Focusing not consistent

[Pumptruffle]

Hi all,

I have been out quite a bit lately, making the most of the nice weather. But I have a slight focusing issue, I'm not sure if it's just me, or if there really is a problem.

I'm using a 100-400L IS on a Canon 80D and I think the centre focus point may be a bit soft/misaligned. I have been using the centre focus point and shooting in high speed bursts, but within a group of shots the focus point seems to move about. It's very evident in AI Servo mode, which I would assume may be normal, but it also happens in one shot too.

It's quite noticeable as I mainly shoot birds, in one shot the eye will be perfectly in focus, in the next shot the focus point will have moved somewhere else. Sometimes, after focusing on the eye and getting the shot, upon review the eye is not in focus at all but somewhere else is!

Is there an issue or is it just me?! I've attached a few shots of a damselfly to show what I mean.

Thanks in advance.

Focus on the eye


Focus moved onto the thorax/wings


Focus again on wings

[Shadowman]

There will be some camera shake between bursts, try testing on a still object and see which of the burst is sharpest.

[Stagecoach]

Welcome to CiC,

I would suggest that trying to come to any focus accuracy conclusion from these shots is pointless as we do not know exactly where you and what the camera actually focussed on. But what we can tell is that your rig and settings have provided sharp/in focus detail on some focal plane or other within the frame.

The problem with focusing on any small critter is that the area within the 'focus calculation box' can so easily change between near and far subject especially when hand holding or taking bursts due to camera movement.

To come to any meaningful assumption I would suggest your first test would be to shoot a fixed target from a tripod and confirm if you are getting consistent results with AF. Set up a good target, take a shot using AF, very carefully manually de-focus and take again. Repeat several times, de-focusing in opposite directions each time.

Then compare all these images and see if there is a noticeable difference.

[IzzieK]

I have Focal Pro to calibrate my lens but time constraint, I haven't done it yet. But a few weeks ago I did do what Grahame suggested herebefore my software arrived , or least the same idea and know how far my focus is sharpest. Tripod helps with this kind of task.

[Pumptruffle]

Thanks for your help, I will set up the test as suggested by Grahame. It's one of those situations where I'm not sure if it's just me expecting too much, or if there is a focussing issue!

With the high speed burst firing off shots as quickly as it does I wouldn't have expected the focus point to jump about so much.

[george013]

Thanks for your help, I will set up the test as suggested by Grahame. It's one of those situations where I'm not sure if it's just me expecting too much, or if there is a focussing issue!

With the high speed burst firing off shots as quickly as it does I wouldn't have expected the focus point to jump about so much.

I wonder if refocussing is done with high speed burst.

George

[chauncey]

FWIW...I've got a history of shooting BIF images in series then combining them in PS for panoramas.
My, now elderly, Canon 1Ds3, from a tripod, would capture 10 images before filling the buffer.

The puzzling part was that only about 20% of these series had every bird in focus and...
there was no consistency in which, of the 10 images, had OOF birds. Go figure.

[Dave Humphries]

Hi Paul,

When you say "I wouldn't have expected the focus point to jump about so much", do you simply mean that different parts of the subject were sharper in different shots? (I think this is what you mean)

OR:

Do you mean that when observing the series of shots in your camera manufacturer's software, or when viewing on camera LCD, you have turned on the feature that allows you to see (via an indicator) the actual focus point it used, and this point moves about within the frame between shots?

Either way, the resultant images would still look as shown above.


I ask because if it were the latter, the solution may be as simple as changing a setting in your camera's AF menu.

The reason I ask is because some AF systems, even if you have "single AF point" selected, may, in say "3D tracking" mode, use points other than the one you manually chose. I'm not a Canon shooter at all, far less an 80D user, so my terminology may not match what Canon use.

Cheers, Dave

[Pumptruffle]

Hi Dave, it's that there are different areas of sharpness. Although now you mention it I will check the point of focus and see if that moves with the sharpness. I haven't had the camera long and still getting used to it, it's quite a step up from my old 500D.

[Manfred M]

Paul - your results are not at all surprising, especially in AI Servo mode. In this mode the camera is continuously adjusting the focus point and the softness you see is just part of the camera "seeking" the appropriate focus point. By selecting the camera to use this focus mode, you have in fact directed it to do so. The autofocus mechanism will overshoot and undershoot the actual focus point (especially on a living target that is in fact moving, as the AF focus lag will amplify the impact of an non-stationary subject) and if you happen to press the shutter release during this "seek" phase, you will get the effect you are referring to.

Add the fact that you are shooting with a long lens with a very shallow DoF, especially at the longer end, I'm not at all surprised that you are seeing this. Same comment goes for the macro shots that you have posted This is why you should be shooting these subjects in a burst mode (fast burst) and some (but not all) of the images should in fact work out to be sharp.

There is of course a possibility that your lens has not been set up properly and it is focusing ahead or behind the subject, but that should result in images that are consistently front / back focused, and that does not seem to be the case here.

[William W]

I think that you are mixing up a few issues which are related but not the same. Also you might not be selecting the best AF Functionality for each shooting scenario.

As an example: Photographing "birds" with an 80D typically could require a different AF set-up to the three sample images that you have provided. Photographing "birds in flight" can be different again - on that point, your OP is not exactly clear.

Performing a controlled test as described by Grahame is a good idea and will put more light of the accuracy of the AF.

But I think that we will find the that issues you are having are more user related and about setting the camera for best outcomes for any one shooting scenario, than they are camera or lens function errors.

The EOS 80D has a complex selection apropos AF Functionality. If there are user related issues and you want to nail those issues then the best way to go about that will be to discuss each shooting scenario separately and using an example or two and the details of the shots.

***

. . . I have been using the centre focus point and shooting in high speed bursts, but within a group of shots the focus point seems to move about. It's very evident in AI Servo mode, which I would assume may be normal, but it also happens in one shot too. I've attached a few shots of a damselfly to show what I mean.

If you want specific comment about the AF on these three images, then would you please post the same three images but next time post them:UNcropped.

***

I wonder if refocussing is done with high speed burst.

Yes, in the configuration as described and using AI Servo: the EOS 80D does.

WW

[rpcrowe]

I would bet that more focus problems are caused by the camera choosing the incorrect focus point than by errors of focus in the lens...

I normally shoot my macros in manual focus, single shot mode. I move the camera back and forth slightly until the camera has achieved focus where I want it to focus and shoot when that focus is achieved. I am sure that this is not the only way to do it but, it works for me!

BTW: I mostly shoot my macros with a 90mm Tamron macro lens but, I am determined to try my new 100-400mm f/4.5-5.6L IS II lens for macro/close-up photography...