Okay, this week’s installment for the p&s photography series is on how to focus.
Now, I’m the first to admit that I am a pure amateur photographer. While using my old Olympus p&s, I’d never thought about trying anything other than the auto functions, and it was only after I replaced it in March 07 (after accidentally dropping it on NYE and smashing the LCD screen) that I began to think more about the equipment.
It was a few months after that before I started to seriously try and learn about the different aspects of taking a photograph, as well as the abilities and limitations of the equipment I held in my hands.
However, this is one thing that has always irked me, particularly when I see photos from other folks. Sure, while there can be some art in in the unfocused image, it is not something that works too well when there is meant to be a focus/focal point. Part of the irritation I feel when seeing these unclear/unfocused photos is due to the fact that focus, particularly with digital cameras, is a pretty easy thing to do!
The image above is meant to be somewhat indicative of a digital camera’s LCD screen – almost all the ones I’ve seen have a little rectangle/square/circle in the middle, and if you haven’t found out by now, this is meant to be the focal point, or where the sharpest part of the image will be. Most, if not all, digital cameras come with a function called AF LOCK these days (in fact I’d be surprised to see any digicam sold in the past few years that didn’t have this function!), and it is this function that takes the pain out of producing sharp, clear photos!
Digital point-and-shoot cameras usually come with two shooting modes – normal (the default setting), and macro (usually indicated by a little flower on one of the camera buttons which is to be pressed to turn it on), and each of these modes has a limited range of focus. This information can usually be found in your user manual, and being aware of their ranges will help you decide which to use for different situations.
E.g. On my previous camera (Olympus Mju 600), the focal ranges were as follows:
- Normal mode: 19.7″ – infinity (50cm – infinity) – used for photos of large subjects or group photos of friends
- Macro mode: 7.9″ – infinity (20cm – infinity) – good for close-up portraits, nature shots etc.
- Super Macro Mode: 2.8″ – 19.7″ (7cm – 50cm) – used for any shot where I wanted to get up close and personal to expose fine detail
So, depending on the distance between you and the subject, you pick a focus mode, set yourself up in front of your subject, decide on an angle and…lightly press down on the capture button till its down about halfway or till you meet some resistance, and try not to move as you hear the camera lens whir as it attempts to focus.
That is the AF LOCK (Auto Focus Lock).
See? That wasn’t so hard, was it?
So, lets summarize what I’ve discussed so far…with pictures!
|I’ve set my scene, gotten into position and taken the shot without utilizing the AF lock.
From the way its turned out, it looks as though the bit of the scene furthest from the camera was almost in focus.
This is obviously a bit too close to the camera to use the normal setting…
|Alright, so now I’ve backed up quite a bit till I’m within the focal range of the ‘normal’ focus setting, used the AF lock to focus on the photo and taken the shot…
Well, its in focus.Too bad it also looks like a congregation of black ants.For something as small as these black sesame seeds, its going to have to be a much closer shot.
|So now I’ve switched to the ‘macro’ setting on my camera, gotten in close so I’m sitting comfortably in the focal range for this particular setting, and used AF lock to focus the photo before pressing the button the rest of the way down to take the shot.
Quite different from the first attempt, wouldn’t you agree?
This is all well and good…but what happens when you’re shooting a scene where there are many elements, sitting at different distances from the camera lens? You think that it would be really great for the image to be focused in one particular part of the scene…but its off centre, and you like the perspective you’ve got in a particular angle?
Well, we can use AF Lock to do exactly this.
|This is the starting image. Imagine that the red circle in the center is the camera’s Auto Focus mark.
Well, it’s focused…but I think it would work much better if I could blur the sesame seeds that are further away, and focus on the ones closest to the ‘front’.
|In order to change your focal point, what you need to do is to change your position so that the AF Mark is over where you want the focus of the image to be, then activate AF Lock by half-pressing the button.
After you’ve used the AF Lock, you carefully move your position back to the previous angle (being VERY careful to maintain the same distance from the subject or you will lose your sharp focus!) before pressing the button the rest of the way to take the shot!
This is not to say that this is necessarily an easy thing to do, in fact, it may take some practice, as its extremely difficult to do with a tripod, and so you will need to get used to visually maintaining your distance and angle from the subject, as if you change your distance from what you’re shooting while you’re repositioning, the focal depth that the camera has been ‘locked’ into will no longer contain a target at the correct distance, which means it’ll be all blurry again! Not what we want!
