Lights are superior to filters?

[Slamfire]

In terms of underwater color correction lights are superior to filters. Correct me if I'm wrong. The reason behind my assertion is that filters provide a subtractive correction whereas lights are additive. In other words, filters prevent some information from getting into your camera sensor and lights add more information. Prevent enough information and you end up with a black picture. In this case more is better.

Furthermore, you can still do subtractive color correction through software after you're done shooting. It will be more versatile and adaptive to varying conditions than merely sticking to one filter only for the duration of your dive.

And finally if you wish to keep on shooting shallower than the depth intended for your filter, lights will not paint your shots with the unnatural red hue that you see with filters. I shot this video without lights nor filters because I was confined to snorkelling depths. I managed to keep most of the surface scenes from turning the red filter hue while still apply "virtual filters" through editing software.

 

[ronscuba]

Lights, filters and SW color correction are tools. Each has their time and place when they are best to use individually or combined.

For example, wide angle sunlight 50 ft. deep, subject is > than 6 ft away, a filter will produce better footage than lights or SW editing alone.

 

[Slamfire]

For example, wide angle sunlight 50 ft. deep, subject is > than 6 ft away, a filter will produce better footage than lights or SW editing alone.

Could you expand on why or how?

 

[Hoag]

Could you expand on why or how?

The short answer would be because you start losing colour, starting with red in as little as about 10 feet. Below that, there has to be a way to balance the colour. The two ways to do this is with lights (which will bring more white light (including red) into the image), or with red filters, which do not add red to the image, they remove the other colours so the net result is an image that is darker, but has balanced colours. With filters, the exposure must be corrected in post production otherwise the image will look dark and under-exposed.

So for the example given, let's look at one characteristic at a time.

• You are at 50 feet: Since you are below 10 feet, you will need to correct somehow
• The subject is greater than 6 feet away: Lights are no longer ideal since the light will have to travel 6 feet from the light source to the subject and then another 6 feet back to the camera (sensor) or a total of 12 feet which is right on the threshold of what their useful range is. A filter will balance the colour regardless of the distance to the subject (within reason).
  
• You are shooting wide angle: Lights are not optimal for wide angle unless the light's Field of View covers at least the Field of View of the camera. (Ideally, they should cover a little more to allow for slight variations in their aiming.) A filter, on the other hand, will normally cover the entire Field of View for the camera.

I hope that helps.

 

[ronscuba]

What Hoag said.

Plus, many cameras are powerful enough to handle the exposure adjustments with a filter in place without the need to correct exposure in editing. Especially at depths shallower than 70 ft.

To expand on that, some cameras are powerful enough they can white balance UW colors without the need for a filter.
High end DSLR's and the newer mirrorless cameras come to mind.

If you are not lucky enough to own a camera like that, get a filter. They are an inexpensive, but powerful tool for wide angle video.

2 video samples. Both shot with filters. Galapagos was shot with a Sony camcorder recording on video tape. Camcorder came out in 2007. Maldives was shot with a Panasonic compact camera 2012.

 

[Slamfire]

Thanks for the answers. It clears up some things. However I'm still not clear on what is the advantage of filters over software. Removing other colors except for red can easily be done in software. Taking out information is easy. Adding information out of nothing is hard -- extrapolating will only get you so far. The only debatable advantage I see is that you may have one less task to do while editing. That is if you do not shoot at different depths that may exceed the white balancing capabilities of the camera with filter that you're using.

I'm not denying the usefulness of filters, I'm saying you can apply them digitally and much more selectively after the dive while editing.

 

[Storker]

However I'm still not clear on what is the advantage of filters over software. Removing other colors except for red can easily be done in software.

If you have just a little red, and a lot of blue and green, you either under-expose the reds so much that there's little information to enhance, or you over-expose the blues and greens so much that you risk that your sensor saturates in those colors.

The point of a filter is to reduce the blues and greens enough to enable your camera's sensor to capture enough of the diminishing reds without saturating in the blues and greens.

 

[Hoag]

Thanks for the answers. It clears up some things. However I'm still not clear on what is the advantage of filters over software. Removing other colors except for red can easily be done in software. Taking out information is easy. Adding information out of nothing is hard -- extrapolating will only get you so far. The only debatable advantage I see is that you may have one less task to do while editing. That is if you do not shoot at different depths that may exceed the white balancing capabilities of the camera with filter that you're using.

I'm not denying the usefulness of filters, I'm saying you can apply them digitally and much more selectively after the dive while editing.

The advantage is in task loading. Whether in still or in video, it is always a better idea to capture the image correctly than it is to try to fix it later. If it is captured correctly, you know you got the shot. if you have to do massive corrections after you get home, then you won't know until long after the shot has come and gone.

I can also put a filter on in a few seconds, but to colour correct in SW will take significantly longer than a few seconds.

 

[ronscuba]

There are limitations to how much you can improve UW video with SW color correction. It is not as capable as color correcting photos. Analogy is color correcting a raw photo vs a jpeg. Only video is not even jpeg quality. If you are recording at 60 fps, every 1 second of video is 60 individual low quality, low resolution photo pictures. Color correcting 10 seconds of video is correcting 600 individual pictures. 60 seconds of video is 3600 pictures.

I think of it as SW can improve the video color, but not correct it. There has to be something there for me to work with. The combination of filter and SW works well. Kind of like a painter using a roller to paint the wall, but a brush for touch ups and details.

I've tried doing SW only and no filter. Worked ok at shallow depths, but below 15 ft, the filter was better and easier. Give it a try at 20,40,60 ft deep. You might be really good at color adjusting in SW. Best case you will be successful. Worst case you will find when to use a filter and when to use SW alone.