7D2 Auto-focus (AI Servo mode)

[awair]

Previously I was using the 7D with either 135/2L or 300/4L: the focus was always pretty accurate. I would generally use centre-spot. Occasionally my target would slip out of the middle, capturing background -or- I would miss an 'in-between' frames shot. Overall the camera performed as expected and I was happy with the results.

Naturally I started to lust after the (rumoured) higher fps and AF of the 7D2, to meet the perceived shortfall. Having purchased the 7D2 I am struggling to realise the camera's potential.

I've heard of the AI Servo issues, and am having difficulty getting as many keepers as before, so I'm trying to determine if it is me or the camera.

I think I've got to grips with the various cases of AI Servo, and sometimes realise that centre spot is not appropriate, but the camera seems especially sensitive and possibly inconsistent.

Swimming is the primary subject that I am having difficulty with: What are the recommendations for AF focus points and AF case for starts and swimmers in the water? I can normally achieve 1/1000 or better, with ISO below 1600.

I am getting some superbly focussed water droplets, and out-of-focus starts. I am leaning towards a different case and focus point for the start and in-water. Does this sound sensible?

Any tips or links would be much appreciated.

 

[awair]

Re: 7D2 Auto-focus - or is it me?

This is a straight crop from my 6D, no processing. I'm fairly pleased with result.

I realise that I was lucky with the timing, however, getting a similar shot with the 7D2 has proved much harder.

 

[Sabaki]

Re: 7D2 Auto-focus - or is it me?

7Dii auto focus capabilities were heavily promoted when the camera launched but in my opinion, it doesn't deliver.

I'm hoping the firmware update brings some magic as I am sick of a 10/15% keeper rate for BIF

 

[awair]

Re: 7D2 Auto-focus - or is it me?

And here's one that definitely(?) proves it wasn't me (this time)...

The previous three in the (burst) sequence all appear to be correctly focused.
(cropped to remove someone else's child - I believe that all the focus/exif data is still embedded)

 

[Spectrum]

Re: 7D2 Auto-focus - or is it me?

It is not you. I got mine over the winter and was very pleased with AF for high school basketball using my 50 f/1.2L (at f/2), 85 f/1.8, and 135 f/2. The focus was just as good as using the 1DX. But now that I am using my 70-200 f?2.8L II for softball and track, I am not as happy as I used to be. Even a 300 f/2.8L with and without the 1.4x II extender is hit and miss for baseball. I am hoping firmware will correct this. Eagerly waiting...

 

[ksgal]

Re: 7D2 Auto-focus - or is it me?

I would try to modify the case so that locking focus is the highest priority. some of the defaults leave it to second shot priority instead of first for af lock.. shutter will fire even if af isn't locked in focus. Then if that does improve the results, adjust to taste.

 

[awair]

Re: 7D2 Auto-focus - or is it me?

Thanks ksgal,

I have had slightly more success over the last weekend, using Case 6 & Automatic AF point selection (AI Servo).

However, the results still vary, depending on whether I am able to shoot the swimmers from a 45+ degree angle or somewhat flatter, across the start line.

If I shoot more or less head-on (45+ deg), then AF mostly captures the acceleration towards me, and the required changing AF point. But not always!

If I shoot across the start line, even with my preferred point pre-selected, I can then see the Automatically selected AF points jumping all over the place, and not where I want. I would say that I got less than 50% accuracy/predictability. Although some of the shots were quite acceptable, they were not of the swimmer/lane that I started with.

TIP: As a tip for setup, Case 6 seems to work well for the swimmers in the water as well, I use the new toggle lever to switch from Automatic AF point selection to Single-point Spot AF after the race start. I also use the joystick (centre press) to return the selected AF point to the centre.

 

[Marsu42]

Re: 7D2 Auto-focus - or is it me?

This is a straight crop from my 6D, no processing. I'm fairly pleased with result.

You don't need autofocus or tracking for this at all, if you know where the subject will be just pre-focus this spot. If it helps, you can use Magic Lantern's trap focus with this - it'll automatically take the shot once the subject is sharp (i.e. if the camera thinks so).

 

[awair]

Re: 7D2 Auto-focus - or is it me?

