A6000, what else do I need to start?

I see all these big double handed grip setups with extensios which I presume I strobe flashes?
But just for up to 15metre, what do I need to start out shooting fish under the water?
Im aware if you dont use colour filters you will end up with essentially just different shades of blue.
That is about as limited as my knowledge is.
I havnt picked out a lens just as of yet but I presume fish eye to wide angle would be best? Or would it be ultra wide angle with a fish eye adapter?

If you're shooting stills, red filters are absolutely unnecessary - they just steal your light, and shooting RAW then using spot white balance in post-processing is a much better way of restoring colors. Video is a more thorny issue, but even there, MWB is generally a better option.

Regarding housings, I really don't see much point in Fantasea FA6000 when SeaFrogs Salted Line has pretty much all the same features at half the cost or less.

For strobes, your main options are Inon S-2000 or Sea & Sea YS-01 for entry level, and Inon Z-330 or Sea & Sea YS-D2 for advanced. The new Retra flashes should also be available in a few months if you're willing to wait, although it's a fairly safe bet that initial production will go towards filling preorders.

For lenses, your main options are:

1. 16-50mm f/3.5-5.6 kit lens - the zoom range is useful for a wide variety of subjects, but on its own it's neither wide enough for the big stuff, nor capable of macro. You can put it behind a flat port with 67mm threads and augment it with wet wide lenses for wide-angle and wet diopters for macro, similar to how fixed-lens compact cameras are used underwater. You can also shoot it behind a dome, but then you forgo the option of wet lenses.
2. 10-18mm f/4 lens - ultrawide, useful for reefs, wrecks, medium sized or larger subjects that let you get in close. Requires a dome port, 6" or larger - flat ports produce extremely strong pincushion distortion at shorter focal lengths. Not useful for small stuff, or shy subjects such as sharks that won't approach you.
3. 16mm f/2.8 with VCL-ECF1 fisheye converter - the only native option for a fisheye, which gives you a wider field of view than even the 10-18mm lens, but at the expense of significant distortion. The wide field of view is useful for getting close to larger subjects such as whale sharks, manta rays, giant groupers, etc, as well as reefscapes or wrecks, but lighting such wide-angle shots is a significant challenge, lack of zoom is limiting, and fisheye distortion can spoil some shots.
4. 30mm f/3.5 macro - cheap, good quality, can do 1:1 macro (i.e. life-sized subject on the sensor; can fill the frame with a 24x18mm subject) but short focal length makes for a very short working distance - in order to shoot these small subjects you need to pretty much bump the lens into them, and the more mobile critters will not tolerate that and swim away. Lighting at such close ranges is also a problem, as the port will shadow your lights or strobes. Can also be used for intermediate size fish portraits and such.
5. 50mm f/2.8 macro - good intermediate focal length, but reportedly has trouble focusing behind port glass.
6. 90mm f/2.8 macro - excellent image quality, great for macro and supermacro, reasonably fast and accurate autofocus, good working distance on the small stuff, but heavy, expensive, eats lots of battery power (I can reliably get three dives out of a battery with 10-18mm, but only two with 90mm), and larger subjects require staying way, way back - outside of strobe range, and way too far away if water clarity is less than optimal.

Strongly consider getting a vacuum system if the housing that you pick supports one. The way it works is, some time before a dive (I usually do it overnight, the previous evening) you use a pump to evacuate air out of the housing, and then a sensor monitors the pressure inside. If any of the seals aren't air-tight, air will leak in and an indicator will start flashing, alerting you to the fact that taking the housing in this state underwater isn't safe.

Kind of stating the obvious here, but underwater photography is a challenging pursuit, and safely handling a camera underwater - particularly if it's a large rig with a dome port and strobes or lights - requires very good buoyancy skills drilled into muscle memory. You have to be able to hover inches off the sea floor without touching it, maneuver in close confines, and do it while concentrating on other things (namely, the subject(s) and the camera). Keep in mind that these camera rigs are quite draggy, and moving one through the water will have a noticeable effect on your air consumption.

Keep in mind that studio sharpness tests are not very relevant underwater. You're shooting through one or more layer or glass or acrylic, and water column beyond that - six feet of water will have a much bigger effect on image quality than any but the most outrageous difference between lenses. Likewise, while 'a set of primes' is a valid approach when you're on land and can change lenses within seconds, it is significantly more limiting underwater, where a lens change involves surfacing, opening up the housing, changing the lens, possibly the port and maybe floats/weights, re-sealing everything and confirming the seals with a vacuum pump. 'Zooming with your feet' is not an approach that works underwater either, as you generally want to get as close as possible to your target, so stepping back to frame the subject with your long prime is rarely an option. In addition, just about everything that can swim is faster than you are, so you can't really control distance with any degree of reliability.

