# Why are my NEF files different sizes?



## OnlyHuman (Apr 13, 2010)

Any of you techi's or gurus able to help me understand why the files from my D2'' show as different sizes? I'm just curious and looking for knowledge.

I shoot raw, uncompressed. Here is an example from a recent shoot:
_S2G'''4.NEF 16.2 MB
_S2G'''5.NEF 16.1 MB
_S2G'''2.NEF 16.3 MB

It seems to correlate in some way to the zoom setting. 

Thanks,
n


----------



## happycranker (Apr 13, 2010)

Depends on the content of the picture, more details biggger size!


----------



## dj_paige (Apr 13, 2010)

Raws (unlike jpgs) don't change in size because of because of image content. They change by a small amount because of changes to the embedded metadata (which includes the zoom settings). I don't think this is anything to worry about.


----------



## clee01l (Apr 13, 2010)

NEF files are not necessarily uncompressed. Nikon uses a lossless compression algorithm. Images with lots of single color areas (like blue sky) will result in a smaller file size. 

I don't own a Nikon camera, so I am not certain if compression can be turned off in the camera setup. 

http://home.comcast.net/~NikonD7'/NikonInfo/NEF_Compression.htm

FWIW, Most proprietary RAW formats are compressed. DNGs are also compressed and uncompressed. Unlike JPEGs all are supposed to be lossless.


----------



## Mark Sirota (Apr 13, 2010)

Clee, the D2'' does not offer lossless compression -- only lossy or uncompressed. These sizes are consistent with uncompressed NEFs from a D2''. The variation is probably largely due to the varying sizes of the embedded JPEG preview, which is compressed, so its size with vary with image content. The other metadata won't vary nearly as much.


----------



## OnlyHuman (Apr 13, 2010)

Thanks everyone. Hadn't thought about the compression of the jpeg preview. That makes a lot of sense. Appreciate it.
n


----------

