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Photography F.A.Q (Last Updated: 2024 Nov 13 3:04 pm)



Subject: HDR photo


Valerie-Ducom ( ) posted Sun, 14 October 2007 at 4:55 PM · edited Sat, 23 November 2024 at 6:14 AM

Increase the dynamic range of your photographs with Photomatix



alexsm ( ) posted Mon, 15 October 2007 at 2:34 AM

I like the final result's on the examples. This is great thing. :) 
But, the darknes of photo, was do with cammera? 
Or can be do it on a programms like photoshop?


Valerie-Ducom ( ) posted Mon, 15 October 2007 at 5:27 AM

For the darkness picture, you make this work before to make "generat" in this program. I don't work with Photoshop like 95% of photographers here but I used Photofiltre Studio 9, so I don't know.



inshaala ( ) posted Mon, 15 October 2007 at 7:16 AM

Photoshop CS2 has an HDR function, but from what i have seen it isnt as good as photomatix when it comes to output.  That is a personal view on it, but i beleive it enough that i am planning on buying photomatix as a plugin for my CS2 (i have it as a demo, but that plasters their watermark over the finished image).

The idea with HDR is you take a range of exposures, so there will be a very dark photo in one of them where the detail of the highlights can be taken by the camera, and the same with a light photo where the detail of the shadows can be seen.  The HDR process combines it all so that every part of the image has enough information and detail.

"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


Valerie-Ducom ( ) posted Mon, 15 October 2007 at 11:01 AM

Inshaala @ : do you know other hdr program ?



inshaala ( ) posted Mon, 15 October 2007 at 11:08 AM

not really - there are some about on the "educational" circuit i seem to remember, which are basically people writing the scripts themselves and the user interface is extremely difficult and un-intuitive.  Plus they arent as good as the commercial ones anyway so no point.  At the moment i think it is just the major image editing softwares and photomatix...

"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


Tanchelyn ( ) posted Mon, 15 October 2007 at 12:03 PM

HDR images are used in 3D applications to get more "real-life" lighting. Their data are used in calculations, but are neither visible nor printable.
What PS and this plugin do is expand the range internally, which is a good thing. Problem is they afterwards have to compress it to 8 bit. This is about the same as trying to pour a lake into a bucket. The new extreme values will be there, but at the expense of loads of lost data in between.

Just like the "sharpen edges" function is about as far from a good edge mask as a jpg capture is from RAW, a "HDRI" converted to 8 bit can be compared to a set of good luminance masks used with bracketed RAW and some curves. Tone mapping may be  faster and easier, but you lose a lot of control and you get easily lost in the marshes of experiments.

In case your application does not have the option to load channels as masks on layers, the plugin may indeed be very useful.

I have been tempted, but I prefer the raw-channel-mask-curves way.

There are no Borg. All resistance is fertile.


gradient ( ) posted Mon, 15 October 2007 at 11:39 PM

I agree with Tanchelyn on all counts...

About two years ago, I started doing HDR work manually like Tanchelyn indicates, using RAW-channel-mask-curves....although it is time consuming, you have complete flexibility and the results are more satisfying.

My last three landscapes were done using tone mapping....that said, I did not end up using the tone mapped image as a final result....it was a component only!  
The HDR programs do not give decent results in many cases (image dependant), they tend to produce significant ghosting around the light/dark interfaces....and I have found they tend to accentuate the blue channel.

To see the what it does in the way of ghosting....try tone mapping an image with some powerlines/wires in the sky!

In the future, I will likely go back to the manual method...and perhaps use a tone mapped image as a layer, similar to my recent landscapes.

@Val
Here are some other HDR links for you;

http://www.powerretouche.com/Dynamic_Range_introduction.htm

http://fdrtools.com/front_e.php

http://www.idruna.com/photogenicshdr.html

http://www.easyhdr.com/
http://www.hdrsoft.com/ 

In youth, we learn....with age, we understand.


girsempa ( ) posted Tue, 16 October 2007 at 10:33 AM · edited Tue, 16 October 2007 at 10:39 AM

I found this method to be very useful, with single images, and without a plugin:

  1. Shoot in RAW (but I managed to use this method with jpg images too)
  2. Open the image in Photoshop (through your RAW editor if it's in RAW format) as a 16-bit image
        or convert it to 16-bit (menu Image-Mode-16 Bits/Channel)
  3. Now convert the image to 32-bit (menu Image-Mode-32 Bits/Channel)
  4. Immediately convert it back to 16-bit; the conversion window pops up
  5. Choose the Local Adaptation conversion mode
  6. Click on the downward arrow and you'll see the Curves histogram
  7. Adjust the curves to your liking (needs a bit of experience, but it's easy to learn)

That way you have an extended control of levels and tonalities...
And you can still use your own additional methods.


We do not see things as they are. ǝɹɐ ǝʍ sɐ sƃuıɥʇ ǝǝs ǝʍ
 


Valerie-Ducom ( ) posted Wed, 17 October 2007 at 8:32 AM

well... I have 2 problems girsempa, I never make picture an RAW and don't use Photoshop :lol:...



gradient ( ) posted Wed, 17 October 2007 at 9:08 PM

@Val;
To get the maximum benefit using these HDR programs, you will need to shoot several bracketed RAW shots of the same scene....ideally, +2.0EV, +1.0EV, 0, -1.0EV, -2.0EV...so, in total 5 shots bracketed around the ideal. Depending on the cam, some may let you bracket even more shots...ie 7 shots.
When you bracket;

  1. You should NOT use auto focus, 
  2. You should NOT shoot in shutter priority
  3. You should NOT shoot in AUTO or any other SCENE mode
  4. You SHOULD shoot in aperture priority
  5. You SHOULD use a tripod
  6. It will not work for moving objects/subjects

You can use a single RAW and then tone map but, the results are not the best.

If you use the manual method outlined by girsempa, you do not necessarily need PShop....but you will need a RAW editor/converter and then use your current photo editing program for curves/masks.

In youth, we learn....with age, we understand.


Fred255 ( ) posted Thu, 18 October 2007 at 2:34 PM

http://www.cambridgeincolour.com/tutorials/high-dynamic-range.htm

This may help

 ecurb - The Devil


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