Controlling Light Falloff

In this post we will see how to control “light falloff” – the difference in light intensity between the areas of the photo who are closer to the light source and the area who are a bit farther away – this will let you create dramatic lighting (for example, cause one side of the face of fall into darkness) or more even lighting that is very flattering in portraits and essential for product photography.

Basically, this is very simple, the intensity of light drops has the subjects gets farther from the light source (no surprises there) but the drop is not even – the light drops off very quickly near the light source but very slowly farther away.

This is because the light falls off according to something called “the inverse square law” – here’s a picture of a wall lit by a flash to demonstrate the effect:

If you look at the area between the rightmost blue line and the center blue line you can clearly see that on the right is much brighter than the center – actually it’s about 4 times brighter (or 2 stops), now look at the area between the center and leftmost blue lines, this area overs approximately the same distance but the lighting difference is much harder to see – I’ve measured it and the center is twice as bright as the left (1 stop).

If we also look at the red ranges around the blue line we can see that in that tiny distance around the rightmost blue line we lost 20% of the light intensity, at the same distance around the center line we lost only 10% of the light and at the leftmost line the light is the same for the entire range.

So what does it mean in practice? let’s take a “one of a kind” toy from Ikea and photograph it with the flash to camera right just out of frame:

We see the left side of the face is completely dark and so is the background, let’s take the exact same picture but move the flash about 2 meters (6 feet) back (and raise the flash power to compensate for the change in distance):

Now the face is well lit because the relative distance between the parts of the face is now small compered to the distance from the flash, also, the background is no longer black (because the distance between light and  to background is no longer much longer than distance from light to subject).

If you remember in previous posts we used this effect to make the background black by placing the flash very close to the subject and to make the background white by placing the flash near the background.

Now, there’s just one more thing, while the light drops in intensity between light source and subject it does not lose power between subject and camera, to show this I’ve taken two more pictures of the same toy, both pictures are taken with the same camera settings (f/8, 1/200 sec, ISO 400, 135mm) and the flash at the same position with the same power settings, the first picture is from the closest distance that fits the subject in frame:

The second picture is from another room, the farthest I could get inside my home:

And here is the first picture and a crop of the same area from the second picture, the colors are a bit different because I forgot to turn auto light balance off but the brightness is absolutely the same:

Hope you enjoyed this post, and that this will help you better control the lighting in your photos.

Using light to show or hide texture

Sometimes you want to show the texture of what you are photographing, for example, you may want to exaggerate the texture of wooden or paper items to make them look more authentic, other times you want to hide texture (and make skin look smother).

Today we’ll see how you can control just how much texture we will see in the images.

Our first test subject is a printout of the dinosaur from the white background post a while back printed on cheap office paper.

For this experiment I’ve set the camera in manual mode, ISO 100, f/8, 1/200, at those settings all the light we see is coming from the flash (without flash the picture is completely black), the camera is on a tripod looking almost strait down at the printed paper that is on a small table.

In the first picture the flash is on the camera pointed directly at the paper and in minimum power (because the white paper reflects a lot of light back at the camera) and we get this:

In the second picture, with the same camera settings and the same flash at the same distance from the subject and still pointed directly at the paper – but this time located to camera left at the same height as the paper and in maximum power (because this time most of the light crosses from left to right without hitting the paper) and we get this:

The picture is too dark so we open the aperture and raise the ISO and get this:

We can clearly see the difference in the paper’s texture between the first and third picture (the second picture is here to prove that the difference was caused by moving the light and not by changing the camera settings).

Now, I’ve chosen those two extreme positions To make the difference obvious in real life, you rarely light your subject directly from the side and, unless you don’t have a choice, you also rarely want the light to come from the camera, in most cases you should choose something in the middle.

Why does this happen? when the light source is close to the camera and the light hits a textured surface all the surface is more or less evenly lit – making the surface look flat.

On the other hand, when the light is coming from the side it only lights one side of each little ridge that makes up the texture – transforming the surface into a series of lighter and darker patches and bringing out the texture.

