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Photography F.A.Q (Last Updated: 2024 Nov 26 6:56 am)



Subject: HDR


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TomDart ( ) posted Tue, 31 October 2006 at 8:57 PM

Ok, so here is a real bugaboo of a question:  Now that most of us have a clue about HDR images, how are these images to be viewed and seen as close to potential as possible?

 

The typical monitor and .jpg files will not do it.   Sure, the web and basic prints do show a fine image with wonderful cover of the scene from white to black, etc.   Yet, how does the “real thing” really look?  Is it closer to what our eyes actually see?

 

Are there monitors capable with the right chip and cards to display HDR properly?

Would the “backlit” film printed images sometimes seen  do it justice?

Will an advanced or normal printing company be able to print at full potential of the HDR image?

 

I want to see how the stuff looks before conversion to 8bit or even 16bit.   Does anyone have an answer to this? 

 

Thanks.          Tom.


TerraDreamer ( ) posted Tue, 31 October 2006 at 10:39 PM

Here's a link on HDRI.  This site has some of the finest examples I've ever seen...

http://www.cambridgeincolour.com/cambridge-gallery.htm

I didn't see this link posted in this thread, if it was, my apologies :)


Onslow ( ) posted Wed, 01 November 2006 at 3:32 AM · edited Wed, 01 November 2006 at 3:36 AM

Thanks Tom I appreciate it - it was your initial experiments here in previous threads that led me to try HDR at all. The render did not take long, I'm far to impatient to mess about with loads of postwork.  Photographing interiors is one of the few uses I see for this technology and churches make an excellent subject.

 To my knowledge the answer to your other question is: you won't ever see it. Human eyes are not capable of distinguishing 16bit, let alone 32 bit images.  The use of this technology is in producing a photograph from a scene with a huge variation in brightness and reducing it to one that our eyes can see with detail.

And every one said, 'If we only live,
We too will go to sea in a Sieve,---
To the hills of the Chankly Bore!'
Far and few, far and few, Are the lands where the Jumblies live;
Their heads are green, and their hands are blue, And they went to sea in a Sieve.

Edward Lear
http://www.nonsenselit.org/Lear/ns/jumblies.html


bobbystahr ( ) posted Wed, 01 November 2006 at 9:30 AM

Awesome, and trés informative link TerrsDreamer...thanx for that

 

Once in a while I look around,
I see a sound
and try to write it down
Sometimes they come out very soft
Tinkling light sound
The Sun comes up again



 

 

 

 

 


TomDart ( ) posted Wed, 01 November 2006 at 9:18 PM

Here is one more link, an article from a paper. Still, some interesting observations are made about HDR and some of the software in use to do these images.       Tom.

http://www.nytimes.com/2006/08/03/technology/03basics.html?ex=1312257600&en=65c5ddf0f463f1c4&ei=5088&partner=rssnyt&emc=rss


Onslow ( ) posted Thu, 02 November 2006 at 1:37 AM

Interesting article but factually incorrect .

The human eye can perceive 61/2 stops in dynamic range, a contrast ratio of 650:1 at any one time.

16bit images have a range of 10 stops a contrast ratio 1024:1 

And every one said, 'If we only live,
We too will go to sea in a Sieve,---
To the hills of the Chankly Bore!'
Far and few, far and few, Are the lands where the Jumblies live;
Their heads are green, and their hands are blue, And they went to sea in a Sieve.

Edward Lear
http://www.nonsenselit.org/Lear/ns/jumblies.html


TomDart ( ) posted Thu, 02 November 2006 at 8:11 AM

Thanks for corrrecting misinformation.  Appreciated.       Tom.


bobbystahr ( ) posted Thu, 02 November 2006 at 8:27 AM · edited Thu, 02 November 2006 at 8:49 AM

Attached Link: http://www.renderosity.com/mod/gallery/index.php?image_id=881825

**Wild thread...I have learned a ton just reading. As a 3D guy, all my previous contact with HDRI has been from an ImageBasedLighting perspective, and in that regard it works wonderfully....if you have an app that will use it. Tried it a bit i the Vue5 demo but that ran out, but an Imagine3D user created a script for using the info with the lightgen plugin that comes free[extra dl as i recall] with the  HDR Shop V1, to create a light sphere or hemisphere for lighting your scenes, and that does really approximate the lighting I was getting in Vue5 demo, but with a much greater rendertime expense. That I feel is the true beauty of true HDRI/IBL lit scenes...massively decreased render times.**

Thanx guys/gals for all the great info, and now it seems I may just have to take up actual Photography as some of these images have just blown my mind.

