Digital Outback Photo
- Photography using Digital SLRs

 

Workflow Technique #033

Dust Removal


 

note by Uwe Steinmueller

 
 

Dust spots are a fact of the life of digital photographers using DSLRs with interchangeable lenses (only the Canon D30, D60, 10D and 300D seem to be less prone. We have the feeling that this maybe more luck than design because the Canon 1D and 1Ds show more dust).

Now Nikon came up with a neat idea to implement a feature in their D70 and D2h that allows to photograph a "dust map" photo and should help to reduce/remove dust from existing raw files.

Reason enough to have a closer look into the theory and practice of this new feature in Nikon Capture 4.x. We used the new feature on three images with different levels of complexity and our 2 day old D70 was a good test object.

Note: This is always the same dust spot in the D70. All images are not sharpened because we do dust removal as one of the first steps.

Round #1: Dust in the sky

We remember when we first saw a dust spot with our Nikon D1 4 years ago and panicked. What is this and life is over :-). We actually cleaned the D1 with canned air and made matters worse (spilled residue onto the sensor). Today we use the Photoshop healing brush all the time and would be rich if we would get a $1 per spot. Cleaning about 30 dust spots in the sky takes us today less than 30-60 seconds.


Dust spot in sky

What if there would be a better way? So we tried the "Dust Off" feature in NC 4.x. We took a "dust reference" photo as described in the D70 camera manual and tried to clean the spot in Nikon Capture 4.1.


Cleaned with NC 4.1

There is only a slight impression left of the spot.


Cleaned with CS Healing Brush

Took me 10 seconds in CS and the result is slightly better.

Round #1: "Dust Off" could be nice

Round #2: Dust in the sky near objects

This time it gets more complicated.


Dust near objects


"Cleaned" with NC 4.1

This was not very helpful and failed to help in real life. Also notice the color shift.


Corrected in CS with Healing Brush

Using the healing brush here is not trivial. We need to use selections. This technique is described in our handbook DOP2000 (sorry we have to finance our site). The solution is way from perfect but could be improved spending more time. But you would hardly see this in a print.

Round #2: Lost by NC4.1

Round #3: Dust on more complex patterns

Now it gets even more tricky.


Dust spot on shirt


Corrected with NC 4.1

Also here NC 4.1 failed to do the trick.


Using Healing Brush

Again not a perfect solution but hard to find in a final print.

Conclusion

"Dust Off" by Nikon is a great idea. The implementation disappoints.

Disclaimer: If this would be the result of a bad dust reference file then it would mean:

  • Why did it work in sample 1?
  • The process maybe very error prone

 

 

 
 
 
 
 

 

 
 
 

   

For Comments post in our News Group

2000-2007 Digital Outback Photo