This is why people say the light from on-camera flash is “flat” it makes 3D object seem flatter and reduces the feeling of depth is the image.

That’s it for today, see you next week.

When not to use flash (flash basics 1)

This is the first post in a long series about flash photography, the series is starting with a few posts about how to use the camera’s built in flash and will continue to external flashes both on and off camera, I will publish the flash posts every few weeks between other topics because I don’t want to write just about flash for months.

I really like to use flash in my photos, it makes life easier and can give wonderful results with just a little bit of expertise and just a little bit of equipment – but flash is not useful in every situation, there are a few areas a flash is ineffective or downright harmful – so I’m starting this series with some situations you should never use flash in.

When your subject is not very close

This is probably the most common flash mistake people make,

Every flash has a maximum range, those ranges (especially for the camera’s built in flash) are very short, anything outside that range is not illuminated by the flash at all – here is a picture of my point and shoot camera firing the flash in the dark:

It’s easy to see that the light is very bright on the right close to the camera but drops off very fast and by the time we get to the left side of the image it’s very dim.

For that camera, according to the manual, the flash is only effective up to 3 meter (9.8 feet) so anything farther is effectively in complete darkness. My DSLR has a more powerful flash that can reach up to 5 meters (16.4 feet), still not much.

This means that if your subject is out of the flash’s range it’s not illuminated by the flash at all – in the past this would have resulted in a black frame but the modern camera compensate by taking the exact same picture you would have gotten with the flash completely off (except it fires your flash in full power and drains the batteries in the process).

If you are photographing a sporting event or a show and you are not in the first row all your flash is doing is bothering the other viewers and draining your batteries – turn it off.

If you are photographing landscape than this is silly, the mountain in the distance is so outside the flash’s range that all it’s doing is draining your batteries and making you look silly – turn it off.

Photographing through glass, fences,  nets, cages, etc.

Any time that you have something between you and the subject there is a chance that something will reflect the flash, let’s show an example:

I’ve positioned my lovely point and shoot on a tripod behind some bars, the camera lens is positioned between two bars and the camera is focused on a small tree in the distance.

And here is a picture without flash, the white thing on the right is a piece of furniture that is standing right next to the tree, on the left side you can see a dark out of focus part of one of the bars.

Turn on the flash and we get this:

First, the dark, out of focus, barely noticeable bar became the brightest and most prominent item in the photo – and as if this isn’t bad enough the light reflected of it totally washes out all the colors in the picture.

Now, let’s close the glass window and take a shoot trough the glass:

Yes, what you see it the light from the flash reflected in the window, everything else is gone.

Anything that is remotely reflective

For your enjoyment, from left to right, an iPhone, a closed laptop and a cake in the oven – all with a big ugly bright burst of light reflecting from the flash:

Another painful effect that you can’t see at this small size is that the light is reflected by every scratch, dirt or fingerprint on the reflective surface – so whatever you are photographing should be completely and totally clean.

This also applies to photographing people who wear glasses – there will be a whole post on photographing people with glasses in the future.

People

Direct flash, especially at close range, is a very unflattering light – it makes the face look flat and highlights every little bit of sweat, also, often in the dark the camera will use too much flash and make the skin look very white, sometime even bright.

And let’s not get started about red eye.

No example pictures here – I don’t want to make people who let me use their pictures look bad on my blog.

So, we shouldn’t use flash?

Flash is wonderful, I love flash (really) – but like any tool it has it’s limitations.

And of course, there are things we can do to overcome those limitations:

To increase the flash range you need… a more powerful flash – but every flash has a range (even the big studio ones) and if your subject is out of range turn the flash off.

To minimize reflections you need to find an angle that reflects the flash’s light away from your camera, there will be a whole post about it soon.

And just to finish on a more positive note I’ll tell you the next flash post will be about things you can do with your camera’s built in flash.

Getting everything in focus–the hyper focal distance

In last week’s post we talked about the factors that effect depth of field and how to use them to increase and decrease it (let’s face it, mostly decrease, everyone just loves to blur the background those days).

