There are two things going on when you're shooting a video. Capturing/Processing and writing to the card.

Capturing/Processing -- You don't have to worry about this part. A manufacturer of any camera will guarantee that it will be sufficient. So it is a given.

Writing -- This is when the data is actually written to the card, and of course not cards are created equal. Will it be fast enough for your purpose? Whichever your purpose may be, capturing videos at various settings or capturing RAW images, the speed you need can easily be calculated from the image/video size.

There is no standard on file sizes of videos or images. So how much space 1 minute video will occupy or how big a RAW file will be, strictly depends on a particular camera in question. This answer, however, is generic and will work for every camera.

Videos -- Take any card, doesn't matter how slow it is. Put it in your camera shoot a video at max setting for a minute. Put the card into your computer and see the size of the video. For example, if the file size of 1 minute video is 60MB, the minimum writing speed you need is 1MB/Sec.

Images -- RAW images need much more Write speed than videos if you shoot in burst mode. Your camera will have a specification for its buffer size, specifically how many JPEG and RAW it can store. Buffer is where photos are stored prior to writing to the card. It's very fast giving the camera ability to take images as fast as you can press or hold a shutter. But also this buffer is usually small. So lets say your buffer is 8 RAW images. If you press and hold shutter button you can max it out in couple of seconds. At which point camera will not take another shot until there's room (or on some older cameras - until the whole buffer is cleared).

So how do you measure the writing speed you need for images? -- Again put any card you have, and take a couple of RAW images of different things. A blank wall, and something with lots of detail. (This is because not all images are the same size, you want to know maximum size it can get). Put the card into the comp and look at the RAW file sizes. If your RAW file is 60MB, and your card's writing speed is 60MB per second, well you can take one photo per second. But keep in mind that having a buffer makes it seem faster because in many situations you need to take a burst, then pause and take some more. For me writing speed of 2 RAW images per second is fast enough. When I had less speed I often found myself in situation when I couldn't take another shot when I wanted to. How fast of a camera and card you need is subjective.

As for capacity, just look at file sizes of the samples you took in this example and apply your requirements. That is, how many 30MB RAW files can fit on a particular size card.

There are two things going on when you're shooting a video. Capturing/Processing and writing to the card.

Capturing/Processing -- You don't have to worry about this part. A manufacturer of any camera will guarantee that it will be sufficient. So it is a given.

Writing -- This is when the data is actually written to the card, and of course not cards are created equal. Will it be fast enough for your purpose? Whichever your purpose may be, capturing videos at various settings or capturing RAW images, the speed you need can easily be calculated from the image/video size.

There is no standard on file sizes of videos or images. So how much space 1 minute video will occupy or how big a RAW file will be, strictly depends on a particular camera in question. This answer, however, is generic and will work for every camera.

Videos -- Take any card, doesn't matter how slow it is. Put it in your camera shoot a video at max setting for a minute. Put the card into your computer and see the size of the video. For example, if the file size of 1 minute video is 60MB, the minimum writing speed you need is 1MB/Sec. Keep in mind this is a close estimate. And the speeds manufacturers of cards provide are also inexact. Because for some very slow cards frames can be skipped, once the video is finished recording briefly examine it. If there are no skipped frames or very few, this means that all or vast majority of frames are good. So in this example, getting a card of 1.5MB/sec write speed should be sufficient to compensate for possible skips and manufacturer margin of error. Getting a card with a speed of 3MB/sec would not improve video recording performance/quality, but is likely to cost extra.

Images -- RAW images need much more Write speed than videos if you shoot in burst mode. Your camera will have a specification for its buffer size, specifically how many JPEG and RAW it can store. Buffer is where photos are stored prior to writing to the card. It's very fast giving the camera ability to take images as fast as you can press or hold a shutter. But also this buffer is usually small. So lets say your buffer is 8 RAW images. If you press and hold shutter button you can max it out in couple of seconds. At which point camera will not take another shot until there's room (or on some older cameras - until the whole buffer is cleared).