As a sample the link shows a scene lit with HDR extrapolation as described above. The HRDI used was also used in .jpg form as the sky/forest background.

 

Once in a while I look around,
I see a sound
and try to write it down
Sometimes they come out very soft
Tinkling light sound
The Sun comes up again



 

 

 

 

 


inshaala ( ) posted Sun, 05 November 2006 at 7:28 AM

ok - for those who havent got CS2 or are not prepared to fork out money for photomatix or whatever there is an open source hdr imgae creation software - i am not completely sure what it means by that but take a look - i am currently trying to install it (you need a bit of computer know how to compile these things in my experience - so this isnt for the technophobe 😉)

http://www.acm.uiuc.edu/siggraph/eoh_projects/eoh2002.html

"In every colour, there's the light.
In every stone sleeps a crystal.
Remember the Shaman, when he used to say:
Man is the dream of the Dolphin"

Rich Meadows Photography


inshaala ( ) posted Sun, 05 November 2006 at 7:43 AM · edited Sun, 05 November 2006 at 7:44 AM

ok - so i just managed to install it - dont bother... it doesnt seem to merge images to create an hdr - it just tonemaps (quite poorly) one image and apparently (tho i couldnt find how to) creates one of those HDR images you see the 3d people drooling over that they use for their lightsources/reflections...

Plus - it only saves the images as a  .hdr file so you cant pass it back to photoshop anyway...

"In every colour, there's the light.
In every stone sleeps a crystal.
Remember the Shaman, when he used to say:
Man is the dream of the Dolphin"

Rich Meadows Photography


Simon_P ( ) posted Wed, 08 November 2006 at 10:31 AM

file_358936.jpg

Photomatix HDR Tonemap

They wouldn’t have made the cane if you weren’t meant to break the rules


Simon_P ( ) posted Wed, 08 November 2006 at 10:40 AM · edited Wed, 08 November 2006 at 10:41 AM

Quote - ok - so i just managed to install it - dont bother... it doesnt seem to merge images to create an hdr - it just tonemaps (quite poorly) one image and apparently (tho i couldnt find how to) creates one of those HDR images you see the 3d people drooling over that they use for their lightsources/reflections...

Plus - it only saves the images as a  .hdr file so you cant pass it back to photoshop anyway...

Photomatix is either a plug-in or stand alone program, the stand alone program is simple to install and quite easy to get to grips with, it is an excellent program and leaves CS2 in the dust.

Photomatix will output a 32bit Radience file (which can be read by CS2) a 16 or 8 bit tiff or an 8bit Jpeg

These outputs can be exposure blended, tomepapped or both, Photomatix offers several other features including single file process from RAW, but best results are from bracketed images processed from RAW to 16bit tiff.

Photomatix is indeed an excellent program, expect to see in on Adobes acquisition list (like raw shooter was)

They wouldn’t have made the cane if you weren’t meant to break the rules


bobbystahr ( ) posted Wed, 08 November 2006 at 1:42 PM

It would be informative to see a single frame of the image before processing if that's a possibility...it looks awesome all the same.

 

Once in a while I look around,
I see a sound
and try to write it down
Sometimes they come out very soft
Tinkling light sound
The Sun comes up again



 

 

 

 

 


bobbystahr ( ) posted Wed, 08 November 2006 at 1:46 PM

@ Rich...FYI if it outputs a Radience file it can be read by the Free HDR Shop ,which can indeed be converted by the lightgen plugin.

