Aperture & Depth of Field made EASY - Photography Course 5/10

so aperture and depth of field now a lot of people think this is about the most confusing part in photography but that's only because people insist on teaching it in a really stupid way there's a very easy way to understand aperture and it'll make perfect sense I promise and just a reminder that this is all covered in the aperture section of our course notes booklet as well that you can buy online and also the plastic summary clip cards there's the aperture sector there which tells you which way to move your F number to do what we did depth of field and all that kind of stuff as well pretty handy so as we already saw in the basic lecture aperture controls what's called your depth of field and depth of field is just the amount of stuff that's in focus in front of and behind the point that you actually focus the camera on so this is a very small or shallow depth of field and this one is a large depth of field where much closer is still in focus and way into the distance is still sharp as well so typically for a portrait type photo where there's only one thing you're supposed to be looking at your subject you want the softest blurry and you can to make your subject stand out against it look more 3d so you want a small depth of field for that blurry background but contrast to that in a landscape you actually want a big depth of field because the close-up plants and flowers and the distant mountains and clouds everything is interesting and you want the viewers eye to be able to travel everywhere in the scene so for a landscape you want a big depth of field and as we already saw in our basic photography lecture you know using a bigger a small depth of field to affect the background has a pretty significant impact on the photo so here's a shot of a zebra using a fairly large depth of field so the zebra is kind of sharp the background is kind of sharp it all feels quite flat and stuck together as opposed to using a smaller depth of field where you can see now beautiful blurry background the zebra just leaps out against that you can see individual hair detail on the mane so what actually is aperture well inside your lens it's this variable sized hole and you can just set that to be whatever size you want and it's defined in these things called F numbers or F stops so you can see here that's F 8 f 4 F 2 and then you go oh hang on a minute the F number is getting smaller but the holes getting bigger and that's about where most people get you trying to understand aperture they suddenly realize there's this whole mental gymnastics you've got to go through to work what on earth you're trying to do with your f-number to do what with the hole and what does that do to the depth of field anyway and it's all just way too confusing but that's only confusing because for some strange reason everyone insists on talking about the size of the aperture hole instead of the f-number you know you live in a world of f numbers if you're setting your camera up to take a shot you're scrolling the F number you're watching the F number get bigger or smaller you know watching your size of the hole inside the lens you hear phrases like open the lens up more or stop the lens down use a bigger aperture this is what apparently is supposed to go through your head if you're trying to take a photo of a person or a portrait shot obviously you want a small depth of field for a small amount of stuff in focus a nice blurry background so you go okay we need a small depth of field well it turns out you get a small depth of field with a large aperture hole say go right so I'm gonna flip it very large aperture hole how do you take a picture with a large aperture hole well you got to remember actually a large aperture hole is a small F number so you flip it again clearly that's just stupid so if we just stick with F numbers it turns out aperture is incredibly easy let's have a look if you use a smaller F number guess what you get a smaller depth of field if you use a larger F number you get a larger depth of field it's pretty straightforward now the actual range of F numbers you can scroll to depends on what lens you have but some of them will go up to numbers about F 40-ish and down to about F one point something so let's pretend F numbers goes from about 1 to 40 so this photo was taken at F 2.8 so as far as F numbers go that's a small F number gives us a small depth of field a small amount of stuff in focus but if we used a bigger F number like f-22 that's a big F number big depth of field big amount of stuff in focus another example you can see here this photo is taken at F 2.8 so that's a small F number small depth of field you can see the background is blurry and just Jess and sharp there in the front if we used a large F number though like F 32 you can see the difference there the background everything is sharp now but back on that small F number small depth of field of course if I'd focused on that bollard half way back or something then that bolide would become InFocus and the ones behind that will be blurry and the ones in and Jess would be blurry obviously whatever you focus on is going to be in focus the F numbers just scroll up or down that depth of field around that point so if you're taking a photo of a thing you're a person or an animal the subject