Autofocus fail for distant subjects. 7D2+5D3 (1 Viewer)

jack2964 · Sep 10, 2018

I love to shoot BIF (raptors) and the place I visit the birds are very far away. Occasionally they do approach to about 50 meters to me but most times they are about 100m or beyond where most of the predating action occurs.
With birds against the sky the focus acquisition is satisfactory but once they drop against a background of trees both cameras will grab the background. I have tried all the various AF cases plus tweaking in the AF Menu and nothing seems to work. I use back-button AF. Am I asking too much from the cameras or am I doing something wrong? Lenses used are 500/F4 Mk1; 400/5.6 and 300/2.8 Mk1.
Would love to hear from experienced shooters how it is done.
Thanks in advance.

Malcolm Stewart · Sep 10, 2018

I'm based in the UK, and I expect conditions here are very different to Thailand - which I assume is where you're having trouble. Gear wise, I have the lenses you list, and a 7D2. I mainly use the EF 500 F/4L on my 7D2, but it also works well on my 1D IV. I assume that you're using AIServo and capturing the birds AF-wise for a short time, before firing the shutter? If that's not working, could there be light wavefront problems between your bird subjects and your lens? I'm thinking of air convection currents between your subjects and you. AF on Canon's DSLRs uses phase across the lens aperture, and I imagine it might well be sensitive to problems here. (In the UK, I've had problems with wide-aperture birding telescopes looking out over hot roofs.)

Hope this helps...

jack2964 · Sep 10, 2018

Before posting here I did some googling and am aware of heat haze but I can't tell if that's really the problem. It does get hot when the sun is out.
For now I can only conclude my subjects are way too small within the frame and the cameras' AF can't detect enough contrast and also compounded by mostly brown feathered birds against background of trees. I sure hope my explanation is wrong and better technique or proper camera settings might improve the focusing.
Yes I always am using AI servo. Thanks for your input Malcolm.

Dave Williams · Sep 10, 2018

If the subject is 100m away I think it's a big ask to nail focus with a confused background. Single AF point expanded to 5 and hope for the best would be my choice. If it's a slow moving target you are in with a shout!
At that distance I'm sure heat distortion will play a big part in soft images though.

Chosun Juan · Sep 10, 2018

jack2964 said:
Before posting here I did some googling and am aware of heat haze but I can't tell if that's really the problem. It does get hot when the sun is out.....

You could check it by looking through some good quality 8 or 10x binoculars. If your targets look hazy in your typical shooting conditions, then it's likely they will in your lens too. How that affects AF - you'll have to run some tests in different conditions, using the bino's for reference.

Chosun :gh:

CalvinFold · Sep 10, 2018

Are you making sure not to shoot at the very max zoom ability, but just a small amount back from maximum?

Dave Williams · Sep 10, 2018

CalvinFold said:
Are you making sure not to shoot at the very max zoom ability, but just a small amount back from maximum?

He appears to use prime lenses Calvin. A friend and I both came to the conclusion that what you suggest was true with our respective 100-400 lenses though.

CalvinFold · Sep 10, 2018

Dave Williams said:
He appears to use prime lenses Calvin.

Go it, my ignorance at play, sorry.

lewis20126 · Sep 10, 2018

jack2964 said:
I love to shoot BIF (raptors) and the place I visit the birds are very far away. Occasionally they do approach to about 50 meters to me but most times they are about 100m or beyond where most of the predating action occurs.
With birds against the sky the focus acquisition is satisfactory but once they drop against a background of trees both cameras will grab the background. I have tried all the various AF cases plus tweaking in the AF Menu and nothing seems to work. I use back-button AF. Am I asking too much from the cameras or am I doing something wrong? Lenses used are 500/F4 Mk1; 400/5.6 and 300/2.8 Mk1.
Would love to hear from experienced shooters how it is done.
Thanks in advance.

