I'm using the K-5, considered one of the ISO invariant cameras. Here are the images:
Properly exposed with ISO1600: https://www.flickr.com/photos/66982297@N02/32559204535/in/dateposted-public/ +4 compensation at ISO 100: https://www.flickr.com/photos/66982297@N02/32179978780/in/dateposted-public/ The colors are where the extreme differences are. The histogram actually goes to the right at about the same spot. On Fri, Jan 27, 2017 at 5:28 PM, Larry Colen <[email protected]> wrote: > > > Gonz wrote: >> >> Ok. I've done some experiments to test this whole ISO invariance >> subject, which some ascribe almost mythological healing powers to >> underexposed images. I'll reveal one pair of experimental images >> after I have my methodology down. Hence this post. The results were >> so surprising, that it made me question my methodology. > > > Which body are you using? > >> >> Here is what I did. >> >> 1. take an image with ISO 1600 properly exposed. Use manual and set >> shutter and aperture for image result that takes up most of the >> histogram (avoid blowing highlights) >> 2. take a second image with same shutter and aperture but at ISO 100. >> I.e. 4 stops underexposed. >> 3. Import into lightroom, compensate +4 exposure on the underexposed >> ISO 100 image. >> >> My lightroom has a limit of +4, hence the selection of 100 and 1600 >> for ISO values. >> >> Images should look roughly the same if this methodology is right? Are >> the ISO values correct? 100 * 2^4 = 1600, or is this wrong? > > > It looks right to me. Before I had heard of ISO invariance, I sort of > discovered it accidentally. When not shooting action, and when I don't want > to bother chimping the histogram for every shot, or when I'm shooting wide > dynamic range images I'll just bracket, generally three exposures +/- 2 or > three stops. > > My preferred auto exposure mode is usually Tav. I noticed that when > bracketing in Tav, after correcting my exposure in lightroom, I generally > couldn't see much difference between the three shots. Do note that in the > "over" shots I'd get a bit more clipping, and in the "under" shots, I'd > sometimes get a bit more noise in the shadows. Also, there seem to be some > nonlinearities in the way LR processes files, so they wouldn't always all > come out exactly the same after processing, but yeah, modulo some channel > clipping, they'd look pretty close. > >> > > -- > Larry Colen [email protected] (postbox on min4est) http://red4est.com/lrc > > > -- > PDML Pentax-Discuss Mail List > [email protected] > http://pdml.net/mailman/listinfo/pdml_pdml.net > to UNSUBSCRIBE from the PDML, please visit the link directly above and > follow the directions. -- -- Reduce your Government Footprint -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
