On Friday we were up for our last 3 dives at Shark Reef the current had not changed but this time I decided to give more a go to the schooling fish after setting up all the backgrounds I wanted.
As you can see from the image on the title we had more of the usual divers chasing fish but this did not deter me this time as I developed a specific technique to do the dive that I used fully on the last two photo dives.
So after a bit of experimental shots like this one
It was time to give it a proper go. To be honest is not that I like batfish that much and probably this is one fish that you can shoot in RAW in ambient light however if you do that you need to sacrifice quite a few ISO stops. With strobes the issue is to get the school in a formation that allows you to do a good job with lighting. This is my best shot for the session.
What I like about this shot is the light on the fish or most of it where you can see yellow fins but also the background and a hint of surface.
Other fish that featured on the day were jacks but catching a school of those running past is quite hard unless the school is really big and they circle you.
In those type of formation you have all sort of issues with hightlights form the strobes in fact I was shooting 1/4 of power.
Giant trevallies made a more interesting single fish shot like this one.
Contrary to what you may think this is a shot with strobes otherwise you would not see the texture of the fish as you see it. Maybe a busy background but good technical exercise.
I also attempted a few anthias shots just to try a well tested technique to get them buzzing out the reef
In the middle of the dives while I was waiting the barracuda school came out to play. Barracudas are quite tough as they require strobes to lit properly and I find the multitude of black and white shots that you see a bit boring as the fish texture is what makes the shot.
You have several challenges with the formation, if the school is big is difficult to take it all unless you are on the bottom or on the top. In the first case you need to control bubbles in the second you shoot the bottom so better be neat.
Anyway with a bit of patience I got the shot that I wanted
It is impossible to illuminate properly all of them but this shot has got the right geometry and I think is quite pleasant.
On the second dive I was lucky to spend some time with a Giant Barracuda that was literally commanding the school at sight, very rewarding from a diving point of view I got so excited that I kept shooting with a relatively slow shutter speed however the fish that is lit by the strobe is well crisp.
This shot is much deeper than the previous so the blue is colder but still makes for an interesting shot.
On dive 3 I decided to do a bit of video although I had not taken my favorite lens so I had to apply a filter directly on the camera lens. Moreover I had forgot the setting Toy effect on from some other experiment and whilst this is off in RAW it came back in video so the result is a soft warmer image…yuk still was fun to put it together so here it goes
It was time to rinse the gear (if you could call that hosing it quickly on the dive platform) and get ready to leave the day after. On the last day we were asked to put together a selection of our best 10 pictures and were give a video with some gopro footage taken by the ops manager plus our slideshow. Considering the time it was spent to do it the result is excellent.I hope this has given you an idea of the workshop that I definitely recommend, on the next post I will write my personal lessons learned from such experience.
After the first 3 days of workshop we got into the core of it and Alex talked about schooling fish and how to take shots.
We had 4-5 varieties to choose from:
Detailed information was given in terms of how to best approach the fish depending on their behavior and also about the etiquette in terms of letting other people best positioned taking their shot first.
The surgeon fish are not that photogenic and actually quite messy I tried to take some shots when the current was pumping and they were all aligned close to the bottom at Yolanda however to me this is not that exciting as a shot. Other people got better results but I frankly was not that bothered about Surgeons. Probably as the fish is pretty dark and does not reflect the strobe much. The featured image close to the title shows what I mean.
During this trip the current was not going north to south as usual but there was near to no current at shark reef and current going outward at yolanda corner. This means the snappers that usually sit at the edge of shark reef were not out to play.
We were left with barracuda, batfish and jacks to choose from. On day 4 I only see few giant trevally but not many schooling jacks so had to focus on barracuda and batfish.
Unfortunately the barracuda were far from the reef and a bit too deep and did not really want to entertain chasing them so I tried with the batfish. Obviously there were not only us but also other boats so it was a bit of a competition for fish.
Also you always managed to get someone in the frame or bubbles
So I focused on trying to get the best backgrounds for the pictures to come like in this case.
Also had some fun taking images of the others and the batfish one or two came out pretty good.
It is quite hard to have the discipline to respect rules when you are with other 18 photographer on the boat so the competitions had to be expected and I was not that bothered.
In the evening we headed back to Ras Katy and I borrowed a Nikon D7100 from Nauticam UK. I asked to have a 9″ dome for the split shot and jumped in the water with the idea of just doing that.
