out of the camera"

I think it a good practice to add lens correction as a preset in LR. When you do it as a preset it is done when you start viewing your shots.

There are a few hard fast rules you shouldn't break for BIF, like lens correction.  Another is always shoot Raw and get closer.  Closer is always better than a better or bigger lens.  Or, any better gear for that matter.  Not using Raw is simply dumb.

 

Whether you like One shot or AI-servo, center point or all of them isn't as important as the ones I listed.

EOS 1DX and 1D Mk IV and several lenses!
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Occasional Contributor
Posts: 7
Registered: ‎08-27-2018

Re: Lens Focus Question

[ Edited ]

Hello ebiggs1

I'm a bit confused regarding these two statements.

 

"I think it a good practice to add lens correction as a preset in LR. When you do it as a preset it is done when you start viewing your shots.

There are a few hard fast rules you shouldn't break for BIF, like lens correction."

 

One seems to contradict the other.

 

What difference does it make if Lightroom does the lens correction as a preset or if the correction is done in the develope mode?

And, why is it a rule that shouldn't be broken for BIF photography?

 

I've haven't heard or read about either of these and I like to know the reasoning behind it.

 

Regarding shooting RAW, that's what I do and yes, I would like to get closer to the birds but not possible in most of my attempts.


 

 

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VIP
Posts: 13,017
Registered: ‎12-07-2012

Re: Lens Focus Question

"What difference does it make if Lightroom does the lens correction as a preset or if the correction is done in the develope mode?"

 

Do you mean, as a preset or as if you do it in the Develop Module? If I understand you correctly, it makes no difference.  It is just easier to do it as a preset because it should be done to every photo.  Doesn't matter that it is a BIF.

I am a big believer in post editing because that is where great photos are made. Lens correction is just one that all photos should have done to them.

 

" I would like to get closer to the birds ..."

 

Although, this is the best advice, you have to work with what you have.  Perhaps a change in technique would help in getting closer. Good photographers always adapt and change. That is just part of the game.

 

1111.jpg

EOS 1DX and 1D Mk IV and several lenses!
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