I need some advice on editing noisy backscatter, thanks!

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alashas

Contributor
Messages
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Location
Charlottesville, VA
# of dives
100 - 199
We were in Virgin Gorda the first part of Jan., and there was more particulate in the water than I've ever seen before. I use an Oly SP350 with TTL YS110 and shoot all of my photos .jpg. I edit with PE5, no plug ins. PE is pretty limited in what you can use to eliminate or reduce the backscatter, and I painstakingly erase particulate a piece at a time with the "spot healing brush tool." It takes quite a while, but I'm reasonable happy with the editing I've done on the photos I took on my first 3 dives at "The Dogs": http://honeymoon2.smugmug.com/gallery/4244120#248395015

After the dives that day, a significant weather system came through and really churned up the particulate matter. I've placed 3 unedited shots from 2 dives I did at the Wreck of the Rhone, as well as 3 more shots from 2 addtional dives the next day, 1 at an airplane wreck, 1 of divers in the water, and 1 of coral here: http://honeymoon2.smugmug.com/gallery/4269021#250001998 There is a lot more particulate in these photos than from the previous day's dives, and I need your advice.

I've used the search engine here, as well as google, for a program that works in reducing or eliminating the backscatter in photos and would appreciate your feedback. Few of the sites at which I've look even give examples of uw shots, much less advice. "Neat Image" gets good reviews, but does not have an Oly SP350 filter. "Noise Ninja" has a profile for Oly SP350. I do not use the noise reduction filter on PE5 because it softens everything else too much, unless I am not using it correctly. From what I've read on ScubaBoard, I assume the specific filter for my camera in Noise Ninja works well, is that correct? I do not know anything about "plug ins." Do I open PE5 and then install the plug in from the NN website, or, download the plug in to a folder and then open PE5 and install it?

I assume the filter has various noise reduction settings. Is there a particular setting that you have found works best on your photos, or that you would recommend on the 6 sample photos I've linked above? Once I use the SP350 filter, is there anything else in the NN program that you like to use? Or, is there a program you prefer rather than NN?

Thanks, alashas http://honeymoon2.smugmug.com/
 
Very nice shots. Too bad about the backscatter. One way to deal with some of it is to isolate the blue areas with a lasso tool and adjust the contrast. I kind of stink at PS. I know that if you make a second layer and alter your settings for contrast, or use an eyedropper to eliminate the white spots then merge the two layers, you can cover a lot of sins. Unfortunately, I'm not good enough at layers and such to be a lot of help. I usually use the healing brush (band-aid) or the clone tool. On pictures like yours, where there's a large area of backscatter rather than a few spots, I've had less luck in curing it.
Hopefully, someone else can help both of us on this. If you have lots of patience, and about 400 hours of reading time available, go to the archives of the digital darkroom forum and you'll find about 100 different resources for exactly this kind of stuff.
 
Noise reduction filters will not remove the particles seen in the water column.

Was the strobe used on the open water shots (divers and wreckage in particular) shown in the 2nd link you gave ? If so you would probably have been better off not using it for the open water images - the subjects were too far away for the strobe to be effective anyway.

If there are lots of particles in the water and I want to light the subject with my strobe I usually try to avoid having any open water in the shot - it helps to bring out the "floaties". Having some reef as a background helps to conceal the particles.

Strobe placement is critical when shooting in poor conditions - here are a few links that may help you. This alone will probably solve most of your issues.

tip_edge_light

http://www.kelpfish.net/strobe.swf

The shot with the wreckage may be salvagable using the Dust and Scratches Filter if you have it available in Elements. Just select the whole blue areas one at a time and apply the filter, play with the settings.
 
Backscatter is not the correct terminology for what you're seeing. Backscatter is when light is reflected off of invisible particulate and transmitted back into the lens. This often creates a hollow circle inside the image. You have simply lit up the particulate along with your intended subject. The best thing to do is move the strobe farther away from the lens and you can angle it out, not quite 45 degrees. This will light up the subject with the edge of the strobe while avoiding lighting up the particles between the subject and the lens. With one strobe, this will be tough to do because one side of the image will be darker. So you might try angling the strobe in at 45 degrees and moving it as far to one side as possible. The advice above when shooting the wreck was sound because the strobe barely reached the divers. With the SP350 you can shoot in RAW so you can gain a stop in photoshop.
 
