7D focusing

[JorgD]

Hi guys,

I was just wondering if other people here have noticed slight focusing inconsistencies with the 7D? I only use the centre focusing point, so I don't take the risk of the camera focusing on something different than intended.

Generally it focuses ok, but every now and then, around 15% of all photos, it seems a little bit off. 15% seems like a lot to me though.

I have included 2 shots taken 4 seconds apart from the same location and as you can see, the focus is not consistent.

http://img121.imageshack.us/img121/7167/img2169focus.jpg (http://img121.imageshack.us/i/img2169focus.jpg/)



http://img405.imageshack.us/img405/399/img2168focus.jpg (http://img405.imageshack.us/i/img2168focus.jpg/)

[Tannin]

I'm not entirely sure that what we are seeing is a focus problem (as opposed to camera movement). Why is nothing in focus? That seems a bit weird.

On the other hand, this is exactly what my remaining 40D does. It comprehensively misses focus maybe one shot in 5 or 10. I mean way out - which is probably what we are seeing above. My other 40D (which now belongs to Belinda) never does this. It is only the problem child - that particular 40D body has been nothing but trouble from start to finish. I haven't bothered getting it repaired because (a) it is out of warranty, (b) it is not the first time this particular 40D has given trouble, and (c) I only use it as a spare body. The other bodies do almost all the actual work, and this 40D is just there for emergency use and for odds-and-ends stuff. I just remember to keep an eye on the unreliable focus mechanism.

If your 7D is behaving like my 40D, then it is most certainly faulty and should be returned to Canon for service or replacement.

[TEITZY]

Agree with Tony. Something amiss here. The shutter speed (1/320) would seem to eliminate camera shake as the cause of softness in the second image.

Cheers
Leigh

[JorgD]

Hi Tony,

thanks for the response. I too have a 40D, which I used until I got the 7D, and it has never missed a beat. I can't recall a single out of focus shot with the 40D, and I took over 50,000 in the 2 years I used it.

I too was thinking about camera shake, but this shot was taken at 17mm with the 17-55 f2.8 IS and at 1/250th of a second. I can't imagine that I camera shake about 1 in 8 photos so badly while standing on steady ground with non moving targets. I had shots at 1/1000th blurred like this and thus ruled out the shake factor.

Some of my other landscape shots, while focusing to near infinity, I can see the foreground 10 metres from me being really crisp.

I had rung Canon about this, who asked me if I was using auto focus or if I had problem with manual focus, and after a short discussion suggested I send the camera to them for inspection with an expected 5-10 business day turnaround.

Just to make sure there was no misunderstanding, I explained everything in painful detail filling a full A4 page of how I take photos and I then cut them a CD with 8 raw files clearly depicting sharp and unsharp photos of the same subject taken at shutter speeds that really exclude the possibility of camera shake. I even sent them one of my lenses, just to make sure the IS has not gone nuts and is vibrating like crazy causing motion blur rather than suppressing it.

5 phone calls and 6 weeks later the 7D was returned to me and apparently had been checked by 2 separate technicians who could not find any fault at all with the camera. They made no attempt at all in even trying to explain the photos I had sent them or the problem I was experiencing. Even when I called them again, saying there is still a problem, quoting the repair number, all they could say is that the equipment checked out fine without going into what else could be creating the results I am getting.

I fully appreciate that time is money and they are unlikely to want to spend 40 technician hours on testing the item, but I do feel they don't pay sufficient attention to what is going on and have no interest in customer satisfaction.

And that is why I am considering switching to Nikon :)

[bigbikes]

Have you tried taking the same shots but this time try using a different lens?
Could it be possible that its not the camera at fault but maybe the lens.
Just a thought.
Let us know how you go.
Good luck

[MrJorge]

My 400D behaves as Tony has talked about. I'll be shooting an action sequence @ footy, the first few focused well, then one in the middle not, before normal focusing resumes for the rest of the sequence.