But some times you want to get everything in focus, a typical example is when you are taking a picture of a person in a nice landscape and want both the mountains in the background and the family member in the foreground to be in focus (and even if you don’t take vacation snapshots it’s still common to have some object close to the camera in landscape photos because it makes the photo more interesting).

When faced with such a challenge you can focus on the foreground subject and blur the background, you can focus on the background and blur the subject, you can use the techniques we discussed in the last post to increase depth of field (use a wider lens, stop down the aperture, get farther from the foreground subject) – or you can learn about a useful concept called “hyperfocal distance”.

What is hyperfocal distance and why should I care?

The diagram below shows what happens when you focus close to the camera, the red triangle is the point of focus and the yellow bar is the distance range that is in sharp focus – when you’re focusing close to the camera the in-focus are is small and relatively symmetric (the sharp area before the focus point is the same size as the sharp are after the focus point).

As you focus farther from the camera your in focus area grows, but the area behind the focus point grows more than the area in front of the focus point, in the next diagram you can see that focusing on the person leaves a wide (but not wide enough) are in focus behind the person.

As you focus even farther the are behind the focus point continues to grow until it reaches infinity – that is everything behind the focus point is in focus – that exact focusing distance is called hyperfocal distance.

When focusing to the hyperfocal distance (or behind) the area of sharp focus starts at exactly half the distance between the camera and the point of focus and never ends (everything from halfway to the focus point and farther will be in focus).

In the diagram below you can see that by focusing to the hyperfocal distance you can get both the person and background in focus – by focusing a bit behind the person.

How do I know what the hyperfocal distance is?

The hyperfocal distance is effected by all the factors that effect depth of field:

  • Focal length – wider lenses (smaller focal length) makes the hyperfocal distance closer.
  • Aperture – smaller aperture (larger f number) makes the hyperfocal distance closer.
  • Distance – well, we are trying to calculate the distance.
  • Circle of confusion – Smaller sensor makes the hyperfocal distance closer.

Like depth of field there are many on-line calculators as well as calculators for every smartphone platform (actually, most depth of field calculators also tell you the hyperfocal distance).

How can I focus to the hyperfocal distance?

If you have a lens with a distance scale you are in luck, after you get the distance from a calculator switch the lens to manual focus and turn the focus ring until you see you are focused just behind the hyper focal distance using the distance scale.

If you don’t have a distance scale you need to find something that is approximately at the correct distance from you and use that to focus.

Quick Tip: focus a little behind the hyperfocal distance because if you accidently focus a little closer the background will be blurred.

Real life example:

I wanted to take a picture where both the subject near the camera and the background are in focus, I started my depth of field calculator app and entered a focal length of 35mm (my favorite focal length) and an aperture of f/8 (for a nice middle of the road aperture) – The calculator tells me the hyper focal distance is 8.20 meter (or ~27 feet).

Armed with this information I went out to a park just across the street from where I live and took this picture I call “dog looking at path” (if you want to buy prints just e-mail me):

In this picture I used the lamp posts to focus, since the posts are more-or-less evenly spaced they give us a nice way to measure distance – I know the post behind the dog is more than 8.2 meter away so I focus on it, I know the post the dog is tied to is about half way between the post I’m focusing on and the post I’m standing next to (it’s out of frame) so by making sure the post near me is in front of me I know the dog is more than half way between me and the focus point.

If I focus on something that is farther than the hyperfocal distance than everything farther than halfway between me and the focus point will be in focus – so that means both the dog and the background.

To prove the point I took 3 pictures, one focused on the dog, one on the background and one on that second lamp post,

Here are 100% crops from those pictures:

The left part is from the picture focused on the dog, the dog ear is sharp but the background is blurred.

The center is focused on the background, the background is sharp but the dog is soft (look at the darker area of the ear that is so clear in the other pictures).

And finally on the right, the right picture is focused using hyperfocal distance and you can clearly see both the dog and the background are in focus.

