Focussing
For me personally, focussing is critical…I cannot stand it when I take what I think is a wonderful photograph only to get it onto my computer and notice it is OOF (out of focus)…Arrrgh!
To save this kind of anxiety there are ways to ensure that you nail the focussing 9 times out of 10 but we will cover most of those in the next module (advanced).
For now, we will keep it fairly simple and to start with we should cover a very important part…focus modes within your camera.
Focus Modes
Note: This is a section more geared towards the next, slightly more advanced module but I have included it here because you may be having problems with this already, and I would hate you to go through this whole section having problems with this.
Focus modes can often confuse the unsuspecting beginner (or even more advanced) photographer. If you are in the wrong mode, you may well be getting all sorts of problems to do with focussing and then thinking it is your fault or that you are doing something wrong…not necessarily so.
Most DSLR’s have 2 or 3 focus modes and these are:
- One Shot
- AI Focus
- AI Servo
Each is radically different and it is important to know what each one does and when it could be best to use each setting.
One Shot
The camera focuses on the subject once when you “half-press” the shutter button and normally gives an audible beep and red light to let you know it is focused. It will not refocus if the subject moves or if you recompose the shot as long as you keep your finger half pressed on the shutter.
I use this 99% of the time because I am in control. If a subject is moving I can track it and keep half pressing, getting the beep and then shooting continuously (see link in AI Servo).
Also, I use just the central focussing point which I keep over the part of the subject I want in focus. This is particularly useful for portraits where I want just the eye or eyes in focus…I can control that.
AI Servo
AI Servo is generally for sports and nature photographers. The better your camera and lenses, the better this will work. AI Servo mode will focus on your subject (using whichever focus point you choose) and hold that position. If the subject moves, the focussing mechanism will track the subject keeping it in focus.
In theory, this is great so long as your subject is either large or you are fairly close to it. Should your focus “point” stray from the subject, it will quickly focus upon whatever it lands on.
For example, if you are shooting a rally car speeding towards you, it is fairly easy to keep say the centre point over the car as it is quite large, especially if you are close, then half press the shutter and keep firing away. Most images should be well focussed as the AI Servo tracks the car.
However, let’s say your subject is a bit further away and smaller like a kite-surfer out at sea. All the time you are tracking the subject well with the centre point over the surfer, all is good but as soon as you move away from the subject, the focussing point will then track whatever it lands on…normally the background causing an out of focus subject. Modern DSLR’s are more equipped to deal with this and have fairly intelligent tracking systems but just be aware.
I would only use this in certain situations where I knew it would work, otherwise I use One Shot focussing and my beep click method…
http://www.all-things-photography.com/200508/
If you rely on all focus points then you are allowing the camera to make judgement on what IT thinks it should be focussing on and that should be your job!
AI Focus
AI Focus is a kind of hybrid focussing system of the two previous methods whereby it uses One Shot focussing until the camera detects movement in which case it then switches to AI Servo….and in general it doesn’t work very well. I don’t use this.
Each camera is different so if you have this mode, try it out and see what happens. I found the results a little sporadic and non-consistent.
Just because it is put there by manufacturers doesn’t mean it HAS to be used or is indeed useful at all.
Manual Focussing
If the camera manufacturers have spent millions of Dollars on perfecting the art of autofocus, why on Earth would we want to manual focus? I remember when the first Autofocus SLR’s were introduced in the mid 1980’s with the very first pioneering camera being the Minolta Maxxum 7000…
Canon soon followed with its brand new EOS system in 1987 (still going today) and the EOS 650
All groundbreaking stuff and for short sighted people like myself, this was a Godsend.
So why use manual focus?
There are situations in many types of photography whereby even today, the camera can get it wrong or you simply want to override it. DSLR’s are intelligent beasts but they still do not have the brains to work out what it is we actually want to “say” in our images…if they did there would be no art left in photography.