[Nikon91ride]

My girlfriends Canon 400D does this too. I was searching hoping the answer would be here, but if she uses auto focus it's fine most of the time close up but won't focus far away. Even when you go into manual focus it will focus as you look through the viewfinder and then be focused somewhere else in the actual image. Not good in portraits when a chin is sharp and not the eyes! I cannot seem to work it out. I thought it could be the diopter for the viewfinder but we've tried that and the fact it won't focus in auto rules that out, I'm hoping the technician at TAFE will be able to shed some light on this for me! I have never seen it happen with my Nikon other than user error :P

[Tannin]

Mate, I have felt the same way at times. But - and here is the nub of the matter - on average, and taking into account everything I see and hear, Nikon reliability is about the same as Canon, and the service can be a good deal worse. I also think of switching back to Nikon sometimes, but then I look at the tales Nikon owners tell and after a while I settle down and realise that I'm still better off where I am. It's not perfect, but for a bird photographer, it is the best choice in town.

What you need to do:

1: Take a series of formal test shots. Use a good tripod, mirror lock up, and 10 second timer. Document your exact steps. You have demonstrated faulty goods, you want them fixed, please.

2: Send that documentation to Canon with a written request that they rectify the problem. Be polite but firm.

3: If they do nothing, send it again, this time also send a copy to consumer affairs as part of a formal complaint. Document that too, and send copies of everything to both Canon and CA - i.e., make sure everybody knows what you are doing and what the consequences are.

[Tannin]

My 400D behaves as Tony has talked about. I'll be shooting an action sequence @ footy, the first few focused well, then one in the middle not, before normal focusing resumes for the rest of the sequence.

Totally different thing. That is just the servo focus system losing touch with a moving subject, then regaining it.

We are talking about a wildly OOF shot even of a completely static scene. My 40D only ever does landscapes.

[JorgD]

@bigbikes yeah, I thought of it maybe being the lens, but I use a number of lenses and they all have the problem, plus I sent a lens in with the camera to Canon just in case.

[kiwi]

Great help here Tony

I do wonder whether you have set the focus on some sort of auto mode, so yes although you use centre point it will also change focus to find the subject. Nikon has group focus mode and 3d tracking, both of which in my experience often result in the very wrong focus target. It looks for an item of high contrast.

[kiwi]

Ahh, yes, googling it the terminology on canons are zone vs spot

[etherial]

Great help here Tony

I do wonder whether you have set the focus on some sort of auto mode, so yes although you use centre point it will also change focus to find the subject. Nikon has group focus mode and 3d tracking, both of which in my experience often result in the very wrong focus target. It looks for an item of high contrast.

That is a good point. I was wondering if the OP is using the camera on AI servo mode. You can have the centre point selected on AI servo and it will start tracking there but can then move to other points to follow a subject. Probably a long shot though.

Can't say I've had this type of issue with my 7D.

Edit: BTW, by only using centre point, you are missing out on all the great benefits of the 7D focus system! Have a quick watch of this (http://www.youtube.com/watch?v=f-K8MP1HFnE).

[JorgD]

@etherial thanks for the link to the video. Very interesting in seeing what it can do for moving subjects.

I use one shot focusing and pretty much all of my subjects don't move. They are either landscapes or buildings, like churches and temples or mountains in the distance, so I never had to worry about AI servo. Even when I shoot people, I get them to hold still while I take the photo.

A lot of my out of focus testing was actually done indoors on a tripod taking photos of books with written text, where the book is at 45 degrees to the camera and I focus on a word in the middle of the page (which I can verify due to dpp showing me which focus point was active) and then marvel at how the focus point is completely unreadable but text 5 cm past the focus point is in focus. Occasionally it is in focus, but often the focus is all over the place. It's totally random.

I have been using Canon SLR's for 25 years now and never had a focusing issue. Admittedly my first 2 were manual focus, so the AI was a bit better. As I mentioned before, the 50,000 images I took with the 40D were all sharp, using the exact same method of centre focus only, one shot, no moving objects.

My wife has already suggested that I just buy a few more 7D's until I get one that actually works and toss the others in the bin, but I am loathed to do this out of principle. Too many times in the past have I purchased multiples of the same item so that I can have 1 working version while the others go back for warranty work over and over. I am just sick of it.