X5S DNG file sizes

[deltalimatango]

Hello all. For those using the X5S, what file sizes are you seeing? My average file size is anywhere between 31 to 35 megs. Are people experiencing larger file sizes or is this normal? The X5S shoots in 12bit RAW, @ 20.8 megapixels. I am thinking that the file sizes are correct but I have been advised that they are too small.

Thanks in advance.

 

[NickU]

Usually around 40-42mb on the microSD card.

What aspect ratio do you have set for the photos (4:3 or 16:9) as that will affect the size?

Also, Are you recording to MicroSD card or SSD? The Dng files saved on the SSD are smaller than those saved on the microSD card tho' that seems to be 21MB vs 42MB Raw DNG size differences between SD and SSD

 

[deltalimatango]

Usually around 40-42mb on the microSD card.

What aspect ratio do you have set for the photos (4:3 or 16:9) as that will affect the size?

Also, Are you recording to MicroSD card or SSD? The Dng files saved on the SSD are smaller than those saved on the microSD card tho' that seems to be 21MB vs 42MB Raw DNG size differences between SD and SSD

Hey Nick. I am shooting in 16:9. Pretty much the same set up that I am using on my DSLR's. I also shoot a Leica Q that uses DNG files with an average file size of 44 megs. On the Inspire, I am recording to an SD card. Thanks for the info.

Another point, does the X5S record in 12 or 16 bit color? This is confusing.

 

[InterMurph]

I would recommend against shooting still at anything but the full resolution.

Shooting at 16 x 9 tells the camera to discard the tip and bottom pixels when saving the image. I think it is always better to record all the pixels, then crop later as appropriate.

 

[NickU]

Pretty sure 16:9 will be the reason. You'll get around 42MB size for the full frame 4:3, and it'll be smaller for 16:9.

Have to agree with intermurph, I always have the photo aspect set to the full 4:3 as it's easy enough to crop later if needed, but it's impossible to add the pixels back if they're not there

 

[PatrickP]

Pretty sure 16:9 will be the reason. You'll get around 42MB size for the full frame 4:3, and it'll be smaller for 16:9.

Have to agree with intermurph, I always have the photo aspect set to the full 4:3 as it's easy enough to crop later if needed, but it's impossible to add the pixels back if they're not there

my typical raw file is ~40M in 4:3

 

[PatrickP]

Usually around 40-42mb on the microSD card.

What aspect ratio do you have set for the photos (4:3 or 16:9) as that will affect the size?

Also, Are you recording to MicroSD card or SSD? The Dng files saved on the SSD are smaller than those saved on the microSD card tho' that seems to be 21MB vs 42MB Raw DNG size differences between SD and SSD

why are the files saved to the SSD smaller? are they similar to the proxy files saved to SD card?

 

[NickU]

I have to admit I was slightly surprised to find the SD card DNG's where at 42MB as I'd expected them to be similar in size to the RAW ones off my 21Mp DSLRs instead of being nearly twice the size!

I'm not sure why there's a difference - I've not had the time to dig in and find out what's going on - They may have a lower bit depth, or they might not have the embedded jpeg... or DJI could have screwed up with the sizes on either memory type .

 

[deltalimatango]

Well it is official. Everyone that suggested that shooting in 16:9 verses 4:3 was spot on. Did a very quick shoot yesterday in 4:3. BOOM! My file size increased by 10 megs. Went from 31mb to 42mb. I was throwing away about 10 megs of data. Many thanks to those here. This is one of the best and most informative groups I have joined.

 

[AMGPilot]

does the X5S record in 12 or 16 bit color? This is confusing.

12bit in Raw 10bit everywhere else

 

[NickU]

Missed that one, for photos the camera will record 12 bits worth of info in Raw DNG. For Jpegs, 8 bits.

The difference comes about because while some cameras can record 12 or 14 bits of info, due to the way that computers are designed and handle data, the camera needs to store those 12 bits in two 8 bit chunks (2 bytes aka 2 x 8 bits = 16 bits). So, when Photoshop, Camera Raw, Lightroom etc open the files they're presented as 16 bit files, even though only 12 bits have photo data in them.