Thanks, this is a lot of helpful advice. I figured the angle of my strobe was the primary reason I was catching so much particulate in my shots, since some shots that I haven't posted are better than others. This camera and strobe is a new set up for me. I used an Oly5050 with no strobe for 3 yrs. Purchased this set up from Cathy Church in Jan., 07. I only used the camera for a couple of dives. I got a little more experience with this SP350 & strobe on Bonaire last May, including slowing down the pace of the dive and and working on stroba angle, macroshots, etc. Flooded the camera part way through Bonaire dives (when I told Cathy C what happened she said it sounded like "O ring failure"). Got a refurbished camera from CC and took the set up to BVI in Sept. Everything worked out of the water, but couldn't get strobe to work under the water. I somehow got a drop of water in the bulkhed and corroded the connections. Replaced bulkhead and cord and finally had the entire system working in Jan. So, I clearly went overboard with the attitude, "come hell or high water, I'm using this damn strobe!" I was pretty happy with the shots I took on the first 3 dives. On quite a few of those, I ended up having the strobe extended all the above me and merely adjusted where the light shot from that angle. Overcast skies on a couple of dives reinforced my desire to use the strobe, but I never could figure out good strobe angles with all of that additional particulate that was churned up. Also, I wasn't stopping long to work on several shots, different angles, etc. Visibility was the worst I've experienced in the BVI, and I didn't want to lose track of the rest of the group, so, it was a lot of point and shoot photos. I turned the strobe off for several distance shots that I did not link above, but never turned it off for the rest of my shots.

Thanks, ce4jesus, for clarifying terminology for me, and for strobe angle suggestions. I've still got a lot of photos to get through, so we'll see if I managed to get a few w/o a lot of particulate. I've never shot RAW, so I'll look more into that. I know folks like it with photoshop, so I'm assuming folks using PE would, too, but I'd appreciate feedback from PE folks who shoot RAW. Thanks.

Thanks, AndyT, for the links and the advice. I turned off the strobe for a few long distance shots, but I believe I had it on for the ones I posted in the link. Here's one I'm fairly happy with that caught quite a bit of length of the airplane at the "Coral Gadens" dive site without capturing much particulate with strobe: http://honeymoon2.smugmug.com/gallery/4269021#250831642
I took 2 other shots of the same plane that had quite a bit more particulate. It was very overcast and the plane was around 55' deep and I imagine a shot w/o strobe would have merely caught the dark outline of the plane with little color.

And thanks for the dust and scratches filter suggestion on PE. I remember getting frustrated trying to use that filter some time ago, so I'll experiment again.

Thanks, Larry C, for the digital darkroom forum recommendation. I've never used that site, but will take a look at it. Regarding PE5, I pretty much just use levels, light, and contrast adjustments, and then the spot healing brush eraser, again, and again, and again. I haven't done anything with layers, so will also experiment with those.

So, it sounds as though a plug in like Noise Ninja is not going to do much for my photos, at least in terms of "particulate reduction." Is there any thing else it does I should be aware of that would help my shots, or uw shots in general? If not, I did not "save a bunch of money on car insurance," but I did save around $80 on software.

Thanks again, alashas
 
Thanks, ce4jesus, for clarifying terminology for me, and for strobe angle suggestions. I've still got a lot of photos to get through, so we'll see if I managed to get a few w/o a lot of particulate. I've never shot RAW, so I'll look more into that. I know folks like it with photoshop, so I'm assuming folks using PE would, too, but I'd appreciate feedback from PE folks who shoot RAW. Thanks.

There are a few Raw programs out there other than the Olympus Master that came with the camera. Rawshooter 2005-6, purchased by Adobe was a nice program. You can probably still find it free on the net somewhere.
 
https://www.shearwater.com/products/teric/

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