That’s it for today, hope that helps the next time you want to photograph something close while keeping something far away in the distance sharp.

Blurring the background–even with a point and shoot or cell phone camera

In this post we’ll talk about controlling the “depth of field” the parts of the picture that is in sharp focus and the parts that are blurred – and I will show examples taken with a point and shoot camera and with my iPhone.

When the camera is focused on an object that object and everything at the same distance from the camera is in sharp focus, there is a range before and after that object that is also sharp and everything outside that range is blurred (more blurred the farther it is from the focused object).

The sharp range can be small (that’s what’s called a “shallow depth of field”) causing the background and objects close to the camera to be very blurry or it can be large (usually called wide or deep depth of field) up to the point everything is in focus and nothing is blurred at all.

There are just 4 factors that control the depth of field (that’s actual physics, backed up by math and formulas) and with most cameras we can control 3 of them, and they are:

Focal Length (How zoomed in you are)

Note that this only works with real optical zoom that is created by moving pieces of glass inside the camera not with digital zoom, so this works all but the cheapest point and shoot cameras but not on most cell phones.

To show the effect I’ve took my lovely Canon 550D with the 18-135 lens and shoot two pictures without moving, one fully zoomed in at 135mm and the other at 32mm (not fully zoomed out at 18mm because that would show you too much of the mess in my garden on the sides of that nice fence ).

You can clearly see that the background is much more blurred in the zoomed in image (you can also see the ridicules construction I used to position the bear, but that’s another subject), but what would happen if I did the same experiment with a point and shoot camera? let’s try, I took my old Fuji S700 (a relatively high end point and shoot from 2007, maybe earlier) and shot the same pictures again, one fully zoomed in at 63mm and one zoomed out at 13mm.

Because the very different sensor size between DSLR and point and shoot the “zoomed-in-ness” at the same focal length is very different, the physical focal length in the point and shoot is much smaller (that’s one of the reasons point and shoots can’t get as shallow a depth of field as DSLRs).

 

 

 

Again, we clearly see the difference in background blur, juts to make it easier to see here is a small part of the upper left corner of all four pictures:

 

The top left is the DSLR zoomed in clearly showing the blurred pattern, the top right is the point and shoot zoomed in it’s so blurred it’s almost a solid color (some of the blur is caused by the lowest quality lens of the smaller camera, if you don’t look in the corner you can see the blurred pattern very clearly), the bottom left is the DSLR zoomed out and the bottom right is the point and shoot zoomed out (the difference in color is simply because the DSLR got a wider area in the picture and caught a piece of the fence that is under a roof while the entire point and shoot image is in direct sunlight).

The focal length have such a big effect on depth of field that at wider focal length (lower number, zoomed out) it’s completely impossible to blur the background, even with a good camera and lens.

One thing that is painfully obvious is that changing the focal length seriously changes the entire composition of the picture and not just the background blurriness – and this brings us to:

Aperture Value (Size of the hole in the lens)

The aperture value is the only option that changes the depth of field without otherwise changing the composition, this is easy to use in cameras that support this, just switch the camera to A or Av mode and set a lower number for smaller depth of field and an higher number for a larger depth of field (if you want to know what those numbers mean look at my previous post understanding f numbers).

But remember all 4 factors always effect depth of field, you can open the aperture wide open (smallest number) but if you are zoomed all the way out you still won’t get a shallow depth of field, especially with point and shoot cameras you have to set the aperture value and zoom in (and get close, we’ll talk about that below) to get a nice shallow depth of field.

To demonstrate I’ve used the Canon 50mm f/1.8 lens on the 550D (because that lens opens all the way to 1.8 it’s easier t o see the difference) the first image the aperture value is set to f/11 to get an extremely wide depth of field:

And in the second picture  I’ve gone all the way to f/1.8 for extremely shallow depth of field (if you look closely you will see that while the bear’s nose is very sharp the ears are blurry).

The aperture value also effects other things in the image (see my previous post on aperture) mostly the amount of light coming into the camera and so the required shutter speed but also how light sources look.

