hello in this tutorial I'm going to give you a guide into the use of nd filters in photography what they do when to use them or effects they can create and so on if you're thinking of buying or using nd filters to create long exposure effects then this tutorial is for you
hello I'm mark Newton from the school of photography and you can find this at the school of photography comm where we deliver the best in photography education in this tutorial I'm going to explain nd filters to you I've also created a ND filter guide that you can download and keep this guide will help you with working out exposure times and what ones to buy and I'll tell you how to get that at the end of this video so firstly what do nd filters do well they help you create images like this and this and this an ND filter acts like sunglasses would to your eyes it blocks like coming into the lens like sunglasses blocks like coming into your eyes an ND stands for neutral density which means it blocks the light in a neutral way without changing the color of the lime so why would you want to block light coming into your lens light is good it's what makes the image it makes sense to think that if you block light coming into your lens you're just gonna make a dark underexposed image well when you block like coming into your lens you are forced to expose the camera to light for a longer period of time you need to open the shutter for longer to allow the correct amount of light to enter the camera I want to demonstrate this to you using water flowing at different rates okay so let's explain what's going to happen here I've got five hundred millilitres of water in each jug that's a pint and rent depending on where you are in the world and water is now the correct amount of light that we need okay so we need 500 millilitres of light I've got here a funnel with a nice big hole like that and I've got over here a funnel with a nice small hole like that and this one here is representing the camera that's got the ND filter on it so it's going to let the light in slower so here we go let's pour the light in and as you can see the camera without the ND filter the lights just poured through with an ND filter on it's letting in the light very very slowly very slowly and that's basically what an ND filter is doing is letting the light through very slowly into your camera okay let's get a look at some pictures okay so let's look at the effect an ND filter can have on an image so here's a normal picture with no filter taken using a tripod at one thirtieth of a second you can see the ripples in the water and the clouds look clear everything has been frozen for that fraction of a second and here is a shot taken just after that one using a 10 stop in d filter and here is a 10 stop ND filter you can well you can hardly see through if I hold it up to my eye or hold up to anything you can hardly see through it it's letting in very little light so that's what a 10-10 stop ND filter looks like and using it in this image it has allowed me to increase the exposure time to 30 seconds so I've still exposed the camera to the same amount of light but this one has been exposed over a longer period of time and when you do that everything that still stays still ie the tree and the mountains and everything that moves blurs or blends in together this shot has also been adjusted in lightroom to pump up the colors and contrast there's a whole tutorial on how I how I adjust images in Lightroom and I'll put that link up here so you can see that if you wish okay so let's look at them both together the one on the Left shot at one thirtieth of a second the one on the right shot at 30 seconds with an N with a ten stop in D filter on again they have both been exposed to exactly the same amount of light but when you add the ND filter you are able to allow that light to enter slowly which allows moving things to blur such as the clouds and it also allows things to blend in such as the ripples in the water also note there's only the shutter speed that has changed the aperture and the ISO has stayed the same and you have to do this when you're doing these kinds of shots and you also have to work in fully manual mode I'll cover that in much more detail in my other tutorial how to use nd filters and I'll put a link up to that when it is ready okay so let's talk about the different types of ND filters you can get because they come in all sorts of shapes and sizes firstly you've got these ones here these are the basic ones I think they're very good value for money and they do the job really well for what they cost this costs about 10 pounds and all you do is you screw it to the front of your lens and you've got an ND filter on it it's as simple as that you have to get the right filter for the right size of your lens now I would recommend that you get one that fits your standard zoom lens if you're just starting and you just want to practice you know your standard zoom lens that you get with your kit when you buy your DSLR look on the front of that lens it will give you and through this ink for instance in this case it says 58 mil it will give you a size the circumference of the lens and the filter size that you need you go on the internet you type in there's loads of different brands it doesn't really matter they are you know they are cheap but they do the job and you can buy one and you can screw it straight onto the front of your lens and you're away and that is the circular type then if you want to make more of a commitment to this type of photography what you want to do is get what's called a filter holder system and here's one here now you can get lots of different brands of these and they're doing very impressed but I'm not here to say which one is better or worse because they're all pretty good but you can get a li filter system you can get one called nice II