DigiPainter wrote:

Thank you. This brings up an issue I have been pondering.
Do you have to buy a new port/bulb for each length of lens?

Depending on the port and the lens - some ports can support multiple lenses, some are made for just one. With dome ports, alignment is important - the lenses entrance pupil needs to be as close as possible to the center of the dome port's curvature. Higher-end manufacturers offer extension rings which can be used to customize the length of the ports' barrel to better fit multiple lenses, but Meikon, at this stage, does not.

You cant change your focal length once under water?

If you have a zoom lens, and a gear to operate its zoom, then you can change the focal length. In some cases, zooming is possible without a gear - for example, on Olympus cameras, if you have a power zoom lens mounted, you can operate its zoom with camera buttons.

Which brings up a couple of things for me.

Would the 60mm macro be a good choice given it will also shoot portrait length but will do macro?

There are no native 60mm macro lenses on Sony E-mount. There is one for Canon APS-C, which I suppose could work fairly well for what you describe. There is also one for M4/3 cameras, but due to crop factor, it's better suited for macro to supermacro work.

Now if I want to shoot ultra wide, do I need a dome port? What does the dome port do for me?

When you're shooting underwater, the light that passes through the water/glass/air boundary at an angle gets refracted - i.e. the light rays' path is bent. The sharper the angle of entry is, the more it gets refracted. If you shoot a wide-angle lens through flat glass, the areas on the edges of your frame are seen at a very sharp angle, and this produces very strong pincushion distortion and image quality degradation. A dome port avoids this by having the water/glass/air boundary be present at a right angle (90 degrees, perpendicular) to the path of incoming light all around the lens. See here for examples of shooting different lenses through different ports in a pool: https://1drv.ms/f/s!AupWSggdlFYKjtRFu-IIxyopM8fvAA

Also I freedive, mostly only to 10m ish, do I really need a filter for shallower depths?

I've never used a filter (besides a yellow one for fluorescence); RAW is a better solution for most situations.

Lastly can the visibility be corrected in lightroom to get more clear shots of the subject? Obviously being as close as possible is best, but is it possible to get rid of the haze etc?

It can help some, but there is no substitute for getting close.

DigiPainter wrote:

So say I shoot something underwater and it turns out all blue, like a school of big predator fish, if I shoot in raw I can bring some colour back to the fish?

You find something in the photo that can serve as a reference grey point - a patch of sand or rock, another diver's tank, etc - and click on it with the spot white balance picker tool. If you don't have anything to serve as a white balance reference, take another shot taken under similar conditions and copy/paste the white balance from there.

Sorry I was thinking of the sigma 60mm f2.8 with a diopter. But looking at prices the 50mm f1.8 sony might be a better go.

Neither of those will work as a macro lens, and diopters are a kludge - they leave you with a very short working distance window; throwing example numbers, you might be able to focus no closer than 4cm and no further than 6cm - if you need to be 10cm away to properly frame the subject, then tough luck.

So essentially you have 2 setups, flat port for shooting clioseups/macro
Bulb port for shooting wide angles and fish eye?

Right. I shoot a Sony 10-18mm f/4 behind an eight-inch dome port and a Sony 90mm f/2.8 macro behind a flat port. For special occasions, I have a 7Artisans 7.5mm fisheye behind a four-inch dome port. An alternative to this would be a 16-50mm zoom behind a flat port, with a wet wide lens for wide-angle (a Nauticam WWL-1 will give you 130 degrees diagonal FoV) and a diopter for macro.

DigiPainter wrote:

I forgot totally about wet lenses, oh boy a new thing to learn haha.
So dont throw my 16-50mm away? Honestly Im not happy with the photos from it. Just not sharp enough, I think thats why i want primes like you 90mm macro, and the ronkinon 12mm.

It's a matter of approach, and there are pros and cons to each. 16-50mm + wet lenses will give you the flexibility to shoot macro and wide angle on a single dive, but the wet wide lenses will give you fisheye distortion which works for many shots but ruins others, and they're too small to shoot over/under splits. Likewise, diopters will limit your focus distance window in both directions, as I already mentioned. There is also the matter of mindset - if you're poring over the reef, scanning for tiny shrimp or pipefish, you're liable to miss a great potential wide-angle coral composition, and vice-versa - while setting up that great wide-angle shot, it's quite unlikely you'll spot that camouflaged pygmy seahorse.

As far as sharpness, a lot of conventional wisdom from land photography flies right out the window once you submerge. The port and its water/air boundaries act as an additional lens element, completely invalidating dry land test results. Aside from a very few exceptions, camera lenses are not built to function underwater, and water itself affects image quality to an extent that dwarfs the difference between various lenses. The humble 28-70mm full-frame kit lenses easily outperform $2000+ 12-24mm/16-35mm setups when placed behind a Nauticam WACP, which is specifically engineered to compensate for the differences in shooting underwater - but WACP costs almost four thousand dollars, and its internals feature some of the largest lens elements produced for the mainstream camera industry; similar to those inside $10k super telephotos.

