help with 7d focus issues with test shots

[Rebel t3i]

I'll try and set a static scene where I have the issue repeatedly and then try some MF shots and compare

 

[woof woof]

There is nothing to focus on between the dogs eyes though.

We have to remember that focus needs an area of contrast to work. In those examples there's very little contrast in the dogs face - that makes it a tricky subject to focus on despite what we might believe the camera ought to be able to do. The camera will look for an area of contrast within the focus point - as it has here; and focussed on the bush.

I said similar things in another thread about focus issues...

People these days think that DSLR focus systems can lock onto anything but clearly they can't and there are things that give focus systems problems. When pushing the limits of what the camera can do I think it's best to give it the best possible chance by focusing on an area that gives the best chance of focus being achieved and even if necessary taking more than one shot. Low contrast areas, sloping targets and cluttered scenes can all cause problems and care needs to be taken and help given to the hardware.

The way I'd begin to approach this 7D issue would be to use centre point and single shot and aim at a high contrast area.

 

[Rebel t3i]

I'll try and set a static scene where I have the issue repeatedly and then try some MF shots and compare

I live by knypersley reservoir in stoke on trent and shall be down there walking the dogs over the week end if any local expert fancies meeting up to educate me it would be much appreciated

 

[Phil V]

why would I want to pick a constant aperture
it was a quick set of simple spur of the moment shots in an attempt to demonstrate the issue I am having
I picked just a few examples from the shots I took which best showed the focusing issues I am experiencing which seems purely random to my untrained abilities
Are you recommending I should select a different aperture if so what

sometimes the camera gets it right often it gets the focusing wrong this is what I am trying to get to the bottom of
It has already been suggested that the camera will struggle at such wide apertures on the subject matter at this range so I am going to try some shots at smaller apertures when the monsoon stops
I took 3 shots last night in low light of the cameras I have focusing on the canon logo
whilst the pics were quite good the 600d had perfectly focussed on the 7d's canon logo as did the galaxy s3, the 7d pic was out of focus on the 600d's canon log and the logo was the spot focus centre point on all 3 test shots the 7 d had clearly focused perfectly on another part of the image
I used my 17-55 f2.8
std camera flash was used and the 600d and 7d were both set to p and the cameras had selected identical aperture iso and shutter speed

Because any kind of testing should be done under controlled conditions, because as soon as you allow variables into experiments you have lost control.
Do you understand the difference between spot focussing and single point focussing on the 7d? Because throughout this thread some wildly inaccurate terms have been used which fills me with a complete lack of confidence (not just by you). I've also seen recommendations for the use of AI Focus mode - which is hideously unreliable - think of it as a green box focus mode.

What I'm trying to say is that the 7d has a very elaborate AF system, which is fantastically customisable, but when it was launched the Internet lit up with people who couldn't make it work. 99% of the time, the problem was user error. If it works sometimes but not others, you have to work out what you're doing differently - and remember - you're telling the camera what to do, whether you fully understand those instructions or not.

I'd recommend starting with a simple set up. One shot AF static subject - centre point AF, if that works, there's nothing wrong with the AF.
2ndly try AI servo AF, I recommend selecting an off centre AF point and with maybe some focus point expansion (depending on tracking and speed of subject). And all the time remember you've got to give it something to focus on.

I always use back button focus, because to me it's more like using a MF camera where I'd control the focus completely independently of the shutter firing. It's too easy when using the shutter button to focus to inadvertently tell it to refocus when I don't want it to.

If you can see all the variables there are just around the AF system, can you see why I'd want to remove any other variables from the equation before testing?

 

[Rebel t3i]

many thanks for that Phil
I am just trying to get to grips with the 7d's advanced focusing system
all the pics were taken with one shot spot centre af focus and as far as I could tell the dogs were perfectly static at the point of shooting

 

[hollis_f]

Because any kind of testing should be done under controlled conditions

Absolutely. Testing AF requires good light, a good target and a good tripod. If you can't get good results under those conditions then there's probably something wrong with the equipment. If you do get good results from those conditions then AF problems under different circumstances are almost certainly down to user error.

 

[Phil V]

many thanks for that Phil
I am just trying to get to grips with the 7d's advanced focusing system
all the pics were taken with one shot spot centre af focus and as far as I could tell the dogs were perfectly static at the point of shooting

I'd turn off the spot focus, it's intended for critical focus subjects in controlled conditions. Single point AF is all that's required as per my post.

 

[Phil V]

Absolutely. Testing AF requires good light, a good target and a good tripod. If you can't get good results under those conditions then there's probably something wrong with the equipment. If you do get good results from those conditions then AF problems under different circumstances are almost certainly down to user error.

