Gadgetory

hello I'm Gary Sims from and oral authority now I'm sure you've had a conversation with some good at the camera in your smartphone and they've asked you both how many megapixels is it now while that's an important thing to us if not the only thing we should be asking about our smartphone cameras so the question before us today is how the smartphone cameras work on what are the important attributes well let me explain so a quick recap on how cameras work there's an out of light in a scene that you want to take a photograph of whether it's indoors or outdoors and that light enters into your camera via a lens behind the lens there is an aperture which is basically a hole that lets the light through to the sensor that's behind it and it can be very to be bigger or to be smaller and once it gets through to the sensor there is a way of exposing the center for a certain amount of time to the light to expose it too much the picture will be all white if your expose enough the picture will be all black now in a DLSR or an SLR that would be with an actual physical shutter with a smartphone basically the sensor is switched on for a certain amount of time to capture and then switched off again and once all that data has been captured wet light information is then sent to an image signal processor an isp which will take all that information and turn it into a jpg photo according to various color profiles and will also apply maybe some post-processing like HDR now there is an analogy to this which you'll find for example on the Cambridge in color photo tutorial website we talked about how if you want to capture some rain now the amount of rain that's pouring down at the sky at any one moment is outside of your control however if you want to capture some water in a bucket there are certain things that you do have in your control for example the size of the bucket the bigger the bucket the more rain will enter into it you can also decide how long you leave the bucket outside and of course you are able to measure how much water you have captured and applying this idea to photographs the width the size of the bucket is the same as the aperture how much rain you're able to get in how much light is able to get into the sensor the duration that you leave it out there is as the shutter speed and of course the ISO tells you how much sensitivity there is how has the ability there is in capturing that water so let's start with the lens so when you read about lenses you'll read a thing about the focal length and that's normally expressed in millimeters so on a DLSR for example this camera that I'm using to record with now has an 18 to 55 millimeter lens that's the focal length now on a wide camera a wide shot is somewhere like 18 20 23 and a zoomed in shot would be much more like 200 250 300 so the focal length basically defines how wound in you are on a particular thing I want the light has gone through the lens we arrive at the aperture now the larger the aperture the more light that's able to get in and having that large amount of light getting in also affects what's called the depth of field the bigger the aperture the narrower the depth of field if you want to get take some of those photos where the background is blurry and the subject is in crisp focus then you need a wide aperture now you'll see that written on sometimes on the specifications about a phone an F 1.7 lens that tells you that's the widest that it can open now here the strange thing about focal length the smaller the number the bigger the hole its inverse so 1.7 means a bigger hole and 8 means a small hole now if you go over to the article that accompanies this particular video there's a whole bunch of details about how the focal length and how the aperture work together to give you those numbers but if you just want to know the basics the bigger the hole the more light they can get in but the shallower the depth of field and the smaller the number means the bigger the hole F 1.7 big F 1.5 big f8 means small now once the light has gone through the aperture it then gets to the sensor and there is a way of controlling how long the sensor is exposed to that light and that's using the shutter speed whether it be a physical shutter or an electronic shutter now basically if you're in a bright sunny day and you've got the aperture open wide then you only want the sensor to be exposed for just a moment to that amount of light but if you're in a low light situation Asian or maybe if you've got the aperture smaller because you want a greater depth of field then you have to let these sensor be exposed for a longer amount of time now the problem with long exposures is we can't hold cameras very very still and that means you get camera shake now of course there are ways around this use a tripod that's one thing there's optical image stabilization in some smart phones that's another thing but at the end of the day the longer the exposure time the longer the slow the shutter speed then the more shape is going to be in your photos now that's not always a bad thing if you've seen those photos of kind of car lights that have been captured at nighttime the red streaming up the road then that's because unless the shutter open for a long time with a small aperture and therefore only a little bit of light is getting in but it's able to trace those car tails as they go through the city