Well imagine right you’re standing in a room with no windows no doors no lamps what do you see? You see nothing unless there is light your eyes are functionless you’ll only see something if you pull out a torch and shine it around and that’s because the torch is going to be sending out light that hitting things and then getting bounce back into your eyes.Â
Same is true for cameras what the camera sees is the light being reflected into it but in most cases light is bouncing around in every single wit way all at once so to make sure you’re getting light information that’s actually useful and not just a blurry haze you also need a lens a layer that takes all the light rays bouncing around and redirects them to meet at a single focused point on the inside that can records that information.
Your eyes have a lens that focuses the light onto your retinas and in the exact same away your cameras have a lens to focus the light onto their way of recording that light information and what’s that well early cameras had film which you can think of as light sensitive material where the pigment will effectively change based on how much light comes through the lens and hits each part of it now obviously if you left the film exposed to light for long periods of time you would just end up with the whole thing having reacted to it and just being a white sheet and that is why you also need a shutter.
The sound of an old school camera shutter which will quickly open and close when you took a photo to expose the film to light for just the right amount of time. Though, cameras have come a long way from the days of film The Core mechanism has not changed nowadays with digital cameras and phone cameras that film is basically just replaced for a camera sensor which instead of chemically reacting to light and being a one time us thing can digitally react to light record what it’s just seen and then ready itself for use,
The other cool thing about using a digital sensor is that while you do still technically need a shutter to make sure that you start capturing the light information at the right times it no longer needs to be a physical mechanical shutter the sensor itself because it’s electronic can just decide how long it wants to collect the light for effectively becoming its own shutter.
SMARTPHONE CAMERAS: focal length comparison
Pic Credit:Medium
There are lot of reasons why the whole interchangeable lens and all doesn’t work on a phone very few people are going to carry around a pocket full of lenses having a detachable part like this is going to make it way harder to fully waterproof your phone and also are you going to take that lens off every time you put your phone away in your pocket.
This hasn’t stopped companies from trying but they are trying knowing that it will never be for the masses and so what’s had to be done on smartphone is multiple cameras multiple completely separate independent cameras each with their own separate sensor just so you can have different lenses available to you when you want them so when you’re in your camera app and you’re clicking between these various magnifications.
As we have three, four camera sensors just so we can have the thing that we actually want which is three different lenses is incredibly inefficient it means that phones will cost more than the otherwise would and also that each individual sensor has to be smaller and the smaller the sensor the less good they’re going to be.Â
So, what are these different lenses actually well aside from the primary camera there’s two types of lenses that we tend to see again and again on phones the first is ultra wide which tends to be the best way to capture everything that’s happening in a room at once as well as on most phones the best way to take a macro photo. Macro essentially means extreme close up and just the way the Ultra wide camera are built gives them a much closer focusing distance than your main camera.
Which is why most flagship phones when you bring them near to something you should notice that little lens shift as the phone moves from its main camera to its Ultra wide. And, then you’ve got the other key lens the Telephoto as you must have heard that 15 Pro Max has a five time zoom lens and that the Samsung has 10 time zoom lens well that’s not technically true.
Like we have a zoom lens and we stick it onto a DSLR camera what it allows us to do is to rotate the ring and physically move the glass on the inside of the lens to increase the distance between the glass and the sensor this magnifies the image and this kind of magnification achieve by physically moving the lens or Optics of the camera is called Optical Zoom.
When you zoom like this the entire area of your sensor is still being used to capture it’s just that your lenses are changing what information is coming in and being delivered to the sensor it’s kind of like when you’re using magnifying glass it’s not reducing the quality of what you can see it’s just enlarging it so that you can see it cleaner.
Zoom lens on your smartphones then is not actually a zoom lens people call it that because it’s easier to understand but really that is the Telephoto lens meaning that while it is zoomed in so the lens on its camera is set in a way that it’s far enough away from the sensor that it’s magnifying the image five times.
As soon as you hit one times magnification your phone will switch over to its main camera and then as you keep zooming up until the point you hit your phone’s telephoto magnification you’ll switch from your main camera to your telephoto. You start off solid with your Ultra wide camera but this tails off even with slight magnification since it’s not the best quality camera.
As soon as you hit one time your quality jumps dramatically to the highest quality that you’re going to get out of your smartphone since your main camera almost always have the largest sensor given that this is always your best camera as you zoom further your quality does fall but not as fast as it did with the ultra wide until it gets to the point where it starts to feel questionable point somewhere between three times and five times that most phones will switch to their third camera the telephoto which will be the only camera used from this point onwards so basically you go after this the more your quality will tail off.
Pic Credit:Riebo
FOCAL length: focal length comparison
Focal length is just a fancy way of talking about magnification but think of it like a universal way of comparing magnification between cameras so while three times zoom on phone’s camera something different to three times zoom on that of DSLR’s camera . SO the most smartphone cameras which have an ultra wide lens they start at around 13 mm your one time main camera will be around 24 mm.
The reason talking about things in terms of focal length is that different focal lengths create images with a different aesthetic.