 

Once in a while I look around,
I see a sound
and try to write it down
Sometimes they come out very soft
Tinkling light sound
The Sun comes up again



 

 

 

 

 


Simon_P ( ) posted Wed, 08 November 2006 at 1:47 PM

This is the only web size version I had to hand, I will sort out a straight capture, and post back later

They wouldn’t have made the cane if you weren’t meant to break the rules


bobbystahr ( ) posted Wed, 08 November 2006 at 1:51 PM

Wow..that was fast...thanx, I'll feep my good eye out for it..the other one is non stop watering to day from me poking myself in the eye as i woke, well just before, I woke up today...LOL

 

Once in a while I look around,
I see a sound
and try to write it down
Sometimes they come out very soft
Tinkling light sound
The Sun comes up again



 

 

 

 

 


bobbystahr ( ) posted Wed, 08 November 2006 at 2:14 PM

Hey Rich, that link in your top post 404's but there's this funny little scrolling message there that gave me a chuckle. ome kind of script so I could only grab bits of it...here's the last bit: this is the web server talking,heh heh heh

Everything here is just mind-numbingly stupid.
That makes me depressed too, since I have to serve them,
all day and all night long.
Two weeks of information overload,
and then pffftt, consigned to the trash.
What kind of a life is that?
Now, please let me sulk alone.
I'm so depressed._

 

Once in a while I look around,
I see a sound
and try to write it down
Sometimes they come out very soft
Tinkling light sound
The Sun comes up again



 

 

 

 

 


Simon_P ( ) posted Wed, 08 November 2006 at 3:45 PM

file_358968.jpg

Here is the original scene (best possible all over exposure) to be fair the light in this scene isn’t really a good test for HDR as there isn’t a great tonal range in it anyway, aside from the dark background and the “HDR effect” there isn’t a great deal of difference.

They wouldn’t have made the cane if you weren’t meant to break the rules


Simon_P ( ) posted Wed, 08 November 2006 at 3:52 PM

file_358969.jpg

The following scene in much more of a challenge to capture in the traditional sense.

Shot as 7 exposures and tonemapped using Photomatix from a radiance file output as a 16bit tiff and converted to 8bit Jpeg for web

Exposure in 1 stop increments covering a full 9 EV’s

I have deliberately gone out of my way to shoot scenes that otherwise would not be possible just to test the HDR technique.

Good/Bad you decide, but its defiantly a little different!

 

 

They wouldn’t have made the cane if you weren’t meant to break the rules


Simon_P ( ) posted Wed, 08 November 2006 at 3:52 PM

file_358970.jpg

Original best possible overall frame exposure.

They wouldn’t have made the cane if you weren’t meant to break the rules


bobbystahr ( ) posted Wed, 08 November 2006 at 3:53 PM

thanx man...still shows improvement which is why we use filters etc...nice shot by the way

 

Once in a while I look around,
I see a sound
and try to write it down
Sometimes they come out very soft
Tinkling light sound
The Sun comes up again



 

 

 

 

 


jimken61 ( ) posted Wed, 08 November 2006 at 4:18 PM · edited Wed, 08 November 2006 at 4:27 PM

file_358976.jpg

I'm not following the rules.....LOL. You can't bracket shoot races cars on the move, but you can go raw and adjust your exposure compensation the do your HDRI. It makes for some interesting pics. Something a little different.


Simon_P ( ) posted Wed, 08 November 2006 at 5:40 PM · edited Wed, 08 November 2006 at 5:41 PM

Quote - I'm not following the rules.....LOL. You can't bracket shoot races cars on the move, but you can go raw and adjust your exposure compensation the do your HDRI. It makes for some interesting pics. Something a little different.

Bracket shoot races cars, maybe not, but you could have a lot of fun trying!

Serously though, I have done the same sort of thing, not with cars this neat looking though, nice shot and work

They wouldn’t have made the cane if you weren’t meant to break the rules


ModestyB ( ) posted Wed, 15 November 2006 at 3:15 AM · edited Wed, 15 November 2006 at 3:16 AM

file_359559.jpg

HDR/tonemapping is amazing tools :)


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