Do you realise how many words it took me to say almost the exact same thing:bonk:

 

[u8myufo]

Because any kind of testing should be done under controlled conditions, because as soon as you allow variables into experiments you have lost control.
Do you understand the difference between spot focussing and single point focussing on the 7d? Because throughout this thread some wildly inaccurate terms have been used which fills me with a complete lack of confidence (not just by you). I've also seen recommendations for the use of AI Focus mode - which is hideously unreliable - think of it as a green box focus mode.

What I'm trying to say is that the 7d has a very elaborate AF system, which is fantastically customisable, but when it was launched the Internet lit up with people who couldn't make it work. 99% of the time, the problem was user error. If it works sometimes but not others, you have to work out what you're doing differently - and remember - you're telling the camera what to do, whether you fully understand those instructions or not.

I'd recommend starting with a simple set up. One shot AF static subject - centre point AF, if that works, there's nothing wrong with the AF.
2ndly try AI servo AF, I recommend selecting an off centre AF point and with maybe some focus point expansion (depending on tracking and speed of subject). And all the time remember you've got to give it something to focus on.

I always use back button focus, because to me it's more like using a MF camera where I'd control the focus completely independently of the shutter firing. It's too easy when using the shutter button to focus to inadvertently tell it to refocus when I don't want it to.

If you can see all the variables there are just around the AF system, can you see why I'd want to remove any other variables from the equation before testing?

Tony, I shot this yesterday @300mm at just under 7 Metres. Far from picture perfect quality but it shows what you should be able to achieve focus wise with the 7D

 

[Robfb]

I have read through this thread and have had similar problems with my 7d. In the end after trying many of the techniqes recommended by others here, I finally came to the conclusion that there may have been a problem with the camera. The clincher was when I was able to take a few shots with a friends 7d and was able to get the sort of results I was hoping for.
The body was sent back to Canon Elstree who calibrated/adjusted the focus mechanism.
The camera is now working as I hoped it would ,so it may be worth sending it in.

Rob

 

[Gaz J]

It could well be that the camera requires adjustment. If so the more information that you can give Canon the better the chances that it will be returned working correctly.

I would definitiely stop using P mode. To be able to come to accurate conclusions you must take as much control away from the camera as possible. The only setting in this case is Av where you control the aperture and the only input from the camera is metering and shutter speed.

Also a tripod is essential. Depth of field on a 200mm lens focussed at 15 feet is approx 3 inches. Given that generally one third (1 inch) of the depth of field is in front of the subject and two thirds (2 inches) behind you can see how just the sllightest of movement after focus has been achieved could impact on the image.

 

[Rebel t3i]

I'll give it a whirl in av mode if I am still having these random issues it might be best I send it to canon with the lenses and see what it's like when I get it back

 

[nog]

Is it worth trying focus using live view?

 

[Phil V]

I'll give it a whirl in av mode if I am still having these random issues it might be best I send it to canon with the lenses and see what it's like when I get it back

Whilst its raining and you can't get out to test it, read the manual. Then read up on a few 7d focus articles on the Internet. Then when the sun comes out, turn off spot focus and do some proper testing as I suggested earlier. Random autofocus issues are almost always user error, because there's no way that a technically broken mechanism will work properly sometimes.

And the fact that your 600d will work exactly how you expect has no bearing on this, as you know exactly how it works and it doesn't have enough variables for anyone to misuse it to the same degree the 7d does.

Or you could send it all to Canon, who'll clean it and test it and send it back to in the same state for a hundred quid or so.

Did I mention turning off spot focus?

 

[Rebel t3i]

I'm sick of reading lol

 

[menthel]

It will help. No one here or at canon can help until you actually show that this is not user error. Your testing so far has been all over the place, different settings and targets. Your comparisons with the 600d have been using different lenses!

Sit down. Reset the 7D, don't put it in spot focus. Use one lens, with the camera mounted on a tripod and aim at a fixed target. This will exclude or prove camera error. It has to be done like this or nothing can be proved or disproved!

(And yes, I do have a science background!)

 

[Rebel t3i]

I only bring the 600d into it to show it isn't a lens issue I only have one of each lens type which I use on both cameras alternately
the comparisons between the 600d and 7d have been with the same lens
the 2 I use for testing are the ef70-200 f2.8l and the ef 17-55 f2.8
I stated the lenses used in the most recent example I posted on this thread, and I clearly stated that I used the 17-55 f2.8 on the 600d and the 7d
I am not comparing image quality with different lenses on the 2 cameras only different cameras
I wouldn't say I was jumping around everywhere I am merely trying different settings to try and resolve the front and back focusing issues I often get
I appreciate all the help and input and shall have another go with the settings and techniques you have all kindly suggested now the monsoon seems to have past

 

[Firetographer]

I'm sick of reading lol

I know exactly how you feel. I bought a 7D 2 years ago and have still to get a decent shot from it. I have spent 2K on glass so that I had the best tools in front of me. I then discover the 7D issues and wonder if its me or my kit. Am I really that bad.

