Digital Outback Photo
- Photography using Digital SLRs

 

Workflow Techniques #113

HDR for creative work

 


Creek Cascades

essay by Uwe Steinmueller

 
 

Photographing moving water (here mainly cascades) is both challenging and fun. There are many ways to skin the cat. Here is a shot from our book "California Earthframes":

 


Merced Cascades

Recently we wanted to check how well Cascades would work using HDR techniques. The classic solution is to use longer exposures (we like about 1/5-1/15 of a second for high speed cascades like in the Merced shot above). But of course it depends on your artistic goals how you would like to present the cascades. In most cases it can be said that a completely freezing of the moving water does not add to the picture.

So we started photographing cascades with multiple exposures:


3 Exposures

We experimented with bracketing of about (-1, 0. +1 EV).

Note: All shots were done into the shadows. Still you will be surprised about the dynamic range of that scene.

Remember you also have bracketed single shots

The first thing to do is to check whether the single shots can be used by themselves. Bracketing was always a proven technique to get the best possible exposures. Now you can use this technique and get shots for HDR at the same time.

If the +1 EV shot would have no data clipping then it would be the best choice because it has the most open shadows with the lowest noise.


Exposure set to -4 in Lightroom for the +1 EV shot

We set the exposure slider to -4. If we feel there are still hot areas than we discard using this exposure. In this case we we don't think the +1 EV is usable. This leaves us using the 0 EV exposure. We then adjust the settings in Lightroom to get a very soft version version with the following property:

  • Absolutely no clipping in the highlights
  • Shadows nicely open and as little clipping as possible
  • We then do the final tuning in LightZone
  • We set the Point Curve to "linear" and also the Blacks slider to 0


Single shot version from the 0 EV version (out of LightZone)

The problem we see is that the water of this single shot picture makes the photo look a bit "busy".

The HDR version

We then combined the 3 exposure in Photomatix (2.4. Beta 6) to a HDR image and then tonemap the HDR file in Photomatix:


Tonemapping in Photomatix

Again our goal is to keep the file soft as in Lightroom. The final tuning is again done in LightZone.


Tonemapped HDR file (out of Photomatix and LightZone)

Interesting that this image looks way less "busy". Now it maybe a matter of taste which version you like best. But this is not really the case. Stay tuned.

Combining the single shot and the HDR version in Photoshop

We put the single shot version and the HDR as two layer on top of each other in Photoshop. You also need to align both layers perfectly. Then we blend the top layer to our taste:


58% HDR on top of the single shot version

This way we can bring back some sparkle from the single exposure shot.

What about HDR and moving objects?

As you may know moving objects are still a big issues for HDR (called ghosting) and water is moving big time. But the water is moving organic and does not have any edges. We find that HDR can produce nice cascade shots. Of course there is a lot to explore in the future. As a nice side effect we also get low noise and open shadows.

Comparing crops of all three versions

We show how different the water looks in the three versions:


Single shot version (0 EV)


HDR version


Combined version

Conclusion

We plan to use more and more bracketed exposures with the following benefits:

  • Pick an optimal single exposure
  • Explore the HDR version
  • Have multiple exposures for the future as we know that HDR tools will evolve

We also want to ask camera manufacturer to improve the bracketing features in their cameras:

  • Allow at least -2, 0, +2 bracketing (Canon 5D and 1Ds Mk. II allow this)
  • Allow to setup at 5 shots for the bracket (5D does not allow this, while the 1Ds Mk. II can do it)
  • Allow exposures beyond 30 seconds without using "bulb". We ran into this limitation quite often in the past.

 

Note:

Very often you may have a TIFF file tone mapped in Photomatix and then ask what were the parameters during Tonemapping. The good news is that Photomatix stores the settings in the XMP section of the TIFF file:


XMP info on Photomatix in Photoshop

 

 

 
 
 
   

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