BTW, 12 bits is a Byte and a half which is a Byte and a Nibble

 

[TheGrumpster]

Nick, did you ever do the bench testing you referred to in the SSD vs. SD card thread? Reason I'm asking is because I noticed this morning that an SSD raw cannot be opened in Raw Therapee (my preferred raw converter) whereas the SD card raw can. I already posted a bug about this.
The scary thing is that the SD raw is about 42MB and the SSD raw is about 21MB, so something has to give. Even on the SD you only get 12 bits per pixel, regardless of what LR says (it is not 16 bits).
One of the posts on the RT bug tracker said that the SSD raw uses jpeg compression, which scares the hell out of me. If I wanted jpegs I'd shoot jpegs. I'm thinking that DJI is pulling a fast one on us here and really shooting video in something like Prores422 and then just writing frames as stills, but I have no idea.
All I know is that you can't get 2x compression without throwing something away. The question is what is being thrown away on the SSD raws.

 

[NickU]

No, I've not had the chance to sit and think out and do a proper bench test.

Yes, you'll always get a maximum of 12 bits of information in the image as that's what the camera is capable of recording, but it will have to use 16bits to record those 12 bits in as that is what the image processing software expects to see. If you've a Dslr camera that records 12 or 14 bit images, then they'd do the same, store it in a 16bit file. The accepted standards are either 8 or 16 bit. So photoshop etc will either report 8 bit or 16 bit files depending on the format used.

As to the difference in SSD and sd raw sizes, I'm musing out loud here.... no definite proof as I haven't an inside line to DJI tech, and I've not sat down and checked any of this out....

- The SSD RAW is recorded when the photo mode is set to 14fps burst or infinite burst, so it's pumping through a lot of data. It could be that in order to sustain the burst frame rate without causing buffering, the DJI techs decided to put in some compression.

- Despite what the ssd file says, it could actually just be giving 8 bit raw instead of 12 bit.

- most Raw files also include an embedded preview jpeg file, I've not checked but it could be that there is no embedded jpeg preview - that would save space and increase speed all round.

- or, simply, There could be a cock-up in the coding for the SSD burst Raw files which is resulting in the lower size, and also the problems you're getting with Raw Therapee.

Out of interest, I haven't yet purchased the CinemaDNG or ProRes licenses (I figured I'd wait on to see how DJI were handling crashes and transfers first!), so I can't check this out... are the Video CinemaDNG raw files recorded for each video frame the fuller 42MB each, or are they smaller?

God knows if any of that makes any sense.... it's late night here

 

[TheGrumpster]

Thanks, Nick. I know zero about video and have never used it. I do have both the licenses because I bought the I2 in December when the only way you could get it was to shell out big bucks for the package deal. So sadly, I can't say what the video files look like.
My bug report over at Raw Therapee is generating some interesting info. One of the devs says there is an error in the dng file, which is odd because Adobe ignores it and processes the file just fine. Also, the devs say that the SSD files have lossless jpeg compression applied to the image data, whereas a normal SD care file does not have this compression applied.
Don't know about the jpeg preview, but highly doubt it is present because it would take too long to generate at 14fps. And not surprisingly, the lens profile is totally absent from the SSD raws, but not the SD raws.
Wish I understood the dng format (I know it's really just a tiff) better and had some decent tools for tearing it apart into all its various pieces.

 

[NickU]

If you've the CinemaDNG license and a 240/480GB cinessd stick, then you can record a few seconds of CinemaDNG video and take a look at the frame file size and see if it's 42 or 21.

A CinemaDNG video is basically a series of individual raw dng photo frames, and each one can be opened in a raw processor like bridge/light room etc. The video software like Adobe premiere, Final Cut Pro or Davinci resolve basically then stitch the stills together into a 'normal' video stream. It kind of like using photo frames to create a time lapse movie... only it does it at 30fps instead of 1 fpm

It's something that I find a touch bemusing... you have to buy the license for CinemaDNG, yet you can record an infinite burst without the license.... they're kind of the same thing in reality....