Converting RAW to jpg


Nov 4, 2009
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#1
I have noticed when i used Lightroom 2 (ver 2.5) and export to jpg at maximum quality settings,file size is 10mb
however,same photo edited in Photoshop CS4 (ver11) saved as jpeg at maximum setting is only 3+mb.

Why is that so?does it mean my jpg from photoshop is of a lower quality?
 

David Kwok

Senior Member
Aug 23, 2008
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#2
When you choose Maximum in PS, is the Quality Level 10 or 12 ? Maximum in PS default is 10, but if you have previously shifted the slider to 12, it will stay at 12 unless you select another setting and reselect Maximum after that.

Extreme Maximum for both application gives you lossless jpeg compression, means the quantization process is skipped. (never mind if you don't understand the part after the comma, it is technical)

The last I checked, they gives very similar file size.

I have noticed when i used Lightroom 2 (ver 2.5) and export to jpg at maximum quality settings,file size is 10mb
however,same photo edited in Photoshop CS4 (ver11) saved as jpeg at maximum setting is only 3+mb.

Why is that so?does it mean my jpg from photoshop is of a lower quality?
 

Octarine

Moderator
Staff member
Jan 3, 2008
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Pasir Ris
#3
On a side note: LR recent version is 3.4.1 with many improvements compared to version 2.
 

Nov 4, 2009
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6
#5
I did a quick test, using same RAW file without any editing, convert to jpg, LR gave me a 7.1mb file while PS created a 6.8mb file....guess its about the same.
I think the reason why the other time around there was such a big difference is cos I used lens blur filter , and painted over quite a large portion of the picture, thus resulting in significant loss of details?

In PS there are 3 formats to choose from when saving as jpg, I usually use the default(Baseline standard). Will there be any difference if i chose either of the other 2 options?
 

Octarine

Moderator
Staff member
Jan 3, 2008
12,491
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Pasir Ris
#7
In PS there are 3 formats to choose from when saving as jpg, I usually use the default(Baseline standard). Will there be any difference if i chose either of the other 2 options?
What are the results if you try out?
 

David Kwok

Senior Member
Aug 23, 2008
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#10
I did a quick test, using same RAW file without any editing, convert to jpg, LR gave me a 7.1mb file while PS created a 6.8mb file....guess its about the same.
I think the reason why the other time around there was such a big difference is cos I used lens blur filter , and painted over quite a large portion of the picture, thus resulting in significant loss of details?
You have not mentioned previously the 2 images are of different contents. Of course it's going to be different. JPEG compression algorithm are inclined towards gradual toned images and will produce smaller files for such kind of images. Sharp edged images will either yield a worse compression ratio, or obvious JPEG artifacts if the compression quality is low.

In PS there are 3 formats to choose from when saving as jpg, I usually use the default(Baseline standard). Will there be any difference if i chose either of the other 2 options?
Both baseline and optimized form will not have effect to your image quality except a slightly smaller file size for the latter. Baseline will be the most compatible

For further reading material, feel free to fall asleep from this article http://www.impulseadventure.com/photo/optimized-jpeg.html, should you are not in the IT faculty :)
 

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