This is all good and nice on higher end cameras but I did mention this is also possible with the iPhone that has a fixed focal length and a fixed aperture – so this brings us to the third factor that is always under your control no matter what kind of camera you have:

Distance to subject

Simply put the closer you are the smaller the depth of field, here are two pictures to demonstrate: in the first, we are near our bear of a model

and than a picture with the same camera settings but from farther away:

For smaller cameras you may have to be very close to get the effect (for the iPhone 3GS, it’s just a few inches), just be aware there’s a something called “minimum focusing distance” – this is, unsurprisingly, the minimum distance  the lens can focus to, everything closer will be out of focus, in point and shoots turning your camera macro mode (icon of a flower) may help, here’s a picture from my iPhone (this time using a toy monkey as a model, with an extra cluttered background – just to make a point):

You can only see the eye because this is how close you have to be to get a shallow depth of field with an iPhone.

Now, depth of field is one thing where a nicer camera really makes a difference, just compare the previous picture – that is the shallowest depth of field I could get with the iPhone and I had to place the iPhone so it was almost touching the monkey to get the shallowest depth of field.

I can easily get much shallower depth of field with my entry level DSLR and lens (Canon 550D with 18-135 at 135mm, wide open at a non-impressive f/5.6, minimum focusing distance):

Or with the cheapest lens Canon make (50mm f/1.8 II wide open at f/1.8, minimum focusing distance)

The difference in depth of field is very obvious, the difference in colors is also obvious – and a large part of it is due to the difference in lighting – the iPhone 3GS doesn’t have any flash at all while the DLSR used an external flash bounced on the ceiling.

Circle of confusion

Circle of confusion is 3 things: 1. the coolest name ever for a technical concept. 2. not important because we can’t control it. 3. A way to describe how out of focus something has to be before we consider it blurry (that is, how big the blur have to be before we notice it).

Circle of confusion is determined by the physical size and resolution of the camera’s sensor and is only important to you if you want to calculate the depth of fields manually or create your own depth of field calculator (or in other words, not at all to most people). 

Using this in practice

Depth of field is one area where a good camera and lens makes a huge difference, with a camera with a larger sensor (like all DSLRs) and a “fast lens” (a lens that can reach lower aperture values) controlling depth of field is easy, just set the aperture and you’re set, for point and shoots you mostly have to work with focal length and distance.

Focal length and subject distance really effect the composition of your image, you can’t just dial them in to set the depth of field – they also interfere with each other, if you want to reduce depth of field by zooming in you have to step back to get the same image and that increases the depth of field due to the change in distance to subject.

If you do want to get a shallow depth of field with a point and shoot try to use all the factors, zoom all the way in, set the camera to A or Av mode (if it has one) and set the lowest number the camera let you and get as close as possible to you subject.

If you have a DSLR you probably want a depth of field calculator so you know what to set in order to keep your entire subject in focus while blurring the background, there are many free ones on the internet and there’s also many free apps for every smartphone so you can carry one with you.

Next week I’ll write about the opposite problem, how to get a widest possible depth of fields (for example, so both the person next to you can the mountain in the background are both sharp).

What to know how to photograph something?

Is there a picture you want to take but just can’t? leave a comment and I’ll do the research and teach you how to take it.

Want tips for photographing animals? mirrors? jewelry? home interiors? or maybe you want to learn how to create reflections in water? use flash better?

Whatever your question, as long as it’s photography related, leave a comment on this post and I’ll find the answer for you.

Macro photography with no macro equipment

Most point and shoot cameras have a macro mode (flower symbol) that let you take extreme close-up pictures of small things, when you move up to interchangeable lens cameras you need special macro lenses to get those pictures – but there is actually one cheap way to take extreme macro pictures without any special equipment.

Take the lens off the camera and hold it backwards – normally your lens take a light from a big area and shrinks it down to the the size of the sensor, if you simply hold the lens backwards in from of the camera you get the opposite effect – the lens take  a picture of something very small and enlarges it on the sensor.

