Archived posting to the Leica Users Group, 2008/09/03
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Actually, this occurs with transparency films as well. Around the over exposed highlights, you will see colour fringes, and that's mostly not because of the chromatic aberrations. On Wed, Sep 3, 2008 at 9:01 AM, Henning Wulff <henningw@archiphoto.com>wrote: > > Actually, the 'chromatic' issues around highlights are not a function of > the lens, but of the sensor and the light qualities that hit it. > > Highlight blowout is due to sensor saturation, ie, the sensor cannot > register the actual number of photons that have hit it as it's a number > that's bigger than what it's maximum. Near the actual highlight, where > every > channel is blown out, is a region where some channels are saturated, but > not > other(s). That will give areas or rings around the highlights of colours > that have not yet saturated. Because some channels have saturated in this > region, the colours will be false as the saturated channels cannot provide > the proper value. > > All digital sensors will do this, but unless the highlight areas are large > with gradual transition areas, it won't be a problem. There are some > workarounds, but they involve 'creating' some colour values in this region. > -- Ken Iisaka first name at last name dot org or com