Difficulty focusing with 7d / 100-400 zoom

DemiLion said:
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!
Click to expand...

So the max aperture affects focus speed, then?

A 300mm f4 would focus faster (better?) than a 300mm f5.6? All other things being equal?
 
jerry12953 said:
So the max aperture affects focus speed, then?

A 300mm f4 would focus faster (better?) than a 300mm f5.6? All other things being equal?
Click to expand...

The reason being that lenses autofocus 'wide open' (at max aperture) regardless of what aperture you're actually shooting at.

The larger the max aperture - the more available light. Light level (along with subject contrast and subject motion) being one of the key elements affecting autofocus.
 
Last edited:
dinners said:
The reason being that lenses autofocus 'wide open' (at max aperture) regardless of what aperture you're actually shooting at.

The larger the max aperture - the more available light. Light level (along with subject contrast and subject motion) being one of the key elements affecting autofocus.
Click to expand...

:thumbs:
 
You get a big step-up when you switch to a lens that is f2.8 or faster, as most cameras have special AF sensors that only come into play with fast lenses.
 
jerry12953 said:
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!
Click to expand...

I photograph birds, occasionally, but it would be a stretch to call me a "bird photographer". Still, here's one from this morning with the 7D and 100-400....

20120528_075823_2047_LR.jpg


One of the best ways to good results is to fill the frame as much as possible. Having a subject which occupies ~1% of the frame, followed by massive cropping, is not the recipe for success. You'll stand a better chance with a sharp prime, but that would be a stretch for the zoom, I think, in anything but ideal conditions, or a liberal dose of skill and luck.
 
500mm L f/4 IS seems to be very popular amongst the bird snappers, nice way to spend four or five grand if you have got it to spare
 
True. But that's where things like fieldcraft are so important. If you want to shoot something small then better to get closer than simply to crop tighter. The 7D and 100-400 are perfectly up to the task if used as intended.

Robins and wood warblers may not offer quite the same challenge, but here is an uncropped and unedited shot of a robin with my 7D and 100-400....

20100108_134922_1778_LR.jpg


I didn't use a hide. I simply waited patiently. For some birds maybe a hide is necessary. I don't know. I'm not a birder.

And filling the frame meant lots and lots of detail which far outweighed any concerns about noise or a little softness....

20100108_134922_1778_LR-2.jpg


Oh, and don't underestimate the importance of the light. It matters. For focus. For mood. For detail. For contrast. For IQ. etc. etc.. Shooting into the shadow side of a miniscule subject upon which you can't even lock focus, and with strong competition for attention from the background..... why bother?
 
Last edited:
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...

I also have set my new 7D up as described here and first time out at a foggy Bempton the combination was fantastic.

Maybe if you reset all the settings to factory defaulkts and start again.

Good luck :)
 
jerry12953 said:
Swans and geese are pretty damn big birds though.......

Not so easy to fill the frame with a wood warbler!:)

What I'm trying to do, actually is "birds in the landscape".

like this -
Click to expand...
OK - just seen your edit. If that's the sort of image you're after then you really should do fine with the 7D and 100-400, but if that's as far as the challenge goes I don't see why a 60D, 50D or 40D wouldn't be equally up to the job. It's the pixel peeping that is the ruin of cameras, lenses and photographers. If you don't intend to take that approach then you should be fine.

Personally I'd prefer a bit more bird and a bit less environment, but they're not my photos. :)
 
tdodd said:
OK - just seen your edit. If that's the sort of image you're after then you really should do fine with the 7D and 100-400, but if that's as far as the challenge goes I don't see why a 60D, 50D or 40D wouldn't be equally up to the job. It's the pixel peeping that is the ruin of cameras, lenses and photographers. If you don't intend to take that approach then you should be fine.

Personally I'd prefer a bit more bird and a bit less environment, but they're not my photos. :)
Click to expand...

Well, in that case so would I. Several times the bird came a lot closer but focus was impossible. Hence my frustration.
 
jerry12953 said:
Well, in that case so would I. Several times the bird came a lot closer but focus was impossible. Hence my frustration.
Click to expand...

