Time for a couple of silly questions

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susie

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So I've been playing with my camera and have got brain overload as I have had rather a lot to absorb recently, so a couple of numpty questions!

1, Focusing on a moving target! If you are focusing on something e.g. a car or racehorse coming towards you at a reasonable speed, how do you move the zoom and the focus rings at the same time as obviously if you are zooming to get the timing right the focus will change as the object moves, or do you set the f/ number and use automatic focus? Not something I have tried yet but trying to get my brain round it before I stand near a road to practice :lol:

2, I have discovered a graph on my camera - I pressed a button to see what it did and it came up along with the picture information :lol: Obviously its there or a purpose but what is it called please so that I can find out what to do with it. I know it will be in the manual somewhere but at the moment the manual is about 15 miles away and won't be back until tomorrow night!

Thanks in advance
 
susie said:
2, I have discovered a graph on my camera - I pressed a button to see what it did and it came up along with the picture information :lol: Obviously its there or a purpose but what is it called please so that I can find out what to do with it. I know it will be in the manual somewhere but at the moment the manual is about 15 miles away and won't be back until tomorrow night!

Thanks in advance
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look for histogram - some nice person on here may post how to read them, if not a quick google will help.

Rob
 
Zooming and focusing at the same time is a pain and near on impossible with most modern lens designs where you have one ring for the zoom and one for the focusing.

If you have the other lens layout it's not so bad. That's one there is one ring on the lens and it twists for focusing and moves up and down the barrel for the zoom bit. There aren't many around these days though, I think the canon 100-400 does.

As for the little graph fella, that's the whole of digital photography right there. All that's good about it is in that little mountain range piccy thingy.

There is lots of info in there but the really important stuff is pretty simple. Those peaks are the photograph in a graph. The left of the box is where the dark stuff is and the right is the highlights. If the graph goes off the box to the right, you have blown highlights. If it goes off to the left, you have blacked out shadows. If it goes off both ends, it's too big of a range of brightness for your camera and you need to choose which bits to lose.

If the whole mountain range is in the box, you have it all exposed and can do whatever you want with it in the post process bit.

It is a bit more complicated than that but that's the essence of it all. :)
 
dazzajl said:
Zooming and focusing at the same time is a pain and near on impossible with most modern lens designs where you have one ring for the zoom and one for the focusing.

If you have the other lens layout it's not so bad. That's one there is one ring on the lens and it twists for focusing and moves up and down the barrel for the zoom bit. There aren't many around these days though, I think the canon 100-400 does.

As for the little graph fella, that's the whole of digital photography right there. All that's good about it is in that little mountain range piccy thingy.

There is lots of info in there but the really important stuff is pretty simple. Those peaks are the photograph in a graph. The left of the box is where the dark stuff is and the right is the highlights. If the graph goes off the box to the right, you have blown highlights. If it goes off to the left, you have blacked out shadows. If it goes off both ends, it's too big of a range of brightness for your camera and you need to choose which bits to lose.

If the whole mountain range is in the box, you have it all exposed and can do whatever you want with it in the post process bit.

It is a bit more complicated than that but that's the essence of it all. :)
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Thats just explained the flashing black bits on a few of the pictures! Most of the graphs are pretty much all in the box, biased a bit towards the left which would seem about right so I can leave that as it is for now!

The focusing looks as if its going to have to be auto or set for the approximate shot and pray!
 
Select 'Dynamic' or 'Continuous' servo AF mode on your camera (or set to 'sport' mode if your camera has one) then the AF system will continually focus on the main subject (in the selected AF area) whilst you have the shutter release pressed halfway, this allows you to adjust the zoom to compose the best picture without worrying about focus.
 
use autofocus, its much easier than manual, set your zoom length and wait for the target to fill the viewfinder
Use af-C, that is - whilst ever your half pressing the shutter button, the camera is Constantly adjusting focus for the moving subject.

dunno what af-c is in Canon speak

sprogged:|
 
dazzajl said:
Zooming and focusing at the same time is a pain and near on impossible with most modern lens designs where you have one ring for the zoom and one for the focusing.

If you have the other lens layout it's not so bad. That's one there is one ring on the lens and it twists for focusing and moves up and down the barrel for the zoom bit. There aren't many around these days though, I think the canon 100-400 does.

As for the little graph fella, that's the whole of digital photography right there. All that's good about it is in that little mountain range piccy thingy.

There is lots of info in there but the really important stuff is pretty simple. Those peaks are the photograph in a graph. The left of the box is where the dark stuff is and the right is the highlights. If the graph goes off the box to the right, you have blown highlights. If it goes off to the left, you have blacked out shadows. If it goes off both ends, it's too big of a range of brightness for your camera and you need to choose which bits to lose.

If the whole mountain range is in the box, you have it all exposed and can do whatever you want with it in the post process bit.

It is a bit more complicated than that but that's the essence of it all. :)
Click to expand...

Aha - thanks for that mate, been looking at my histogram and manual and can't quite make head nor tail of it
 
Canon Bob said:
It's AI Servo in Canonese
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Ah thanks, I have already set that to enable, I just need to find a safeish road thats got steady supply of targets to practice on.
Anyone want to lay bets as to how many people slow down if I am sitting at the side of the road wearing a reflective jacket and pointing a camera at them :lol:
 
I think (manual still miles away) AI focus automatically changes from still mode to AI servo if what you have focused on starts to move
 
susie said:
Anyone want to lay bets as to how many people slow down if I am sitting at the side of the road wearing a reflective jacket and pointing a camera at them :lol:
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Probably not as many as if you sat there with nothing on :naughty:

As far as I understand it.....

AI focus The camera will switch to AI servo if it detects motion in the selected focus point or points.
AI Servo The camera will continually focus irrespective of any motion sensed.

In a nutshell, AI focus means the camera has to make the decision whereas you are probably better able to anticipate the need. If you have a smaller apertture set then it will take more distance change before the camera requests a lens move as you'd still be in the region of what the camera determines correct.

Have a read of this http://www.shutterfreaks.com/Tips/CanonAIServo.html

Bob
 
If I sat there with nothing on everyone would spin round and head back the other way in terror :lol: :lol:

I was pretty close on the servo functions, perhaps parts of the manual have been sticking in my head, there is hope for me yet!
 
we had a thread about ai servo and ai focus about a month ago, conclusion appeared to be:
- "ai servo" is useful for moving targets,
- "ai focus" is a liability

try doing a search for the thread

a useful trick is to set the camera to use only one of the focus points so you can control what its focussing on. Use the centre focus point by preference (it is more sensitive as it has both vertical and horizontal sensors, the surrounding sensors have either vertical OR horizontal, the direction of the rectangle in the viewfinder is a clue) but use one of the others if it is an offcentre subject.
Centre focus point is good for one-shot focus mode as you can easily set focus on your subject by half pressing the shutter to lock focus, then swing offcentre to complete the shutter press and take the shot. That doesnt work for either of the AI modes as you are moving the camera around and it'll keep adjusting rather than holding the focus, it'll just get confused.
I am also currently learning, especially with the 50mm f1.8, that when the depth of field is very shallow (millimetres) that one-shot focus is a liability, my body sway between focus and shot is enough for the subject to drift out of the depth of field, in these cases I am now trying ai servo mode.

useful link about histograms here:
http://www.photozone.de/7Digital/histogram.htm

and also here:
http://www.nikonians.org/html/resources/guides/digital/histogram_101/index.html
its written in nikonese but is still easy to understand and applies to canon too.
 
Thanks, the first link is very useful, things with illustrations are a lot easer to understand!
 
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