I actually put it back in the box as I presumed I was either not cut out for photography or my kit had something wrong with it. I guess what I really need is someone local to me to have a go with my kit and show me some stunning images. I will then know that its me and concentrate on that. However, I sometimes thing I am trying to learn photography with kit that is not sharp.

Having read this thread, I am now keen to give it another go. Unfortunately if I discover my kit has some issues, its out of warranty.

So all in all I am following this topic closely.

 

[Rebel t3i]

It will help. No one here or at canon can help until you actually show that this is not user error. Your testing so far has been all over the place, different settings and targets. Your comparisons with the 600d have been using different lenses!

Sit down. Reset the 7D, don't put it in spot focus. Use one lens, with the camera mounted on a tripod and aim at a fixed target. This will exclude or prove camera error. It has to be done like this or nothing can be proved or disproved!

(And yes, I do have a science background!)

done that before I will do it again and refresh myself of the results

 

[tijuana taxi]

Must say it does sound like the camera may need calibrating, not noticed any problems with mine, never seen much in the way of noise either

Here is a heavy crop from 200mm, resized and unprocessed from a neutral in camera setting jpeg

[/IMG]

 

[den]

Hi, my 7d was a upgrade from the 1d mkii n and it took me a while to master the 7d (very simalar focusing system), and i am still just about getting to grips with it now, when we purchase a good camera and a L series lens we seem to believe our photographs should improve overnight,i am not saying that's what you yourself excpects it's just a phase i think we go through ,youn need to get to know your camera and persevere as thier is nothing wrong with the 7d and it's focusing system......

 

[Rebel t3i]

just out testing my dodgy sigma 30mm f1.4 from ebay
done as suggested and have found ai focus on is improving things so user error or just that I am old and wobbly lol

 

[Lbm]

just out testing my dodgy sigma 30mm f1.4 from ebay
done as suggested and have found ai focus on is improving things so user error or just that I am old and wobbly lol

I think the general consensus is to use 'One shot' for static subjects and 'AI Servo' for moving subjects.

Not AI Focus. I don't bother with this 'in betweener' option.

But if it's working for you...

 

[Mad Badger]

What he said, get out of AI focus, go back button and AI Servo, reinforces to me that your difficulties are probably user error rather than 7D malfunction.

 

[Phil V]

just out testing my dodgy sigma 30mm f1.4 from ebay
done as suggested and have found ai focus on is improving things so user error or just that I am old and wobbly lol

Really pleased you took note of the advice you were offered!

. I've also seen recommendations for the use of AI Focus mode - which is hideously unreliable - think of it as a green box focus mode.

 

[lizzy23]

it's taken me 8 months to get to grips with my 7D, what i found was it was totally unforgiving compared to my 40D, after lots of practice i'm finally getting shots i'm happy with


_MG_3971 by jalizcazan, on Flickr

 

[Rebel t3i]

Really pleased you took note of the advice you were offered!

lol
not had chance to down load the test shots to lr4 yet
I have tried the advice given including ai servo
will check the results properly shortly
a quick review in camera at the time showed I was getting better
so I'll bin ai focus and stick with ai servo

 

[Rebel t3i]

it's taken me 8 months to get to grips with my 7D, what i found was it was totally unforgiving compared to my 40D, after lots of practice i'm finally getting shots i'm happy with


_MG_3971 by jalizcazan, on Flickr

if all my shots were as well focused as that I'd be jumping for Joy who ever she is

 

[lizzy23]

if all my shots were as well focused as that I'd be jumping for Joy who ever she is

But i've also put a hell of a lot in the bin

 

[u8myufo]

Just to add another spanner in the works Tony Have you tried different tests and changed the distance scale on the lens. I remember with my old 70-200F4L if it was set on whichever distance there would be times depending on distance of subject what I would describe as no mans land, where the lens would lock on and fire, although it looked ok in the viewfinder it would come out soft. Step forward or backward a foot or three and there was no problem whatsoever.

 

[Rebel t3i]

Just to add another spanner in the works Tony Have you tried different tests and changed the distance scale on the lens. I remember with my old 20-200F4L if it was set on whichever distance there would be times depending on distance of subject what I would describe as no mans land, where the lens would lock on and fire, although it looked ok in the viewfinder it would come out soft. Step forward or backward a foot or three and there was no problem whatsoever.

interesting I have experienced a similar thing
just bought another 7d off a member here to test against mine, bit extreme but I am single now just me and the kids so no naggy moaning wife any more and I can do what I want
and my eldest is into photography and so one each

 

[Rebel t3i]

Well it is definitely me
bought a second 7d from killy off here, was out testing yesterday at knypersley reservoir and the shots are similar to my original 7d
I must thank kelly for the 7d absolutely immaculate as is the box
Just got to master this complex focusing system but we are getting there
don't get me wrong I get some excellent shots just not as many as I'd like
interestingly we had to add +3 to MA for the ef 70-200 f2.8 L IS to kelly's 7d which is the same as I had added to my own 7d