As we know the Sony RX100 cameras, we will refer to both Mark I and II as the lens is the same, do not offer the best out of the box super close up performance.
To be clear no compact camera really does macro, as no compact can capture an area 36×24 mm in size without being on top of the subject and having a shadow cast on it.
The RX100 however are particularly unexciting as the capture area is pretty large at 76x51mm at the minimum focus distance of 5cm. This means a reproduction factor of less than 1:2 so things are half life size in traditional terms.
In water the minimum focus distance increases and so does magnification so performance is all in all the same.
This means that a typical small subject like a medium size nudibranch measuring 4cm will fill a bit more than half the frame, not great.
The problem can be addressed by close up lenses that have a set power that determines the focal length and working distance where we can use the full camera zoom.
So the close up lens sets the working distance whilst the camera zoom sets the magnification.
A typical close up lens will have a power of 5 or 6 diopters with a working distance in water of 200 or 165mm, what does it mean for the RX100?
I have done some testing in water using a ruler and an Inon UCL165 this is the result:
Our capture width is now 46mm so our 4cm nudibranch will nearly fill the frame. The working distance of this lens is 165mm so this is a very versatile solution as most critters have no problem being approached so close.
What happens with a +10 close up lens with a focal length of 100mm, this is another test
A +10 diopter like the Subsee or Inon UCL100 achieves exactly 35mm so life size macro. However a lens like this will not focus at longer focal distances without zooming out, furthermore there are plenty of subject that do not need this magnification.
Close up lenses can be stacked so this is the result of two + 6 diopters
The width is now 32mm which is 1.1:1 so more than macro. This is adequate even for pygmy seahorse and with the incredible resolution of the RX100 cropping is not a big issue. Working distance is around 8.5cm which is still tolerated by small critters.
For completeness I have also tested a +16 combination
At around 26mm this is 1.4:1 so real super macro, the working distance is however only 6.25cm which is really close and will scare most critters away.
Without any close up lens the RX100 can only capture 5cm objects without extensive cropping
A close up lens with a working distance of 165mm allows for most of the critters we consider small but without super macro effects unless cropped
Two stacked +6 diopters offer super macro and can also be cropped for more suggestive effect
A single +10 close up lens achieves real macro however it is not versatile enough for every day usage
Stacking lenses does introduce chromatic aberration but this can be eliminated in photos and is barely noticed in video
Pay attention when you select your close up lenses that the focal distance that is in the specification is measured in water otherwise you will find yourself with a useless purchase
I have just received this week the NA-RX100II housing also known with product code 17408
This housing is essentially identically to the already very successful NA-RX100 more specifically it looks identically to the NA-RX100V video version.
This looks apparent if we look at the left side of the housing where a screw can attach a bulkhead
According to Nauticam you can attach both the SmallHD 4.3 LCD monitor to use as external monitoring for video or an electrical sync cord to attach a strobe via a hot shoe 5 pin connector. This will not support TTL but will allow to fire an external strobe without triggering the internal flash. This means that there will not be any issue of recycle time especially true at wide angle or when using strobe with edge lighting.
Now I believe this is great news for those underwater photographer that are downgrading from DSLR as this was probably one of the key limitation of the RX100 that will now be overcome.
Remember that the RX100II seems to have other significant improvements with respect to the Mark I in terms of corner sharpness that can make this already excellent camera an absolute killer.
I wonder if it is possible to enable and disable the hot shoe and use both electrical and optical connectors as in macro TTL the camera performs very well indeed and this would only be available with optical connections.
If you are interested in the mini video review of this housing you can find it here
I will do some tank tests for corner sharpness in the next days so stay tuned
The housing is priced at £699 in UK as it was with the Mark I so should be $950 in US. Great value for the additional bulk head port!
Update the M16 port on the side will have an hot shoe accessory but won’t have an HDMI bulkhead, this because there is not enough space to connect the HDMI cable on the bottom of the RX100. The V version will have some more space under the camera to allow the cable to go in
I have been fortunate to receive one of the first RX100M2 that have reached the market so I thought of sharing with you my first impression and what I believe will be the potential for underwater imaging use.
This is the link to the unboxing video of the camera
I posted a summary of the RX100 capabilities for underwater video some time ago on this blog the post is here:
Probably the best thing is to revisit my review and update any significant differences between the RX100 Mark 2 and the original version which is still on the market and will remain at least until the end of 2013.