So how do you measure the writing speed you need for images? -- Again put any card you have, and take a couple of RAW images of different things. A blank wall, and something with lots of detail. (This is because not all images are the same size, you want to know maximum size it can get). Put the card into the comp and look at the RAW file sizes. If your RAW file is 60MB, and your card's writing speed is 60MB per second, well you can take one photo per second. But keep in mind that having a buffer makes it seem faster because in many situations you need to take a burst, then pause and take some more. For me writing speed of 2 RAW images per second is fast enough. When I had less speed I often found myself in situation when I couldn't take another shot when I wanted to. How fast of a camera and card you need is subjective.

As for capacity, just look at file sizes of the samples you took in this example and apply your requirements. That is, how many 30MB RAW files can fit on a particular size card.

There are two things going on when you're shooting a video. Capturing/Processing and writing to the card.

Capturing/Processing -- You don't have to worry about this part. A manufacturer of any camera will guarantee that it will be sufficient. So it is a given.

Writing -- This is when the data is actually written to the card, and of course not cards are created equal. Will it be fast enough for your purpose? Whichever your purpose may be, capturing videos at various settings or capturing RAW images, the speed you need can easily be calculated from the image/video size.

Videos -- Take any card, doesn't matter how slow it is. Put it in your camera shoot a video at max setting for a minute. Put the card into your computer and see the size of the video. For example, if the file size of 1 minute video is 60MB, the minimum writing speed you need is 1MB/Sec.

Images -- RAW images need much more Write speed than videos if you shoot in burst mode. Your camera will have a specification for its buffer size, specifically how many JPEG and RAW it can store. Buffer is where photos are stored prior to writing to the card. It's very fast giving the camera ability to take images as fast as you can press or hold a shutter. But also this buffer is usually small. So lets say your buffer is 8 RAW images. If you press and hold shutter button you can max it out in couple of seconds. At which point camera will not take another shot until there's room (or on some older cameras - until the whole buffer is cleared).

So how do you measure the writing speed you need for images? -- Again put any card you have, and take a couple of RAW images of different things. A blank wall, and something with lots of detail. (This is because not all images are the same size, you want to know maximum size it can get). Put the card into the comp and look at the RAW file sizes. If your RAW file is 60MB, and your card's writing speed is 60MB per second, well you can take one photo per second. But keep in mind that having a buffer makes it seem faster because in many situations you need to take a burst, then pause and take some more. For me writing speed of 2 RAW images per second is fast enough. When I had less speed I often found myself in situation when I couldn't take another shot when I wanted to. How fast of a camera and card you need is subjective.

As for capacity, just look at file sizes of the samples you took in this example and apply your requirements. That is, how many 30MB RAW files can fit on a particular size card.

There are two things going on when you're shooting a video. Capturing/Processing and writing to the card.

Capturing/Processing -- You don't have to worry about this part. A manufacturer of any camera will guarantee that it will be sufficient. So it is a given.

Writing -- This is when the data is actually written to the card, and of course not cards are created equal. Will it be fast enough for your purpose? Whichever your purpose may be, capturing videos at various settings or capturing RAW images, the speed you need can easily be calculated from the image/video size.

There is no standard on file sizes of videos or images. So how much space 1 minute video will occupy or how big a RAW file will be, strictly depends on a particular camera in question. This answer, however, is generic and will work for every camera.

Videos -- Take any card, doesn't matter how slow it is. Put it in your camera shoot a video at max setting for a minute. Put the card into your computer and see the size of the video. For example, if the file size of 1 minute video is 60MB, the minimum writing speed you need is 1MB/Sec.

Images -- RAW images need much more Write speed than videos if you shoot in burst mode. Your camera will have a specification for its buffer size, specifically how many JPEG and RAW it can store. Buffer is where photos are stored prior to writing to the card. It's very fast giving the camera ability to take images as fast as you can press or hold a shutter. But also this buffer is usually small. So lets say your buffer is 8 RAW images. If you press and hold shutter button you can max it out in couple of seconds. At which point camera will not take another shot until there's room (or on some older cameras - until the whole buffer is cleared).

So how do you measure the writing speed you need for images? -- Again put any card you have, and take a couple of RAW images of different things. A blank wall, and something with lots of detail. (This is because not all images are the same size, you want to know maximum size it can get). Put the card into the comp and look at the RAW file sizes. If your RAW file is 60MB, and your card's writing speed is 60MB per second, well you can take one photo per second. But keep in mind that having a buffer makes it seem faster because in many situations you need to take a burst, then pause and take some more. For me writing speed of 2 RAW images per second is fast enough. When I had less speed I often found myself in situation when I couldn't take another shot when I wanted to. How fast of a camera and card you need is subjective.