This is my best shot
Personally I do not like split shots where the surface line is very distorted to avoid that you need to make sure your lens is near to rectilinear and it is better to shoot portrait as there is little distortion on that axis. What I wanted to capture in this shot is layers, the reef, water under and over, the boat and sunset colors.
I think it came out pretty good but it is painful to take 100 shots just to get one right and I wish I had some fish in the frame but never mind is good enough like this. The water was not really flat so that was an additional challenge as you can see the wave breaks on the lens creating a little thicker line but overall a good shot.
Who has followed my initial LX7 tests is aware of the few issues I have had at wide angle with the LX7.
One was the reflections back on the lens that I have now hopefully resolved using a black marker and changing the camera from white (and silver lens ring) to black and the other was flare.
Flare is an issue at wide angle even on land. What causes flare? Stray light coming from the sides that washes out the picture and eliminates contrast in the process.
Wide angle lens tend to have an ability to catch stray light from the sides and top and this is the reason why wet wide angle lenses have to be really coated well so that this effect is diminished, however it still can happen.
And it did happen to me with the Inon UWL-H100. The general advice to eliminate or reduce flare is to have a lens hood however lens hoods are generally not an option for wet lenses with an M67 thread mount. The only lens that I know that can position the hood on a screw mount is the fix UWL28M52 or UWL04 most of the other lens do not have a hood and have a circular lens unprotected from stray light. And this usually means at some point you will get flare.
So how do you get around it? In the case of the LX7 is pretty much a forced choice as the Inon UWL-H100 is the only lens that does not vignette at 28mm equivalent focal lenght so the possible solution is to put a hood on the lens.
Inon sells a hood for the UWL-H100 but the hood is attached through 6 allen bolts and its position can’t be fine tuned so to use the hood it is a requirement to change mount from M67 to the LD bayonet. You need also to convert the lens itself into an LD bayonet. If you go to your Inon dealer there is a relatively cheap service part that allows you to convert your M67 lens into a bayonet.
The LD bayonet is the latest incarnation of bayonet mount released by Inon. Whilst the old AD mount relied on a mechanical action to secure the lens, the new LD bayonet is much shallower and relies on a pin lock release to stay in place. There are two adapters on the market that are capable of attaching LD bayonet lenses to an M67 thread, one produced by Nauticam themselves and the other by the Japanese Fisheye Fix.
There is a price difference between the adapters with the Fix being 20% more expensive.
The Nauticam adapter is the largest of the two. It has 6 allen bolts on the front and a thumb screw lock on the back to fix it in position. With LD lenses there is only one position to put the lens hood in the correct place so if for some reason the thread ends in the wrong place with your housing you will need to unscrew the front of the adapter to ensure the release lock is on the upper left of the port this happens the same way on the fix adapter. Make sure the little spring does not jump off in the process…Once the release lock is in the right area the fine tuning of the hood position is done with the thumb screw. A possible weakness is that if your housing port has no room for the thumb screw then this adapter is not good for you.
Whilst the Nauticam is made of plastic and metal the Fix seems to be 100% aluminum, this adapter looks better but does not have a mechanism to fix in place it relies on the strength of the M67 thread, however this locking system is compatible with any 67mm threaded port.
The fix allows to perfectly fine tune the hood position and it shows.
The alignment mechanism of the Nauticam adapter creates an alignment issue with the hood where the lens is few degrees turned clockwise.
With the fix this does not happen.
The hood can be properly aligned. Note that in both cases this does not mean more vignetting as the corners are not covered by the hood.
The other check I do is the position of the back of the lens, if there is a gap between the thread and the back of the lens this can create vignetting so it has to be as close as possible or even protruding as the Inon UWL-H100 mount type 2 does.
Let’s have a look at the back of those two adapters with teh UWL-H100 28LD attached.
The Nauticam thread is somewhat too long so the lens sits slightly more inside the thread line.
With the fix the situation changes sightly.
There seems to be little difference we will now check if there is an impact on the possible vignette in water.
As we can see there is a little bit of residual vignette on the bottom right corner when the lens is at 28mm equivalent focal length,
This is the same situation with the Fix
There is still a dark bottom right corner but it is less.
Inserting a 1.25mm spacer between the inner housing and the left side of the camera improves matters, this is because the lens of the LX7 is somewhat misaligned in the Nauticam housing and this corrects it.
With the spacer in the housing and the Nauticam adapter there is a tiny little residue of vignette but overall this is ok.
