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Old Aug 10, 2010, 11:46 AM   #1
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Default The HDR Cafe

THE HDR CAFE - a place to chat about some fancy stuff

1. Starter
Why that thread? Many people are interested in HDR and some other stuff like DRI (HDRI, LDRI), tonemapping and image manipulation in general. All these people - including the Pentax users here - try to use those technologies to make their images "better" in one or many ways. Now for our monthly challenge in August frogfish decided to choose "HDR" as the topic. You can find the August challenge thread here: http://forums.steves-digicams.com/pe...challenge.html

After the first postings I came up with the idea, that two threads might be better than one and frogfish agreed to that, but can't really spend much time on it at the moment, so I decided to start this thread and hope he'll chime in.

The goal behind two threads is simple:
- the August monthly challenge thread is for the images and the stories behind those images, etc.
- this thread here will be a place for all the technical, philosophical and whatever postings regarding that "HDR" stuff. Questions you always wanted to ask, interesting stuff you found while browsing the web, stuff you discovered on your own, programs, filters, whatever...
That way we can concentrate on the photos as such in the challenge... what do you think about that?


2. Main Course
Come in, come in - make yourself a home, grab your preferred drink and take a seat somewhere. To give something to think about I'll start with a little magic trick and I invite you to watch and do it on your own.

For the trick I need some software, for example "Luminance HDR" (Link: http://qtpfsgui.sourceforge.net/) and a RAW image file... I've got one right here: "clouds.pef" (sorry, I am still using my DL2 and have no DNG).

I start the program, select "new HDR image" and from the file dialog I choose "clouds.pef". I accept the default settings and after a short while an image is displayed. Now I select "save HDR image as" and choose Radiance RGBE as file type. I name my file "clouds.hdr" and press OK. And here it is! A true HDR image, generated in just a few seconds! (Now is the time for the applause by the way) Woohoo! I carefully place the precious HDR image file in my "HDR Cafe" folder and wonder, what I can do with it... PSE (Photoshop Essentials) won't open it, my webbrowser just shrugs and the Windows Explorer refuses to generate a thumbnail. The Windows image viewer doesn't know the filetype. Hm. What's the hype about that HDR stuff anyway??? I mean... I've got a HDR file here, or not? Well - maybe I find out later what to do with it (hint, hint!)

Leaving the stage I grab the latest magazines and find me a nice chair in the corner. I start reading and there are some reviews for current dSLR cameras. Well... about what do they write? ... body ... white balance ... noise ... dynamic range ... - wait: DYNAMIC RANGE?
- Pentax K-x 9.4 f-stops,
- Pentax K7 8.5-9 f-stops,
- Nikon D300S 10-10.9 f-stops,
- Canon 50D up to 11.1 f-stops
They aren't talking about color-depth (3*12bit for the K-x) here, that's interesting... I start to look around to see who is here and might be interested to chat a bit...


3. The Dessert
I am not a moderator for stevesforums, but still I want to remind everyone to "behave". We are in a cafe here, not a boxing ring. If you start to yell at someone, the other people might give you some strange looks, and who wants that in a public place like a cafe, right? Bring some friendly faces, a lot of patience and understanding when you meet all the others here - I know, that HDR stuff is good for some provocative discussions, but keep it nice and friendly, ok?

Kind regards,
Th.

P.S. I hope you don't mind the somewhat unusual way to start that thread, I was just in the mood for it.

Last edited by thkn777; Aug 10, 2010 at 11:56 AM.
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Old Aug 10, 2010, 12:29 PM   #2
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I like this idea as a place to find resources / discussion on the programs and techniques involved.

I would really like to stress though that HDR can be as simple or as complicated as you want it to be. A single shot in something like HDRTist and Voila ..... there is your HDR photo, nothing could be simpler, or alternatively you could go the PS5 route and get involved with layers and different techniques. All depends on you really.

I'm going to copy paste the programs from the other thread so people can easily find something to suit them :

To aid us all there are a few free HDR programs (others are 30 day free trials), some that can even apply a HDR effect even to a single shot, so you don't have to worry about taking a range of varying exposure shots.

MAC :
HDRtist (free)
Luminance HDR (free) http://qtpfsgui.sourceforge.net/about.php and tutorial here : http://garmahis.com/tutorials/hdr-tu...free-software/
Photomatix (free trial) http://www.hdrsoft.com/
Gimp (free) http://www.gimp.org/ and tutorial here : http://garmahis.com/tutorials/hdr-tu...free-software/
DPHDR (trial) http://www.mediachance.com/hdri/index.htm

PC :
Picturenaut (free - I wish they had this for the Mac ! ) http://www.hdrlabs.com/picturenaut/index.html
Photomatix (free trial) http://www.hdrsoft.com/
Luminance HDR (free) http://qtpfsgui.sourceforge.net/about.php
Gimp (free) http://www.gimp.org/ and tutorial here : http://garmahis.com/tutorials/hdr-tu...free-software/
DPHDR (trial) http://www.mediachance.com/hdri/index.htm
AutoHDR by Martin Sykes (free) http://www.autohdr.co.uk

Also if you already have it CS4/5 or Topaz Adjust I believe can apply HDR effects.