RESOLUTION:
A camera’s resolution is the total amount of pixels on the sensor. Think of each pixel as its own individual unit on that sensor that every time you take a photo will be assigned its own exact color . So in a simple way we had a camera sensor with a 4 pixel resolution or 16 pixel resolution the photos you will see are very different this is so because the more pixels you have the more detailed your image can be because you got more points of information being registered.
Most phone cameras do something called pixel binning which is basically grouping together clusters of small pixels to make them more reasonably sized again so that each pixel is at least a quality pixel. This is why the iPhone even with its 48 megapixels of main camera only takes 24 megapixel photos by default and why Samsung with its 200 megapixel main camera only take 12 megapixels photo by default in a way this is smartphone makers just trying to solve the problem they’ve created by trying to cram too many pixels into tiny space.
SENSOR SIZE: focal length comparison
If you kept all other things same and you just increased your sensor size there would basically be a direct up put correlation to image quality because with the same number of pixels but spread across a larger area each pixel is bigger gets more light and so is less likely to be noisy and then the thing that sits in the background all this helping each of these other elements to achieve their potential is the stabilization system.
Early smartphones use something called electronic image stabilization which is essentially when using electronic image stabilization your phone is going to crop into that Total Image lose a little bit of quality but gain the ability to even out your hand movements so if your hands suddenly jerks down a bit your phone will move a little bit up within that image to reduce the impact of that downwards motion.
Then Optical image stabilization came in which is where the Optics of your camera the lens physically moves to do the exact same thing that electronic image stabilization did but without that hit quality this has evolved on some Modern phones to something called sensor shift stabilization but it’s kind of the same thing it’s just the sensors moving instead of the lens but the key takeaway is that modern phones basically use a combination of both Optical and Electronic this is why when you move from photo to video on your phone it tends to zoom in a little then you’ve got:
Pic Credit:Poorvika
APERTURE: focal length comparison
It controls how much light your lens can let in it’s actually kind of shocking how similar the camera is to the human eye because yes this is exactly what the irises in your eyes do by dilating or constricting your pupils.Â
Most phones kind of whole Zoom thing have fixed apertures there are times when you want to restrict light but especially on a smartphone camera where you’re already fighting to get enough light in you really just want your aperture to be as wide as possible. The thing that does throw a lot of people off though is the aperture counts backwards so an F2 aperture is wider and lets in a more light than an F4 aperture and so in smartphone use cases would be the preferred option and a sub to the channel would be magnificent.
COMPUTATIONAL ASPECT: focal length comparison
Early phones were very simple what you see is what you get but two things have happened over the years one that companies have really started to push the optical envelope to its limit meaning that if e continue trying to make our phone cameras like we make our camera cameras then we can’t really improve them any further without making a massive camera bump and inconveniencing the people who don’t want that.
Two at the same time as the optical development has slowed down the intelligence of phones has not meaning that more and more they have the Headroom to be able to understand the images that you are taking and enhance them using machine learning. So, HDR or High Dynamic Range is one of the most noticeable examples while with most non-smart cameras when you take a photo you take one photo with most modern smartphones when you take a photo you actually taking between 9 and 15 shots on that camera depending on the exact model some with low exposure, some with medium exposure and some with exposure matching them up to each other and fusing them together into the final.
PORTRAIT MODE: focal length comparison
Portrait mode is the big one its the modern smartphone’s way of using computation to get around the fact that they don’t have massive sensors when you take images or video with big sensor cameras you get this distinct mix of a crisp foreground and a blurry background we’ve come to associate this with the feeling of cinematic and so to try and recreate this phones started off by using the fact that they had two different cameras that they were set slightly apart to look at the world and estimate depth and if you close one of your eyes your depth perception you’ll find it goes right out the window and so being able to estimate at least how far away things are from you allows you to simulate how blurred out they should be if you are filming on a bigger camera sensor.
Face Unblur is actually even more fascinating it’s like Google Pixel is leading the pack with and it figures out when your phone is moving a lot and so there’s a high risk of a blurry face and now phone like iPhones starts automatically capturing with the ultrawide camera as well as your main camera because ultra wide camera is less sensitive to movements and more stable so it can still in most cases get a lot of key details of the shot sharp and then fuse those back into the main camera shot that you were taking but arguably more advanced than all of that is night mode which phone like Google Pixel is a lot of things once to try and maximize detail in times where the available light information is very low it’s the taking and stacking of multiple images like what happens with HDR it’s fusing long exposure shots which keep the sensor registering information for longer to get more light in and reduce noise and short exposures to quickly get the core structure of the image without motion blur.
Nowadays, you don’t even to select night mode your phone will make all of these decisions for you. It’ll use its image sensors to figure out how dark it is and then its gyroscope to figure out that how still it’s being held which determines how long it can afford to keep its long exposures going for without risking blurring the image and phones now are even using something called semantic segmentation not just to different images but to different parts of the same image so the photo going through a completely different processing pipeline as the tree.
