Luminous Landscape Forum

Raw & Post Processing, Printing => Digital Image Processing => Topic started by: Quentin on May 25, 2005, 06:20:57 am

Title: CS2 merge to HDR
Post by: Quentin on May 25, 2005, 06:20:57 am

Hi Giedo,

I think you may be confusing resolution with dynamic range.  Your HDR shot is not going to have any more resolution than an ordinary shot will have.  The HDR image will be large because of the increased bit depth, but you can't use the HDR file directly,  it has to be converted back to 8 or 16 bits, when (as you have discovered) its the same size as a regular shot at 8 or 16 bits from the same camera.  Print size will be the same from the converted HDR file.  The benefits in this process are in preserving highlight and shadow detail.

You can only use HDR with tripod mounted shots.  You should not have an alignment problem if you do.

Quentin

Title: CS2 merge to HDR
Post by: Giedo on May 25, 2005, 02:53:43 pm

Thanks Quentin, David,
I guess you can't have it all: stitching for more pixels and HDR for more dynamic range. Maybe stitching in combination with contrast masking is the best choice here (if you want more pixels AND more dynamic range).....
and I know I should use a tripod. Just don't feel like taking the thing with me all the time.
Thanks again and keep shooting!
Giedo

Title: CS2 merge to HDR
Post by: BernardLanguillier on May 26, 2005, 06:50:59 pm

A scanning back for 4*5 gets to look like a flexible solution... :-)

But I guess that it doesn't adress the DOF issue, does it... you'll still have to take 6 images.

Cheers,
Bernard

Title: CS2 merge to HDR
Post by: Giedo on May 25, 2005, 03:45:34 am

Just tried the merge to HDR-feature on CS2. I was a bit disappointed because of the drifting images/ lack of alignment (but that is because of bad technique...) but also because I expected the output to be much larger in pixel size, so that I could print very large and keep detail.
The final image still is 8,2 megapixel. Why is this? Wouldn't it be great to use al the information available to create bigger files with more detail? Or is this sth that is technically just not possible?

Best regards, Giedo

Title: CS2 merge to HDR
Post by: DiaAzul on May 25, 2005, 06:20:59 am

Merge to High Dynamic Range (HDR) in photoshop increases the dynamic range (bit depth) at each pixel, but does not increase the total number of pixels in the image.

What you are refering to is stitching, where several images are matted together to increase the number of pixels, though it doesn't increase the bit depth (dynamic range) of each pixel.

Title: CS2 merge to HDR
Post by: Tim Gray on May 25, 2005, 03:46:41 pm

So here's the ultimate nightmare...

I can capture (say) 6 images to get wide dynamic range...
I can capture (say) 6 images (or more) to stitch to get higher resolution....
I can capture (say) 6 images to layer in Helicon or Combine-Z to get higher depth of field....

Imagine keeping track of processing and combining 216 images?