I've done a few HDR images now hopefully I've just attached my latest effort. I'm just wondering is there a disadvantage of doing an HDR from a single image. With Photomatix Pro there is the facility to do just this.
You may wonder why I'm asking and well it's just because on occasion I can't carry enough back up space on location so taking a single image and HDRing it later would potentially save me lots of memory.
Maybe taking a single image HDR restricts your EV spacing.
Any thoughts...
The main differences between actual bracketed exposures and the one-image "HDR" are as follows, in no particular order:
For single-image:
1) If there are any truly blown highlights they will not be recovered.
2) Increasing the exposure will increase the noise in the shadows.
3) If the image did not cover the entire contrast range, the results will still lack the whole contrast range.
4) If the image did capture the whole contrast range of the scene, but, say, had pale skies and too-dark lower tones, such a pseudo HDR may improve the look of the image but it will not be as rich as a real HDR made from bracketed exposures of the same contrast range.
For a properly bracketed series of RAW's for HDR:
1) The entire contrast range of the scene will be captured.
2) any part of the scene will occur on 2 or more images, and the likelihood of the final tonemapped image reproducing the range of tonalities will be very good, depending on your skill and the HDR program.
3) Most of the work can be done in the 32 bit HDR file before converting down to 16 bit color, giving smoother reults tone-wise.
I'm sure there are more differences. As far as shooting single images only, for the reason of storage space, the price of CF or other flash cards has come way down. In addition, if you have a laptop with you, there are 2.5 inch portable drives with huge capacity for not very much money (compared to a few years ago).
Don't forget that if you were shooting film and wanted to bracket the shots you would have been spending larger amounts on the film and processing.
The only advantage I can think of in doing single-image HDR's is the elimination of ghosting caused by either subject or camera motion.