ISO
Tomas George
Lesson Info
9. ISO
Lessons
Introduction and What You're Going to Learn
00:29 2Video Resolutions
04:15 3Frame Rates
07:25 4Aspect Ratios
02:40 5The Rule of Thirds
01:19 6The Exposure Triangle Introduction and Light Meter
01:18 7Shutter Speed for Video
03:04 8Aperture
05:22ISO
06:35 10PAL Region Downloadable Guide/Cheatsheet
02:04 11NTSC Region Downloadable Guide/Cheatsheet
02:36 12White Balance
03:51 13Different Types of Camera Lenses
05:17 14Focal Lengths
01:15 15Thread Sizes and Lens Mounts
01:22 16ND Filters
04:52 17Polarising Filters
00:53 18UV Filters
00:58 19DSLR vs Mirrorless Cameras
04:01 20Talking Head Video Setup Walkthrough
12:18 21Outside Higher FPS Video Walkthrough
12:18 22Thanks and Bye
00:11Lesson Info
ISO
Hi there and welcome to this video. I'm going to be talking about is O or ISO. So shutter speed and aperture control, the amount of light that enters your camera and ISO is essentially a digital light that you can use to help properly expose your image before digital cameras you would have film and the film would have numbers on the box such as 102 104 100 which were the ISO numbers for the film. These ISO numbers still apply the digital world, but now there's a lot more numbers available on your digital camera. Most digital cameras will have a base level iso of maybe 8100 or 200. And that's ideally where we want our iso to be to get the best possible image. So for example, iso 100 is a low iso amount and has a low sensitivity to light depending on the conditions. Though we can't always use the base level iso or the image or video may be underexposed or too dark. I recommend first adjusting your aperture to try and properly expose your image. Remember though when recording videos, we d...
on't want to adjust the shutter speed as this needs to be double the frames per second. So after adjusting your aperture, if your image is still under exposed, then I recommend increasing your ISO. However, when you increase your iso, you're basically adding digital light to your image using a high iso can be useful if you're recording in a dark room or if you're recording at night. But increasing your ISO does have some side effects. And the main one is digital noise. This is something that you will introduce when your ISO number is too high. And the higher the iso number, the more digital noise you have in your image or video and digital noise can make your image look grainy higher iso values will also decrease the color accuracy and the dynamic range of your colors. So just bear that in mind too when using higher iso amounts. However, you do really need to experiment with your camera and see how high you can push your iso without damaging the quality of your image. Some modern mirrorless cameras allow to increase your iso quite high with only a small amount of noise, especially compared to say a phone's camera. That's because of the size of the sensor. The sensor on the phone's camera is much smaller than the sensor on A DS L or mirrorless camera. Basically a larger sensor can handle higher is OS better than the smaller sensor can generally speaking, the bigger the sensor, the larger ISO number can go without the image looking too noisy. So when doubling the iso from 100 to 200 the camera needs half the amount of light for the same exposure. And this brings me on to stops, which I'll quickly mention now. So you'll notice a pattern here. 200 is double 104 100 is double 200. 800 is double 400 so on and so forth. Going from one of these numbers to the next, it's called a stop and stops. Work in doubles and halves, increasing one iso stop will double the iso number and will halve the amount of light needed to properly expose our image. So going down a stop from 200 to 100 this will halve the ISO and we need to double the amount of light to properly expose our image stops. Also apply to shutter speed and aperture. You should be able to change your iso with a dial or using a button or scroll whe with your camera. Let me show you how to do this on my Sony A 7 S3. But if you're using a different camera, it should be very similar to this. OK? So now let's have a look at a few different iso examples as I mentioned before. Generally, you want to have your iso as low as possible so that you get the least amount of noise and allows you to get the highest quality image or video possible. However, that's not always possible. There are situations where you may need to increase the iso for example, higher sows are may be needed for slow motion or higher frames per second footage as you will need to increase your shutter speed. So when you increase your shutter speed, your image will get darker. And if you can't increase your aperture anymore, or if you don't want to increase your aperture, then you may need to increase your iso to properly expose your image if it's too dark. For example, this footage here, I've increased the frames per second to 100. I've increased the shutter speed to 1 200 of a second. I've also increased the aperture to F 1.8 which is the highest it can go with this lens. Now to properly expose the image, I will need to increase the iso as the image is currently under exposed and too dark. Also, if you're filming at night and you don't have any video lights with you, then you may need to increase your iso to properly expose your image as there's just not enough light. Also, if you're filming in a room that's dark or not properly lit, even when you increase your aperture to the maximum amount, the image may still be underexposed. Again, we may need to increase the iso to properly expose the image. However, if you're recording a talking head video, like the one I'm doing right now I do recommend using some video lights or at least sitting opposite a window. So you get some natural light. So you don't need to increase your iso number too much as again, it can add noise to your image. But if you're recording in a location where you can't control the light increasing, your iso can help you properly expose your image. So here we're in a well lit room and this image is properly exposed, the apertures at the highest it can go for this lens which is F 1.8 the shutter speeds at 150 of a second, which is double our frames per second as I'm recording at F BS you can see here the ISO is at 100. But if I turn off the video lights, you can see the image isn't properly exposed anymore and we need more lights. So let's increase the iso and you can see now the image is properly exposed. However, in situations like this, you may wish to turn up the video lights and decrease your iso because as I said, adding too much iso can add noise to your image. Let's now have a look at an example outside where we can't control the light. OK. So now outside and it's very bright, even when the ISO is at the base iso, the image is overexposed. So in situations like this, we may need to lower the aperture to properly expose the image or use an ND filter. So if you don't want to lose that shallow depth fulfilled by decreasing your aperture, you may wish to use an ND filter. This is basically like sunglasses for your camera to help you properly expose your image. I also recommend using a variable ND filter which means you can select how dark you want your ND filter to be. This can be really useful when recording videos outside as every situation can be different. However, I will be talking about ND filters in detail later on in this course. OK. So let's have a look at another example. So here we're outside again. And for this shot, I want to have a wide depth fulfilled because I want the viewer to be able to see the trees as well as the subject. So we need to decrease the aperture to get a wider depth of field. But this will let in less light and will make our image darker. Now we need to increase the ISO to properly expose the image again. Ideally, you want to be shooting at your base level iso but there are situations where you may need to increase your iso remember increasing your iso may add some digital noise. Also the larger the sensor, the better it can handle higher iso values, which is why investing in a good camera with a large sensor can really help in low light situations. OK? So that's ISO I hope you found this video useful and I'll see you in the next one.
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