On 05/11/06, Tom C <[EMAIL PROTECTED]> wrote: > If I take a RAW .PEF file and adjust exposure -1 and +1 stop, saving each as > another .PEF in Adobe Camera Raw, would that not for all intents and > purposes, be the same as having taken three separate exposures at -1/0/+1 ? > > Could I conceivably then process the three as an HDR and get the same > results and have the same flexibility in post-processing as if I took three > exposures in-camera?
Not even close Tom, if you have more than one frame at different exposures you have an absolute differential of the difference between the exposures beyond the absolute range of the RAW file. By carefully controlling the adjustments during RAW conversion the entire latitude of any exposure can be realised in a single conversion. If your RAW converter doesn't have a curves tool then of course there is limited scope to control the gamma via contrast if you need to push the brightness to extremes. However if you generate a 16 bit output files then fine gamma adjustments can be effected without loss in any decent image editor using a curves tool. Of course the validity of even applying HDR techniques depends upon the subject matter and lighting. IOW if the subject brightness range lies within the latitude of a single exposure then the technique may yield very marginal advantage. -- Rob Studdert HURSTVILLE AUSTRALIA Tel +61-2-9554-4110 UTC(GMT) +10 Hours [EMAIL PROTECTED] http://home.swiftdsl.com.au/~distudio//publications/ Pentax user since 1986, PDMLer since 1998 -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net