With the fix adapter this is the result.
No dark corners left.
So this is the recap:
You can change the UWL-H100 28M67 into an LD version with a cheap service part
Once the lens has an LD mount it is possible to attach the hood this will reduce flare
Vignetting is slightly increased but can be eliminated with a spacer with the Fix adapter
There is an issue of hood alignment an increased vignetting with the Nauticam LD adapter
A final note: inserting a spacer in the housing is risky, you need to know what you are doing as in theory the chance of flooding could increase so this is not for everyone.
My recommendation to those who want to improve contrast with the UWL-H100 is to convert to LD mount, attach the hood and get a Fisheye Fix LDF-M67 Pro adapter. Changing to bayonet has other advantages making lens swaps in water much faster and easier compared to the thread version especially with a lens as heavy as the UWL-H100.
There are few design issues and manufacturing errors in the Nauticam LD adapter that create issues with the LX7, most likely other cameras that are not so fussy will have no problems but if you have an LX7 avoid the Nauticam adapter entirely until a new production version is defined. I have given Nauticam the feedback and they will probably react.
So I finally had the opportunity to take the LX7 on a trip after some pool tests.
After my attempts last year with the Sony RX100 I was a bit skeptical that I could actually find something better for video but I think the LX7 beats it.
I put together a sample just to give an idea of equipment used and how it works, please note this is not altered in any way
There is a picture of the rig in this blog on a specific page but let me confirm once again in detail
Nauticam LX7 housing
Ultralight TR-DM tray with extension TR-DUP and two TR-DH handles without ball.
12 segments locline arms on 3/4″ mount base and reducer on the handles
Two sola 1200
Nauticam wet mate
Inon UCL165AD on bespoke M67 adapter
Inon UWL-H100 28M67
Inon M67 double lens holder on custom mount
In a previous post I highlighted that for most the wet mate will be the only lens needed however I had some wreck dives and the 18mm of the Inon wide angle are more appropriate.
I also gave a try to the panasonic intelligent zoom that allows for 2x digital magnification and sharpening that for me works very well and you can see it in the footage. This allows a user with just the wet mate to further zoom without need of a close up lens or a use with a single +6 diopter to achieve super macro.
I found the white balance of the camera excellent on both my hand or sand. I had issues with my padi slate that many times returned a ‘scene too bright’ error. Maybe this is the reason why backscatter failed this camera for video?? Who knows.
You can see that even at 36 meters the colour are as good as they can be.
For macro shots I used the temperature setting at 6500K, I found the white balance tint fine tuning to be excellent to further enhance it.
I shot in shutter priority the whole time with shutter speed of 1/100 or 1/50 depending on conditions and type of shot. The camera autoISO and choice of aperture privilege noise reduction however as the lens of the LX7 is really sharp the relatively wide aperture did not mean soft corners.
I tried the various photo styles and at the end settled for the standard one, I found the natural really to have too little contrast.
I thought of shooting in mp4 for wide and AVCHD progressive for close up but this would have meant two different frame rates to edit, at the end I shot at the highest available setting to avoid confusion.
I had received a new port from nauticam so I had no vignette at 28mm and the full 100 degrees the inon lens can offer.
The ergonomics of the camera that have fixed commands for aperture and shutter proved to be convenient and the built in neutral density filter was very effective at shallow depth or on the surface.
In essence I think that the issues backscatter mention are non existent.
I did have a few problems with the wet lenses though.
The wet mate proved to be a great little tool very sharp and light however none of the sides of the glass have anti reflective coating. In bright scenes or backlit scenes I did not have many issues with flare however I could see the marking on the lens reflected back on the wet mate and in the picture. I suggest putting an inon anti ghost sticker or gaffer tape to hide those shining markers or to colour them with permanent black ink.
Other than this the wet mate performs very well in all reef scenes and close up of critter a few inches big.
The inon diopter did not cause any trouble other than the obvious vignetting until 70mm. One pleasant surprise is the LX7 autofocus. Having struggled with the poor focus of the RX100 at high magnification I was astonished that the LX7 finds focus even with two stacked diopters and keeps it!!! I never had to use manual focus that with the RX100 was the norm at macro range.
I had bought the UCL165 and UCL330 in m67 format but decided to sell them as I will actually switch to bayonet very soon for the wide angle.
