Export to JPEG methods?


When I downsize Nikon RAW (NEF) files to JPEG by about 90-95% and use Bicubic sharper as the interpolation method there’s often a noticeable increase in sharpness.
Not however with Sony RAW (ARW) files.
Obviously a lot of pixels get thrown away.
Can someone educate me in how this is done and why the result might be sharper in some file formats and not others?

(Platypus) #2

Tried to reproduce what you describe with a pair of almost identical images taken with an EOS 5D and an EOS 5D Mk3. Same object, lens and light used, (only) difference being the resolution of the two camera bodies, suspecting that megapixels might make a difference. The resulting jpgs look identical and - to my taste - oversharpened which clearly shows around high contrast edges.

Let’s check the other sharpening options:

  1. the default bicubic sharper setting creates the sharpest looking images - iff you can live with the sharpening halos.
  2. the other two options look similarly less sharp than when the default option is used.

I’ve been using DPL for a while and used it in almost all cases as an accessory to Lightroom, which is my main tool. Therefore, I almost always create final output in Lightroom…


I don’t downsize in PhotoLab because there is no post-resize output sharpening (as noted earlier, Bicubic Sharper produces ugly halos). I prefer using a Lanczos resampling algorithm and some small radius sharpening that doesn’t produce obvious light halos. Lr and C1 have nice output resizing/sharpening, and when it comes to free applications RawTherapee and XnViewMP could be used to batch resize/sharpen as well.

I have no idea why your Sony files should behave differently with respect to the Bicubic Sharper method. I have used PhotoLab with Sony a6300 and a6400 ARW files and they behave just like my Pentax PEFs or Nikon NEFs.

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Thanks folks.

The NEFS start as 20 mp and the ARWs as 24 mp but are almost always cropped in editing by a quarter to a third as they’re bird shots.

The default sharpening is applied.

Then downsizing to get a file under 625 kb for forum posting.

There are two ARW sources - FE100-400 & 1.4 TC, FE200-600 & 1.4 TC. Both recorded on the A9. The former need little if any sharpening beyond the editor default , the latter definitely do.

If I crop those by half and export them to JPEG at that size the IQ is acceptable. But for forum posting they have to be downsized at least to 1500 pix long side and the result of that isn’t.

I’ve experimented with cranking up the editor sharpening settings and it looks ugly.

I appreciate the sow’s ear/silk purse limitation may apply.

(Platypus) #5

It looks like DPL jpegs are not usable. We might post a feature request asking for a more refined way to produce these jpegs as well as tiffs, they are subject to similar issues.

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