How the 5D IV crop factor in video affects low light performance

hermit383 said:

Hey everyone, I just thought was thinking about this just now and wasn't sure where to find an answer after some google searching without any results.

The questio I have is this : Does the crop factor used for 4K video affect the way that it performs in low light compared to a camera with less of a crop factor?

For example, Will the performance of the5d IV's video be the same in low light as the 1Dx ii 's for example which has less of a crop factor?

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rmexpress22 said:

Kind of a tricky question. I think the 1Dx2 is a little cleaner. Not because of it's lesser crop factor in video, but because it's generally a less noisy sensor.

Because both camera are taking a crop of their entire sensor the noise should be similar as If you were just capturing a jpeg picture using the full image size with the respective cameras.

In this case, the crop of the 5D4 should have no negative of positive impact on noise.

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Great Bustard said:

rmexpress22 said:

Kind of a tricky question. I think the 1Dx2 is a little cleaner. Not because of it's lesser crop factor in video, but because it's generally a less noisy sensor.

Because both camera are taking a crop of their entire sensor the noise should be similar as If you were just capturing a jpeg picture using the full image size with the respective cameras.

In this case, the crop of the 5D4 should have no negative of positive impact on noise.

Click to expand...

The primary source of noise in a photo is due to the amount of light that made up the photo. A 1.7x crop uses only 35% the amount of light as the full sensor, which would have the same result as using 1.5 stops less exposure with the full sensor.

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Timbukto said:

Great Bustard said:

rmexpress22 said:

Kind of a tricky question. I think the 1Dx2 is a little cleaner. Not because of it's lesser crop factor in video, but because it's generally a less noisy sensor.

Because both camera are taking a crop of their entire sensor the noise should be similar as If you were just capturing a jpeg picture using the full image size with the respective cameras.

In this case, the crop of the 5D4 should have no negative of positive impact on noise.

Click to expand...

The primary source of noise in a photo is due to the amount of light that made up the photo. A 1.7x crop uses only 35% the amount of light as the full sensor, which would have the same result as using 1.5 stops less exposure with the full sensor.

Click to expand...

It's a tricky question however because even if video is sampled using the full sensor, sometimes due to processing constraints lines or pixels are thrown away. So in the end you just need to see well done video compares (Tony Northrup despite how much I dig at him at times does a really good job at this).

So instead of thinking of it as a typical photo crop, video crop can be every other line, or sets of pixels, such that the framing is the same, but the light gathering area is more sparse.

Click to expand...

Great Bustard said:

Timbukto said:

Great Bustard said:

rmexpress22 said:

Kind of a tricky question. I think the 1Dx2 is a little cleaner. Not because of it's lesser crop factor in video, but because it's generally a less noisy sensor.

Because both camera are taking a crop of their entire sensor the noise should be similar as If you were just capturing a jpeg picture using the full image size with the respective cameras.

In this case, the crop of the 5D4 should have no negative of positive impact on noise.

Click to expand...

The primary source of noise in a photo is due to the amount of light that made up the photo. A 1.7x crop uses only 35% the amount of light as the full sensor, which would have the same result as using 1.5 stops less exposure with the full sensor.

Click to expand...

It's a tricky question however because even if video is sampled using the full sensor, sometimes due to processing constraints lines or pixels are thrown away. So in the end you just need to see well done video compares (Tony Northrup despite how much I dig at him at times does a really good job at this).

So instead of thinking of it as a typical photo crop, video crop can be every other line, or sets of pixels, such that the framing is the same, but the light gathering area is more sparse.

Click to expand...

Sure. By "the full sensor", I meant the whole of the sensor was being used. If we skipped every other line, for example, then only half the sensor would have been used.

Click to expand...

riknash said:

Great Bustard said:

Timbukto said:

Great Bustard said:

rmexpress22 said:

Kind of a tricky question. I think the 1Dx2 is a little cleaner. Not because of it's lesser crop factor in video, but because it's generally a less noisy sensor.

Because both camera are taking a crop of their entire sensor the noise should be similar as If you were just capturing a jpeg picture using the full image size with the respective cameras.

In this case, the crop of the 5D4 should have no negative of positive impact on noise.

Click to expand...

The primary source of noise in a photo is due to the amount of light that made up the photo. A 1.7x crop uses only 35% the amount of light as the full sensor, which would have the same result as using 1.5 stops less exposure with the full sensor.

Click to expand...

It's a tricky question however because even if video is sampled using the full sensor, sometimes due to processing constraints lines or pixels are thrown away. So in the end you just need to see well done video compares (Tony Northrup despite how much I dig at him at times does a really good job at this).

So instead of thinking of it as a typical photo crop, video crop can be every other line, or sets of pixels, such that the framing is the same, but the light gathering area is more sparse.

Click to expand...

Sure. By "the full sensor", I meant the whole of the sensor was being used. If we skipped every other line, for example, then only half the sensor would have been used.

Click to expand...

But.. aren't we comparing the 5D4 to the 1DX II which I understand in 4K video mode is very close to the same, the difference being directly related to pixel density difference? Therefore the square area difference is marginal and wouldn't make a significant difference of total light gathered between the two. Yes/no?

Click to expand...

Great Bustard said:

Great Bustard said:

But.. aren't we comparing the 5D4 to the 1DX II which I understand in 4K video mode is very close to the same, the difference being directly related to pixel density difference? Therefore the square area difference is marginal and wouldn't make a significant difference of total light gathered between the two. Yes/no?

Click to expand...

The 1Dx2 is 1.4x in 4K, right? Then that makes it marginally better than the 1.7x of the 5D4. The pixel size/density doesn't play a role here.

Click to expand...

Wing2 said:

I don't agree their video mode are very close (1DX2 is better in rolling shutter effect, better crop factor and higher maximum frame rate)

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Wing2 said:

Great Bustard said:

Wing2 said:

But.. aren't we comparing the 5D4 to the 1DX II which I understand in 4K video mode is very close to the same, the difference being directly related to pixel density difference? Therefore the square area difference is marginal and wouldn't make a significant difference of total light gathered between the two. Yes/no?

Click to expand...

The 1Dx2 is 1.4x in 4K, right? Then that makes it marginally better than the 1.7x of the 5D4. The pixel size/density doesn't play a role here.

Click to expand...

1.4x vs 1.7x means 1DX2 is 50% bigger in pixel size in terms of area - not that marginal.

Smaller crop factor is not just lower noise, it is also less demanding to the lens used - you don't need to use the sharpest lens to get a sharp 4K image.

In some sense, 1.4x crop factor is a good compromise because many FF lens are not so good in vignetting, aberration, distortion and sharpness near their corners.

1DX2 4K can do 60 fps and its video tested shown much less rolling shutter effect than 5D4

I don't agree their video mode are very close (1DX2 is better in rolling shutter effect, better crop factor and higher maximum frame rate)

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