Sony RX100 3 VS 4

[asus1987]

I am going to be buying either a MK3 or MK4 for our upcoming holiday and a fantasia housing,
we have previously used the likes of gopro's and canon compacts but feel now is the time to invest in a better camera,

For this holiday (and because I don't think I can stretch to far) I am going to try with natural light and get used to the camera underwater, Unless anyone can recommend a small strobe or light,

Also am I correct in thinking there is underwater mode? so to start with can play around with that rather than adjust settings etc?
last of all I see posts saying no need for red filters etc, and others seem to indicate it is worth having, Any advice on this? ( and is the 4 worth the extra £)

 

[Boaty McBoatface]

Good underwater pictures is at least as much about having good lighting as the camera. It's worth investing in lighting to the extent you can. See the lighting and strobes sub-board for ideas.

Filters:
Magic Filters
If you're going to shoot video, you'll want a filter. If you're going to shoot stills, the best possible results will come from shooting raw, so the filter wouldn't matter. But, if you're not going to shoot raw then you'll want the filter.

RX100 iii vs iv:
I looked at this for myself, and these were my observations...
+The IV got a sensor upgrade. Look at some formal reviews on the iv to get an idea of how big that upgrade was (to me, not massive, but every bit helps).
+The iv shoots 4k.
+The IV got a bump to it's burst rate and buffer
+The IV got a much more useable electronic viewfinder (which we can't use underwater but helps a lot if you'll also use it on land)
+The IV got a much faster top shutter speed. (If you also plan to shoot wide open on land on bright days you may run out of shutter headroom even with the built in ND filter on the iii -- I don't know that to be the case, but you might want to investigate. One if my Sonys has a Max of 1/4000 with no ND and I've run out of room using bright lenses on bright days)
+ The IV was the first RX100 to get Auto ISO Minimum Shutter Speed. In my opinion, this is a massively useful feature and worth the entire price of the upgrade.

-The iii has a little better battery life
-The iii is cheaper.

Also, the Fantasea housing for the iv works for the V so you could potentially upgrade your camera later when the v is cheaper and use the same housing. However the main improvement of the v is the autofocus. Not clear how is much better it would be underwater. Definitely better for action photos on land.

The underwater mode is a type of auto white balance tuned for underwater. I shoot raw and haven't messed with it, personally. Maybe someone else can weigh in. Beyond white balance, you can set the whole camera on automatic to lower your task loading, sure.

 

[asus1987]

i do plan on adding strobes at a later point, But first ill get used to just the camera underwater, Great i will pick up a filter then,

Lastly In reading a review on the RX100 , i did see the mention of a diffuser, and also just using the internal flash, Do you generally always use a diffuser ( if you do not have strobes etc)

Obviously dont get a lot of chance to test in the underwater environment so trying to learn before i go

 

[Boaty McBoatface]

I would suggest you get used to the camera on land.

(I'd also take the housing down without the camera in it to make sure it doesn't leak. Then, add the camera and check out the buoyancy of the assembly in a pool, or at least a big sink.)

There are better lighting experts than I, I'm sure, but generally the diffuser...
* ...Softens the light
* Especially the line between lit areas and shadows
* ...Reduces the total power of the light (maybe 1/2-1 stop?)
* ...Has a greater impact the closer the subject (the range of an onboard flash is already short and all flash ranges are curtailed under water)
* Mitigated by multiple lights from different angles and/or good ambient lighting

I think it's more about the look you're going for in a particular image, so it's a creative choice. Personally, I want nature scenes to look natural. Undiffused lighting looks more stark and artificial to me, so I pretty much leave the diffuser on, but I'm sure there are some scenes that would benefit from having it off and a boost of contrast.

 

[YCW]

If your housing is not translucent polycarbonate type, internal flash may have no effect at all since there is no way for the flash light to go through the housing to light up your subject.

However if the housing allowed the flash light through, more often than not you will need a diffuser. Without one the light will be too harsh with a good chance of the light catching the front end of the housing, creating unpleasant shadows.

One good way to find out is to test the camera on land inside the housing. Turning on the flash light and take a few test shots. That way you will find out what you really need.

 

[ggibson]

If you're sticking to shallow dives or just snorkeling (<15m) you can get away without a strobe or light. You can start off without one, but I think you'll quickly find that in most circumstances your images are going to be far better when you can light your subject. You could go with an underwater light if a strobe is too difficult, but it will be quite a bit less powerful and narrower generally. Another thought would be to get the similarly priced Sony RX100 housing which comes with a small diffuser for the camera's own flash. Your light source will probably cause quite a bit of backscatter being close to the lens, but it's better than nothing.

For red filters, their usefulness for video is probably between 5-20m deep. Deeper than that, there's not much red light left. Your red filter will lose you a lot of light and not really change the look of your results. And near the surface your video will be really red. It'd be helpful to be able to take the filter on/off with a flip adapter so you don't have to screw/unscrew it. For stills, like other said, just shoot RAW and you can color balance afterwards. Personally, I don't bother with red filters. I'd rather spend the money on lighting.