Difficulty focusing with 7d / 100-400 zoom

jerry12953

jerry12953

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Jeremy Moore
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New Canon 7d / secondhand 100-400 zoom.....originally posted in talk nature but hoping for more response here.

I'm using the central spot focus point and recomposing where necessary. Problem is, sometimes it just won't focus. I can point the central spot at a bird on a branch and it will sometimes focus in front or behind the bird, or on nothing; sometimes it will find focus but not lock on making it impossible to press the shutter.

Maybe I'm asking too much of autofocus? A wood warbler in spring foliage.....is that just too green on green for the AF mechanism to recognise the bird?

Most of the documented 7d focus problems seem to involve incorrect focus rather than no focus.

Any thoughts? (And I have read p98 of the manual;))
 
I have the same combination, and would agree that it is not entirely consistant - it generally works as expected, however even using the central spot focus, it does not always pick up on a small object (for example, it can struggle with noticing a branch that is about the same width as the 'inner' focus spot, leaving the focus on the objects nearby). Anything that roughly fills the 'outer' focus box is normally ok (assuming that there is enough light!)
 
What have you got the AF set to; ie, spot, point, point + assist, area, auto etc?

Have you disabled prevent shot being taken when AF not acquired (can't remember the full CFn description?
 
DemiLion said:
What have you got the AF set to; ie, spot, point, point + assist, area, auto etc?

Have you disabled prevent shot being taken when AF not acquired (can't remember the full CFn description?
Click to expand...

There are a lot settings which I just haven't got to grips with yet. But as far as focusing goes I'm using centre spot focus. (the smallest target area).

Custom function 3 settins are -

1 (sensitivity) slow (as recommended on web for tracking birds)
2 (AI servo 1st/2nd img priority) 0
3 (AI servo AF tracking method) 0
4 Lens drive when AF impossible - 0 (Focus search ON.)
6 AF area selection mode - 19 point and zone disabled.
7 Manual AF pt. selec. pattern - 0 (stops at Af area edges)
9 Display all AF points -enable
10 Focus display in AI servo/mf - enable

I think those are the important ones although those relating to AI servo are not relevant to this situation, are they?

I had a lot of success over the weekend on Skokholm island when subjects were more easily distinguishable from backgrounds. Maybe I am asking too much of AF?
 
EdR said:
I have the same combination, and would agree that it is not entirely consistant - it generally works as expected, however even using the central spot focus, it does not always pick up on a small object (for example, it can struggle with noticing a branch that is about the same width as the 'inner' focus spot, leaving the focus on the objects nearby). Anything that roughly fills the 'outer' focus box is normally ok (assuming that there is enough light!)
Click to expand...

That seems to be my experience so far. Interesting.
 
I presume you have the min focus distance set to 1.8m and not 6.5m?
 
do you have a sample OOF pic?
 
jerry12953 said:
There are a lot settings which I just haven't got to grips with yet. But as far as focusing goes I'm using centre spot focus. (the smallest target area).

Custom function 3 settins are -

1 (sensitivity) slow (as recommended on web for tracking birds)
2 (AI servo 1st/2nd img priority) 0
3 (AI servo AF tracking method) 0
4 Lens drive when AF impossible - 0 (Focus search ON.)
6 AF area selection mode - 19 point and zone disabled.
7 Manual AF pt. selec. pattern - 0 (stops at Af area edges)
9 Display all AF points -enable
10 Focus display in AI servo/mf - enable

I think those are the important ones although those relating to AI servo are not relevant to this situation, are they?

I had a lot of success over the weekend on Skokholm island when subjects were more easily distinguishable from backgrounds. Maybe I am asking too much of AF?
Click to expand...

Change from spot to point focus.

Set:

2. 1
4. 1

That should help a bit.

Don't use spot focusing for distant objects. It's designed for macro!
 
Totally agree with EdR in that it's picking out something other than the bird, hard to avoid on a lot of occasions

Mark's advice above is well worth heeding, point focus is like a concentrated centre point, ideal for picking out and focussing on something like an eye rather than just the head
 
hollis_f said:
As I said in the other thread - read page 89 of the manual. Specifically the bit that says
Click to expand...

It was experiencing the problem in normal spot focusing mode that made me switch to centre spot focusing. I can understand why it would be difficult with a moving bird but I would have thought it should be ideally suited to small birds.
 
jerry12953 said:
And another thing! (Should be in capital letters.....)

Coming from a 5d2 I'm surprised at how noisy the 7d is! :eek:
Click to expand...

Oh don't get me started on that! :bang:

I'm not having any issues focussing with my 7D and 100-400mm... I think a little side-by-side comparison at Ynys-Hir might be in order at some point! :)
 
It's hard to judge how far away the subject is but let's say it's 10m, at that distance the DoF is 13cm which is just about this size of the bird. Also, there is a heap of branches and twigery near the subject (min distance) and blue sky through the the tree (max distance)to confuse the camera.

Was it locking onto something else or not locking at all and was the motor 'hunting'?