Thanks Marsu for the tip - will look at Magic Lantern for other scenarios.

In this case, I am trying to get a burst of 3-5 shots, so pre/manual focus won't be an option.

I did try manual focus for one start, and even though the camera indicated focus lock, the results contradicted this.
Also DOF from smaller apertures is not viable due to the light levels.

I'm attaching some examples, from a sequence of 8. These are as shot by the 7D2 (no crop, only with size reduced for posting). No.1 is out of focus (but shouldn't have been?), but the rest seem OK, although the focus did track to another lane in later shots.

 

[awair]

Re: 7D2 Auto-focus - or is it me?

And the final three frames...

 

[awair]

Re: 7D2 Auto-focus - or is it me?

I forgot to add - I 'cheated' with this sequence by using my 24-70, which gave me a more reliable chance of focus.

What I really want is a similar sequence of just one swimmer using my 135/2L - once I know what (I am or) the camera is doing, with regard to the AF point selection and tracking.

 

[Marsu42]

Re: 7D2 Auto-focus - or is it me?

In this case, I am trying to get a burst of 3-5 shots, so pre/manual focus won't be an option.

I understand your thinking, but being cursed with the 6d af system I've come to believe that one sharp shot is better than 5 "nearly" sharp ones that only work for downsized res. But with the 7d2 you definitely should have more luck

I did try manual focus for one start, and even though the camera indicated focus lock, the results contradicted this.

In that case, the tracking system would have failed, too - it's the same focus confirmation. The advantage of crazy-high fps speeds is that one image might turn out in focus even if the camera though it isn't (i.e. set "release priority" in the firmware).

No.1 is out of focus (but shouldn't have been?), but the rest seem OK, although the focus did track to another lane in later shots.

From the cameras I own (6d, 60d) the af tracking system definitely needs a short "swing in" time, so if you start tracking right away the first shots will be out of focus unless you set "focus priority" in the firmware.

 

[awair]

An update on progress since my last post.

My 7D2 is currently with Canon for a second time, and has received more "adjustments". They are convinced that there is nothing wrong with this camera, and I should use 'Auto Exposure' to solve my focus issues...

I've just shot another swimming gala (5000 shots over 2 days), at the same location as previously. I was lucky enough to be using my new 1Dx with 70-200/2.8L IS II (55%), in addition to the earlier lenses (300, 30%; 135, 15%).

I used (as before) a fixed setting for the entire day: Manual Exposure 1/1000 with f/2.8 (ISO 1600), f/4 (ISO 3200) or f/2 (ISO 800) with all three lenses wide open.

As before, one of my main aims was to get a burst of 6-10 shots of diving starts from the blocks.

Previously my 7D2 would confirm focus achieved (as reviewed in software, afterwards) but a couple of the sequence would be OOF. I couldn't tell if it was due to incorrect settings or technique, but I had read the (AF) manual!

While I would expect the 1Dx to produce superior results, it does have the same UI for AF settings (cases, points/zones etc). Accordingly I would expect similar accuracy of operation.

I was absolutely stunned and delighted with the results, even from the 300/4! Every burst captured all frames in focus, as expected. Typically this was either using Case 2 or Case 4, with Spot or Single point focus.

Apart from thoroughly loving the 1Dx and the results achieved, I can only assume that the 7D2 has been overhyped or I have a dud, in respect of AI Servo mode for the sporting action shots that I expected to capture.

 

[Act444]

So I'm not the only one then....interesting.

The 7D2 is a nice camera in general, but it let me down BIG time when I really put its AF system to the test at an indoor show. In fact, keeper rate was down from my old 7D even though I had the two cameras configured similarly. It went from ~60-65% down to below 40%...I figured the issue was on my end, perhaps needing to play around with the settings some more, but the AF tracking just seemed a bit inconsistent to say the least - at least with the 70-200 2.8 II. (it seemed fine with the 70-300L)

It almost has me already thinking of replacing it even though it's only barely a year old

 

[awair]

For those who would like a little more detail...

Here are some sample shots: a sequence from the 7D Mark II (Case 6, Automatic point selection) & the 1Dx (Case 4, AF point expansion surround). I've chosen these two sequences as they are taken from the most similar aspect/distance with the same swimmer.