but if you have to do that one a tripod try to do it by hand then they'll all be shaky all over the place so a slow ship speed isn't it's really bad but for a quick snap you need to be aware that you want a quick shutter speed and then of course the light gets through to the sensor itself now the sensor can be tuned to have a certain amount of sensitivity and that's tuned in the same way as film used to be tuned with an ISO number iso 100 iso 400 iso 800 and that basically means how sensitive it was that photographic paper to light and now how sensitive is the sensor to light now basically sensitivity means how much is there a difference between one level of british satellite and another if there is a big difference between the different color shades then that means that there is going to be lots of crisp details however if there was a small distance then any kind of variation in the light will produce a variation in the color and what actually happens when you go way to the other extreme maybe you start to get up to 1600 3200 and even higher than what you actually get is you get noise in the picture because the camera can't really tell the difference between one bit of light and another bit of light and it seems their two shades of grey two shades of red and your picture starts will expect all they start to look dirty because the color isn't uniform so that's a danger of high ISO speeds they introduce noise into the pictures and then the sensor itself has a physical dimension the sensors in maybe in DLSR cameras or in other compact cameras might be for example 35 millimeter is the biggest that comes back to the idea of when we had film and then you might have the Micro Four Thirds system for example and then down in a camera you they called like 1 over 2.5 inches I won't go into this now in each mean 16 millimetres of course is not this again is a hangover from an old days of lenses and cameras but basically it's like one over to half an inch one over 2.5 one over three a third of an inch and that shows you that it is quite small now the smaller the sensor the less light it can capture that's obvious but this is where megapixels come in if you have many many many megapixels packed into a very very tiny sensor then each of those pixels can only pick up a fraction of that light well in fact the size of the sensor divided by the number of pixels there are now if you have less megapixels and a bigger individual pixel size then each individual pixel is able to capture more light if you go too big without increasing the sensor size then the camera will start to produce more noisy pictures and it won't have the the resolution in terms of light and that's when people start to talk about it's got a 1.4 or 1.7 micrometer pixel size so this is an interesting things that people manufactures are now talking about how big are those individual pixels now if you go up to a big camera like a DLSR or a Micro Four Thirds system out of that and of course you got a much bigger sensor and there if you've got a 20 megapixel or a 21 megapixel camera that's much of a different game than it is if you have 21 megapixels in a small camera on a small sensor and once that light has been captured by the camera is passed over to the ISP the image signal processor and companies like our make an image signal processor for their customers Qualcomm have their own image signal processor in their Snapdragon chip and basically it's responsible for taking all that data and producing the JPEG file and some cameras it can produce a raw file it has to apply the color profile has to do any post processing like HDR and that it all handled inside of the ISP and I have other quick things to talk about one is autofocus the picture needs to be focused and there are different methods for doing autofocus including a dual pixel method including phase detection if you go over to the article that accompanies this video you'll see more details on how these different auto focus systems work and finally let's mention dual cameras if you look at the phone at the LGG sic what LG have done is they've put in lenses with two different focal lengths one with a wider one and one with a more standard one and that means it's able to have options when it comes to taking photos you look at a system like the wild wave p10 then that's using two senses one monochrome one color and the isp is able to take the data from the monochrome sensor and really double up the amount of light that's coming into the picture particularly good for when you're doing things like HDR or your in low-light situations now I'd like to see more dual camera systems on smartphones I think it's a good way to compensate for the particularly small sensor size and the limitations that we have in having such small lenses I think dual cameras is the way to go however we noticed that Samsung didn't put that in the f/8 this year so we interesting to see what we get further down the road from companies like Samsung well I'm Gary Sims reminder authority I hope you enjoy this video I hope you understood now some of the key attribute of smartphone cameras if you did please do give this video a thumbs up also dedicate to subscribe to and all thority ever get to hit that Bell icon so that you get notifications whenever we publish a video and please do go over to and report accom because we are your source for all things Android