M240 DNG Files Are 48MB Imported Into Lightroom

[RayD28]

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Never noticed this before but my imported files are much bigger than 24MB, which I think is the resolution of an M240.  I can understand how including meta data will increase the file size but doubling the file size seems unusual.  Any advice or comments are appreciated.  

 

My camera settings are:

 

DNG only, DNG Compression is off, Firmware is 2.0.3.0, Sharpness and Saturation and Contrast and Film Mode are off.

 

My Lightroom import settings and resulting meta data are: 

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[bags27]

ditto the Q in dng. I just assumed this was usual. it's that size before imported to LR, PS, or anywhere else.

[Luke_Miller]

Each of the 24 million pixels in the M-240 has data associated with it.  The file size reflects the storage of that data.

[01af]

... my imported files are much bigger than 24 MB ...

What makes you think the files were supposed to be 24 MB?

 

 

... which I think is the resolution of an M (Typ 240).

The camera's resolution is 24 MP.

[RayD28]

Each of the 24 million pixels in the M-240 has data associated with it.  The file size reflects the storage of that data.

 

Thanks, Luke.  It still surprises me the non-image data is so large.  

 

What makes you think the files were supposed to be 24 MB?

 

 

 

The camera's resolution is 24 MP.

 

Just thought the file size should be close to the resolution.  I just looked at some raw files from my Nikon D800 that has 36MB resolution and they are 46MB.  

 

I just now did a google search and apparently pixels don't reflect file size.  I'm still a bit confused so I will study up.

[Exodies]

Switch compression on. It’s of the lossless type.

[01af]

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It still surprises me the non-image data is so large.

It isn't.

 

One raw pixel's data is 14 bit. So 23,856,192 pixels' raw data is 333,986,688 bit or 41,748,336 byte or 39.8 MB (1 MB = 1,024² byte = 1,048,576 byte). Add a couple of kilobytes for embedded JPEG preview images and metadata, and you'll arrive at 40+ MB.

[RayD28]

It isn't.

 

One raw pixel's data is 14 bit. So 23,856,192 pixels' raw data is 333,986,688 bit or 41,748,336 byte or 39.8 MB (1 MB = 1,024² byte = 1,048,576 byte). Add a couple of kilobytes for embedded JPEG preview images and metadata, and you'll arrive at 40+ MB.

 

 

Thanks, O1af.  That's the most straightforward and understandable explanation I've seen.  Very helpful.  

[jaapv]

Never noticed this before but my imported files are much bigger than 24MB, which I think is the resolution of an M240.  I can understand how including meta data will increase the file size but doubling the file size seems unusual.  Any advice or comments are appreciated.  

 

My camera settings are:

 

DNG only, DNG Compression is off, Firmware is 2.0.3.0, Sharpness and Saturation and Contrast and Film Mode are off.

 

My Lightroom import settings and resulting meta data are: 

There  is no reason to switch compression off.

[pico]

Another factoid: a file on an SD card will be larger on a typical computer drive due to cluster

factor - sort of a rounding-up of allocation on large drives.