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Red filters for cameras

(john Kerr) #1

Hi I’m completely new to this. I’m contemplating my own design build. I recently took my GoPro snorkelling and came back with some video which was rather horrendous. Very washed out and far too blue. My question is with the cameras being used is there a need for filters or are the videos of a good standard?

(Kevin) #2

Because the ROV brings it’s own light, this isn’t so much of a problem. If run without lights, you will lose your red colors and a filter is a good way to bring them back unless you know how to do it in post processing.

(john Kerr) #3

Thanks for the speedy reply. That makes perfect sense and has put my mind at rest.

(undersearobotics.com) #4

One thing to keep in mind is that if you do use lens filters it will reduce the amount of light that reaches the camera. For this reason some photographers prefer to fix the colors in post.

(Roy Petter Dyrdahl Torgersen) #5

It’s definitely something to consider. As @paul-unterweiser mentions, if you use a filter you will reduce the total amount of light that reaches your lens, which might not me so much of an issue on a nice sunny day, but will affect your footage on a dull overcast day, or at greater depth. Another thing to consider is that the red wavelength gets attenuated with depth, so your color filter for -30ft will not work well at -100ft. If you want to check out color filters for your Go-Pro, you could check out backscatter.com, they have all sorts of stuff.

On the other hand, you could work with the footage in post. However, most people shoot in some sort of lossy compression format, normally JPG for still images and mp4, h.264 movie-jpg or similar. In these cases, the compression might affect your footage in such a way that post production is the worst of your options. To improve image quality all over, Go-Pro created the Cineform codec a few years back with the release of the #3. This is a “raw-ish” (as in non-compressed) codec that will allow you to bring out more color than the standard format; however, if you shoot in this codec you have to do post coloring, as the Cineform format stores your data in what is called a flat Look Up Table (LUT).

Also bear in mind that there is another factor which is more important than any other when it comes to video in low-light environments: sensor size. The physical size of the actual photosites determines how much light they can absorb, so a larger sensor is more important than many pixels. It’s something most camera companies don’t tell you today. This is why most phone and action cameras take great pics or videos during daylight, but sub-par shooting night scenes. More info on sensor size: http://newatlas.com/camera-sensor-size-guide/26684/

A couple of resources on video stuff:

And probably the best action camera out there right now:

Hope that’s of any help!