you want to use a small F number for a small depth of field nice blurry background to help it stand out but if you're taking a photo of a landscape shot where you want a big depth of field you just use a big F number like this one f-18 there's another way that I find some people find even easier to remember the whole F number thing and that's just to try and imagine that there's a whole lot of F's lined up from the end of your lens going out into the distance F F F F F F F F F now if you only wanted two of those s to be in focus it doesn't matter which two whichever two you focus on I guess but if you only wanted two FS to be in focus you'd pick F two if you wanted ya 10s to be in focus you'd pick F 10 if you wanted all 40s to be in focus you just pick F 40 basically you can boil it down to the more things you want in focus the more F's you want aperture doesn't get any simpler than that and it really is quite easy aperture really is your most powerful creative tool for making your photos look much more professional you know using a small F number for a small depth of field is a really powerful way of directing the viewers eye exactly where you want them to look like in this photo you can't look anywhere else really your eye is just drawn straight to that one chest piece also blurring stuff out that you don't want is incredibly useful in a zoo you might have mesh cage mesh in front of what you're photographing in the real world you're gonna have a bird deep in a tree somewhere and there's little sticks in front of it or they'll it's a grass popping up in front of your lion if you can actually focus carefully on your subject though and use a very small F number for a small depth of field you can make your subject nice and sharp but anything in front like these little sticks start to become blurry and if you use a smaller half F number and you can get close enough to that thing you're trying to blur out you can actually make it disappear look at this example this mesh here is a one centimeter mesh so there's no way I could hope to poke my camera through there and get a nice clean shot but if I carefully focus on the cat inside there that's a cat in there and then use a small F number then anything in front of the cat becomes blurry and the cage wire as you can see has completely disappeared that mesh you can see in the background there that's the other side of the cage behind the cat but there's literally six or seven wires going across in of its face but you just can't see them because they've been blurred out pretty amazing another example bird on a stick so f-22 that's a fairly big F number big depth of field so the bird is sharp the background leaves it quite distracting there and obviously the chicken wire in front is really annoying but if instead we just scroll down to a smaller F number F five point six and take the same shot again then look at the difference there the background is now a nice soft pastel e kind of background and the chicken wires gone fantastic and don't think that that is something you can only do with really expensive incredible lenses I deliberately took that pair of photos with the cheapest crappers lens money can buy but even with really cheap dodgy lenses you can do amazing things with the depth of field so you're supposed to be thinking now before you take a photo ask yourself the question where do you want the viewers eye to go in this photo what are we supposed to be looking at is there only one thing of interest allure one subject then you probably want a small F number for a small depth of field nice blurry background to make it stand out but if there are multiple things at different distances like a landscape then you want a big F number for a big depth of field and make them all come out nice and sharp incidentally if your camera has a landscape mode basically that's just telling the camera to pick a larger F number for you so you get a larger depth of field or a portrait mode that's just telling the camera to use a small F number give us a bit of a smaller depth of field nice blurry backgrounds now that's definitely better than Auto mode for sure but it's nothing like as powerful as going over to aperture mode like we're gonna have a look at in a second to really drag that F number exactly where we want because often you know landscape mode doesn't pick a very big F number it might think about if seven-night whereas you could probably drag your F number all the way to F 20 if you wanted to so you can just get much more control and more exaggerated effects by going to aperture mode and telling the camera exactly what you want it's worth realizing that the region of stuff that's nice and sharp is not actually centered around the point that you focused on turns out that about two-thirds of the InFocus stuff is behind where you're focused only one-third of it comes forward and you might think who really cares about that seems a bit pedantic but it's actually really important particularly for a landscape shot where you're trying to maximize your available depth of field so a situation like this one we want a huge depth of field so we're going to use a big F number like f-22 or something great then where do you focus a lot of people make the mistake on their landscape photos of focusing on the distant mountains and the problem then is