Aperture Exporting JPEG's from RAW: file size and quality questions?

[mscriv]

Hey Everyone,

So, I'm using Aperture 2 and I've got some questions about exporting from RAW to JPEG. I shoot with a Nikon D70 so original RAW files are 5-6mb in size. After doing some basic post processing when I export the pics at "full size" with picture quality of 11 out of 12 then the resulting JPEG is about half the file size of the original RAW file. For example a 5.6mb RAW becomes a 2.6mb JPEG. The resolution in pixels per inch and and the overall image size remain unchanged. Have I lost picture quality due to the exporting JPEG being smaller in file size?

My friend who works with me prefers to edit in Photoshop and when he follows the same workflow his saved JPEG from the identical RAW file in Photoshop is minimally smaller in file size, say 5.6mb to 5.3mb. He's telling me that my Aperture edited photos are losing quality and resolution.

Is he right, are my pics of lesser quality due to being a smaller file size? I've always been told that the quality of a picture is not in the mbs, but the pixel density.

I've bee told that Aperture has a better compression engine and that the resulting files are of the exact same quality because the PPI and image size are the same. Is that what explains the much smaller file sizes in Aperture.

I tried changing the picture quality in the export menu to 12 out of 12, but the resulting JPEG then becomes larger than the original RAW at over 7mbs.

Can someone please help me understand this better? I don't want to lose picture quality if that is indeed what is happening.

Thanks in advance for your help.

 

[HBOC]

JPEG is a lossy file type. It compresses each time you save it. RAW to TIFF will INCREASE in size, maybe 2-3 times the size of the original RAW or CR2 file, depending on the camera, settings used, color space, etc.

When I export my RAW files (CR2) from A3 into CS4, it converts the RAW to a TIFF. I only convert to a JPEG if i am displaying on the internet.

 

[toxic]

Jpeg is a lossy file format. it's what you trade for smaller file sizes. if you don't want any data loss, use TIFF or PSD.

PS CS4 does something weird with Jpegs, I never figured out what - all the Jpegs (of the same quality) are larger than those from CS2 or Aperture. dunno about CS3 or 5. I would imagine Jpeg 12 is Jpeg 12 regardless of what program it came from.

 

[leighonigar]

The RAWs on the D70 are themselves compressed, which is why you are able to save larger JPEGS. Can you see the difference in the JPEGs from the original files? What are you exporting for?

 

[mscriv]

^^^ It's mostly wedding photography so the images will be used for print and album creation. Albums are usually the new style with images printed directly on the page in various formats and arrangements as opposed to actual pictures in page holders.