DPP4 saved jpegs far bigger than DPP3

[Dreamager]

So I've mostly been using DPP3 to work on my RAW files as I've a 500D, but I've just got round to using DPP4 now that it supports my camera. I make a few simple edits, and unless I'm going to work on the photos further in PSP I convert and save as a jpeg for general use. I leave the jpeg settings at a quality of 10 (the highest) and in DPP3 that would result in a file size of between 3-4Mb per photo. Doing the same in DPP4 however gives me a file size of around 12-13Mb.

Is there something different about DPP4 I should be compensating for eg. quality 10 in DPP3 = quality 5 in DPP4, or is there something different going on here? I want to keep my simple workflow and picture quality the same, but I don't want my files quadrupling in size.

Any info would be greatly appreciated.

[kvbarkley]

I am assuming you are using a new camera. Does it have a larger image size in pixels?

That being said, it is certainly possible that the 10 setting in DPP4 applies lighter compression than DPP3. I have heard that those quality settings don't refer to any absolute JPEG settings, but are relative numbers.

[Dreamager]

Still using the same camera, the only difference is the version of DPP. I could reduce the 'quality' number until the filesizes match, but I'd want to know that's not making my DPP4 photos worse than DPP3, or I'll have to go back to using that.

[kvbarkley]

Photoshop used to have a function that would compress a file, compare it to the original, lower the compression and compress it from the original for all 10 settings. It would then show a graph of how much the compression was affecting the image.

[kvbarkley]

I am guessing that DPP4 changed things so that a "10" is equivalent to large, fine compression which is very light JPEG compression.

[RobertTheFat]

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@kvbarkley wrote:

I am guessing that DPP4 changed things so that a "10" is equivalent to large, fine compression which is very light JPEG compression.

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I've always been under the impression that the "10" setting implied no compression.

What about the color space setting? If DPP4 got set to use one of the wider gamuts, would that make the JPEGs larger?