sure you've got a big F number gives us a big depth of field but if you focus on those mountains two-thirds of that depth of field is now wasted behind the mountains only 1/3 of it comes forward and your foreground rocks and pebbles and stuff are still gonna be out of focus so the actual answer is when you're photographing a landscape scene you just try and arbitrarily focus about a third of the way into your shot so you just briefly point the camera down about a third of the way in focus lift it back up and take the shot now it's just maximizing the the use of your available depth of field okay so let's take a look at aperture mode so aperture mode on a Canon is a V and for every other brand it's just called a so in aperture mode you can pick whatever aperture value you want as long as the lens is capable of it and the camera will pick the right shutter speed to match up for it so that you get correct exposure or whatever exposures you've asked for if you've asked for a darker or brighter photo so be using aperture mode whenever depth of field is the almost creatively important element in the photo so if you're taking a portrait shot or a landscape shot which to me is most of the photography you ever take so I actually stay on aperture mode almost all the time and this is typically how aperture mode works you wake your camera up by pressing the button and it comes up with the last F number that you used and that's quite different to P mode remember how P mode always gives you that default auto mode middle kind of value you can always scroll to the same f-number if you wanted to but it rapidly gets pretty repetitive in P mode if you're taking a bunch of landscape photos for example in P mode you go and it comes up and says how about 5.6 and you go how about f-16 for a big depth of field let's go let's go Stroh f-16 take a shot being trying to take your second photo and you have press it and it goes how about 5.6 and you're like ah how about f-16 again and you have to keep moving it or if the lighting changes or you point somewhere else in P mode you're not really nailing anything down everything keeps kind of shifting around but in aperture mode if you put in f-16 it'll stay on f-16 no matter what the lighting does or where you point the camera the shutter speed will just keep being updated for you so you end up with whatever exposure you asked for let's say you make the photo brighter so you use your plus/minus exposure compensation and you say plus 2 it's got to be a lot brighter in aperture mode it's not allowed to open the hole up anymore because you're still saying the same f-number but it's somehow it's got to let more light in so your photos brighter so you'll just find that it leaves the shutter open for longer so more light comes in or if you asked for a darker photo you'd find it would just be using a faster shutter speed for you so that not so much light got in basically aperture mode you pick your F number it works out the shutter speed so that you end up with whatever exposure brightness you asked for so looking here obviously as we scroll our F number are bigger and bigger getting a bigger depth of field good for landscapes and so on you noticing the aperture hole is getting smaller and therefore the shutter has to stay open longer and longer so we still end up with that same correct exposure that's something to be aware of really large F numbers really small holes they often end up requiring quite a long slow photo so you've got to hold the camera really steady or put on a tripod or something that's why landscape photographers and things always bother to bring a tripod where someone else can just walk past with a happy snap and go click didn't need a tripod but no they're using such a big F number for such an amazing depth of field that the photo is going to be quite slow going the other way then scrolling smaller and smaller F numbers getting smaller depth of field good for portraits nice blurry backgrounds and conveniently also nice fast photos at the same time just a point to note don't expect to see the depth of field change when you're looking through your viewfinder it's not actually til you get the photo back that you'll see the depth of field because when you're looking through the viewfinder in a DSLR in fact the lens stays open to the largest hole it can so you can see wouldn't be much good if you'd asked for f-22 which is a really small hole and the lens just shut down you wouldn't be able to see through the camera anymore so in fact it stays open no matter what F number you ask for until you actually take the shot and then it briefly jumps down to a different size it takes the photo then it opens back up again so you can see it just means you can't see the depth of field changing in real time the other thing to remember is you're not entirely safe anymore in aperture mode it won't stop you selecting an F number if there actually is no shutter speed to match up to it for that current lighting condition maybe it needs more than 30 seconds or maybe it needs faster than the four thousandth of a second limit that the camera can do so you can pick whatever F number you want as long as the lens can do it but there just might not be a fast enough or low enough shutter speed to match up to it so you've got to be aware of that the camera will warn you it'll