The Inon UWL-H100 was probably the most disappointing find of the trip. Image was sharp in normal condition however this lens tends to flare quite a bit and this creates block noise in the water column in video, when I used my hand to shade the lens the flare went away. Inon sells a lens hood for the 28LD version of this lens but not for the M67 as there would be issues to align the hood petals to the frame.
Considering that the lens is very heavy in water at 350 grams and that screwing and unscrewing was a concern mid water I have decided to convert the lens into an LD bayonet. Inon sells a replacement service part for the 28LD that can be used to replace the M67 thread of the lens. Other than this part the two lenses M67 and 28LD are identical. I will use a nauticam m67 LD adapter I hope this will not increase the vignette. I will connect my AD mount close up with a AD->LD converter when using the wide angle and then use an AD->M67 converter when I use the wetmate. This saves me buying two different diopters and I can stack the two UCL165AD I already have. They do vignette a lot at medium but who cares when you shoot at full zoom.
I look forward to testing the UWL-H100 with the lens hood I am sure results will be better. On the other hand when the sunlight is behind the shots have incredible sharpness with this lens.
So the LX7 gets 5 stars from my side and I leave you with two recommendations:
1. Apply a form of anti ghost sticker to the LX7 lens
2. If you want to get the Inon UWL-H100 go for the LD mount so that you can put the lens hood on
When compact cameras were designed for 35mm it was quite common to shoot just with a camera and strobe; this allowed the average user to take decent close up pictures as long as the camera was capable of focusing within a couple of inches from the subject.
Years later manufacturers started introducing wider lenses first came 28mm equivalent and most recently 24mm, these cameras give an increased field of view on land of 75 and 84 degrees diagonal.
So why is it a bad idea to shoot just with the bare camera and no add-on lenses?
Two key reasons:
Once in water the 84 degrees diagonal of a 24mm equivalent camera reduce to 54 or less because of the water medium
At focal lengths shorter than 35mm pincushion distortion becomes stronger to the point the pictures are awful.
So if you plan to use your wider compact camera underwater without lenses make sure you zoom to 35mm to avoid distortion.
This is the same picture at 35mm note how the image is now rectilinear.
At 35mm we are back were we were in the mid 2000 and all we can do is close-ups so there is no advantage having a wider lens for underwater use with a compact.
Another common misconception is that a compact camera takes great macro just with the internal flash. Firstly a macro picture has a 24mm height of the capture area, nearly no compacts on the market are capable of this: the Panasonic LX7 and the Canon G15 within the current range are the exceptions. However at 1cm distance the internal flash is completely obscured by the lens, which means there really is no macro without a strobe and a close up lens: all you can shoot are close-ups.
This explains the need for wet lenses in water, wide-angle lenses to increase the field of view and allow us to get closer and take advantage of artificial lighting, close up lenses that also allow us to get closer using the full zoom of the camera and shoot at increased magnification without being on top of our subject.
The needs of photography and video differ as lighting tools differ, photos require strobe to freeze motion, video instead uses fixed lights. Photos are also taken at much wider angle than videos and fisheye effect is accepted, an effect that in video is generally not welcome.
With this in mind what are the wet lens options for the Panasonic LX7?
It depends of course on the planned usage of the camera.
The LX7 has extremely good close up capabilities out of the box, however the capture area is around 12×8 cm that is not exactly small. If we want our nudibranch of shrimp to fill more of the frame we need a close up lens.
From my tests the Inon UCL165 brings around 2.5x magnification with the LX7.
I have tried stacking two UCL165 but the amount of chromatic aberration is too much for my liking, I found that 9 diopters is the max before fringing becomes a real problem and I do not recommend stacking two of those lenses or two equivalent Dyron diopters. I think the most flexible set up is a UCL165 and UCL330, this covers all possible working distances. I do not have a UCL330 yet so I can confirm but I have taken shots with a very similar lens (Olympus PTMC-01) and the results are excellent with a capture area of 48×32 mm that is very close to real macro. The zoom of the LX7 is the real limit here as it maxes out at 90mm versus the 120 of a Canon S110 or 140 of the Canon G15.
For close focus and ambient light wide-angle the bad news is that there is no fisheye lens that works well with the LX7 this is due to the extremely large lens.
I have tested the Inon UWL-H100 and I had to wait for a new port to be delivered from Nauticam as their original one was too long and had vignetting even at 28mm. This lens yields more than 100 degrees diagonal and is my preferred choice for the LX7 for stills. There is however a good amount of blue and yellow fringing if I really have to be picky so the extended field of view comes at some price.