Looking at that pic I think it's a big ask for that body lens combo to attain perfect lock in that situation.
 
admirable said:
It's hard to judge how far away the subject is but let's say it's 10m, at that distance the DoF is 13cm which is just about this size of the bird. Also, there is a heap of branches and twigery near the subject (min distance) and blue sky through the the tree (max distance)to confuse the camera.

Was it locking onto something else or not locking at all and was the motor 'hunting'?

Looking at that pic I think it's a big ask for that body lens combo to attain perfect lock in that situation.
Click to expand...

Not when it says 44.4m in the Exif!

I agree though - it's asking way too much of the combination.
 
I saw that in the exif but I don't think it's accurate
 
admirable said:
It's hard to judge how far away the subject is but let's say it's 10m, at that distance the DoF is 13cm which is just about this size of the bird. Also, there is a heap of branches and twigery near the subject (min distance) and blue sky through the the tree (max distance)to confuse the camera.

Was it locking onto something else or not locking at all and was the motor 'hunting'?

Looking at that pic I think it's a big ask for that body lens combo to attain perfect lock in that situation.
Click to expand...

In this case it locked on to something else but often it wouldn't lock on to anything and the shutter button couldn't be pressed. :bang: even if the subject was plainly in view and in focus :bang:

Maybe I just am expecting too much. I had a great weekend on Skokholm island recently and I had very few problems with seabirds on cliffs

Re: 44.4 m - it is possible that the far twigs which are in focus are that far away, isn't it?
 
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Are you using one shot or machine gun mode?
 
I'm also struggling with the 7d auto focus not as easy to use as my 600d
i was expecting the all singing all dancing 7d Af to be easier and better than the 600d
Struggling to get shots in focus no matter what I try
seems hit and miss
I'm sure I'll master it in the end
 
Rebel t3i said:
I'm also struggling with the 7d auto focus not as easy to use as my 600d
i was expecting the all singing all dancing 7d Af to be easier and better than the 600d
Struggling to get shots in focus no matter what I try
seems hit and miss
I'm sure I'll master it in the end
Click to expand...

There's quite a lot on the internet about poor focusing on the 7d. They reckon that canon have known about a problem for along time but done nothing about it.

It seems to be a different problem however....more of a front/back focusing thing, as opposed to the lack of focus that I've experienced.

I too was expecting better results from the 7d.
 
Jeremy a couple of things that help with Nikon kit, not sure if it would be the same with canon, but worth a try.

1. Clean the lens contacts, pencil eraser is the recommended tool for this. A poor contact can cause focus lagging / hunting.

2. On my Nikons the AF sensors are below a slot at the base of the mirror box, dust can accumulate there, on a Nikon raise the mirror for cleaning and blow out the slot with a rocket blower. I have known this resolve issues in the past on Nikon bodies.

As I said I know nothing of how a Canon works, but I would have thought the principals are the same, and at the stage you are at, anything is worth a try :thumbs:
 
The bit I'm not getting is this "often it wouldn't lock on to anything and the shutter button couldn't be pressed". The shutter should fire even if it is not focused correctly.

Perhaps you have a custom setting activated to disable the shutter from firing somewhere?

I would also try back button focusing.
 
Martyn... said:
Jeremy a couple of things that help with Nikon kit, not sure if it would be the same with canon, but worth a try.

1. Clean the lens contacts, pencil eraser is the recommended tool for this. A poor contact can cause focus lagging / hunting.

2. On my Nikons the AF sensors are below a slot at the base of the mirror box, dust can accumulate there, on a Nikon raise the mirror for cleaning and blow out the slot with a rocket blower. I have known this resolve issues in the past on Nikon bodies.

As I said I know nothing of how a Canon works, but I would have thought the principals are the same, and at the stage you are at, anything is worth a try :thumbs:
Click to expand...

Thanks :thumbs:

As the 7d is new I doubt it is the latter but I'll try cleaning the lens contacts, although as said above I've had some good results in possibly easier situations, where the actual point of focus is much clearer.
 
admirable said:
The bit I'm not getting is this "often it wouldn't lock on to anything and the shutter button couldn't be pressed". The shutter should fire even if it is not focused correctly.

Perhaps you have a custom setting activated to disable the shutter from firing somewhere?

I would also try back button focusing.
Click to expand...

CFnIII.2
 
admirable said:
The bit I'm not getting is this "often it wouldn't lock on to anything and the shutter button couldn't be pressed". The shutter should fire even if it is not focused correctly.

Perhaps you have a custom setting activated to disable the shutter from firing somewhere?

I would also try back button focusing.
Click to expand...

No, I was surprised as well. The bird was there, it was in focus but not locked on and the shutter release would not work. :bang:

Once it locked on the shutter release was fine.

I've been using back button focusing a bit since then.

So many ******** custom settings on the 7d though...who needs em?
 
jerry12953 said:
Thanks :thumbs:

As the 7d is new I doubt it is the latter but I'll try cleaning the lens contacts, although as said above I've had some good results in possibly easier situations, where the actual point of focus is much clearer.
Click to expand...

