gus
Posts: 305
Location: United Kingdom
Registered: 19 Jun 2007
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Fake HDR and PTgui
Posted: 8 May 2008 at 12:50 GMT
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Is it possible to feed PTgui 3 sets of Tiffs, 2 of which have been adjusted for exposure by decreasing the exposure in the RAW set by 2EV, and increasing by 2EV.
This will increase the tonal range, (not as much as true HDR), but it has the benefit of eliminating problems with moving objects and people between bracketed images.
I tried doing this in PTgui, by loading the 3 sets, and enabling HDR stitching, but PTgui ,quite rightly, detects from the EXIF that all the images are actually the same exposure!
Has anyone else tried this method?
gus
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DorinDXN
Posts: 1565
Location: Timisoara, Romania
Registered: 14 Nov 2006
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Re: Fake HDR and PTgui
Posted: 8 May 2008 at 12:55 GMT
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Hi gus,
You can use ExifTool(Gui) to set the exif info in those Tiffs
Dorin
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John Houghton
Posts: 2011
Location: Hitchin, United Kingdom
Registered: 17 Jan 2005
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Re: Fake HDR and PTgui
Posted: 8 May 2008 at 13:39 GMT
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I raised this with Joost in connection with fusing two sets of images generated from one set of RAW images. He said the parameter that determines which images go in which blend plane is the exposure data. You can edit the data on the Image Parameters tab, so set different exposure data for your different exposures. Any dummy value will do, as long as the different exposure sets are distinguished by the exposure time.
John
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Smooth
Posts: 1438
Location: Australia
Registered: 21 Jul 2004
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Re: Fake HDR and PTgui
Posted: 8 May 2008 at 13:40 GMT
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Simply double click the exposure in PTGui and change the exposure time to anything your choose (doesn't matter) so long as the "3" exposure are different.
Regards, Smooth 
www.smooth360.info
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gus
Posts: 305
Location: United Kingdom
Registered: 19 Jun 2007
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Re: Fake HDR and PTgui
Posted: 8 May 2008 at 15:41 GMT
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as easy as that!!
 will try tonight
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Robert Piontek
Posts: 88
Location: Germany
Registered: 26 Jul 2007
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Re: Fake HDR and PTgui
Posted: 8 May 2008 at 15:56 GMT
updated: 8 May 2008 at 15:58 GMT
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Another idea would be just to do your fake HDR after you've already stitched it.
edit: no, you should do this with the RAW files... sorry!
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gus
Posts: 305
Location: United Kingdom
Registered: 19 Jun 2007
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Re: Fake HDR and PTgui
Posted: 8 May 2008 at 16:00 GMT
updated: 8 May 2008 at 16:01 GMT
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I believe it's possible to squeeze a wider tonal range out of a RAW image than a tif.
edit: but then you realised that after you wrote the post I guess 
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gus
Posts: 305
Location: United Kingdom
Registered: 19 Jun 2007
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Re: Fake HDR and PTgui
Posted: 8 May 2008 at 22:00 GMT
updated: 8 May 2008 at 22:06 GMT
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Worked like bomb. Although this scene was not a perfect candidate, I managed to reduce the blown-out area of the sky significantly by including the (fake)underexposed set of images. I might as well have stitched 2 seperate equis, and masked the blown out sky with the underexposed sky. Havent tried this yet, maybe next time.....
tinyurl.com/5ahdvs
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Doug Aurand
Posts: 219
Location: Albuquerque, NM, United States
Registered: 2 Jan 2008
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Re: Fake HDR and PTgui
Posted: 8 May 2008 at 22:40 GMT
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gus
Depending on what program you;re using to composite the images, you may be able to use multiple copies of the same image to composite with.
Photomatix's Composite function will let me use 2 of the same image to get more if the impact of that exposure like using the -0- exposure twice in the set of images being composited to get more "blue" back into the sky
Doug Aurand
Albuquerque, NM
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Mark Schuster
Posts: 638
Location: Welwyn Garden City, United Kingdom
Registered: 25 Jan 2006
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Re: Fake HDR and PTgui
Posted: 9 May 2008 at 22:17 GMT
updated: 9 May 2008 at 22:19 GMT
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Gus,
www.panoguide.com/forums/qna/4654/
With this thread I told of my woes trying to fuse artificial brackets with Enfuse. Eventually, with all of your help, I got it to working.
Later I realized I could skip Enfuse and simply drop all the artificial brackets into Autopano Pro and let it do the work. Same sort of thing you’ve been doing with PTGui, I think. Mind you, you can go away and cook the Sunday joint while Autopano stitches, renders and blends. Hopefully PTGui is faster.
Although artificial bracketing a single set of RAW files into two +/- 1EV sets (in my case) certainly can increase dynamic range within limits, it is as well to keep these limits in mind. Completely blown windows or blacker-than-black shadows can’t be corrected with the exposure slider in Adobe Camera Raw, but of course could have been compensated with true bracketing.
But Gus, you speak of increasing tonal range and I of dynamic range. Now I have a question: What’s the difference?
Mark
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