I use Inon lenses however a possible candidate is the Epoque DCL30, this lens is reported to work with 28mm equivalent cameras however the rear lens is smaller than the Inon so I believe this needs confirmation. There is a $70 difference in US and £70 here in UK between the two lenses and considering that a dome will not worth I encourage testing this lens as the results may be acceptable. I think bluewater photo markets this lens in US under their own brand.
If you plan to use the LX7 for video the situation is different, as the camera close up performance is extremely good and usually macro video is very hard. Most time we shoot with ambient light and if visibility is acceptable getting that close is not so important considering the LX7 ability to manipulate white balance.
The first suggestion is to get a Nauticam Wet Mate, this is a sealed air dome that gives us back the air field of view and works extremely well without any chromatic aberration and extremely sharp corners. This lens keeps the image rectilinear that is also a good thing for video.
For majority of reef dives the wet mate is all is needed as this also allows the full use of the zoom without soft corners that occur if you zoom into a wet wide-angle lens. This lens is the most versatile for general video use and costs $250, great value from Nauticam.
There are however specific situations where the wet mate is not sufficient, as before close up performance with the bare port is good but not great for smaller critter, so a close up lens would be the next addition, again an Inon UCL165 or a Dyron Double Diopter would work just fine and have the same power.
When shooting at closer distance with lights, or when there is large fish or wrecks a wet lens is important as the 84 degrees diagonal of the LX7 are actually only 76 horizontal. Again the Inon UWL-H100 is my choice but would check again for the Epoque DCL-30. One characteristic of the LX7 that is interesting is that the diagonal field of view of the camera remains constant when picture format changes, this means the horizontal field of view is larger at 16:9 movie mode than it is at 3:2 for pictures.
Field of view with the LX7
Those are the maximum angles of coverage horizontal of the LX7 as I measured them at 3:2:
Bare Port 24mm: 50°
Wet mate 24mm: 71.5°
Inon UWL-H100: 88°
At 16:9 there is a wider field of view of:
Bare Port 24mm: 54°
Wet mate 24mm: 76.2°
Inon UWL-H100: 93°
In general terms with the wet mate we can cover 1.56x the horizontal field of view of the flat port and with the wide-angle 2.1x.
The wide-angle offers an additional 35% over the wet mate don’t be mislead by the apparent small difference between 84° and 100° as those are diagonal measures not horizontal and those few degrees more count.
At 1 meter distance the maximum subject size with the wet mate in movie mode is 1.56 meters and with the wide-angle this becomes 2.1, that confirms that the wet-mate is good for general use and the wide-angle is only required for close scenes of larger fish or wrecks.
Those are the three lenses I have used for those tests. A final consideration is about the lens mount. I will use the LX7 for video so my choice has been a 67mm mount, because this is the only format that the wet-mate offers.
If I was using the LX7 only for pictures I would prefer the flexibility of the Inon LD mount even if this costs a bit more as it makes it so much easier to swap lenses in water when you have a bayonet mount.
Some people will recognize the Canon PowerShot A570IS, the Canon S95 and the Panasonic LX7. The first shot VGA video, the second 720p HD and the last AVCHD 50/60p. If you look carefully you can also see how the front aperture of the lens gets progressively bigger and bigger.
Year after year compact cameras are becoming more powerful having electronics that allow higher resolution and image quality, I think the GoPro is a demonstration of what you can do pushing the limits of simple optics using ultra integrated electronics.
Compact cameras like the A570IS used to have lenses that would be equivalent to a full film camera with a 35mm lens, this has been a popular choice for long time. Some years go Olympus and afterwards Canon, Sony and others started offering plastic housing for those cameras to take them underwater this was the start of consumer underwater photography.
There are however a number of challenges using a 35mm camera for underwater photos and the most obvious is the field of view, because of the magnifying effect of water those compact had really narrow coverage that limit them to close up of macro shots. However a little time after wet wide angle lenses come into the market and offered range of coverage up to 100º some manufacturers also produced seme-fisheye lenses with coverage of 165º the most well known being the Inon UFL165AD.
All went well and compact camera photographer could take wet lenses with them and in one dive take pictures of a nudibranch as well as of a wreck thanks to removable lens in water.