Never dismiss an option "because it is new", check, clean and eliminate it as a possible cause. :thumbs:

I take your point though that it does work on certain subjects, which makes it a swine to nail what the issue is, good luck getting to grips with it.

I had wondered if it was because the lens is f5.6, but my long glass and TC's is at f5.6 and with the 1.7x fitted f6.7 and they will pick up birds without too much problem.
 
I have the same combination and 99 times out of 100 it locks on. I use Deep Green Photograpys as my base settings. Even if you dont try or use them its a good read for a new 7D owner :)

I do think your shot above is a tad optimistic?
 
Kev.s said:
I have the same combination and 99 times out of 100 it locks on. I use Deep Green Photograpys as my base settings. Even if you dont try or use them its a good read for a new 7D owner :)

I do think your shot above is a tad optimistic?
Click to expand...

Thanks for the link. I'll read it at leisure.

You may be right about my expectations. But there were cases where I just couldn't believe it wouldn't lock on.

Thanks to all for their suggestions.
 
Based on the one sample photograph, and assuming the subject to be that fuzzy blur in the centre, it looks to me as if you have a dark subject which is possibly in its own shadow and is offering nothing with sufficient contrast for the camera to lock on to. Sometimes you can work around that by aiming for the edge of the subject where there might be more contrast with the background, such as clear sky, but in this case the background is so cluttered and the twigs and branches have such strong contrast with the sky that they look almost certain to win the battle.

What you can try is repeatedly attempting focus, with slight movements of the camera until you get lucky and it locks the right subject, but with something like this I think your results are not altogether unexpected. One advantage of BBF is that once/if you can get a focus lock you can then release the BB and have the freedom to recompose or wait for the decisive moment without worrying that the shutter button will cause a refocus that lands you in the poo again. Also, with BBF the camera will allow the shutter to be released even when focus lock is not secured.

If you have a tripod then another possibility is live view and manual or live AF with 10X magnification to aid with focusing. I've used that approach several times in the past, even with good light, simply to make sure focus was nailed on the subject and not a little bit off. It also works even with a TC fitted to an f/5.6 lens - handy for moon shots, for example.

Out of interest, would you say your lens is a sharp copy, because, just thinking aloud, a soft lens is presumably going to pass lower quality data to the AF system than a piercingly sharp one, and since focusing is always performed with the lens wide open that is another point to consider. What may not work too well with a slow (f/5.6) and relatively soft 400mm zoom lens might actually be much better with a fast (f/2.8!) 400mm prime.
 
Many thanks for your input, Tim.

I think I just have to accept that the situations I was asking my equipment to cope with were just too difficult -small, very mobile, pale green birds moving quickly amongst twigs and leaves. In other easier situations the combo has worked fine, although I am surprised at how noisy the 7d is!

Being new to the 7d I wasn't sure what to expect. The lens is not new, I bought it 2nd hand, so it may not be a top quality performer. Some of the results look a bit soft.

I'm now using BBF and it does have its advantages as you have pointed out, Tim. Wouldn't using live view on a tripod be a bit too restictive in most bird photography situations though?

all the best,

jerry
 
Jerry

I have been shooting this combination for some time and at first was concerned with the issues that you note. So did lens micro adjustment etc etc. Over time i have begun to realise that the 100-400 at 400 is slow to AF compared say to 7-200, often i manually focus to the general area as it is quicker and the Af then kicks in well.

Light is very interesting - your image to me is dark so i think my lens would hunt around. Yesterday i was shooting mid size birds of prey but with the light contrast it proved very difficult when they flew past contrasty areas even with all the custom settings on - I did get some keepers but not as many as you might think.

It is a good lens but does have some serious limitations (as does the 7d), it took me a while to understand what these were - I am considering the 400mm prime but the not the expensive one.
 
pauld said:
Jerry

I have been shooting this combination for some time and at first was concerned with the issues that you note. So did lens micro adjustment etc etc. Over time i have begun to realise that the 100-400 at 400 is slow to AF compared say to 7-200, often i manually focus to the general area as it is quicker and the Af then kicks in well.

Light is very interesting - your image to me is dark so i think my lens would hunt around. Yesterday i was shooting mid size birds of prey but with the light contrast it proved very difficult when they flew past contrasty areas even with all the custom settings on - I did get some keepers but not as many as you might think.

It is a good lens but does have some serious limitations (as does the 7d), it took me a while to understand what these were - I am considering the 400mm prime but the not the expensive one.
Click to expand...

I wonder if any serious bird photographers actually use the 7d or 100-400 zoom, in that case. It could end up being an expensive addition to my list of subject matter!
 
The 7D/100-400mm is a perfectly workable combination provided you realise the limitations of the kit and work within it.

As for focus speed, I found mine rapid enough for both field sports and BiF, as long as you bear the above in mind. It's hardly surprising that a 70-200 focuses faster than the 100-400 at max focal length- it's at minimum a full stop faster!
 
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