Here is a picture of the setup, flash pointing at the ceiling (we’ll talk about this in a moment) and the my hand is holding my 18-135mm zoom, fully extended at 135mm backwards, I actually shot the pictures for this post hand-held, in this picture the camera is on a tripod because I have one hand holding the lens and the other hand taking the picture with my cellphone.

Now, you need to be careful, the lens is not attached to the camera and you don’t want to drop it, also, you are using it not in the way it’s designed to be used – be very careful and if you damage your equipment don’t blame me.

You may have to enable some setting on the camera so it takes a picture without a lens attached, also, because the lens isn’t attached to the camera there’s no auto focus or aperture control.

The depth of field you get from this setup is extremely shallow and you focus by moving the camera forward and backwards until your subject is in focus, I recommend trying the live view focusing trick wrote about last week.

The aperture control is very brand specific, on Canon when the lens isn’t attached the aperture is wide open – making the already too thin depth of field even thinner – but there’s an easy trick you can use to stop down the lens on Canon cameras (this should also work with other brands where the aperture control is electronic) – attach the lens, set the aperture and press the depth of field preview button (locate right behind the lens on the lower left, right below the lens release button) – now, with the camera on and the DOF preview button still pressed detach the lens – the aperture blades will remain in the same position.

On Nikon when the lens isn’t attached it’s stopped down all the way – good for DOF but making us need a lot of light and can make the picture soft due to diffraction (if you don’t know what  diffraction is that’s ok, but I’m not going to explain it now because it’s not the topic of this post), for Nikon (and other brands where the aperture connection is mechanical) there’s a little lever on the back of the camera you can push to open the aperture (at your own risk, I don’t own a Nikon and never tried it myself).

Marco photography needs lots of light, for those pictures I’ve used my flash on camera pointed at the ceiling – not to soften the light (with the flash head physically larger than the subject I expect the light to be soft anyway) but because at that distance the lens would have cast a shadow on the subject if I used direct flash.

So, let’s see what do we get, first, this is the setup, I’ve put the pencil there to show scale, it’s not there in the macro pictures (also, the picture was edited to remove a barcode that was visible on the corner of the paper, the edits are nowhere near the flowers).

Here’s the yellow flower in the middle with a reversed 50mm F/1.8 lens, stopped down to F/8 using the DOF preview trick (click to enlarge):

And the same flower with the 18-135mm at 135mm wide open at F/5.6:

We can clearly see that longer focal length means more magnification.

We can also see that the depth of field is painfully shallow – so take lot’s of photos, a tiny camera movement will move your focus and the more pictures you take the better chance you have to get one where the focus is just right.

After you take a few reversed lens macro pictures if you discover you like it you can buy a cheap “macro lens reversal ring” that let you mount your lens backwards without having to hold it in your hand, here’s one that fits Canon DSLRs and the Canon 50mm F/1.8 for less than $7 on Amazon (at the time I wrote this) and such rings for other lenses for Canon, Nikon and all brands (also on Amazon), make sure you get one that fit’s your camera and the filter thread size of your lens.

The next step up in macro photography is extension tubes –  if you want me buy a set and write about them click any of the links in the previous paragraph and buy something on Amazon.

When auto focus fails/ Easy manual focus

What do you do when auto-focus fails? well, there are two ways auto focus can fail, either it focuses on the wrong thing or it doesn’t manage to focus on anything at all, we talked about what to do when auto-focus locks on the wrong subject last week, today we will talk about what to do when the camera can’t auto-focus at all.

There are 3 common reasons for auto focus failure:

  1. You are too close – each lens has a “minimum focusing distance” and it’s just can’t focus light from something closer (for interchangeable lenses cameras that distance is usually printed on the bottom of the lens) – if you are using a point and shot camera you can go into “macro” mode (that usually has a flower icon) for camera’s with interchangeable lenses you need to switch to a macro lens, move back or read next week’s post about how to take macro pictures with no extra equipment.
  2. You are pointing you camera at something that is just a flat color – the camera need something to look at, if you point your camera at an evenly lit single color wall (for example) it can’t find focus because the in focus picture looks the same as the out of focus picture – in this case you can hold something next to the surface you are photographing, focus and then remove the object and take the picture.
  3. The third and most common case is not enough light – the camera is not as sensitive as our eyes (at least when auto-focusing) and can’t focus on something it can’t see – in this case a simple flashlight can help (light the subject, focus, turn off the light and take the picture) but sometimes that’s just not possible and you have to focus manually.