Then the consumer market pushed manufacturers to increase field of view so it was the start of 28mm equivalent cameras like the Canon S90, this format is still very popular with the Canon G series and the new Sony RX100, in addition to that there was more and more demand for extended zoom so that the camera could be useful in all situations, today is not uncommon to have compact cameras with 20x zoom.
The introduction of 28mm equivalent cameras meant that the cameras would vignette with a lens designed for 35mm so wet lenses had to be readjusted and re-designed. The extensive zoom by this you mean over 4x meant that the wet lens would be so far from the camera lens that effectively no wet lens would be useful, this has been the curse of the Canon G series a great camera that never had any good wet wide angle solution until very recently with introduction of zoom wide lenses from Inon.
The other bad news is that at 28mm the flat port of the housing introduces already pincushion distortion and fringing as we can see from this photo
We can see the effect of pincushion distortion in the deformation of the shape of the slate, it is quite apparent when you look at the lines and how skewed they are you can also see a purple tinge to it.
A wet wide angle lens not only expands field of view but also corrects pincushion distortion and chromatic aberration, this is the key reason why some form of wide angle is always required.
In the last two years manufacturers have come up with 24mm equivalent cameras, such as the Canon S100, Olympus XZ-1 and Panasonic LX5, unfortunately those camera have even more pincushion distortion, and for this reason should never be used in water at wide end to take pictures without post correction that can be quite hard to achieve so as a matter of fact many people live with ugly deformed pictures.
Those cameras make it even more difficult for wet lenses to work and to date there are very few lenses that work without vignetting, those lenses require a wide aperture on the side of the camera also to allow larger and larger image sensors that camera makers use like the LX7 in the feature image.
To give a demonstration of why is a bad idea to take your 24mm camera in water without any wide angle lens we just have to look at the picture above. Shocking!
So with 24mm cameras we are stuck, the wet lenses with dome that work well with the 28mm cameras end up vignetting so badly that all the advantage is lost when you zoom in. In effect with a 24mm camera all we can aim is 100-110° field of view that for stills is not really that much, there are exceptions like the Canon S100 but in general terms options are limited.
Camcorders on the other hand always had a range between 30mm and 150mm if not more with extensive zoom, you would have needed a dome port atteched to the housing that would allow zoom to give the same functionality in water or diopters to zoom at close range.
A user of a Sony camcorder in a gates housing would be looking at 30mm like a very wide lens!!! Typically you need fathom lenses to reach 90° and lenses with 110° coverage cost $4,000+ so definitely not affordable to the average shooter.
Where does this leave us? Well surprise good news for all 24mm compact users that want to shoot high quality video there are plenty of options that don’t break the bank!!!
When zoom cameras like the Canon G7 come into the market some manufacturers like Fantasea, H2O tools, Ikelite started producing wet domes.
Those domes are made of two lenses with an air space and if set really close to the housing port have the effect of restoring the original field of view of the camera. Now for a 28mm equivalent like the Canon G series this is not that exciting as we are talking about 75º diagonal but for the 24mm camera users we are talking of 84° diagonal coverage, a value that a professional camcorder user would be very happy with. In addition you can also use the zoom which means that if the camera has really close focusing distance a wet dome is all you may need for 85% of shooting circumstances.
So when I got the Panasonic LX7 this is what I was planning and I got a Nauticam Wet-Mate this is the slate from before at the same distance
As you can see the image is not only wider but also rectilinear no barrel distortion as if we were shooting on land.
Personally I do not like barrel distortion for video, and this is the reason I don’t like videos shot with fisheye lenses so this suits me fine. Of course 84° are not really wide for large wrecks, whale sharks or similar for those situations you still need a wet-wide angle lens but the Nauticam Wet-Mate costs $250 plus taxes so you really can’t complain.
At telephoto the flat port does not have pincushion distortion but it could be painful to remove the wet mate in the water the good news is that with the wet-mate you can still make use of the full zoom so if your camera has a really short focusing distance this may be good enough for most situations.
To finish off this is the Nauticam Wet-Mate, there are as I said similar products made by other brands. It is build of Aluminum with two lenses with a sealed airspace, construction seems very similar to some fix products.
So if you have a 24mm compact camera that takes HD video and you are frustrated with still there is a whole world in front of you with those dome adapters you could be well set for underwater video at very little investment.
Those are just some cameras that have high quality HD video the list is of course longer:
And the good news is that you do not need an aluminum housing just something that takes a wet dome, Ikelite for example has 67MM thread on most housings for those cameras.