Author Topic: JPEG compression  (Read 198 times)

Offline elianoimperato

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JPEG compression
« on: May 06, 2017, 02:22:20 am »
Exporting JPEG using Photo Mechanic I can't get a good compromise between size and quality that, instead, I get saving files using Photoshop. Why?

Offline Odd Skjaeveland

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Re: JPEG compression
« Reply #1 on: May 06, 2017, 03:15:25 am »
Exporting JPEG using Photo Mechanic I can't get a good compromise between size and quality.... Why?

My guess is that it follows from the fact that Photo Mechanic does not create jpeg from raw data. PM relies on the jpeg preview the camera did embed in your raw file. Repackaging jpeg from jpeg means loss of quality. Building a high quality jpeg from a preview image,possibly of of low resolution and highly compressed, is a tall order.  My Nikons embed a full size (all pixels) jpeg in each raw file for preview, so does my Leica Q, while my Sony A6000 embedded a low resolution jpeg for preview.  When I occasionally need a jpeg straight from PM, I just let PM extract the preview image as is to a jpeg-file on disk.
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Odd S.

Offline elianoimperato

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Re: JPEG compression
« Reply #2 on: May 06, 2017, 10:55:20 am »
Exporting JPEG using Photo Mechanic I can't get a good compromise between size and quality.... Why?

My guess is that it follows from the fact that Photo Mechanic does not create jpeg from raw data. PM relies on the jpeg preview the camera did embed in your raw file. Repackaging jpeg from jpeg means loss of quality. Building a high quality jpeg from a preview image,possibly of of low resolution and highly compressed, is a tall order.  My Nikons embed a full size (all pixels) jpeg in each raw file for preview, so does my Leica Q, while my Sony A6000 embedded a low resolution jpeg for preview.  When I occasionally need a jpeg straight from PM, I just let PM extract the preview image as is to a jpeg-file on disk.

I understand. Thank you!