As for capacity, just look at file sizes of the samples you took in this example and apply your requirements. That is, how many 30MB RAW files can fit on a particular size card.

There are two things going on when you're shooting a video. Capturing/Processing and writing to the card.

Capturing/Processing -- You don't have to worry about this part. A manufacturer of any camera will guarantee that it will be sufficient. So it is a given.

Writing -- This is when the data is actually written to the card, and of course not cards are created equal. Will it be fast enough for your purpose? Whichever your purpose may be, capturing videos at various settings or capturing RAW images, the speed you need can easily be calculated from the image/video size.

Videos -- Take any card, doesn't matter how slow it is. Put it in your camera shoot a video at max setting for a minute. Put the card into your computer and see the size of the video. For example, if the file size of 1 minute video is 60MB, the minimum writing speed you need is 1MB/Sec.

Images -- RAW images need much more Write speed than videos if you shoot in burst mode. Your camera will have a specification for its buffer size, specifically how many JPEG and RAW it can store. Buffer is where photos are stored prior to writing to the card. It's very fast giving the camera ability to take images as fast as you can press or hold a shutter. But also this buffer is usually small. So lets say your buffer is 8 RAW images. If you press and hold shutter button you can max it out in a second. At which point camera will not take another shot until there's room (or on some older cameras until the whole buffer is cleared).

So how do you measure the writing speed you need for images? -- Your camera will have a small light which will light up/blink while it is writing to the card (so you don't take it out in the middle causing corruptions). Again put any card you have, and take a couple of RAW images of different things. A blank wall, and something with lots of detail. Put the card into the comp and look at the RAW file sizes. If your RAW file is 60MB, and your card's writing speed is 60MB per second, well you can take one photo per second. But keep in mind that having a buffer makes it seem faster because in many situations you need to take a burst, then pause and take some more. For me writing speed of 2 RAW images per second is fast enough. When I had less I often found myself in situation when I couldn't take another shot when I wanted to. How fast of a camera and card you need is subjective.

There are two things going on when you're shooting a video. Capturing/Processing and writing to the card.

Capturing/Processing -- You don't have to worry about this part. A manufacturer of any camera will guarantee that it will be sufficient. So it is a given.

Writing -- This is when the data is actually written to the card, and of course not cards are created equal. Will it be fast enough for your purpose? Whichever your purpose may be, capturing videos at various settings or capturing RAW images, the speed you need can easily be calculated from the image/video size.

Videos -- Take any card, doesn't matter how slow it is. Put it in your camera shoot a video at max setting for a minute. Put the card into your computer and see the size of the video. For example, if the file size of 1 minute video is 60MB, the minimum writing speed you need is 1MB/Sec.

Images -- RAW images need much more Write speed than videos if you shoot in burst mode. Your camera will have a specification for its buffer size, specifically how many JPEG and RAW it can store. Buffer is where photos are stored prior to writing to the card. It's very fast giving the camera ability to take images as fast as you can press or hold a shutter. But also this buffer is usually small. So lets say your buffer is 8 RAW images. If you press and hold shutter button you can max it out in couple of seconds. At which point camera will not take another shot until there's room (or on some older cameras - until the whole buffer is cleared).

So how do you measure the writing speed you need for images? -- Again put any card you have, and take a couple of RAW images of different things. A blank wall, and something with lots of detail. (This is because not all images are the same size, you want to know maximum size it can get). Put the card into the comp and look at the RAW file sizes. If your RAW file is 60MB, and your card's writing speed is 60MB per second, well you can take one photo per second. But keep in mind that having a buffer makes it seem faster because in many situations you need to take a burst, then pause and take some more. For me writing speed of 2 RAW images per second is fast enough. When I had less speed I often found myself in situation when I couldn't take another shot when I wanted to. How fast of a camera and card you need is subjective.

As for capacity, just look at file sizes of the samples you took in this example and apply your requirements. That is, how many 30MB RAW files can fit on a particular size card.