Raw, Red filters & WB...oh my!

[cpanddp]

I understand shooting RAW gives me ability to make any necessary adjustments to image in software later but I'm a bit confused about something.

Do I need to use a red filter when shooting RAW? Why and if so under what conditions / depths.

or

Can I shoot RAW and just white balance the scene at depth (white slate) whithout need of a red filter.

or

??????

Guess what I am asking is what is going to produce best and most accurate results
RAW only...edit
RAW & red filter....edit
RAW & manual white balance at depth...edit
RAW, red filter & manual white balance at depth...edit
or other??

 

[Gilligan]

RAW = no filter required.

RAW = no white balance calibration required while diving.

RAW = doesn't matter much what white balance setting you use to shoot since you adjust it in post-processing. I use the "underwater" WB setting for non-strobe shots and the "auto" one for strobe shots just because you have to pick one.

HERE is a sample of adjusting WB on RAW files with the Canon software.

For non-strobe shots = RAW. JPEG will not suffice.

For strobe shots = RAW. JPEG will suffice.

For best results on all shots all the time = RAW.

 

[spoolin01]

Is there a downside to shooting RAW with a red filter? Would it create a more balanced RAW image to work with from the start?

 

[Gilligan]

Is there a downside to shooting RAW with a red filter? Would it create a more balanced RAW image to work with from the start?

It will not create a more balanced RAW image. There is no advantage to using a red filter when shooting RAW. The downside IMO is you are carrying an extra piece of equipment that you don't need.

 

[spoolin01]

If the water is filtering out one region of the spectrum, optically shouldn't you be able to compensate with additional filters, so that the end result is like a neutral density filter? Just as a matter of simple spectroscopy. If that's not a better starting point for software-based processing, I'm interested to understand a little of why that is. Assuming overall exposure isn't limiting, it's not better to start with more natural relative levels of the primary colors? The sensors must have working ranges, isn't it better to not feed them lots of blue relative to red, assuming that you can feed them enough of each once they're back in better balance?

 

[Jak Crow]

If you're using RAW, you don't need to bother with any filters. You can fix everything post-process.

 

[spoolin01]

Why not fix it pre-process? Is there really no difference? Why is it better (or indifferent) to start with an image that's all blue?

(Livermore was my home town!)

 

[beautybelow]

One good reason not to use a red filter is it cuts out light.

Another is that sometimes you may not need all of the "correction" that the red filter applies. For instance if you are shooting up and have a lot of sun lit area in the image you may not get the desired effect throughout the entire image.

 

[Gilligan]

Why not fix it pre-process? Is there really no difference? Why is it better (or indifferent) to start with an image that's all blue?

(Livermore was my home town!)

Non-strobe shots:
>You can't fix a JPEG shot pre-process other than by calibrating your white balance off a slate or the like and at varying depths and ambient light conditions. It yields the best results for shooting JPEG and requires the most work underwater. I did it for years until I bought my G10 with RAW and even then it took awhile to convert me.
>You get blue photos if you shoot JPEG in the "auto" white balance setting.
>You get better shots if you shoot JPEG in the "underwater" versus "auto" white balance setting if the camera has it. And that setting diminishes in quality as you get deeper.
>You get the best results by shooting RAW then using the eyedropper tool in the post-processing software. JPEG pales in comparison.
As "beautybelow" stated a red filter reduces the amount of light. Red filters went out the window when RAW was born.

Strobe shots:
>You don't need a red filter if you are using an on-board strobe or an external strobe as the strobe supplies the light.
>If you shoot JPEG and calibrate your white balance for a non-strobe then forget to switch it back to "auto" for a strobe shot you get a red photo and it's toast.

When you post-process a RAW file you can save the changes you made to it and if you change your mind when you open it again you can revert back to the original shot.

>JPEG's can yield good results when using a strobe and the camera in Manual or Tv or Av mode.
>JPEG's can't touch RAW for non-strobe shots.

 

[mjh]

I understand the comments about fixing everything in RAW but recall a review of the D7000 done on Wetpixel where I think for video they did use a filter.