Some people can just look trough the viewfinder and set perfect manual focus every time, I’m not one of those people – so what do people like us that don’t have perfect eyesight can do?

Turn on live view, use the live view zoom function to zoom all the way in and turn the focus ring until the zoomed in picture is sharp – it’s that easy.

It’s easier to do this if the camera is on a tripod and the subject is not moving, but if we are in low light condition than you need a tripod and a stationary subject anyway.

That’s it, this was a shorter tip than usual, next week, as I said before we will talk about cheap macro photography.

Controlling the point of focus

I was walking around the countryside when I turned a corner and seen the most amazing site – a farmer fighting a real life dragon! so I took out my camera and quickly snapped a picture before the dragon has a chance to fly off (or set me on fire), I got home with the picture that would make me rich and famous, quickly loaded the picture on the screen and – the farmer and dragon are both completely blurry because the camera focused on this stupid cow at the distance – so much for fame and fortune  and back to blogging about photo techniques.

A more common version of the same problem (for people who don’t get a chance to meet a dragon) is a photo of a couple at a wedding or similar event where the couple is blurry but some aunt in the distance that is visible between the two people you are trying to photograph is crystal clear.

There are actually two easy ways to completely control the camera’s point of focus:

Focus and recompose

“Focus and recompose” is the oldest, quickest and simplest way to control the point of focus.

You start by setting your camera to always focus on the center point of the picture, check your camera manual about how to do that – for simple cameras and cell phones that don’t let you preset the focus point you can skip to the next technique.

Now, to photograph a lion wandering into a quiet farmyard point the camera strait at the lion (the composition is way off and we see stuff that is supposed to be out of the frame – but we don’t care at this point we’re not taking the picture just yet):

Half press the shutter button and hold- this will make the camera focus but not take the picture:

Now, with the shutter button half pressed, move the camera so that you see the picture you want to capture (but don’t move closer, back up or zoom in/out as those will change the focus) and press the shutter all the way:

And we get the exact picture we are looking for – the lion is in sharp focus and the farm animals blurry – who are both closer to the camera and near the center – so if we leave it to the camera they will be the most obvious point of focus (note that resizing pictures to smaller size makes them sharper and so the farm animals don’t look so blurry in the small version, to better see where the focus is note the difference in the level of detail between the face of the lion and the face of the cow).

It’s important to know this technique does fail miserably in one situation – when you have a very shallow depth of field (when the subject is very close the the camera, you set a very wide aperture or you are using a long lens) in this case the area of focus is so small that by moving the camera you are moving the focus enough to blur your subject – for those cases we have the next technique.

Choose the focus point

Here instead of focusing and then moving the camera we just tell the camera exactly where we want it to focus.

For cellphones, point and shoot cameras, DSLRs in live view mode usually focus by using the image captured by the sensor, there will be a frame on the screen that tells you where the camera will focus, just move this frame (usually by using the arrow keys, or tapping the screen for touch screens) so it covers the area of the picture you want to be in focus:

For DSLRs using the viewfinder and other cameras that have the faster and more accurate “phase detect” auto focus method the camera has actual multiple special focusing sensors and you can choose which of those sensors to use – if you look trough the viewfinder you will see black dots on the image, each of those dots represent an auto focus sensors, and when you half press the shutter button a dot that is in focus will glow red, you can tell the camera to use just one specific auto-focus sensor) (or, in more expensive cameras, to use only part of the sensors) – here is the focus point selection screen on my camera with the top left point (that is right on the lion) selected :

This technique is more accurate than “focus and recompose” but is slower because you have to mess with the camera settings.