get one called hi-tech and you can get one called kookiness where coucang are probably the more budget ones out of all of them so again if you're if you're just starting maybe you want to start off with that one and try getting some secondhand stuff as well and you know maybe that's quite good to get you started but basically the filter system works a little bit different because you can get your filters and you're gonna take that out for a minute and here you've got a 10 stop ND filter a 10 stop ND filter and what you do is you slot it into your filter system like that and then you're away and you're ready to take a picture now the only thing to note here is that you need to get what's called how to take that off an adapter ring which is this thing here and that needs to be the correct size for your lens again it's the filter size that you're looking for this one is an 82 mil one you screw that on your filter system goes on it and you're away another good thing about using a filter system is that you can use graduated ND filters like these so here I've got hard grads and here I've got a soft grade and what you can see is this line in the middle here is a lot harder than this line in the middle here which is a soft grade so the hard grades like this one here they're for her is basically the sea or if you've got a nice horizon line that's very sharp then you use a hard grade and it works really well if you've got like trees or I don't know buildings or something like that then you might want a soft grade and graduated filters are really simply there to darken the sky to balance out your exposures and you need to use a filter system for one of them so you can't get the screw on grads you're going to have to use a filter system and this is the reason why because you slop the mean and you look through your viewfinder and you slot them in and when you're outside and I'll show you this in the other tutorial which when we're when we're out using them and you push them down and you can see how the graduated filter is blocking the light from the sky and that's what you normally use them for so grad filters for only four filter holder systems so let's look at an example of using a hard grade ND filter the one on the left is a normal picture shot using what the camera fault was the correct exposure so the camera has fault to itself that this is the correct exposure it's looked at the sky it's looked at the ground and it's given you a kind of in-between but what you can actually see is it's blown out the sky the ground looks okay is quite well well exposed but the sky certainly isn't and that's because the sky on this particular day was really bright and when we look at the one on the right this one's got a two-stop hard red ND filter on and this is darken the sky by two stops to give you a much more balanced exposure then when you use a 10 stop ND filter together with the ND gred and add some lightroom and photoshop trickery to it you can get a shot like this so now let's talk about different strengths of nd altars and how you work out exposure times when using them I'm going to put all of this on your free nd filters guide which you can download at the end of this video so don't worry about it you can always refer to that but basically nd filters are created in stops and a stop in photography is either having or doubling the amount of light making the picture one stop darker or one stop lighter in the case of nd filters you are always having or reducing the amount of light so a one stop ND filter will be stopping the light by 50% or half a 10 stop MD filter is stopping the light by 10 half's in a row now you have to do it sequentially it's really important you can't just go times 10 so let's look at a simple scenario remember when you're doing long exposure shots it's only the shutter speed you want to be changing if you have a two-second exposure without a filter then you put a one stop ND filter on you have effectively half the amount of light coming into the camera so to counterbalance this you have to increase the amount of time you let light coming into the camera in this case by doubling it so here I've created a little graph for you and what you can see is you are having the amount of light with the filter so you have to double the amount of light with the shutter speed a two-second exposure doubled into a four second exposure you are letting in the same amount of light but over a longer period of time and that's the basic principle of nd filters they stop light coming into your camera which forces you to compensate by letting in light over a longer period of time let's look at this in a table which I've included in your ND filter guide on this graph you can see that I've put the exposure time as one second there out so if we go to the first one one second you put a one-stop ND filter on it doubles the time to two seconds if you have a one second exposure time normally and you put a two-stop ND filter on it it doubles it twice so it goes to two and two four and it keeps going down like that so it's not simple it's just time to knit by ten or whatever it is you have to double and double and double again in a sequential way just to confuse you more different manufacturers will advertise different numbers for stops for instance instead of just saying a to stop ND filter they might say it has an optical density of nought point six or an ND factor of four why they do this is beyond me there's no need for it in my opinion but they don't and just to help you out I've made another table on that guide which gives you all of these numbers with the same meaning so let's just have a quick look at that so I can go through it for you okay so here's the graph that I've done for you and let's go to nd filter stops - and if you go across there you can see that it has an optical density of nought