Off centre or moving subjects. When you are shooting such things, the focus points can become confused and focus on entirely the wrong aspect of the image because the camera is designed to do your thinking for you as intelligently as it can. This means that the subject you are shooting may become blurred.
If the distance between you and the subject stays fairly constant during shooting, you can fix the focus on the subject, switch to manual and fire away knowing that you will not lose that focus.
This is particularly useful when photographing fireworks. Because the scene is dark, your camera will struggle to lock on focus most of the time meaning many shots are out of focus.
By using autofocus on one particular object that is approximately the same distance as the fireworks, and using a smaller aperture to give better depth of field, you can then switch the focus to manual and lock it in which will pretty much guarantee sharp shots every time (as long as you use a tripod for long exposures).
Macro photography. When using a macro lens (meaning ultra close for small subjects) the depth of field (amount of the image in focus) is at its absolute minimal regardless of aperture size.
We don’t need to go into the why’s and wherefore’s here but you just need to know that is how it is.
So if using a macro lens it is best to use a tripod for stability and manually focus on your subject (if it is not moving) otherwise the lens will continue to “hunt” for focus on any part of the image due to the lack of depth of field.
If the subject is moving then this coupled with a macro lens will make it difficult even for a professional so do not be disheartened if it takes a while to get it right.
This image was taken of a small fly on a leaf that was blowing about in the wind of a very dark part of the New Forest. I still set the camera’s focus to manual, focussed as best I could on the fly and then shot a number of images whilst waiting for the fly to move “into focus” as it got blown by the wind…I stood perfectly still.
The same rule applies if you are shooting any inanimate object in a studio for stock photography etc. Nail the focus and lock it into place using manual.
There is a fantastic tool called the depth of field calculator…it can be priceless when starting out as it will give you the exact depth of field for any lens/camera/setting combination.
If you take a full frame camera (Canon EOS 5D/II), a 100mm lens, F2.8 and put the subject 10 inches away (macro work), the depth of field (or area of the subject that is in focus) is a pathetic 0.03 inches. No room for error there!
So, if the object you are shooting is say 5 inches “deep” and you wanted it all in focus using that lens and camera”, you would need to move back to 40 inches away and use an aperture of f.22.
When shooting in these conditions, you are better off making all the focus adjustments needed and then switching the lens to manual focus. That way you are not relying on the cameras judgement and auto focus, but your own!
Here is that tool…
Another example of when to shoot manual focus would be at say a show jumping event. You could position yourself where you can get the best shot of all the horses as they make a jump on one of the pre-arranged gates (look for the best light and composition).
Work out the depth of field needed to get it all in focus, set your camera up on a tripod and you should be able to just fire away with those settings knowing that you are nailing the focus on every shot.
Auto Focus
This is where you simply allow the camera and lens to work together to obtain the best focus it can.
To be honest I use auto focus most of the time because even on full auto focus, most cameras have the ability for you to override and control the focus regardless. Again we will cover this in more depth in the next module but my advice for now would be to practice focussing on any number of subjects as your main priority.
You can adjust and correct under or overexposed images during post-processing to a point but you can NEVER regain focus from a blurred image.
Focus Points
Your camera will have anywhere from 3 to 45 focus points as you look through the viewfinder.
You can allow the camera to use all of these and “intelligently” work out what to focus on and lock it in or you can choose any one of the single points to use as the main focus area.
The danger of using all points is that, for example, if you are shooting a moving target such as a kite-surfer, the camera can switch its focus from the main subject to the background view and then back again continuously.
It doesn’t know that you need the kite-surfer in focus. This can cause many of your images to be blurred.
I tend to use a single point (the central point) 99% of the time. I can focus on the subject using this central point by depressing the shutter part way, the point will light up when focus is achieved and I will hear an audible beep. I can then either fire away or recompose the shot (keeping the shutter “half pressed” to retain focus) and then shoot.
Try this method of focussing out for yourself and practice with it.
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