This is the Virgin River in Zion NP.  I wanted to get the smooth blurred water but I couldn't stop down enough to get the look I wanted and I didn't have a ND filter.  After numerous attempts on bright day I got what I could and accepted the fact that I wasn't going to get it that day.  After giving it some thought I loaded three shots into PSP that were shot from a tripod with the same perspective.  I pasted each shot onto a separate layer in one file. So I ended up with one file with three layers.  Then I alternately turned the visibility of one of the two top layers off and switched the blend method to "difference" to check the alignment for the visible layer.  There will likely be some some small misalignment if you touched the camera between shots to adjust settings.  If there is misalignment it will show as light areas around stationary objects. 

I then used the move tool to slide the top layer into alignment with the background then turned off the visibility of the layer that I just aligned and turned the other layer viability back on and repeated the alignment process for the other layer.  When your layer blend method is set to difference you can see one layer move relative to the one under it making alignment possible. When best alignment is achieved turn on both upper layers and change the layer blend mode to "lighten" for both of the layers above the background.  This brings up the lightest pixel in the stack to the top.  With everything but the water being stationary the lightest pixel will be the moving water.  There was some movement in the vegetation between shots so I erased the vegetation in the two top layers to produce sharp edges in that area.  When your happy with your stack of images, flatten the layers and PP as necessary.  Sounds complicated but very easy once you try it.

The more images you stack, the smoother it gets. I'll post some screen shots later to demonstrate this a little clearer.  But I gotta go for now.  End result. - Joel

 Did you try setting your camera at the lowest ISO and setting a time value of 1/8th second or 1/4 second? Maybe there was too much light?

Cool way to get around it if there was no other way.

Dave

Dave W:

Did you try setting your camera at the lowest ISO and setting a time value of 1/8th second or 1/4 second?

The three shots I took were at 1/15, 1/8 & 1/4 second at various f stops and ISO 100.  In reality the 1/4 second shot was, "not bad" but still wasn't quite there for the look I wanted.  I thought I would try and combine them and see what kind of result I could achieve

Joel.

 there's more than one way to skin a cat! good save.

Dave

 I promised some screenshots so here they are.  I didn't take any shots of the one I did the other day as I was working on it so I recreated part of it to show the difference.

 I used PT Assembler this time to align the images and output them as multiple TIFFs.  I tried to bring all three into proper alignment but the program was having a problem with one of the images so I just used two of the three.  I then loaded the two TIFFs into PSP X2 and stacked them on separate layers, set the top layer blend method to lighten and erased the areas of vegetation around the edges.  Here is the difference between the single shot without the second image blended in and the second one with the blended image.

You can see that there is some of the desired water blur but enough for what I wanted.

 Here it is with both images combined.

Now that's more like it.  Smo-o-o-o-o-o-th.

Joel

Interesting.  It makes it a little bright, but that's fixable.

Eric L:

Interesting.  It makes it a little bright, but that's fixable.

That's the beauty of the lighten blend mode no matter how many layers I stack it isn't going to blow it out (unless the original shot was blown to begin with).  It does not alter the value of any given pixel like the Multiply, Screen or Overlay modes.