Qtpfsgui 1.9.2 Update Info

[David]

Hi again to anyone interested in Qtpfsgui, aka by me as Cutiepie. Over the last couple of months I've been trying to get the latest version, 1.9.2, to work with raw files from my Canon 40D. However, to my great frustration, the resulting HDR's seemed to be blown in the light areas, were extemely noisy, and had been given a colour cast. Not surprisingly, I have been put off what I thought was a great piece of software. I thought the problem lay with a change in format in the Canon CR2 raw file data. Now, having returned to the problem, I know better. Cutiepie uses the famous raw conversion algorithm Dcraw, by David Coffin, to produce the working images that will be combined to give the HDR image. The authors of Cutiepie have installed a default parameter "-T" for Dcraw in the Raw Import Options box (accessed via Tools>Prefences). This parameter specifies an 8-bit TIFF output file. The options need to be changed to "-T -4 -q 3" (no quotes). The "-4" specifies 16-bit TIFF output and the"-q 3" specifies use of the Adaptive Homogeneity Directed (AHD) interpolation. Having carried out this change, Cutiepie is again working correctly. Unfortunately, the software authors did not mention any of this in their blurb.

I cannot claim to have worked this out for myself. A clever guy at [URL="http://www.flickr.com/groups/qtpfsgui/discuss/"[/URL] called scottkinsf figured it out. I found it by Googling. The flickr group for Cutiepie contains some very useful stuff and many fantastic results. One possibility that appears popular is to create tone-mapped images via two different options (Mantuik and Drago, say) and blend these ( eg via overlay) in an image editor.

David

[McQ]

Thanks David for the update on your experiences with Qtpfsgui.

[_GUI_]

This post is a bit old, but anyway this info can be of use for all those who have a Canon 40D.

It seems to me from my tests over several RAW files from this camera, that the default saturation point for it, at least at ISO100, is too high in DCRAW's source code. I have reported to Coffin about this, but he didn't change the value so far, so maybe this changes from one unit to other.

If you are experiencing [COLOR="Magenta"]magenta casts in the highlights on your Canon 40D RAW files, the solution is to set the right saturation point. The cameras I tested all saturated at 13823, while the default value considerd in DCRAW is 16224. If Qtpfsi allows to enter DCRAW commands just add -S 13823 to the command string.

More info about this in 'SENSOR SATURATION LEVEL' in the DCRAW Tutorial.

BR

[David]

Hi Gui - Thanks for the info on this. I shall check it out. Does the saturation point vary for other Canon models e.g. the 20D?

David

[_GUI_]

sure, each camera has a different saturation point. many saturate at the maximum of their range (4095 in 12-bit cameras, 16383 in 14-bit cameras), but some like the 40D saturate at lower values.

The 350D for instance saturates at 4095 and the 5D at 3683. Looking at DCRAW's source code, it seem the 20D also saturates at 4095 but there seems to be 2 versions of 20D and sat is not indicated for one of them (0xfff is 4095 in hex):

{ "Canon EOS 10D", 0, 0xfa0,
{ 8197,-2000,-1118,-6714,14335,2592,-2536,3178,8266 } },
{ "Canon EOS 20Da", 0, 0,
{ 14155,-5065,-1382,-6550,14633,2039,-1623,1824,6561 } },
{ "Canon EOS 20D", 0, [COLOR="red"]0xfff,
{ 6599,-537,-891,-8071,15783,2424,-1983,2234,7462 } },
{ "Canon EOS 30D", 0, 0,
{ 6257,-303,-1000,-7880,15621,2396,-1714,1904,7046 } },
{ "Canon EOS 40D", 0, [COLOR="red"]0x3f60,
{ 6071,-747,-856,-7653,15365,2441,-2025,2553,7315 } },
{ "Canon EOS 300D", 0, 0xfa0,
{ 8197,-2000,-1118,-6714,14335,2592,-2536,3178,8266 } },
{ "Canon EOS 350D", 0, [COLOR="Red"]0xfff,
{ 6018,-617,-965,-8645,15881,2975,-1530,1719,7642 } },