Sony RX100 – Tips for UW Video Part 2 – Rear Dial Buttons

In this second post we will look at how to set the rear dial buttons to best suit underwater video.

The RX100 has got a whole load of settings and not the most user friendly menu structure so it is important to have the features you need at your fingertips when the moment comes.

There are 3 essential features that a camera needs to have for underwater video:

  1. AF lock
  2. Exposure Lock
  3. Set custom white balance

Unfortunately as Backscatter noted in their review of the RX100 there is no possibility to set a custom white balance in any of the video modes, however in the next post I will guide you through the best available workaround that minimizes the chances of you getting completely lost in the menus…

It may be beneficial to understand first why those features are important so let’s have a look one by one.

AF Lock

Have you ever experienced being in a school of fish? Or looking at some frantic behavior in front of you or simply seeing glassfish swarming in front of your camera lens?

It will look something like this…

This is not a still picture but a snapshot of a clip taken at 1/125 sec shutter speed, the action was actually fairly fast.

This is the clip if you want to check it out,

this scene is in the first part of the movie and  has been shot with AF Lock on a Sanyo Xacti HD2000.

What would have happened without AF Lock? The camera would have been looking for focus and mistaking some of the fish coming close with the actual subject and as result the clip would have been unwatchable. So this makes focus lock very important for us in all situation where we operate in tripod mode with moving fish in front of the lens.

The RX100 does not offer AF Lock with a single push, and in video mode the choice is between tracking auto focus and manual focus. To emulate the AF Lock feature I follow this procedure:

  1. Track my focus point with tracking AF
  2. Switch to Manual Focus

Note that is not possible to simply cancel tracking AF to obtain AF lock as the contrast detection system will still wonder around the center of the frame.

This means that one of the rear dial buttons accessible in the menu settings 2 should be set to AF/MF Control Toggle that will allow us to quickly operate the steps above and move with one click from tracking AF into manual and effective locked focus.

Exposure Compensation

Another essential feature of video as we don’t want the camera to continuously adapt to the changing light conditions of the scene. To give an example let’s have a look at this picture:

This is a swim-through that is a common features of little caves or even wrecks. We don’t want the camera to compensate for the lack of light whilst we go through as that would increase the ISO and make the footage grainy, also the scene would get brighter and not reflect to the viewer the same experience we had.

Exposure lock avoids this situation so when we are at the beginning of the cave we lock exposure and the scene stays dark so that the end of the swim through gives a beautiful effect. Another example with this technique

So we should reserve another of the rear dial buttons to Exposure lock that on the menu system is called AEL Toggle

This is how my rear dial configuration looks in the Setting menu 2

Note that I left the center button to standard as that corresponds to tracking focus. That is required for the pseudo AF lock in conjunction with the Right button as discussed earlier in this post.

7 thoughts on “Sony RX100 – Tips for UW Video Part 2 – Rear Dial Buttons”

  1. I have an RX100 and have had very little sucess with the camera underwater. Pic’s are not crisp and macro is non existant. I live in the Pacific NW and the waters are darker but I still seem to have problems in Warm water? My previous camera was a Canon S90 which I had great results, I am at wits end trying to get consistantly good pic’s… you have settings Ideas that I could try?? Much appreciated if so….THANKS!!
    Mike Phillips

    1. hi Mike. If you read my post 7 around macro you can figure out yourself that this camera needs a diopter and for still photos also a focus light as the autofocus really produces inconsistent results. I don’t know what housing you have however I would recommend at least a +5 or +6 diopter just to put it on par with your S90. I use Inon UCL165 and I don’t take stills with my RX100 however Epoque produces a very bright dimmable 1000 lumens focus light that costs less than $250 that I use on the S95. Also make sure you shoot with small apertures f8 to f11

      1. Thanks for the info, I do have a diopter and a nice focus light but still have problems. You mention small apertures f8 to f11. I have a problem there also, if i try to use an fstop higher than f3.5 to4 the screen turns black and i cannot see my subject or focus point? In warm water it’s tough to get to f8 because of the same issue. I may have some obscure setting causing this problem but i sure have not found it yet. Thanks again for your time and information

      2. I try to shoot in Aperture priority and use an ISO of 100 and then the camera chooses a shutter speed of 30-60, when I have tried Shutter priority I try to use around 125 but then the camera chooses an aperture of 1.8 ? The video I have shot with large sharks at Tiger Banks with my wide angle Lens worked well and there i used Shutter priority of 200

      3. Mike for general wide angle the program mode works find look at my post number 5
        For stills the camera always looks for the lowest ISO and then sets the other variables accordingly
        I am going to get my set up for stills and see what he does
        I would suggest manual is better for macro mode but let me check it

      4. Thank you again for your help…as I said I was at wits end and thinking i have made a very expensive mistake buying this camera because my results to date are far backward from my old S90 (which i flooded at Wakobi late summer)

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