That’s it for today, next week we will talk about what you can do when auto focus doesn’t work at all.

Soft Light and Hard Light

At first soft and hard light seems like red and purple music – the word just don’t make sense, but soft and hard light are actually very important and simple concepts in photography.

In a nutshell soft light is a light that makes shadows with softs edges and a gentle gradient change from light to shade while hard light makes shadows with hard well defined edges.

To help demonstrate the effect of hard and soft light I’ve taken two pictures of my friendly neighborhood lion (that made its first appearance in the aperture post), for the first picture I’ve put the lion on a tripod near a window and just took a shot on Av mode – we will talk abut why windows give soft light below, you can see the very pleasing change from the brighter right side to the darker left side and that the left is well lit even with just one light source on the right side.

For the second picture, I’ve put the lion on a pillow and used a flash on the far right, we will talk about why a far a away flash is considered hard light in a second, you can see the left side of the head is dark, the fast light transition on the face and the sharp line the shadow makes on the pillow in the bottom right and top left sides of the picture.

If you look at the texture of the lion’s fabric you can see that in the soft light picture it looks, well, softer, everything looks smother and small features (like the seem in the middle of the lion’s body) are visible but look small and insignificant – this is why this is a very good portrait setup, it makes skin look softer and smother and is generally a very flattering light.

The hard light picture on the other hand makes the lion seem rougher, small features are more exaggerated (the seem in the middle of the body is now a very clear dark line) – this is why this light does not generally make people look good, but it does add drama and can work for photographing people if you want that dramatic look and don’t want to make our subject look like a fashion model.

Now, how do we create soft or hard light? simple, the bigger the light is and the closer it is to the subject the softer the light, let me explain:

If we have a light source that is a single point, like the left diagram below, there are areas that are lit and areas that are completely dark – all the light comes from a single source and each ray of light can only hit one thing before it’s reflected back – but if we make the light source bigger, like the right side of the diagram, not all the light comes from a single point, and there are areas where light from one side of the source is blocked but is still lit by the other side – those are the areas of soft shadows.

As we make the light source larger the soft shadow areas grow until, if the light source is very large compared to the subject, the dark area disappears completely, in the diagram below we see a much larger light source at the same distance as the previous diagram.

And finally, in the next and final diagram, we see a light source of the same size closer or farther away and we see that the farther we take the light source the smaller the soft shadow areas become and the light get’s closer to a point light source, that is why the sun, while huge, is a very hard light source.

So, the sun is a hard light source because it’s far away and our flash is a hard light source because it’s small – so where do we find soft light?

We get soft light by reflecting or diffusing light on some surface, for example, light outside on a cloudy day is soft because the light “spreads out” on the clouds and the entire sky becomes one large light source, also, during sunrise and sunset the sun is lower on the horizon and so the light passes trough more of the atmosphere resulting in a softer light.

Window light is also soft because the entire window acts as a light source and so is light reflected from any large surface.

For flashes, aiming the flash at a wall of the ceiling softens the light because the light source is now a big piece of the wall instead of the tiny flash bulb – also, there are a lot “light modifiers” you can put between the flash and subject to soften the light, the most common is without a doubt the umbrella (instead of the flash head the entire umbrella is the light source – making it much bigger).

Hard light is also much more prone to reflections and specular highlights than soft light.

It’s important to mention that when we are talking about small and large lights we mean in relation to the subject, your camera’s flash is tiny when photographing a person from across the room but quite large for a close-up picture of an insect.

So, to summarize, here’s a table of the properties of soft and hard light and two pictures of a red plastic dinosaur, taken with the same camera settings, the right side was lit with a bare flash far away (hard light) and the left side with a small softbox right out of frame (soft light) – click image for larger version:

  Soft light Hard Light
Shadows Soft edges Sharp edges
Texture Smooth Rough
Light transitions Gradual Immediate
Reflections Less reflections More reflections
Light Source Big and close Small or far
Good for Beauty shoots Dramatic pictures