RAW + Jpeg: My Olympus EPL-5 has a 16mp sensor, when I take photos in RAW they are usually around 14-15mb in size, the Jpeg photos however are around the 8mb size. It may be a silly...

johneccles Loc: Leyland UK

My Olympus EPL-5 has a 16mp sensor, when I take photos in RAW they are usually around 14-15mb in size, the Jpeg photos however are around the 8mb size.
It may be a silly question bu why is there a difference.
Thanks, John.

chiya Loc: Wellsboro, Pa.

johneccles wrote:

My Olympus EPL-5 has a 16mp sensor, when I take photos in RAW they are usually around 14-15mb in size, the Jpeg photos however are around the 8mb size.
It may be a silly question bu why is there a difference.
Thanks, John.

Jpeg compresses the files and you have some data lost.

Morning Star Loc: West coast, North of the 49th N.

I won't vouch for the accuracy of this article, John, but I believe Digital Photography School is well-respected.
Have a look what they have to say about this, it will answer your question:
http://digital-photography-school.com/raw-vs-jpeg

johneccles Loc: Leyland UK

Thanks for that, have just read the article and that explains why. I process RAW with Zoner Photo Studio and when converted to Jpeg they still remain around 11mp in size, but when I use PSE 11 the Jpeg size comes down to around 4mp another mystery to me.
Once again thanks for your help,
John.

RWR Loc: La Mesa, CA

johneccles wrote:

My Olympus EPL-5 has a 16mp sensor, when I take photos in RAW they are usually around 14-15mb in size, the Jpeg photos however are around the 8mb size.
It may be a silly question bu why is there a difference.
Thanks, John.

The responses to my post may help your understanding. Sure did for me. :)
http://www.uglyhedgehog.com/t-207705-1.html

Morning Star Loc: West coast, North of the 49th N.

johneccles wrote:

Thanks for that, have just read the article and that explains why. I process RAW with Zoner Photo Studio and when converted to Jpeg they still remain around 11mp in size, but when I use PSE 11 the Jpeg size comes down to around 4mp another mystery to me.
Once again thanks for your help,
John.

This may have to do with the compression rate. I use PSE, usually version 12, but also have 9 and 11 on my computer. It's the same for all three versions though: When I save a .jpg, besides choosing a location to save the image to, I am also asked what compression I want to use: A little box pops up, called JPEG Options. In it I can set the quality at 0 (Low) or at 12 (Maximum) or anything in-between.
The picture I used to check this, will be 59.5kb at quality 0, or 235.8kb at quality 12. As you can see, quite a difference.

amehta Loc: Boston

johneccles wrote:

My Olympus EPL-5 has a 16mp sensor, when I take photos in RAW they are usually around 14-15mb in size, the Jpeg photos however are around the 8mb size.
It may be a silly question bu why is there a difference.
Thanks, John.

There is no fixed size for jpeg pictures, given a sensor resolution. The compression quality can be set to different values which results in very different file sizes.

In this case, the 15mb raw data becomes 45mb of RGB data, then the compression reduces it to 8mb. Other compression levels can result in 11mb, 4mb, or even 0.4mb.

Blenheim Orange Loc: Michigan

johneccles wrote:

Thanks for that, have just read the article and that explains why. I process RAW with Zoner Photo Studio and when converted to Jpeg they still remain around 11mp in size, but when I use PSE 11 the Jpeg size comes down to around 4mp another mystery to me.
Once again thanks for your help,
John.

The size size of a JPEG depends upon the degree of compression.

JPEG files are compressed to reduce file size. When you save a file with JPEG compression, there will be data loss.

If you save, then open again, and save an image in JPEG format again, each new save will degrade the image more.

Working in PSE 11, when you save an image as a JPEG, an options dialog box should open. You can then choose the amount of compression.

Mike

CaptainC Loc: Colorado, south of Denver

Blenheim Orange wrote:

The size size of a JPEG depends upon the degree of compression.

JPEG files are compressed to reduce file size. When you save a file with JPEG compression, there will be data loss.

If you save, then open again, and save an image in JPEG format again, each new save will degrade the image more.

Working in PSE 11, when you save an image as a JPEG, an options dialog box should open. You can then choose the amount of compression.

Mike

All correct, but the first sentence is not complete - we need to add. "...and the amount of detail in the image." A photo of a single odor wall will compress to a much smaller file than will a photo of a complex landscape with lots of detail and many colors

Uuglypher Loc: South Dakota (East River)

CaptainC wrote:

All correct, but the first sentence is not complete - we need to add. "...and the amount of detail in the image." A photo of a single odor wall will compress to a much smaller file than will a photo of a complex landscape with lots of detail and many colors

"...photo of a single odor wall..." ??????

...maybe re-cast that sentence?

Dave in SD

CaptainC Loc: Colorado, south of Denver

Uuglypher wrote:

"...photo of a single odor wall..." ??????

...maybe re-cast that sentence?

Dave in SD

Dam auto-correct! COLOR wall!

Morning Star Loc: West coast, North of the 49th N.

CaptainC wrote:

Dam auto-correct! COLOR wall!

And here I was hoping for something like lavender or jasmine....

Blenheim Orange Loc: Michigan

CaptainC wrote:

All correct, but the first sentence is not complete - we need to add. "...and the amount of detail in the image." A photo of a single odor wall will compress to a much smaller file than will a photo of a complex landscape with lots of detail and many colors

True. Very good. Thanks.

Mike

Blenheim Orange Loc: Michigan

CaptainC wrote:

Dam auto-correct! COLOR wall!

I heat it when that happens!

:lol:

amehta Loc: Boston

Morning Star wrote:

And here I was hoping for something like lavender or jasmine....

Mmmmm.... I had lavender ice cream and jasmine tea in the past few days! Much better than the odors I was thinking of. ;-)