Raw vs JPEG

[DrJohn]

Raw vs jpeg is a highly controversial topic. However there are different formats of jpeg with different compression ratios. One test I performed with a Sony camera resulted in:

Standard jpeg 3.5 mb
Fine jpeg 6.6 mb
Extra fine jpeg 13.7 mb
Raw 25 mb

The above will vary depending upon the data contained within a photograph. One could roughly conclude based on file size that the extra fine jpeg is compressed approximately 2:1. The fine jpeg is compressed approximately 4:1. The standard jpeg is compressed approximately 7:1.

Personally, I shoot raw + jpeg.

John

Edited July 31, 2018 by DrJohn

[Pieter]

Calling a jpeg file a compressed RAW doesn't really make sense to me: both files contain totally different information and therefore can't be considered compressed versions of the other.

[Chrissie]

@DrJohn: why are you cross-posting this?

[DrJohn]

Because it applies to both Crop sensor and Full Sensor cameras.

John

[DrJohn]

5 hours ago, Pieter said:

Calling a jpeg file a compressed RAW doesn't really make sense to me: both files contain totally different information and therefore can't be considered compressed versions of the other.

No one said that

[Pieter]

On 7/31/2018 at 3:18 PM, DrJohn said:

One could roughly conclude based on file size that the extra fine jpeg is compressed approximately 2:1.

How should I read this then?

[DrJohn]

A compressed file (JPEG) is compressed from the Raw file. A raw file is uncompressed.

 

Edited August 2, 2018 by DrJohn

[sixzeiss]

2 minutes ago, DrJohn said:

A compressed file is compressed from the Raw file.

 

How is it compressed?

[sixzeiss]

2 hours ago, DrJohn said:

Because it applies to both Crop sensor and Full Sensor cameras.

John

Please don't cross-post, ever.

Now we have two controversial topics to follow   ?

[DrJohn]

8 minutes ago, sixzeiss said:

Please don't cross-post, ever.

Now we have two controversial topics to follow   ?

So, where should I have posted it?

John

[sixzeiss]

23 minutes ago, DrJohn said:

So, where should I have posted it?

John

DPReview : https://www.dpreview.com/forums   ?

 

Otherwise the general forum ... 

[Chrissie]

12 minutes ago, DrJohn said:

A compressed file (JPEG) is compressed from the Raw file. A raw file is uncompressed.

 

Outsch! This absolute statement is plain wrong in most of the cases.

Any file type which has some repeating information in it has the potential to benefit from compression, the aim of which is the saving of storage capacity, faster transfer times and so on.

Compression can be lossless (like in a zip-file archive), in which case it can be undone without any detriment. You can compress and uncompress the same file an infinite amount of times losslessly and never loose any information along the way.

Then there is lossy compression, which always throws away some of the original information and thus degrades quality. On every re-encoding cycle.

Raw files can be compressed or uncompressed. If compressed, this compression can be done lossy or losslessly. To my knowledge (see 2nd link below), Sony does not offer a lossless compression of their Raw files.

For jpeg files basically the same applies. Except, that lossless jpeg is a very rare variant of jpeg which not many programs can handle.

Suggested further reading:

https://www.dpreview.com/articles/2834066212/the-raw-and-the-cooked-pulling-apart-sony-raw-compression

https://photographylife.com/compressed-vs-uncompressed-vs-lossless-compressed-raw

https://en.wikipedia.org/wiki/JPEG#Typical_usage

[Pieter]

My point exactly Chrissie. A jpeg can be the same size as the original RAW (thus being uncompressed by your definition John) yet still tons of data is lost in the conversion process. The initial statement of 'extra fine jpeg is compressed approximately 2:1' therefore doesn't make sense: jpeg conversion isn't compression, it's just lossy conversion. Even if done at the same file size.