Luckily, most digital p&s cameras tend to come with three different focus modes these days, which means that if your camera has these functions, you won’t need to worry about with mucking about with the AF Lock 😛
The three modes you’ll most likely be working with are:
- AiAF – when looking at a cameras specifications, you’ll see that your camera has a certain amount of ‘auto focus zones’. With this focus mode selected, when you try to use the AF Lock, the camera will scan each of these zones and automatically focus on the one that is either closest to the centre or has the most contrast (which is, incidentally, how cameras auto focus…and why it is so difficult to take sharp photos of things such as a pile of cream on a white plate). If you know anything about using a camera, I’d suggest steering clear of this setting. That is, unless you just don’t care about where the camera is focusing.
- Center focus – The name pretty much explains this, ’nuff said.
- Flexifocus/Area focus – SCORE! You guess it – this function allows you to move the AF Mark on your camera screen around so that you can do that instead of having to tiptoe carefully about so you can try not to upset dear ol’ AF Lock!
Now, some of you reading this lesson will be able to stop right there. I’d guess that only about 1/4 – 1/3 of digital point-and-shoot cameras on the market at the moment allow for any manual fiddling with the aperture, so if your camera doesn’t give you the ability to adjust this setting, don’t worry about the stuff under this point. However, if your camera does allow you to muck about with aperture (hint – if your camera allows you to shoot in Av mode…then that’s a yes. Av is ‘Aperture Priority‘ mode), and you’ve never used it or don’t know how it works, continue to read on…
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Alrighty, so you’re one of those point-and-shoot users who have control over aperture, but you’re yet to figure out what this means or how it works, huh? Well, its really quite simple once you do away with all the jargon and wankiness.
Aperture refers to the opening in your camera’s lens that controls the amount of light being allowed through to the camera’s image sensor the moment that you take a picture. This is actually quite a simplified definition, but its about all you really need to know in terms of what it means. Aperture is expressed in f-stops (e.g. f4.0), and if you have control of your aperture then you will find what aperture range your camera has inside your user manual, for example my current point-and-shoot has a range from f2.8 – f8.0.
So, what do these numbers mean?
Lets go back to the first image I used in this post for a second.
Using my camera as an example, those two circles display the range of f-stops that my camera has, with f2.8 being the larger dashed circle and f8.0 being the smaller red circle. I know, you want to know why the smaller f-value indicates the larger sensor and vice versa, huh? To be honest, I haven’t bothered looking into that as its not critical to your use of this function.
There are just two things you need to bear in mind when using aperture control – the first is Depth of Field – often expressed as DoF, this refers to the range of sharpness in an image. The smaller your f-value, the shallower your DoF will be. Look at the following table for an illustrated example of how this works: (meaning that the area of sharpness will be quite small, with a small range within which objects gradually become more unfocused, and beyond this point you achieve an effect known as ‘
|Aperture value: f5.6
Taken in macro mode, this image has a field of focus which is about half the image size, then the amount of blur in the background increases the further out that you go, before you hit the wall and all detail in the seeds is lost and they are just little blobs of colour.
|Aperture value: f4.0
Both the main field of focus and the field within which image blur is increased has gotten smaller, with a larger area in which our subject has lost detail/shape.
By far the smallest field of focus from the three examples, this is a great setting to use when you’re shooting a very small subject and want to use the gradient blur to give the photo a sense of ‘depth’ and dimension.
|Here is a side by side comparison of these three f-values at work, and you can clearly see how the area of focus and blur has been affected according to what aperture has been used.|
The second aspect of aperture is the light, and this is where things get a bit tricky. When you are shooting in auto mode, the camera will adjust the size of your aperture depending on the amount of light available – in low light conditions, it will open up the aperture as much as necessary so that enough light can reach the image sensor. On the other side, when you’re shooting in bright conditions, the camera will make the aperture much smaller so that too much light does not reach the image sensor, protecting you from overexposing your photo.
When you are shooting in Av and exerting manual control over your aperture, you will also need to adjust the exposure compensation in order to make sure that the correct amount of light is being allowed through the lens. From the image on the left, you can see the effect of the aperture on the light being allowed through.
Because focus and light go hand in hand when adjusted by aperture, you will need to pay attention to both and alter the settings accordingly, depending on the environment/situation/subject that you’re shooting! Having managed to make your way through this marathon post, hopefully you’ll now understand enough to be able to do so without too much headache
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I think that’s pretty much it as far as the equipment side of point-and-shoot cameras goes, but if you think I’ve missed something or there’s a topic you’d like more info about, leave a comment to let me know!However, if there’s no suggestions in as what other elements of point-and-shoot cameras you’d like to know, then next week will be a brief summary as well as a guide for choosing your next p&s camera! The week after that, I’ll start the guides on basic photo editing to bring your photos to life! I hope you’ve enjoyed the series thus far, and please bear in mind that feedback is always appreciated
[tags]point and shoot cameras, guides, beginner photography, aperture, tips, focus, light, f-stops[/tags]