Other resources & information :
http://captainkimo.com/hdr-software-review-comparison
http://digitalphotographyclass.net/page/hdr.htm
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Old Aug 10, 2010, 1:09 PM   #3
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As you may or may not be aware, if you venture out of "Pentax" we do have a forum dedicated to HDR. Which is open to share experience from all users, since HDR has little to do with what brand of camera you are using.
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Old Aug 10, 2010, 1:44 PM   #4
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Quote:
Originally Posted by Hards80 View Post
As you may or may not be aware, if you venture out of "Pentax" we do have a forum dedicated to HDR. Which is open to share experience from all users, since HDR has little to do with what brand of camera you are using.
What's that you say ? Venture outside of Pentax ? Mon Dieu, sacrilege !

Thanks Hards - since I rarely go 'outside' I didn't know that !
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Old Aug 10, 2010, 1:48 PM   #5
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Quote:
Originally Posted by Frogfish View Post
What's that you say ? Venture outside of Pentax ? Mon Dieu, sacrilege !

Thanks Hards - since I rarely go 'outside' I didn't know that !
LOL

Of course the thread here is perfectly fine, just pointing it out as any info that may be relevant here may be good to share with those that don't venture IN here.
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Old Aug 10, 2010, 2:10 PM   #6
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Quote:
Originally Posted by Hards80 View Post
LOL

Of course the thread here is perfectly fine, just pointing it out as any info that may be relevant here may be good to share with those that don't venture IN here.
Hello Hards80,
I guess you mean the complete HDR section here --> http://forums.steves-digicams.com/hdr-98/

At the moment I am not very sure, how things will develop here, so better start small and not take the mouth too full (my opinion). If we really dive deeper into the HDR waters and produce some good discussion, a crosslink or a friendly mod can always help

Good point with the people that don't venture IN here, though... hm.

Th.
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Old Aug 11, 2010, 2:25 AM   #7
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Another day in the HDR cafe, early morning, nobody here but me - but coffee is good and I decide to do something with the empty walls. Decoration is always nice so why not hang some pictures?

PHOTO EXHIBITION - "The water lily" - Part 1
I place 4 images on the left wall and attach small signs below:
#1 - 1/2/8
#2 - 2/4/64
#3 - 3/8/512
#4 - 4/16/4096

(hint: the forum places the images in the following pattern: from left to right, then top to bottom)
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Old Aug 11, 2010, 2:26 AM   #8
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PHOTO EXHIBITION - "The water lily" - Part 2
I place 4 images on the right wall and attach small signs below:
#5 - 5/32/32768
#6 - 6/64/262144
#7 - 7/128/2097152
#8 - 8/256/16777216

(hint: the forum places the images in the following pattern: from left to right, then top to bottom)
Attached Images
    

Last edited by thkn777; Aug 11, 2010 at 2:41 AM.
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Old Aug 11, 2010, 2:47 AM   #9
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After you watched my little exhibition I invite you to have a look at these 3 histograms H1, H2 and H3 for some of the water lily pictures.

- H1 is for #1
- H2 is for #4
- H3 is for #8

I'll leave it up to you to draw any conclusions for now (other than me being somewhat crazy and having a strange way of explaining/pointing out things... I know that already ) and get me another cup of coffee.

Kind regards,
Th.
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Old Aug 12, 2010, 12:54 AM   #10
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DYNAMIC RANGE

Uhoh... one of those killer phrases when it comes to HDR stuff, right? To make sure we talk about the same thing I'll start with wikipedia:

"Dynamic range ... is the ratio between the smallest and largest possible values of a changeable quantity, such as in sound and light."

(source: http://en.wikipedia.org/wiki/Dynamic_range, there is also a special chapter for photography)

So basically we talk about the difference or range between the darkest and the brightest area of an image, that your camera sensor detects.

(Sidenote: don't get confused about the dynamic range on your monitor or a printed image - this is the reproduction part of the story.)

DYNAMIC RANGE IN MY CAMERA
Some camera sensors are better in that field than others.

Q: How will I know about the dynamic range capabilities of my sensor?
A: Well - only through reviews and tests, usually the companies like Pentax, Canon, Nikon etc. won't give technical specifications about dynamic range.

COLOR DEPTH IN MY CAMERA
Q: But what about the color depth? (i.e. 3*12 bit when using RAW mode for a Pentax K-x)
A: That's not the dynamic range. That value describes how many (maximum value) nuances or shades your camera will tell apart from each other between the darkest and brightest possible area your sensor can detect. It won't tell you, HOW BRIGHT the brightest detectable area can be.
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