You can view the full resolution images with meta-data at the Dropbox link below.

 

[awair]

If you look at the focus points selected (using DPP), you can see that the (7D2 from the previous post) focus is initially directed to the correct point, it drifts away and selects something that is not in the closest focal plane. This is not what would be expected?

Here are the 1Dx images:

 

[awair]

I realise that the Case chosen and AF points used make direct comparison difficult. However, the results are typical of (my/) the lack of success with (this/) the 7D2.

These were taken just before the camera went to Canon for the first time. The results were similar after its return. I had tried all of the AF Cases, generally in multiple scenarios, and all of the appropriate cases for these type of sequences.

Capturing this kind of shot is difficult, especially if the swimmer has an unpredictable motion. Despite this,
AF point (ie me doing the work) has proven more successful. I expected that the camera should be able to cope with this automatically.

The link to the full resolution images is:
https://www.dropbox.com/sh/5w586jrseiptmmh/AABNy3fVKZWRo5X0UrDzWjdpa?dl=0

Unless I hear back from Canon, I am left as a frustrated customer, and consider this thread closed.

Hope the information provided helps others, and thanks again for the feedback.

 

[rishi_sanyal]

If you look at the focus points selected (using DPP), you can see that the (7D2 from the previous post) focus is initially directed to the correct point, it drifts away and selects something that is not in the closest focal plane. This is not what would be expected?

Here are the 1Dx images:

This is something we at DPReview have talked about extensively: that subject tracking is simply not as reliable on Canons as it is with Nikon's 3D tracking (https://www.youtube.com/watch?v=wQ4rEvbCNuw). Have a look even at the D7200's tracking, with a 50x lower resolution metering sensor (used for tracking) than the D750 in the previous example: http://www.dpreview.com/reviews/nikon-d7200/11

We talked about this very issue in the 7D Mark II review. When a subject is very well isolated in depth, Canons perform well - because we think they primarily use distance information to subject track (as a 5D Mark III would, lacking a hi-res metering sensor altogether). But as soon as you have multiple objects at similar depths as your initial subject, things get hairy. Nikons (and some mirrorless cameras) continue to function quite well even in these circumstances because they appear to significantly weight pattern matching from image analysis more when subject tracking, which offers significant benefits over depth-based subject tracking (see our video explaining the difference here: https://www.youtube.com/watch?v=F58xGAaxhrA)

Canon's latest iTR implementations do better, though, with distant subjects at telephoto focal lengths, due to such subjects being relatively well-isolated in distance/depth.

-Rishi

 

[awair]

Rishi,

Thanks for taking the time to post the links. I'll have a look.

Rahul,

I think you are being unnecessarily hard (biased?) on the post above.

The more we know and understand about the limitations of any system (or how it really works), the greater the chance we have of improving as photographers.

I stated initially that I was unsure whether this problem was down to technique or the camera. I'm sure there are some techniques (for this type of shot) that I might use to improve the results. However, in the final analysis (of this case only), I believe the camera was more to blame than me.

Canon also has to address a wide audience, from highly technical Pros, to gifted artists, and also to those who will neither read nor understand a manual. I'm one of the 'odd ones' that likes to read every manual, reference, explanation, tip or theory about a system and how to get the best, or the unexpected from it. The Canon documentation is as much to blame, as the camera or user, when it is not being used in the optimal manner for the desired results.

 

[Deleted member 91053]

Re: 7D2 Auto-focus - or is it me?

7Dii auto focus capabilities were heavily promoted when the camera launched but in my opinion, it doesn't deliver.

I'm hoping the firmware update brings some magic as I am sick of a 10/15% keeper rate for BIF

If you are only getting a 10/15% rate for BIF then either you are photographing extremely difficult subjects or there is something badly wrong!
In pretty horrible light my 7D2 managed 90% (focus hits) + on Short Eared Owls in flight on it's first outing. Unfortunately the keeper rate was next to zero - but that was due to the very poor/hazy light and certainly not the AF system. Note it was still on the out of the box Case 1 setting and the firmware is 1.05 (I think!). What lens were you using? Perhaps some MFA is needed?
Just a thought.