DNG iPhone Exports are massive ???

[mbbphoto]

Using exactly the same Lightroom export settings on my desktop Mac

(No size change, JPEG , 80 quality)

My 16 megapixel Nikon NEF RAW files export at between 2-3 mb per file

iPhone 7 12 megapixel DNG RAW files export at about 10 mb per file

Why are the DNG iPhone exports so much larger???

mbbphoto

[johnrellis]

My 16 megapixel Nikon NEF RAW files export at between 2-3 mb per file

That sounds very small for a raw file using lossless compression. Which camera?

Looking at sample Nikon NEFs at dprview.com:

- a 24 MP D3400 raw is 20.7 MB (0.86 MB/MP)

- a 20.7 MP D500 raw is 22.9 MB (1.1 MB/MP)

- a 14.7 MP D5 raw is 18.4 MB (1.3 MB/MP)

iPhone 7 12 megapixel DNG RAW files export at about 10 mb per file

That's 0.83 MB/MP, which is a little smaller (per MP) than the Nikons I sampled above.

[mbbphoto]

Thanks for your input John.

I wasn't clear enough in my description.

I am comparing the exported JPEG file after I have edited in Lightroom.

I'm not comparing the raw files.

Marc

[mbbphoto]

FWIW the Nikon RAW files are from a 16 megapixel D4s...

[johnrellis]

Got it, sorry for the misunderstanding.

[johnrellis]

I just did a test and didn't observe what you did.  I exported an iPhone 7 DNG (12 MP = 4032 x 3024) at JPEQ Quality = 80 and got a 2.7 MB file.  I exported a 12 MP D700 NEF at JPEG Quality = 80 and got a 3.4 MB file.   LR CC 2015.8 / OS X 10.11.5.

If you upload an offending DNG to Dropbox or similar and post the sharing link here, others can take a look to see what might be going on.

[Jao vdL · Accepted solution]

If you are talking about exported Jpeg files, there are two things to be aware of. One, the iPhone images will have far more noise in them than equivalent files from a full-frame DSLR. The pixel size difference is massive between the two. Second, jpeg files size depends on image content (complexity really) and on the amount of noise. So for comparison, make sure that not only do you use the same quality setting but also make sure the image content is the same. For the same image content, a noisier image will not compress down as far as a less noisy image. So one expects the iPhone images to turn out larger. Note that this counters the often repeated myth that bigger files mean higher quality. They don't.

[mbbphoto]

Excellent response!

I treated the iPhone image with a huge amount of grain and clarity for effect...

If I remove the grain the export size becomes much more reasonable.

Here is a low res version of one of the images.

The raw capability truly makes the iPhone a pro tool...

Many thanks!

Marc

[Jao vdL]

Aha. Yes indeed adding grain will inflate the jpeg size by quite a bit! It functions just like noise in that respect.