Bright Lens – Not changed
The RX100M2 has exactly the same lens of its predecessor RX100, it is true that when zoomed the minimum aperture drops down to f/4.9 however this is not a concern for underwater imaging as usually long focal lengths are for macro and we are interested in very small aperture to allow for greater depth of field.
Low Noise – Improvement!
In virtue of the new retro illuminated sensor the mark 2 has one full f-stop advantage over the original RX100. This means that ISO800 is a breeze and potentially we could go as low as ISO1600. I would not do that but what it means is a cleaner image at depth in ambient light.
Image Quality – Improvement
Image quality is outstanding and the lack of aggressive contract and sharpness filters in the default settings means more room for correction in post processing.
Video Mode Control – no change
The RX100 had complete control on video mode and the mark 2 maintains the standard. Very important is that the program mode is excellent and keeps the shutter speed at 1/100 or 1/125 when used in active mode which is ideal for 50/60p smooth footage.
Manual Focus – no change
Same as for the RX100
Battery Life – Improvement
According to Sony battery life has improved from an already outstanding CIPA 330 to a declared value of CIPA 350. The new Mark 2 has also an hot shoe so in theory if any manufactures produces a wired TTL enabled housing this means plenty of shooting before changing the battery pack. We suspect though that only ikelite will have this option on the housing.
Active Steadyshot – no change
I initially slagged the RX100 stabilization system based on performance on land. However at a more in depth analysis it turns out that the RX100 active steadyshot, even if at cost of an image crop is very effective for sudden camera movement and for high magnification macro. The Stabilizer is not as sticky as others so when you eventually vibrate it does not jump. Although the performance for stills is poor to irrelevant and so is the normal mode the active mode is very effective for underwater use. The mark 2 is built exactly with the same algorithm and combination of optical and electronic.
Tedious Workarounds Comparison
Some of the ergonomics of the RX100 are not the best and seriously deduct from an otherwise excellent experience, the most annoying issues:
Lack of focus lock – no change
For some reason Sony decided to skip on this essential feature, the workaround involves switching to manual focus however it is then possible to accidentally change focus if the front ring is set to control focus. The RX100M2 has the same issue.
Setting Custom White Balance in Video – No change
Setting custom white balance is only possible in the still modes, while in fact if you shoot RAW don’t actually need white balancing. This is the largest non sense of this camera that requires the user to navigate out into Program to ensure white balance is set correctly and you don’t end up with the Custom WB Error message. Though this is annoying is not such a killer as it would initially seem if you take your movies in one of this still modes which is valid for wide angle and ambient light shot. For macro you will need to switch to movie mode aperture priority in AWB. If you keep this discipline this is issue is mitigated. The RX100M2 does not change this and I believe this is due to the fact that the shutter button that is used to set custom white balance is disabled in video.
Lack of 24/25/30 progressive modes at 1080HD – Improvement!
The RX100M2 shoots at 50/60p as well as 25/24p in addition to that you can switch between PAL and NTSC which is great!!!
AVCHD – Improvement!
The RX100M2 has not only the progressive modes at double frame rate but also AVCHD 1.0 compliant format, this means that if you choose the 24M 24/25 p mode you can import with all editing programs without issue. Not only that but if you use the wireless import utility this converts also the AVCHD progressive files in mp4 for you. This is great improvement
Key Weaknesses comparison
The RX100 had also some key weaknesses let’s see how the mark 2 fares.
Macro Performance – no change
Exactly the same as its predecessor the RX100M2 has a minimum focus distance of 5cm on land that becomes around 7 in water. Like with the RX100 because of the large capture area you will need diopters for macro shots. On a positive note once you have a close up lens the performance is incredible when coupled with manual focus with peaking.
Sony has adopted a lens shift approach in this camera instead of the sensor shift of the higher end alpha, maybe due to large size of the sensor compared to the camera body. They have then added some software processing in camera but the results are just average. There are many other cameras that do better than the RX100.
Soft Corners at Wide End – Improvement
The RX100 first generation had soft corners until f/5.6 the situation changes dramatically as we can see in this test card comparison shot. Not sure if there was an issue with the RX100 original sensor but this looks excellent and as sharp as the panasonic LX7 or Canon G15.
Look for yourself!!!
