Author Topic: Gradation high/low (Read 2444 times)

jr · « **on:** March 30, 2011, 03:38:02 PM »

Does anyone know what the gradation high/low actually does? I can see the auto mode compresses the DR by bumping the shadows up but what do the others do? Increasing the shadows is just going to increase the noise so I'm not bothered about using auto. Do the others play about with the image or just the exposure?

It's funny that Olympus can put so much R&D into creating such an amazing and complicated piece of kit and then produce a user guide that is so lacking in detail! They must have plenty of internal documentation on this stuff from when they spec'd and designed it.

Brianetta · « **Reply #1 on:** March 30, 2011, 03:43:10 PM »

High and low just sets the key for the JPEG engine. You have a 12 bit per pixel raw file, and will end up with an 8 bit per pixel JPEG. Some information is discarded when this happens. You get to choose whether more bright information, or more dark information, is discarded. Setting gradation to auto is practically the same as making an HDR image. Turning it off just sets it for a middle of the range key, as far as I can tell.

Brianetta · « **Reply #2 on:** March 30, 2011, 04:06:36 PM »

Right, if you can make your browser window big enough, these will line up in a row on screen here. Otherwise, they'll appear below each other as well.

These were taken from the same exposure. The raw file was re-processed, with the gradation being changed each time. Nothing else happened barring the resizing, and you can click any image to get the JPEG that the camera spat out. There's not much in it, but it should give you an idea.

From left to right, top to bottom, we have the following gradation (in camera menu order):
Auto, Norm, High, Low

jr · « **Reply #3 on:** March 30, 2011, 04:13:27 PM »

Mmmm... I'll have to think about this for a while

It's 1 in the morning here so I'll think about it tomorrow. Thanks much for the answer brian.

Brianetta · « **Reply #4 on:** March 30, 2011, 04:15:37 PM »

Quote from: jr on March 30, 2011, 04:13:27 PM

Mmmm... I'll have to think about this for a while

It's 1 in the morning here so I'll think about it tomorrow. Thanks much for the answer brian.

Yeah, here as well... time for bed. (:

The Pen's raw editor is, for me, its killer feature.

jr · « **Reply #5 on:** April 02, 2011, 03:33:36 PM »

Yep, think i get it now! But if you select this in the camera rather than PP then it also affects the cameras chosen exposure. For a given shot at hi an low grad there is a stop difference in the cameras metered exposure. Normal and auto are the same at half a stop in the middle of hi and low. It's an interesting setting. I guess it's just governing the curve used to create the jpeg affecting brightness and contrast but I find it difficult to get a handle on exactly what it is going to do.

yotsuba · « **Reply #6 on:** May 14, 2011, 01:42:57 AM »

When I set gradation to a setting that is not "low", horrible noise would appear in the dark areas of the photo, even if it was shot at ISO 200 in broad day light.

I only use "low" gradation now.

adash · « **Reply #7 on:** May 14, 2011, 02:05:31 AM »

Quote

When I set gradation to a setting that is not "low", horrible noise would appear in the dark areas of the photo, even if it was shot at ISO 200 in broad day light.

I only use "low" gradation now.

You are probably comparing it to Auto, which makes a lot of noise in the shadow areas because it tries to brighten them up.
Shooting in Low makes detail disappear in the shadows as the camera darkens them additionally.
Try Normal gradation.

yotsuba · « **Reply #8 on:** May 15, 2011, 04:59:48 AM »

Ok, thanks for the suggestion.

Does setting it to normal means "gradation" is off?

ratobuhler · « **Reply #9 on:** May 15, 2011, 07:14:57 AM »

Very helpful info. Thanks

adash · « **Reply #10 on:** May 15, 2011, 08:10:40 AM »

Quote

Does setting it to normal means "gradation" is off?

No. It's more natural. It doesn't (or at least shouldn't) apply an exposure compensation and shouldn't smash detail in shadows (as Low does) or in highlights (as High does).

voyager · « **Reply #11 on:** May 15, 2011, 04:12:29 PM »

Yeah, the gradiation settings are incredibly important. If you have it set wrong, you'll get horribly noise at low ISO, along with a ton of underexposure.

Gradation high/low