point six or an ND factor of four now that's there for a lot of different technical reasons that you don't really need to worry about but my best advice to you is to just stick to the stops how many stops does the N filter have now let's talk about what stop filter to use for what type of shots don't forget there's also a tutorial on how to use nd filters on this channel where I'll be out in the field showing you how to use them in situ I'll definitely put a link up there to that when it's done but in general for these types of long exposure shots with clear water and blurred clouds you will want a ten stop or a six stop ND filter and this is because you will want your exposure time to at least 30 seconds and up to 4 minutes the highest stop filters will enable you to get those long exposures for shots like this you might want a two stop filter as this is shot at one fifteenth of a second now I did this shot as a panning shot of him obviously of mountain bikers and it was in the middle of the day with really bright sunshine so even at one fifteenth of a second I was at ISO 100 it was still blowing out the exposure so I just had to stop the light coming into the lens a little bit so this shot was taken with just a two-stop ND filter on it which allowed me to just increase that shutter speed just a bit to get this shot now let's talk about some of the equipment you will need a good sturdy tripod is a must don't even bother taking out them small flimsy lightweight white ones that they just won't work you're going to need a bit of weight because it's going to need to hold your camera Fermi to the ground for a long period of time if our tutorial on tripods on this channel I'll put a link to that so you can go and see that if you want to you will also need to buy a cable release or a remote trigger here's a remote trigger and here's a cable release and you're going to need them because you're going to need to shoot on a setting called bulb and I'm going to do I'm going to cover that in the using ND filters when we're out in the field but these this is a really cheap one I got off of off the internet and it got works with my 5d and these are remote ones and they do the same thing so you're going to need a cable release or a remote trigger as well then of course you need some ND filters so my recommendation if you're just starting with this technique is to get the cheaper ones that screw on the front of your lens these ones they're really good you have a load of fun with them they're cheap they're about ten pound each and I would recommend that you get to start you off you get a 6.1 and a 10 stop one and you should avoid getting those variable in filters there are the types of ones that they screw on to your front of your lens and they've got another screw thing on the front and you twist them and it gets a lighter and darker they seem like a really good buy but they're not they're quite hard to judge the exposure times on them even if they've got the numbers round the side and the other thing I don't like about them is when you turn them to their strongest setting let's just say if you had an eight stop one eight stops you tend to get these lines running through your shot and it's they seem like a good idea you know like one filter fits all but they're not and I would I would recommend getting the straight fixed screw on ones or if you've got more money and this is something that you want to invest in and practice with more in the future then get yourself a filter holder system with these really nice glass and resin ones like this my advice on when to use them is this if you want that glass looking effect in the water you need the water to be fairly still and calm just slight ripples it's what's going to be perfect be crashing waves up against rocks it just won't work it won't give you that smooth glass effect also have a few clouds in the sky this will give the shot some texture a fully overcast day will just give you a a plain grey sky and although clear skies can look good and lovely clear sky a bit of clouds that gives you a bit of texturing that's in the sky so wait for a bit of clouds if you can also try and catch the sunrise or the sunset if you're trying to shoot in midday the light will be to Wyatt and it might also be too bright even if it's even with a 10 stop filter on you still might not get them 30 seconds exposures which is what you want and there you go nd filters explained don't forget to check out the how to use the nd filters tutorial where I'll be out in the field using them that will be up when it's ready so if it's if the links not there yet then it will be there soon so just hang around you can also download the free guide to nd filters via the link in the description of this video I hoped you've liked this if you did click the thumbs up and subscribe to the channel for more we'd also love for you to join our photography learning community on social media so please make sure you follow us on your preferred site thanks for watching and remember
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In this tutorial, I’m going to give you a guide to ND filters in photography. What ND filters do, what ND filters to buy, what effects they create and so on. I’ve also created an ND filters guide that you can download and keep. This will help you with working out exposure times and what ones to buy. You can download this via the link below. If you’re thinking of buying or using ND filters to create long exposure effects, then this tutorial is for you.
I hope this tutorial has given you a good guide to ND filters. If it did please like and subscribe to the channel for more. If there’s anything you want us to cover here at The School of Photography put it in the comments below, it gives us great ideas for new tutorials.
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