Is the sony 90mm really awesome?

It's a great lens to use in clear tropical water. If you're diving in temperate waters, where visibility is less, its working distance may prove excessive, particularly when mounted on a crop sensor camera.

Long lenses and powerful strobes won't help you in poor visibility conditions; you'll just end up lighting up the particulate matter in the water. Think of it this way - would you bring a telephoto lens to shoot in dense fog? I don't dive in cold water, so I can't offer personal experience in your conditions, but in general, when visibility degrades, I put on a macro lens and look for the tiny stuff.

DigiPainter wrote:

Barmaglot_07 wrote:

I've never used a filter (besides a yellow one for fluorescence); RAW is a better solution for most situations.

Lastly can the visibility be corrected in lightroom to get more clear shots of the subject? Obviously being as close as possible is best, but is it possible to get rid of the haze etc?

You can actually do quite a bit to make things look clearer, but there are costs.   I like to use the Lightroom Black slider, pulling the shadows down until the histogram almost touches the left side.  That darkens the whole scene, so I then often need to add some exposure.  THAT affects the highlights, so I then have to reduce them a bit to avoid clipping.  Done with care, you can definitely make a lot of the haze mostly disappear.  Examples below.

It can help some, but there is no substitute for getting close.

Agreed, though you can't do much about it when shooting wide.

So say I shoot something underwater and it turns out all blue, like a school of big predator fish, if I shoot in raw I can bring some colour back to the fish?

Yes, but...   You need enough light, and again, you need to be 'close enough'.

For instance, I shoot strobes with manual power settings, often 1 step down from full power, with apertures like F10-16 and ISO 64.   So no power left for a fish that swims by 10-20 feet away.

I can take the shot, and I can crop in a lot (I have 45mp to work with now), but it will be underexposed, and it will likely have significant haze.   I can only bump up the exposure so much, and if it's not too badly underexposed, it can look fine.  I then often have to use massive amounts of contrast to get definition, plus try to reduce the haze.

So essentially you have 2 setups, flat port for shooting clioseups/macro
Bulb port for shooting wide angles and fish eye?

That's my dilemma.  A single prime for mostly macro.  (Actually mostly close-up.  I rarely am close enough to achieve 1:1 macro).   Shot through a flat port.

And a wide zoom, shot behind a big dome port.

I've tried splitting the difference, using a short zoom (60mm in my case, down from my usual 105mm).  The idea was that I could get a shot of a whole larger fish, or most of a diver, while still being able to do macro.   Problem was, the working distance of the 60mm was so short as to be unusable for me.

I also tried adding a 1.4 teleconverter to my 105mm macro prime, and I wasn't happy with the sharpness.

So basically it's shoot with a 105mm and do a lot of cropping.  Shooting anything not macro with the 105mm generally has it far away enough that I have significant haze and under exposure to process.

Here is my 'clear it up with black slider example'.   I also used the eyedropper tool to set white balance on some metal bit in the dive gear.   (I do not find it that hard to get a decent white balance.   There is a LOT of 'pure' white underwater, in coral or shells.  Or black (sometimes a fish eye).  Or black, white or metal bits in dive gear.

Out of camera:

Processed with white balance and use of black slider:

Haze looked more like the first image in reality.    (St Thomas...)    You can see it's easy to block up the shadows and lose detail in the dark parts of the dive gear.

Also jumping in this.

Been looking at the seafrog saltline for my sony a6000. My main lens is sigma 16mm 1.4 - is the 6" dome the best option to get with it with the seafrog? is the sigma a good lens for all around use for diving (10-30m)?

I would suggest getting the A6xxx Salted Line unit because it is the most budget-friendly model on the market as well as you get full control of your camera.

Depends on what you like to take pictures off and where you are (what the water conditions are).

I have the salted a6xxx Housing and use it together with flat port + short macro flatport. I usually use the 30mm Macro or the SEL1650pz and might try it with the 24mm Zeiss on my next vacation. In addition I used a Inon flash.

I was actually thinking about the same combination of the Sigma 16mm and the dome port, but decided against it. And got myself a light and filter for fluoro diving.

Tl/dr: Seafrog housing is stellar, everything else comes down to conditions and what you prefer.

30mm Macro, this is how I usually use it, as a Closeup, not a Macro

30mm Macro plus flash, 16mm would have worked here also I guess.

closeup with the 1650pz at 16mm (flash died shortly before)

1650pz at 16mm