OK. Well so long as the focus distance limiter was not the reason for the obstinate focus I think it comes down to working out a solution on the spot - looking for areas of high contrast on the subject, or something close by in the scene which appears to be at an equivalent distance.

For example, looking at your second image, if you were to try to focus on the bird's chest I can see the possibility of a problem, but moving the focus point around the bird a little I would really expect the camera to be able to find something to latch on to. I'm guessing, though, that this wasn't actually a problem shot, unlike the earlier example.

If you are having problems, and the bird is perched rather than flying then make sure you're in One Shot AF mode. It should help. AI Servo is great for things that move, or static things in easy conditions, but One Shot can do a better job when the camera is struggling to find contrast.
 
Right, I've just been out in the back garden at 20:10 tonight (camera clock was on GMT). Daylight pretty weak, about 4-5 stops below "sunny 16", and my 7D and 100-400 had no problem locking focus onto birds darting around in a bushy shrub or blending in with a background of the same colour and tone. These were all hand held with Spot AF in One Shot mode at 400mm, 1/400, f/5.6, 800 ISO.

As photographs they suck, and the IQ close up is ropey, but the AF was fine.

20120528_190953_2146_LR.jpg


20120528_190956_2147_LR.jpg


20120528_191051_2150_LR.jpg


20120528_191101_2153_LR.jpg


20120528_191111_2156_LR.jpg


Here's the first one with a few tweaks, still presented as "environmental".

20120528_190953_2146_LR-2.jpg
 
Last edited:
I popped out again this morning to have another crack. Light still not dazzling, at least from my shooting perspective, and mostly back lighting the subjects, so far from ideal, but once again the AF had no difficulty locking on to the right subject. This includes birds buried in twigs, dark birds in the shadows at 1600 ISO, distant birds with nearby interference, and a plane so far away that through the morning mists and poor light direction it is barely visible, but no problem with instant AF lock.

The only subject which gave some hesitation was the shaded blackbird, which needed to pick up on the contrast with the background at the edge of the bird rather than the dark body of the bird itself and required me to wiggle the camera around until lock was secured.

Everything here was shot with Spot AF and One Shot.

20120529_053227_000.jpg


20120529_053257_000.jpg


20120529_053435_000.jpg


20120529_053526_000.jpg


20120529_053609_000.jpg


20120529_075029_000.jpg



Again, these are not good photos, just examples of focus being secured. A sharper lens would be preferable, as well as a higher shutter speed and lower ISO, but this is all I have. Results would be much better with the light working for me instead of against me, but why make things easy when you're trying to challenge your gear? To be honest I wouldn't actually call this a challenge in any case, but I'm not sure what I need to do to emulate Jerry's problematic circumstances. It just works.

Jerry, can you give any more information about the shooting conditions which are causing you problems? I mean, I can see your photos, but I don't understand why there is a problem.
 
Last edited:
All very interesting. I really appreciate that you have taken SO much time and effort to try to replicate my problem, Tim. But it seems like you have failed!

It does look like there is a problem somewhere along the line with my gear, possibly the lens, possibly the 7d. Unfortunately I've sold the 40d so I have no alternative to the 7d - although I recall that several other posters said they have similar focusing problems with the same combination.


What I was trying to do was photograph the wood warbler, which is a small greenish/brownish bird, as you can see, in amongst branches and twiggery under the canopy in spring woodland.

Quite often it would lock focus successfully.

But to my great frustration sometimes it would lock on to something behind or in front of the bird, sometimes it wouldn't focus at all, sometimes it would focus on the bird but not lock and it was impossible to release the shutter.

I tried the same sort of thing with a pied flycatcher which is black and white and I don't recall the same problem. I've also done quite a lot with seabirds on cliffs and it seemed to focus fine.

This suggests a problem recognising a low contrast subject, perhaps?
 
jerry12953 said:
What I was trying to do was photograph the wood warbler, which is a small greenish/brownish bird, as you can see, in amongst branches and twiggery under the canopy in spring woodland.

Quite often it would lock focus successfully.