I'm a rank amateur using a 7Dmk2 with the 100-400 mk2 and always have the same problem as you - the autofocus on the 7D mk2 is basically no use, in any mode, for anything vaguely distant against a background. OK against the sky as you say. The small square focus mode (inside central square) doesn't seem to work at all - I've tried photographing owls in cavities, at say 50m, with the set up on a tripod and the focus won't pick up the well-illuminated owl. Fingers crossed the 7D mk3 has better autofocus.

cheers, a

johnf3f · Sep 10, 2018

100m for BIF - that's a long way! Even with my 800mm F5.6 L IS I don't bother when the subject is that far. Even if it is a big slow moving bird then the image degradation due to atmospherics is going to reduce it to a record shot under all but the most exceptional circumstances.

Is there a way you could get closer?

jack2964 · Sep 12, 2018

Thanks to everyone for replies. I guess I'll have to accept the targets are too distant and the cameras weren't designed to perform the way I wish they would. Most likely heat shimmering makes matters worse.
Sometimes when they get to within 50m as they may do when they chase after prey or engage in play I might get a few shots which aren't award winning for sure but gives me great pleasure in capturing the action. Just to give you an idea of the distance I attach a few pics I have taken with 7D2/500+1.4TC Last one is uncropped but resized. Distance would be about 100m.

Barred Wobbler · Sep 12, 2018

If the focus point moves even a fraction from the subject the 7dii focus is so rapid that it will grab the more interesting background behind the subject. I’ve had the same problem for years and the fault doesn’t lie with the autofocus, but with the accuracy of the pair of hands that is tracking the subject.

I’m once more in Spain in the Tarifa area for the autumn migration. Often the birds are distant, but often they are very close indeed. Against the sky it is fine, but against a hillside it’s a nightmare, because no matter how hard you try the wind will cause the bird to deviate or the momentum of the lens will carry it just that fraction off target to allow the lens to refocus. In previous years I would pat myself on the back if I got a handful of focussed shots of, for example, a booted eagle flying past into the wind at a range of 50m against a hillside a hundred metres behind it.

This year I have found a solution. I use a sigma 150-600 sport and the sigma dock allows for customisation of focus settings. Before I had C1 set to 2.8 to 20m for the likes of close passerines and C2 set to 10m to infinity for fliers and distant stuff. A couple of months ago with this trip in mind I had a brainwave and reset my C2 to limit it to about 120m maximum. This also has the advantage of stopping me getting carried away and photographing approaching raptors at too great a distance. It has worked a treat. Where before I was hitting focus on one in ten or less, today I was tracking honey buzzards, eagles, kites and Egyptian vultures against a hillside and was failing to focus on maybe one in ten. The vast majority were spot on or almost so. If the wind buffeted the bird I might miss, but a pump with the thumb on the focus button found it again.

If I really need to focus on something over 120m, then I just set the custom switch on the lens to ‘Off’.

It’s been a revelation on this trip.

lewis20126 · Sep 12, 2018

Barred Wobbler said:
If the focus point moves even a fraction from the subject the 7dii focus is so rapid that it will grab the more interesting background behind the subject. I’ve had the same problem for years and the fault doesn’t lie with the autofocus, but with the accuracy of the pair of hands that is tracking the subject.

This doesn't explain the camera's inability to focus on a relatively small stationary object, when the camera is tripod mounted. Re-focus is obviously an issue on moving birds, but the camera has a definite problem with relatively small subjects, per se. Yes, it's great to have birds close, but not all are so obliging.

cheers, alan

Barred Wobbler · Sep 12, 2018

lewis20126 said:
This doesn't explain the camera's inability to focus on a relatively small stationary object, when the camera is tripod mounted. Re-focus is obviously an issue on moving birds, but the camera has a definite problem with relatively small subjects, per se. Yes, it's great to have birds close, but not all are so obliging.

cheers, alan

That’s not what I read from the op, to which my reply was directed.

jack2964 · Sep 13, 2018

I do admit I have great difficulty keeping my target on the chosen focus points be that single point or zone AF. All points being the easiest of course but it then grabs the background even faster. I find the 5d3 a little worse than the 7d2 in this regard.