sit there flashing the f-number at you or it might go red or nickens normally say high or low there'll be some some warning there letting you know that the f-number you've picked is basically out of range for the current lighting conditions it'll sometimes happen in a situation like this let's say you're trying to take a photo in the dark and you make it worse by using a large F number now when I say you're making it worse that's because the large F number is a small hole so there's already almost no light out there and you're forcing it to come in through a pinhole it's gonna take forever to get enough light in there for the photo well and truly more than the 30-second limit that the camera can do itself but it won't stop you taking the picture it'll just flash 30 seconds at you're basically saying don't do it if you take this photo it's your own silly fault it'll just stay open for as long as it can which is only 30 seconds and then it'll give you a photo back that just looks dark it's just it couldn't stay open long enough to give you the correct brightness the same thing can also happen at the other end if you use too small and f-number so too big a hole and you're pointing straight at the Sun or some really bright light source then so much light comes gushing in there the camera only really needs to be open for a millionth of a second to get the correct exposure but you know the quickest photo it can do is maybe four thousandth of a second and still too much light's gonna get in and you'll end up with an overexposed photo so that's a bit of a telltale if you're looking at a photo and just seem to be getting you know inexplicable exposure like I asked for it to be brighter and it's not getting brighter or something like that it probably was telling you that there was something warning something flashing at you you just missed it so just don't use such a large or such a small F number until it kind of calms down and doesn't have any flashing warnings at you another thing you can do to combat that is change your ISO but we'll leave that to the ISO lecture an interesting side effect you can get with using a large F number apart from having a large depth of field actually tends to make any point light source turn into a bit of a star bit of a starburst it can look really cool some people hate it but I think if it's used properly it can be quite nice so to get that effect you have the Sun actually hiding behind the leaf or the building or whatever it is while you're half press and set the exposure and focus it all that kind of stuff because remember if you have the Sun already in the shot it might throw out your metering you'll end up with a silhouette so you have the Sun hidden half press beep and then you move to the side just until the son Jeff starts bleeding over the corner of the building take the photo just before you go blind basically obviously don't look at the Sun with a really long lens this effect works better anyway with a very wide lens if you look at the Sun through a long lens you're actually risk going blind it's like looking at it through a telescope you can just burn a hole through the back of your head so try not to do that all right so it's time to go out with your aperture crack which is actually a pretty straightforward prac you just pick up your camera make sure you're on aperture mode AV mode or a mode and then you just want to find a subject and take two different pictures of it one with the big F number one with a small F number and then just compare the two and you should be able to see the background blur out in one of them and become sort of sharper and more distracting in the other one look at these two photos which one of these has the smaller F number the smaller depth of field definitely it's this one in fact the closer you get to your subject and the further away the background is and the more you zoom your lens in that'll all help to give you a nice blurry background if you're really not able to see any difference between your big F number and your small F number shot you just probably didn't pick a good example you know you got to get closer or find something that's not so many different things that are similar distance away it's getting closer you'll get there in the end you should be able to see a fairly dramatic difference another common problem you might have with this prac is if you're using your large F number so if the big depth of field you expect the whole thing to be nice and sharp but you might actually have a problem where the big F number makes your photo so slow there you get camera shake and in fact the whole thing goes blurry just from subject movement and camera shake nothing to do with the F number so if you're getting camera shake problems then just turn your ISO up more and then come back in and look at the next lecture which is exploring shutter speed you

Channel: Chris Bray Photography

Views: 1,483,579

Keywords: aperture, depth of field, explain, simple, photography, basic, photography course, free, understanding aperture, av mode, a mode, camera, dof, using av mode, blurry backgrounds, landscape, portrait, lesson, f-number, f number, aperture vs f-number, camera course, blurry background, soft background, free photography course

Id: EdxKl5np9KE

Length: 17min 21sec (1041 seconds)

Published: Thu Sep 29 2016