1-Image HDR

Alpha · Dec 30, 2007

By definition there is no such thing. HDR stands for High Dynamic Range. Every photograph has a discreet dynamic range. It is possible to reduce, but not expand it during post-processing. Analogous to "single-image HDR" would be making an infrared image from a panchromatic one during processing, which of course is non-sequitur.

usayit · Dec 30, 2007

Ok.. so whats the question or the topic of this thread?

abraxas · Dec 30, 2007

multiple range tone mapping

Sideburns · Dec 30, 2007

I think what Max's point is...is that you can't make a true HDR from one image. Lots of people think they can, or think it's almost the same. It really isn't.

Alpha · Dec 30, 2007

Sideburns said:
I think what Max's point is...is that you can't make a true HDR from one image. Lots of people think they can, or think it's almost the same. It really isn't.

Exactly.

Throwing three raw "exposures" of the same image into an HDR program is simply another way of manipulating shadow and highlight detail. It is less tedious, though also less precise, than manually doing such manipulations using adjustment layers.

Trenton Romulox · Dec 30, 2007

You can make HDR-like effects using Photoshop can't you? I took one exposure and duplicated layers and ran high mapping or something over it and then blended the layers and it looked almost HDR-like. I'm a total PS-novice and really have no idea what I'm talking about. I don't think I contributed to this thread much.

Alpha · Dec 30, 2007

Trenton Romulox said:
You can make HDR-like effects using Photoshop can't you? I took one exposure and duplicated layers and ran high mapping or something over it and then blended the layers and it looked almost HDR-like. I'm a total PS-novice and really have no idea what I'm talking about. I don't think I contributed to this thread much.

I think perhaps you're talking about layer masks and high-pass filtering.

Joves · Dec 30, 2007

Yeah Ive seen far too many of the quote/unquote HDRs and, they are always terrible, Im really not a fan of HDR but, I can appreciate a well done one.

Garbz · Dec 30, 2007

There is no question it's a discussion.

I have nothing against these "one image HDRs" providing people don't call it that. I agree with max. Call it what it is. It's an image with tonemapping applied. Nothing more, nothing less.

You most definitely don't need 3 jpegs each with different brightnesses to do it. No you don't get extra range from using RAW files. And to side with Joves I've only seen 2 or 3 HDRs in the past year which either looked incredibly realistic with the extra dynamic range, or which looked artistically pleasing (woodsac's images).

leopardforest · Dec 30, 2007

For HDR images is it better to have more than 3 exposures if possible or is it just pointless?
I have tried some via changing the exposure in RAW like Max was talking about and that did not work, but I also tried one HDR using multiple exposures (5 separate exposures) but the final HDR did not seem any different than the normal exposure, what gives?

Trenton Romulox · Dec 30, 2007

MaxBloom said:
I think perhaps you're talking about layer masks and high-pass filtering.

Yeah! That's it. I tried it once, it came out like hell, but I figure with some practice on PS I could get pretty good.

Jeff Canes · Dec 31, 2007

MaxBloom said:
I think perhaps you're talking about layer masks and high-pass filtering.

why is that not the same think?

Jeff Canes · Dec 31, 2007

I’m sure everyone has seen those landscape with prefect lighting all over the entire or 90% of the view with no blown out or blacked out areas, well that’s is not natural, that's HDR

Helen B · Dec 31, 2007

The dynamic range of a scene is limited by the dynamic range of the scene. It doesn't matter how many different exposures you take, you can't expand the dynamic range of the scene.

It is possible to capture the entire dynamic range of a scene in one exposure, especially if you are using negative film.

Suppose that the scene has a brightness range of 12 stops - which is a lot for a naturally-lit scene. That's not difficult for film (and possibly some sensors) to cope with in one exposure. If you display that scene brightness range with a device (monitor, print, whatever) that only has a dynamic range of, say, seven stops then it will look awfully flat. Twelve stops compressed into seven. If you tone map it, or otherwise change the contrast locally (eg dodging and burning), you can bring life to it.

I don't see why it matters whether one exposure has been used, or many. What matters is the total dynamic range that has been captured.

Best,
Helen

Garbz · Dec 31, 2007

Yes but firstly all evidence I've seen for dynamic range of film/sensors point the range between blown highlights and pitch black to be around 5-6 stops for sensors, around 6 stops between loss of detail and blown highlights in slides, and around 7 stops between loss of detail and blown shadows in negatives.

Like when you photograph into the sun, the sensor is far inadequate for the required dynamic range of many scenes and something's got to give. HDR is just dynamic range compression. Taking multiple exposures with different EVs and combining them into a 32bit image with full dynamic range. Now this is fine when you use a HDR viewer which dynamically alters the brightness of the scene based on the area you want to see detail in.

The limitations are in the sensor not in the scene, otherwise HDR wouldn't exist in the first place.