Canon 30D and high speed shooting mode

desantnik

desantnik

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A quick question...

Can anyone explain to me how the high speed continuous shooting mode on the 30D works? It is different to the normal continuous shooting mode in same way...

The first shot is nearly always OOF, the second is normally ok, the third also a bit out and the 4th ok again.

And its fairly consistent in this.

I know on the 1D N's you can change it for focus accuracy vs FPS so clearly there is some sort of Canon technical reasoning behind it.

But its worth noting because you can really b****r your day up if you have been carefully squeezing off shots with it in high speed mode only to find you've got OOF all over the place...
 
Basically Hi Speed Shooting Mode just shoots more frames per second than usual.

I personally find it a bit optimistic to expect every frame in a hi speed sequence to be sharp with a fast moving subject. A lot depends on the subject you're shooting, obviously, but the next big decision is to decide whether to select one AF point in Servo Mode or all AF points. Some cameras like the 1 Series Canons allow you to select intermediate numbers of AF points.

What are you shooting primarily?
 
Using single centre AF point (best chance of fast focus on a 30D) because all focus points is too slow by and large and Servo AF mode.

Obviously there is a fair chance that not all of my shots will come out sharp (ha! I wish they were!), but its noticeably different in high speed mode - even if you are just squeezing off individual shots and not a sequence.

I wonder if in high speed mode it actually gives the AF less time to think, so it can get the speed.

Oh and I am shooting motorsport :D
 
Well when you think what has to happen between every high speed exposure

Aperture closes
Mirror goes up
Shutter opens and closes
Shutter re-cocks
Mirror comes down
Aperture opens....

After the mirror goes up each time, the camera has lost any reference to the AF point and has to find it again for the next shot. It's a wonder to me any of the shots are sharp!

This has come up a few times with motorsport pictures.

If you're using one AF point, it only has to drop momentarily on an area of the car with no detail to focus on - a plain bit of paintwork for example, and AF is just impossible until that AF spot is in an area with enough detail to focus. It's surprising how many times problem images have been black cars.

I don't shoot motorsport, but why not try shooting with all AF points enabled? My understanding of using all the AF points is that once the camera has AF lock on one AF point, it passes focus from one AF point to the other as the pattern of AF points changes in relation to the position of the car in the viewfinder.

I've shot birds in flight with all AF points enabled with a high percentage of sharp shots.
 
Re your process, yes, indeed BUT at 3fps there is more time for focus to think about it than 5fps. Try using servo mode to just stare around you and see how long it takes to lock onto subjects, its fast but not that fast. And I definitely think thats it, it sacrifices AF time for FPS. Remembering of course that in continuous mode it has a predefined amount of time to AF before the shutter goes.... but of course it remains odd that the 1st shot of the sequence is nearly always poor - that should have all the time in the world if you are holding down the button to engage AF...

I have actually tried with all the focus points enabled, it does take significantly longer to get lock, which can be waaaay too long at the side of the track.

As for the black cars, yes any object with low contrast is an issue. In fact I'd go further than that and say that even certain colours of cars/bikes give problems - I had this conversation with a group of other tog's on Friday at Brands, we were talking about certain bikes that none of us had good hit rates with. It must be some sort of wavelength issue or some bizarre feature of certain paintwork.
 
All fair comment - 1 Series camera do have a load of options for the speed of AF in Servo mode, so that's perhaps the way to go for you? The 1DMK3 has even more AF focus set up options.

Or shoot birds! ;)
 
Excellent, I shall tell my wife I have to have that 1D MkIII N now because CT says its the only way its gonna work :D

If you see a cross woman armed with an axe running at you this week, you will make the connection!! :D
 
:lol:

Well that's what the 1D 1.3 crop series is all about - action - and it does it better than anything else. :woot:
 
But anyway, was really looking for comment from other 30D or maybe 40D owners...
 
desantnik said:
The first shot is nearly always OOF, the second is normally ok, the third also a bit out and the 4th ok again.
Click to expand...

Are you tracking the subject (for a second or so) prior to taking the first shot?

If you want to make sure all your shots are in focus switch to AI mode because then the shutter won't fire unless the camera has achieved focus but you'll lose fps as a result.

Another thing to consider is shutter speed, the faster it is the more time between frames the camera will have to correct for subject movement so keep it as high as possible.
 
Yes, track the target it with the AF running...

Might try AI mode, not quite sure how it might work, but will try it.

As for the shutter speed, for motorsport it needs to be relatively slow if you are going to get any sense of speed from the pic. Certainly higher speeds give a higher hit rate, but at the same time, less pleasing pics...
 
What type of shots are you seeing the poor results with? Panning across frame or subject moving towards you? For panning shots you might find results are better if you move AF to the * button (CF4-01) and release it once you've got focus - that would at least stop it going out of focus between shots.
 
Yes, generally panning type shots. I already use the CF4-01 function :D
 
pxl8 said:
If you want to make sure all your shots are in focus switch to AI mode because then the shutter won't fire unless the camera has achieved focus but you'll lose fps as a result.
Click to expand...

AI mode is something I have never really understood... one shot and servo sure... well until I found this:

http://www.canon.co.uk/For_Home/Product_Finder/Cameras/Digital_SLR/eos30d/features/autofocus.asp

AI Focus AF – switches automatically between One-Shot AF and AI Servo AF modes based on subject movement

So probably not much use then :D

The speed for object movement in servo mode did surprise me though... I knew the figure was low, but 50kph? Thats well slow!
 