I have no knowledge of the Sigma 150-600 but am intrigued by your being able to assign C1 to C3 to specific focus distances. Are there any Canon long lenses that offer this or is it already hidden in some Menu I have overlooked?

jack2964 · Sep 13, 2018

@Lewis... I know exactly what you mean about the 7d2 failing to focus on stationary tiny subjects. For perched targets like owls, a raptor on a branch or a preening tiny song bird I often engage Live View with magnification at 10X and manually focus the target. I get decent results with this and added bonus is no mirror slap.
Edit: Always have remote shutter release handy for Live View.

mr_birdman · Sep 17, 2018

jack2964 said:
I love to shoot BIF (raptors) and the place I visit the birds are very far away. Occasionally they do approach to about 50 meters to me but most times they are about 100m or beyond where most of the predating action occurs.
With birds against the sky the focus acquisition is satisfactory but once they drop against a background of trees both cameras will grab the background. I have tried all the various AF cases plus tweaking in the AF Menu and nothing seems to work. I use back-button AF. Am I asking too much from the cameras or am I doing something wrong? Lenses used are 500/F4 Mk1; 400/5.6 and 300/2.8 Mk1.
Would love to hear from experienced shooters how it is done.
Thanks in advance.

Your biggest issue is distance and not knowing how your cameras and their AF systems work! 100m is too far for good focus acquisition generally (especially with small subjects) and to be able to achieve decent image quality overall. Try using a ghillie suit to be able to get closer to raptors or a 2x converter on the 500/4, but your AF will be not very good anyway with 1000mm focal length only reasonable with a blue sky background. With practice you can get very usable images with a 2x though.

But if you have to persevere, use spot AF (the smallest possible AF point) and set your AF tracking to slowest via custom functions then hope that you can maintain the AF point on the subject itself. I never use multiple AF points unless I am shooting against blue sky backgrounds. When you have mixed tonalities in the background, eg forests, hills etc and especially if your background tonal range is similar to that of your subject and you use multiple points, your AF points will pick one of the points to lock which has the greatest contrast available at that moment and if it is in the background then that's it. You will struggle to reacquire focus properly usually.

Everyone has different views on what is acceptable to shoot subject wise and with regards to the image quality as well. For me personally 100m is too far away for effective image making as a rule.

Best wishes

jack2964 · Sep 17, 2018

I know the images I get will never ever be sharp and crisp owing to subject distance. My aim is more to capture the action when a raptor swoops low to try to snatch food from storks foraging among the vegetation.
Unfortunately the spot I shoot at is a Non-hunting sanctuary and no one is allowed to wander or wade onto the marsh to get closer.
I'll keep in mind your tips and hopefully with more practice I might get some half decent at least acceptable shots for myself.
Thanks for your input.

HermitIbis · Sep 18, 2018

I like the three photos, apparently showing courtship flights. 7D2 background issues aside, your raptor shots are pretty good, considering the 100m distance.

In comparison, my Nikon V2 + CX70-300 did worse - lack of detail, sharpness. A peregrine with its prey (a dove) 5 meters away from its nesting place on a 80m tower. My own distance was roughly 100m.

I hope this post isn't seen as trolling. I am genuinely interested in comparing long-distance shots of 100m and beyond, as I regularly meet raptors or small waders at similar distances, and cannot get closer.

jack2964 · Sep 18, 2018

I am grateful for anyone to share their knowhow and experience with distant subjects. I know for sure at where I am shooting, I won't be getting sharp and fine feather detail images. However when I am in a hide shooting birds at about 4 to 8 meters and in reasonably good light I get decent results.
Browsing the many images on the net I am envious of guys who capture great BIF images with great detail and sharpness and I often wonder how far their subjects were.
I don't know about your Nikon gear so I can't comment. But I wouldn't be surprised if other brand cameras+lenses would face the same limitations. To resolve fine detail at long distances would require a very large diameter objective lens (think astronomical telescopes).

Autofocus fail for distant subjects. 7D2+5D3 (1 Viewer)

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