JPEG vs RAW conversion File Size Question: I capture both Fine JPG and RAW out of the camera. This morning I wanted to change one of the settings (actually a couple) on some pics, so I...

fjrwillie Loc: MA

I capture both Fine JPG and RAW out of the camera. This morning I wanted to change one of the settings (actually a couple) on some pics, so I made the changes to the RAW file and converted to JPG. In every instance the converted RAW's to JPG were much larger than the JPG's coming out of the camera.

For instance 1 pic was JPG out the camera 7198kb converted RAW 9671kb or 34% larger, another 9029kb JPG out of the camera vs 10936 converted RAW to JPG or 21%

Why is this so. The only thing that comes to mind is the RAW to JPG contains more info and maybe a better pic than the in camera processed JPG

Anybody know ??

amehta Loc: Boston

fjrwillie wrote:

I capture both Fine JPG and RAW out of the camera.... (show quote)

You can change the quality level of the jpeg when you export it. If your software is saving at a higher level than the camera, your file sizes will be larger. The numbers you give seems like the difference between levels as close as 96 and 98. Saving at a higher quality means that a little more fine detail is preserved in the jpeg, but it is not a perceptible amount. If you do the open, do a minor edit, and save process several times, maybe 10, then you might start to see a difference. If you do the same but save at a quality level of 80, then you will start to see a difference. But you shouldn't do that process 10 times on any image, so the real world effect is negligible.

Rongnongno Loc: FL

A JPG created inside a camera is always smaller due to the limitation of the camera on board processor.

As you already suspect, this is because not only the RAW has more data after you edit and export it but also because the computer has much more processing capabilities than the on board camera processor. The computer produces a more accurate color rendition not to mention a compression with a lesser loss at the same ratio.

Note: I do not know if you do it already or not but when editing a RAW in any software, set the color depth to 16 bit. If you do not it will be edited at 8 bit...

pecohen Loc: Central Maine

fjrwillie wrote:

I capture both Fine JPG and RAW out of the camera.... (show quote)

There are a lot of variables in producing a JPEG file from a RAW one. The size of the image in pixels can be changed, for example, but also the JPEG format allows a wide variety of compression options. In most software you can bring up a slider to adjust the percent of compression and this will affect the resulting file size; with some software (PSP X6 for example) you can bring up a wizard that will allow you to choose different compression for different parts of a single image.

A final note on the compression is that editing a photo to bring out detail (e.g., sharpening) will generally result in a larger image size even when all of the compression parameters are kept the same.

fjrwillie Loc: MA

Rongnongno wrote:

A JPG created inside a camera is always smaller du... (show quote)

The 16bit vs 8bit is only available if you convert to TIF ?? Correct ?? or am I missing something here

fjrwillie Loc: MA

pecohen wrote:

There are a lot of variables in producing a JPEG f... (show quote)

I am a PSP user, when you talk about different values is this using PSP RAW converter or something else. Very interested in the concept, which begs another question, when would you use this variable compression technique.

Willie

pecohen Loc: Central Maine

fjrwillie wrote:

The 16bit vs 8bit is only available if you convert to TIF ?? Correct ?? or am I missing something here

That is almost correct. There are other formats that support 16-bits (e.g., JPEG2), but it is likely that with whatever conversion software you prefer that TIFF is the only option. It is a good choice though; with a TIFF image you can be sure there is no compression and therefore no loss of information.

amehta Loc: Boston

fjrwillie wrote:

The 16bit vs 8bit is only available if you convert to TIF ?? Correct ?? or am I missing something here

You can also save in DNG with a 16-bit image. But I think some programs also let you control the bit-depth that the software will use while doing the processing, and that absolutely should be 16-bit.

With Adobe products such as Lightroom, PSD is another option.

amehta Loc: Boston

Rongnongno wrote:

A JPG created inside a camera is always smaller du... (show quote)

I do not think the camera's processor has anything to do with the jpeg file size or the jpeg image characteristics. And if the jpeg compression level is the same, then the loss of detail will be the same.

Chris F. Loc: San Francisco

fjrwillie wrote:

I capture both Fine JPG and RAW out of the camera.... (show quote)

In addition to all the technical information on RAW & JPG, your camera may allow you to select photo sizes. Canon for example, allows me to select RAW or JPG or both and choose the size of the shots for each that I want to take.

Chris

fjrwillie Loc: MA

pecohen wrote:

That is almost correct. There are other formats that support 16-bits (e.g., JPEG2), but it is likely that with whatever conversion software you prefer that TIFF is the only option. It is a good choice though; with a TIFF image you can be sure there is no compression and therefore no loss of information.

Thanks I am using the RAW converter that came with my Nikon D5100 ViewNX 2 and it only gives me 3 options

JPG, TIF 8 bit, TIF 16bit. When I do some of my post processing in Photomatix I always convert the RAW to 16bit TIF and process that way.

Willie

pecohen Loc: Central Maine

fjrwillie wrote:

I am a PSP user, when you talk about different values is this using PSP RAW converter or something else. Very interested in the concept, which begs another question, when would you use this variable compression technique.

Willie

When you click on "Save as ...", one of the buttons on the pop-up is "Options..." and it will bring up the menu that you want.

The reason for choosing more compression is to get a smaller file size but the downside is that image quality suffers. Sometimes this is a problem on only a small part of an image - perhaps someone's face. In this case you might want to reduce the amount of compression for just the small region or regions of greatest interest.

fjrwillie Loc: MA

Chris F. wrote:

In addition to all the technical information on RAW & JPG, your camera may allow you to select photo sizes. Canon for example, allows me to select RAW or JPG or both and choose the size of the shots for each that I want to take.

Chris

Nikon does as well, and I have the JPG saved at the highest least compressed level.

Willie

amehta Loc: Boston

fjrwillie wrote:

Nikon does as well, and I have the JPG saved at the highest least compressed level.

Willie

When you do this, the image size (in mp) of the raw and the jpeg files are the same, so this does not affect the file size issue you are seeing.

Wahawk Loc: NE IA

fjrwillie wrote:

I capture both Fine JPG and RAW out of the camera.... (show quote)

If you take the JPG directly from camera, make no changes, but in your PP software, do a SaveAs and select "Minimum Compression/Highest Quality" and that file will be significantly larger than the original even though you made NO changes. I have my PSP and Picasa set to save at Highest Quality and by doing so the degrading after multiple saves is so slight that it usually cannot be detected.