I can't help answer your original question but I too have seen the difference in OOF, although not sure it is always the first shot that is poor in the sequence.

I have only noticed this panning a car or bike. If I shoot fixed at the exit of a corner, it seems OK.

Have you tried it on the 3fps setting or did you ever get round the problem?
 
Mikesphotaes said:
I can't help answer your original question but I too have seen the difference in OOF, although not sure it is always the first shot that is poor in the sequence.
Click to expand...

In AISERVO mode the camera is configured to optimise the first frame for speed rather than focus. This means it can take the shot without getting a focus lock. The second frame is optimised for focus.

This is why your first frame can be OOF and the second one is in focus.
 
Mike, yes the answer is to use 3fps only... or to look for a new camera :D

Gord, its never explicitly explained on the 30D, you don't get the whizzy options like you do on things like the 1D or D300...
 
CT said:
I don't shoot motorsport, but why not try shooting with all AF points enabled? My understanding of using all the AF points is that once the camera has AF lock on one AF point, it passes focus from one AF point to the other as the pattern of AF points changes in relation to the position of the car in the viewfinder.

I've shot birds in flight with all AF points enabled with a high percentage of sharp shots.
Click to expand...

This is something I have wanted to query about for a while.

I'm I correct in thinking that if I use all focus points enabled and the camera locks focus on a runner coming towards me with a left side AF point, and the the runner moves across the frame the camera will change the AF point to say a middle AF point and then the right side AF point to keep the runner in focus.
 
It does exactly what you describe on the D300's "51 point focus with 3d tracking", but not on any Canon AF system I have heard of..

Apparently it works by identifying the initial subject through a user chosen focus point, then sampling the colours there which then enables it to locate it if it moves across the frame and reaquires it with another focus point. Nikon do say it can be an issue if your frame contains lots of the same colour... doh!
 
desantnik said:
Gord, its never explicitly explained on the 30D, you don't get the whizzy options like you do on things like the 1D or D300...
Click to expand...

Whilst there is a big differences between the AF system on the 1D compared to the xxD range as far as I'm aware AI Servo works in the same way.

http://cpn.canon-europe.com/content/infobank/autofocus.do#container

Page 3 explains it better than I did. Within that article points that differ for particular models or ranges are highlighted. It makes no reference to AI Servo working differently on 1D models to xxD models. I take that to read that the operation is the same for all models.
 
Actually, reading that article Gord, it describes I think the problem with the 30D (and 40D and 50D...) in that in AI Servo you cannot ask for focus lock before firing, it doesn't even attempt it. That is a thing you can control on the 1D (MkIIN and MkIII for sure, not sure about the others) and also on the D300 I tried the other day.

Also their comment about shutter lag also is fairly critical... in motorsport anyway! Look at the figures they quote!

I didn't realise the sensitivity of the 1D's centre focus point described on page 1... I always thought it was a 2.8 cross point like on the xxD range - but its f4 on the 1D!
 
Indeed. I've owned the 20D, 30D and currently have a 40D. With aviation photography I always shoot with the mindset that the first frame will be discarded. Start to shoot a little early and also shoot a burst of at least 3.

I picked up a 1D mk II last week and did notice the custom function to force AI Servo to wait for a focus lock but as of yet I've not set it.

The shutter lag is indeed an interesting figure, especially when you compare the xxxD range to the xxD. They have them listed here in the second table....

http://www.the-digital-picture.com/Reviews/Canon-EOS-50D-Digital-SLR-Camera-Review.aspx
 
there is a custom setting on them to help prevent oof shoots, but its nowhere near as accurate as the 1d. Havent got a 30d anymore but ill have alook n the 40d later
 
Gord,

That is interesting on the shutter lag!

You really need to spend some time with the 1D looking at the custom functions for AF - there is quite a lot of control there and it can make a BIG difference for action shots.

Russdaz,

No, on the 40d there is only Custom Fnc. III.1 which if enabled basically stops AF if lock cannot be achieved. That should stop AF hunting, but do little else.

You certainly haven't got all those nice AF controls the 1D and D300 have...
 
Very interesting information given, thanks for that.

I still don't quite understand why every second shot can be soft or OOF though?

Will have a go with the 3fps this weekend but it rather negates one of the reasons for buying the 30D over a D80.

Ho hum!
 
Mike,

Its like it is because basically it doesnt wait to focus before releasing the shutter... so its just luck whether or not the subject is in focus if its moving. Remember as CT said earlier, shutter release starts the whole focus process again.

When you drop down the frame rate it does have a little more time to think about it and so it stands more chance.

Pure and utter luck...

Unless of course you have a top end Canon or Nikon in which case you can control this behaviour.

However, the problem I don't understand is that even squeezing off single shots in high speed drive mode seems to result in less hits than in 3fps continuous.

Its a massive pain in the arse!
 
desantnik said:
Russdaz,

No, on the 40d there is only Custom Fnc. III.1 which if enabled basically stops AF if lock cannot be achieved. That should stop AF hunting, but do little else.

You certainly haven't got all those nice AF controls the 1D and D300 have...
Click to expand...

That was the setting the i was thinking of, my 70-200mm f2.8 id say 1 in 2 are spot on, on the 400mm f5.6 it is around 1-3 spot on in focus. The hit rate seemed(s) higher with that setting enabled.

Oh and i do hope my lastest adition does have all them focus toys :suspect:
 
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