But to my great frustration sometimes it would lock on to something behind or in front of the bird, sometimes it wouldn't focus at all, sometimes it would focus on the bird but not lock and it was impossible to release the shutter.
Click to expand...

Jeremy most of my photography is photographing small birds, I use Nikon kit but the following settings should be possible on your Canon gear.

Rear button focus, disabling focus from the shutter release, this allows me to stop the camera homing in on a distracting branch / twig once I have focus on the bird, as once I have focus I let go of the button.

I have set my shutter to release when I tell it, not when it only has focus confirmation.

Single centre point focus, it is the most sensitive and eliminates other points locking on an item with stronger contrast.

I always position myself with the sun behind me, I rarely take shots up high in the tree with a bright grey sky behind the subject, they never look good.

I shoot at 1/500 and f7.1, faster shutter speed if the light allows, stopping down increases the depth of field and gives some latitude to cover minor focus errors.
 
Well contrast is always the key, and sharply defined, bold, contrasty edges in your subject are the best. The actual light levels are not as important as the visible contrast in the subject. Cameras these days don't need much light in which to focus, but without contrast they are sunk. If your subject is lacking contrast then find a way to let the camera see some. Pick the branch the bird is on, for example, rather than the bird itself, and use subject outlines as a possible source of a contrast edge instead of aiming straight at a plain toned belly.

I wouldn't normally bother with woodland shots - not my thing - but I'll take the camera out today when I walk the dog and see how I get on. I'm as interested to learn about my equipment and its limits as anyone. Watch this space. :)

EDIT :Just seen Martyn's reply. I agree completely with all his advice and opinion. It's no different for my Canon gear. Get the sun over one shoulder and try to avoid shooting against a bright sky. Under the canopy that may not be easy, which is why I don't shoot that way. This is my more typical angle of attack and lighting situation; subject size too. No edits on this...

7D + 100-400 at 390mm, 1/1000, f/5.6, 800 ISO.
20100126_141237_2635_LR.jpg
 
Last edited:
Well I took the camera with me this morning while I walked the dog and did my best to seek out some challenging birdies in the canopy, but there were very few visible, never mind photographable. So I shot a varied assortment of stuff, some of which might fit the brief at least a little. The only time the focus got itself tied in knots was when I had twigs crossing directly in front of the reed bunting and the camera couldn't make up its mind what to focus on. Apart from that it was a sterling performance.

Here's a short slideshow. Everything was shot at 400mm and f/8, with varying shutter speeds and ISOs to suit needs. All are uncropped apart from the dog, but several have been tweaked. Subjects are dead centre because I was testing focus, not composition, and since the subjects are all so small there is plenty of cropping potential to improve framing.

https://picasaweb.google.com/106744...gCMn04c_73KudPw#slideshow/5747950059072453842

The whitethroat result is pretty fair, considering the obvious need to snipe between the reeds....

20120529_135632_000.jpg
 
My experiences echo Tims...

I have extensively used the &d and 100-400 to shoot various shots without any major issue in AF performance....

Some examples...







a quickr pickr post
 
Jeremy I'd consider trying another long lens like the 400mm f5.6 or the 300mm f4 and see how you get on, at least it removes a variable from this equation.

Despite it's popularity, I didn't really get along with my 100-400 either, although mostly because I just found it a bit unwieldy rather than any focusing issues. I traded it for a 300 F4 L IS which is now on my 7D the majority of the time, a bit shorter yes, but it has close focus and IS, so pretty good for flowers & any random wildlife too :)
 
Just thought I'd update this.....I'm sure you're all dying to know......;)

I've tried a couple of different combinations, and compared ease of focusing on "difficult" subject matter with each. There wasn't a lot of difference, so I just need to understand the limitations of my gear. Combo's were -

7d + 200mm + 1.4x TC
7d + 100-400mm zoom
5d2 +100-400mm zoom

It wasn't at all necessary to find a bird in foliage, different foliage at different distances was just as tricky.

Thanks to all who contributed ......
 
Last edited:
You must log in or register to reply here.
Back
Top