Help with video settings on Rx100 V

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On my last liveaboard trip, the guides were shooting videos with TG-4 cameras, and our guide was using the palm of his hand as WB reference - seemed to work out okay. However, the manual white balance on Sony cameras is limited to 9900K - last time I tried setting my A6300 to manual white balance underwater, it just kept giving me errors. On the other hand, I have read since then that despite throwing the error, it does actually set the white balance to an appropriate value, the camera just doesn't show it - I have another trip coming up in three weeks, will be able to test it then. In any case, the underwater white balance option (the fish sign, rather than auto - if your camera is running an early firmware version, you need an update to add it) seems to produce pretty good results.

Regarding focus - try shooting in manual mode, with aperture set to f/8, exposure to 1/60 (the '180 degree exposure' equivalent if you're doing 30fps), auto ISO, and focus set to AF-C with wide focus area. You should see little green squares dancing across your frame, indicating the areas that PDAF (phase-detection auto-focus) is locking on to. Narrower apertures give you greater depth of field, but f/8 is the smallest aperture that PDAF will work with - if you go to f/11 or higher, the camera is limited to the much slower CDAF (contrast-detection auto-focus) and the greater depth of field will be offset by slower tracking.
 
Great info Barmaglot, thank you! Everything I have seen indicates I should be using AWB, but I got some really horrid green and blue movies which I couldnt really fix acceptedly in LR or Premiere. Willing to try anything at this point.

I would love to try a liveaboard!

Can I pick your brain on something else?

I have been practicing shooting with A mode. Im choosing F8, but the shutter speed shows very low, like 1/30. I need a fast one to shoot moving fish with.....I spent some time this afternoon with my rig set up like I was underwater...I have a sea and sea ys ds1 set to TTL, F8, and uploaded them to LR. to view. They look pretty good but I was thinking I need at least 250 shutter or so? Is this just a display thing with Sony or?
 
Great info Barmaglot, thank you! Everything I have seen indicates I should be using AWB, but I got some really horrid green and blue movies which I couldnt really fix acceptedly in LR or Premiere. Willing to try anything at this point.

I would love to try a liveaboard!

Can I pick your brain on something else?

I have been practicing shooting with A mode. Im choosing F8, but the shutter speed shows very low, like 1/30. I need a fast one to shoot moving fish with.....I spent some time this afternoon with my rig set up like I was underwater...I have a sea and sea ys ds1 set to TTL, F8, and uploaded them to LR. to view. They look pretty good but I was thinking I need at least 250 shutter or so? Is this just a display thing with Sony or?

You can shoot F8 with a faster shutter speed. Try shooting in manual mode on your strobe and cranking up your strobe to fire brighter.
 
OOO, tried that and all it did was make my pics too bright, the shutter speed remained the same.

Scandi--I am going to try that once I get a grip on the A mode and getting the F8 and shutter to be acceptable.
 
Keep in mind that shutter speed priorities are different for video and still images. For stills, yes, you want the shortest practical exposure in order to freeze the subject motion - but for video, you typically want some motion blur in each frame - not too much, mind you, but videos of moving subjects shot with high shutter speeds appropriate for still images can end up looking jerky, unless filmed at very high frame rates. Some even use neutral density filters (they limit the amount of light reaching the lens; your camera has one built-in - it can be engaged through menus) in order to be able to shoot with a wide aperture (to control depth of field, leaving selected portions of a frame out of focus) and relatively long shutter speed (in order to get motion blur) in bright light without over-exposing the image. On the flip side, if, for example, f/8 and 1/60 results in underexposed images, you can always bump the ISO setting upwards (within limits of course, excessively high ISO will give you a grainy image) and get a brighter result.
 
Couple more things - if you're shooting stills with a strobe, shutter speed has very little effect on your foreground exposure. Basically, the strobe pulse is extremely short but also extremely bright, and for nearby objects, this extremely short pulse provides the overwhelming majority of light that reaches the sensor. However, your lens diaphragm (the part of the lens that controls the entrance pupil size, commonly referred to as aperture) controls the amount of light that passes through the lens, and the ISO setting of your sensor controls how much of that light is actually captured and recorded. Therefore, when shooting with strobes, you control your foreground exposure not with shutter speed, but with aperture, ISO, and strobe power - that last one is actually your effective shutter speed, as the xenon bulbs in strobes always fire at maximum intensity, but the electronic circuitry in the strobe can vary the duration of the pulse, brief as it is, in extremely precise amounts, which is how strobe pulse power is varied.

For example, using totally made up numbers, consider that your strobe pulse lasts 1ms (1/1000 of a second) and is 100 times stronger than natural sunlight. If you shoot at 1/1000 shutter speed, 99% of your foreground exposure will come from the strobe, and only 1% will come from natural light. If you shoot at 1/50 shutter speed, then you let in 20 times more natural light - but that still results in 80% of your light coming from the strobe.

Rules change for background exposure - powerful as your strobe is, it's nothing in comparison to the sun, and the light it emits dissipates with the square of the distance to subject, with water absorption on top of that - and then the light has to be reflected by the subject, and it dissipates again, with the square power of the distance, as it travels back to your lens. This results in reflected light intensity dropping off to the power of four as distance increases - i.e. double the distance, and the light intensity drops sixteenfold. This means that unless your background is quite close, your strobe light will have little to no effect on it, and you need to time your exposure to let in enough natural light to expose the background properly. On the other hand, you may decide that you want to cut out the background entirely - in that case, you can use extremely short shutter speeds (and your camera can sync with flash at up to 1/2000, unlike interchangeable-lens cameras which are typically limited to 1/160-1/250) to cut out natural light entirely, and end up with your subject starkly lit on a black background (light snoots to limit background illumination help here).

However, when you have your camera set to automatic mode, or one of the semi-automatic modes (aperture priority, shutter priority, program auto), it doesn't know what it is that you're trying to achieve with your shot - it just tries to balance the settings in order to avoid an underexposed image, or an overexposed image, or a grainy image, and water is a very challenging environment for it to begin with. This is why it's trying to set a relatively long exposure when you're closing down the aperture - it wants to balance that with what it considers to be a reasonable ISO value, assuming your ISO is not locked - and that's why the M (manual) mode is your friend: you can control the shutter speed with the lens ring and aperture with the rear dial (or vice versa, whatever you prefer) and let the camera's auto ISO setting tweak the exposure, or even lock the ISO (most helpful if you're shooting stills with strobes) and either rely on strobe TTL to achieve proper exposure, or set the strobes to manual power and control everything yourself.
 
That's a lot of info! It all makes sense but I tend to panic underwater when it comes to settings--I don't want to have to worry too much about them because in my haste I seem to always make the wrong decision. When rushed by guides to keep moving I cant think! So when choosing F8 all my pics have 1/30 shutter speed...isn't that unusual? Strobe or not this is what Im getting, and it seems strange to me. When shooting a moving school of fish would that be good enough? I agree, I do need to learn more about the M mode but when using in the past I have not been very successful!
 
Yeah, I know the feeling - but practice makes perfect. You also have a memory recall mode on your camera - you can set it up with settings for video and switch there with a single twist of top dial when you want to shoot a video clip, while keeping the settings for stills (wider aperture, shorter exposure) in the PASM modes.
 
https://www.shearwater.com/products/perdix-ai/

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