topic Re: 5D4 Frame Grab size in EOS DSLR & Mirrorless Cameras

5D4 Frame Grab size

jemanner — Sat, 17 Sep 2016 17:05:09 GMT

Canon specifies a 8.8 megpixel frame grab from 4K videos with the 5D4. However, experimenting a bit grabbing few frames, only getting about 2.8MB. Yes, I have the recommended speed of cards, of which frame grabs from both are only 2.5-2.8 MB. Is there a variable I am overlooking? Megapixels do not equate to the file size?

Re: 5D4 Frame Grab size

TTMartin — Sat, 17 Sep 2016 17:28:10 GMT

@jemanner wrote:
Canon specifies a 8.8 megpixel frame grab from 4K videos with the 5D4. However, experimenting a bit grabbing few frames, only getting about 2.8MB. Yes, I have the recommended speed of cards, of which frame grabs from both are only 2.5-2.8 MB. Is there a variable I am overlooking? Megapixels do not equate to the file size?

Megapixels do not equate to the JPG file size. Look at the dimensions of your frame grab photo.

Re: 5D4 Frame Grab size

Waddizzle — Sat, 17 Sep 2016 23:06:11 GMT

How are you grabbing the frames of video? Some software does nothing more than take a snapshot of the screen.

Re: 5D4 Frame Grab size

jemanner — Sun, 18 Sep 2016 00:04:38 GMT

Using the built-in function of the camera, and the instruction manual indicates the captured frame will be 8.8 megapixels. As the previous post pointed out, megapixels does not equal MB. However, when I take a RAW photo, the resulting file size is 31 MB, and the camera has a 30.4 megapixel sensor. So, it correlates there. Still a bit confused.

Re: 5D4 Frame Grab size

Waddizzle — Sun, 18 Sep 2016 11:20:43 GMT

Have you looked at the pixel dimensions of the image, yet, ast TTMartin suggested?

Re: 5D4 Frame Grab size

RobertTheFat — Sun, 18 Sep 2016 12:27:36 GMT

@jemanner wrote:
Using the built-in function of the camera, and the instruction manual indicates the captured frame will be 8.8 megapixels. As the previous post pointed out, megapixels does not equal MB. However, when I take a RAW photo, the resulting file size is 31 MB, and the camera has a 30.4 megapixel sensor. So, it correlates there. Still a bit confused.

In designing a RAW file format, you don't dare sacrifice any data, and RAW images don't take well to lossless compression. So your options for doing any compression of the original data are severely limited. JPEG images are a different story. Some lossless compression is possible; and there are several levels of lossy compression, each of which adds only a little to the degradation of the image. So you should expect a JPEG file to be somewhat smaller than its corresponding RAW file would be.

Re: 5D4 Frame Grab size

TTMartin — Sun, 18 Sep 2016 12:30:35 GMT

@jemanner wrote:
Using the built-in function of the camera, and the instruction manual indicates the captured frame will be 8.8 megapixels. As the previous post pointed out, megapixels does not equal MB. However, when I take a RAW photo, the resulting file size is 31 MB, and the camera has a 30.4 megapixel sensor. So, it correlates there. Still a bit confused.

The differnce is one is RAW and the other is JPG.

Change your camera to capture RAW + JPG and compare the two file sizes of your 30 megapixel images.

Re: 5D4 Frame Grab size

jemanner — Sun, 18 Sep 2016 14:59:32 GMT

Good to go! The captured image is 4096 x 2160 pixels. Thanks to all who repiled. Just a novice at this...