Without seeing your export settings it's just a guess, but it sounds like you are set to downsample and/or compress images during the export.
Hi guys. Thank You for a fast response.
Well it seems like I make it right way. Here are screenshots of exporting PDF setings and the exported file info. Below theres JPG, just to compare outputs.
Here's the exported PDF file info :
And here's JPG export:
You can see that PDF resolution is much lower than JPG.
Thanks in advance.
In addition to Danny's comment, the OSX info is showing the page dimension in pixels where one pixel equals 1/72"—same as InDesign's pixels as a measurement unit. If you set your ID rulers to pixels and check Document Setup you should see 1984 x 2834 as the page dimensions.
If you want to get the pixel dimensions and resolution of an image in an exported PDF you can use Acrobat's Object inspector—set Preview to Object Inspector and click on an image. Here I've imitated your document, placed an image with an effective res of 500ppi, and exported with no down sampling:
High Quality Display Performance looks much worse than original jpg itself. And the exported pdf is 2000x3000 pixels size which for a 70x100 cm project with lot of details doesn't look good. I miss lot of details and it simply looks like not enough high resolution.
Also the High Quality display is still showing a proxy and not the actual image pixels—I've seen cases where the preview quality degrades with big pixel dimensions and available memory is short. Check the image in your exported PDF to see the final pixels.