View Full Version : Can one achieve HDR from one image?


OnkelMorfar
02-23-2008, 08:23 AM
hey all..

It may have slipped my radar.. BUT.. is it possible to take 1 raw pic.. screw around with the levels to create 3 diff exposured pics and THEN merge them in the HDR software?

or does it have to be 3 pics taken in the given situation?

DannyRaphael
04-23-2008, 08:55 AM
Excellent question worthy of its own thread. As one new to RAW, ACR and HDR, I, too, would be interested in the opinions of others.

Ziaphra
04-23-2008, 09:23 AM
I wouldn't have thought so as even though all 3 seemingly have different exposures, they would essentially still all have the same information. Having said that however, this makes for an interesting read: http://forums.macrumors.com/showthread.php?t=237266

DannyRaphael
04-23-2008, 10:23 AM
I wouldn't have thought so as even though all 3 seemingly have different exposures, they would essentially still all have the same information. Having said that however, this makes for an interesting read: http://forums.macrumors.com/showthread.php?t=237266You rock! Very good info. The light is growing a little less dim. :)

Is it fair to say, then...

Generally speaking combining multiple images with varying exposures of the same high contrast scene has the potential for more dynamic range than what's possible by exposing a single image to extremes (via RAW converter) and combining the RAW-generated exposures?

DannyRaphael
04-23-2008, 11:09 AM
A plugin for .jpg files:
http://www.mediachance.com/plugins/redynamix.html

palms1
04-23-2008, 02:17 PM
I thought i would do a experiment

all done in dynamic photo hdri software (from the same people in the link Danny has provided )

1. one image opened then apply image applied with multiply selected as blend mode, and again with apply image and screen as blend mode ( making three images with the original ) then took into dynamic photo and i let the software "guess" the values ( I had read somewhere of someone doing this )

2. the same images as above used but this time i manualy put the values in of -1 for the multiply, 0 for the original, and +1 for the screen

3.Then i used just one image on it's own ( refered to as fake hdr)

In dynamic photo i used the same setting for all three (eye catching at the default settings) just for comparison other wise i would probably of tweeked them

for more comparison take a look here as i posted the outcome i made with 5 separate images (same subject) and took through the same software

http://www.retouchpro.com/forums/hdr-hdri-tone-mapping/21613-trying-out.html

I suppose it depends on the outcome you want and the image subject

perhaps someone would like to do a similar experiment using the merge to hdr function in cs3 or one of the other softwares ?

Palms

crazyfly1
04-24-2008, 02:34 AM
[QUOTE=OnkelMorfar;184086]hey all..

It may have slipped my radar.. BUT.. is it possible to take 1 raw pic.. screw around with the levels to create 3 diff exposured pics and THEN merge them in the HDR software? QUOTE]


No.

Weelll, OK it's possible, but what you get is not a true HDR image. You can use any of a number of different software programs/plugins to attempt that and you will get a greasy grimy oversaturated, highly contrasty...copy of the same image.

I just posted a photo in the april contest that is a blend of the same image developed three times in raw, but not with the idea of creating an HDRI. Same concept, sort of. One side of the face was underexposed so I did one exposure just for that and then blended it with the others.

Anyway, HDR is about taking the best of each exposure capture and blending it, this gives you the High Dynamic Range, that is to say, darks and lights that are outside of what your monitor can show you and, as a byproduct you get deeper, richer color.

If you just want more color take a regular jpeg and take it into 32bit mode you can way oversaturate it just by virtue of the fact that it (32bit) is an increadibly larger color environment to work in.