Paper based red filter and when to use them?

[stanw]

1. How far down do you typically wait to put on a red filter? Do you wait until you hit 10-ft? OR do you just keep it on from the surface all the way down?
2. Anyone have any thoughts on using a paper based red filter inside the GoPro that can not be removed once in the water, something like this:

Amazon.com: GoPro Accessory - Red Filter for the GoPro Hero 3 Camera: Camera & Photo

 

[EL Pistoffo]

I wouldn't expect too much out of that filter. Looks awfully cheap. You'd be better off going with at least a Polar Pro Amazon.com: Polar Pro Filters C1014 35mm Camera Lens Color Correction and Compensation Filters: Camera & Photo

Red filters are intended for depths beyond 25 ft. There are some specialized filters for shallower depths. I have an SRP red filter and this past weekend I was diving down to 20 ft and my red filter was still too red for use. The water I was in was not the pristine Caribbean blue water as they are intended for, the water was more on the greenish side and a little bit cloudy. In water, or at least water like I was in, after 5 ft you can actually start loosing some color. In my case since my filter was too strong yet a lot of color was also being lost in my dive down to 20 ft I had to fix the color on my own in post using WB cards.

With that inside paper filter your stuck with it through out the whole dive and I don't think it will give you stellar results.

These are screen shots at the same depth, somewhere between 10-15 ft (goes to show how much color can be lost at such a shallow depth), with filter, without filter and with post color correction:

 

[stanw]

1. How do you gauge when it's time to pop the filter on? Are you able to tell when ALL the reds are gone or do you kind of just guess at a certain point?

2. Do you shoot video of the WB card just once or do you do it at different depths?

 

[EL Pistoffo]

1. How do you gauge when it's time to pop the filter on? Are you able to tell when ALL the reds are gone or do you kind of just guess at a certain point?

2. Do you shoot video of the WB card just once or do you do it at different depths?

Even though I haven't tried my new filter at greater depths yet, in some cases you can kinda go with what your eyes can see. That green water screen shot above is pretty much how it looked to my eyes. But in any case I probably wouldn't use it till depths greater than 25-30 ft because that's probably when the water is void enough of red that the filter will balance it out.

I shoot the WB cards at different depths or any changes in lighting conditions. On this dive I was under a bridge so I shot the WB cards at the inlet of the bridge, 10 ft into the bridge, dead center of the bridge, etc. All those changes in lighting made it more difficult so I had to display the cards more often but you get much better results in post. If it were a more normal dive, like a consistent depth and open water, then just shoot the cards once in a while. If it becomes overcast, shoot them again.
Once you put on your red filter at depth, you shouldn't need it. I've seen some videos with nice results. I will probably try it in conjunction with WB cards just to see what kind of results it gives me. Maybe even better color accuracy with the red filters. It's a trial and error kind of thing.

---------- Post added August 12th, 2013 at 10:16 PM ----------

Actually I just tried WB card correction while using a Red Filter, not too good:

Red filter only Red filter with WB card correction applied

Not very natural looking to me. The WB cards can only do so much. There is simply too much of a red hue too be removed by those means.


My conclusion at this point is that the WB card method is a useful method of color correction at shallow depths without any color filter. If my findings change I will post them.