Usual reasons behind a PIQ verdict

Bicot · 10-28-2011, 07:39 PM

Hello all, got a few pics rejected for poor image quality and I'm trying to pinpoint what are the reasons that trigger such a verdict such as blurry, no DOF, cheap camera rendering, bad composition, etc... I'm a little lost, help me

Here's the latest: http://www.railpictures.net/viewreje...&key=614681143

Thanks, Marc

Hatchetman · 10-28-2011, 08:00 PM

hmm. That does not scream PIQ to me. Did you apply a lot of noise reduction?

Bicot · 10-29-2011, 02:15 PM

Noiseware was used on original picture before any other work was done using presets in the software, same as I did for the last 3 years... This is where I'm a bit confused because my post treatment hasn't changed for quite while and my camera either...

To think of it, maybe it's the overall balance of the pictures submitted, hard to tell...

DWHonan · 10-29-2011, 04:25 PM

Quote:

Originally Posted by Bicot

same as I did for the last 3 years... This is where I'm a bit confused because my post treatment hasn't changed for quite while and my camera either...

Maybe the screeners' standards have changed. I had the same thing as you describe happen to me; I spent two and a half years applying the same amount of unsharp mask to photos, then suddenly this summer got a spate of "oversharpened" rejections. I reduced the amount of sharpening applied to my images and haven't had a problem since.

Hatchetman · 10-29-2011, 05:08 PM

I've mentioned this before, but I wonder if they look at a histogram and can see evidence of oversharpening there.

JRMDC · 10-29-2011, 05:20 PM

Quote:

Originally Posted by Hatchetman

I've mentioned this before, but I wonder if they look at a histogram and can see evidence of oversharpening there.

I don't understand this. How would the histogram change?

I just tried it, I opened a shot and cranked up the sharpening to a ridiculous level. The histogram shifted slightly, but not in any discernable pattern.

Hatchetman · 10-29-2011, 06:44 PM

When I do it, sometimes the edge of the "mountains" gets all rough, rather than smooth. I have no idea if there is anything to it. Just trying to figure out how they evaluate sharpness.

Hatchetman · 10-29-2011, 08:52 PM

scroll through this link. it's way more advanced than I am, but you can see the histogram shows a difference in sharpening (toward bottom).

http://www.gimp.org/tutorials/Smart_Sharpening/

JRMDC · 10-29-2011, 11:31 PM

Quote:

Originally Posted by Hatchetman

scroll through this link. it's way more advanced than I am, but you can see the histogram shows a difference in sharpening (toward bottom).

http://www.gimp.org/tutorials/Smart_Sharpening/

Interesting!

My strong suspicion is they evaluate sharpening directly, not via a metric. Same with exposure.

There is no ideal histogram, but the histogram is valuable in evaluating how to process an image.