No Neutral Density Filter – marginal deterioration
As its predecessor there is no neutral density also on the mark2. A little tip for video is to shoot with filters that take away 1 1/3 f-stop. This is not ideal but helps. There were some speculation that because the minimum ISO in RAW is now 100 instead of 80 sunballs would be more difficult to shoot. 1/3 of an f-stop does not really make any difference I believe this is more a statement so that the RX100 housing that are in stock sell out at full price.
I have to say that the tilting screen is fantastic to shoot on a tripod on lens. I doubt any housing can accommodate for this but the feature is outstanding
And this is the rear
So the question is should I buy the RX100M2 or the RX100 maybe grabbing a deal? Recsea has already announced a housing for the mark 2 and Nauticam is working on it. I believe that when it comes to still photography the difference between the two cameras are not substantial as many shots are with strobes I have however noticed a much faster internal flash cycle time. I do not want to be definite but looks like a full dump takes around seconds to recharge. Also to be considered that in US the price difference is $100 so definitely the Mark2 is the way forward. In UK/Europe the difference on the list price is £150/€180 which is much more.
So I would say if you are planning to use the camera for video go for the RX100M2 the improvements are significant both in terms of video formats but also in terms of sharpness at wide apertures. If your main interest is photography and you live in US go for the mark 2 in Europe instead I would grab a deal on the RX100 when the price of the housing drops.
I am waiting for a test housing from Nauticam as soon as I have it I will post an unboxing video followed by some pool tests.
I was in Indonesia during the second part of May and I had in mind to take some clips and stills of mating mandarin fish
Mandarin Fish are very skittish creatures. During the day if you can see them they are usually hanging right close to sea urchins to make your life difficult.
Their movements are jerky and fast and they are very hard to capture. Mandarin fish mate every day at sunset, and they can be seen in specific spots around the world. Indonesia is the country that has more of those spots that are public knowledge.
The spot where they mate is usually shallow, 3 to 5 meters depth, and made entirely of rubble of broken coral.
So when you go and see Mandarin Fish mating all you are going to see is Mandarin Fish as other than the fish that prey on their eggs and the odd nudibranchs or squid there is really nothing else.
The rubble is usually quite light color and unpleasant to film, mandarin fish go swimming around those broken coral bits and only emerge from it for their mating ritual that lasts 4 seconds in total until the disperse eggs and sperm into the water.
Mandarin fish hates our light especially video lights and anything more than 150 lumens means the fish will just not show up and choose another place to make. This is very bad news because it means that all mandarin fish footage has to be taken at high ISO or high gain, with a lot of noise in the picture, it is important to have a camera that performs well in low light conditions and will produce footage that is watchable.
Video requires continuous light and as said before mandarin fish hate light especially cold light as your typical 6500K video light.
In order to make our set up more mandarin fish friendly there are few options:
Buy two special red stealth lights such as Sola Photo light
Buy red filters for your normal video light those also serve the purpose of reducing power output
Use some sort of red diffuser for your lights
If you already have video lights and they don’t have the special red beam you are left with option 2 and 3.
A set of 2.2″ red filters will do the trick for the Sola lights
I had ordered two red filters for my Sola video lights and of course these did not arrive on time for the trip so I had to improvise as you can see in this pictures that features my red speedo shorts!
As you can see the mandarin fish really hang out on the rubble.
The red weak light does not disturb the mandarin fish when they come out to play and allows you to get quite close shots.
I took a video whilst in Bunaken using my Panasonic LX7. I used the flat port and zoom between 50 and 90 mm. I performed custom white balance on the rubble with the red lights on.
The result is in this video
I also shot few stills in another dive. If you want to take pictures of mandarin fish you have a similar challenge in terms of not scaring the fish but also you need to be able to know when to shoot.
Those are my suggested settings:
Shoot a normal lens around 90mm equivalent
Disable any form of pre-flash as that scares the fish and stops the mating act
Try to pre-focus as you will be in low light and don’t want blurred pictures
Try to follow a couple of fish from the start and count to 4
The eggs are released at 4 any other shot can be taken earlier
If possible (it was not possible for me) try to point the camera up to avoid the rubble
Set high shutter speed to have a dark background and get rid of the rubble
The featured image and this other one are my two best shots, there is minimal cropping
I took all my shots at the minimum aperture to have maximum depth of field but this I believe is an error and gives too much detail of the rubble behind.
I think the video that is shot at wide apertures is better and less distracting.
Another tip of environmental nature is that usually the rubble patch with the mandarin fish is small more than 2 cameras and there are just too many and the max is 4 dives plus the guide. I am glad I did my mandarin dives in Bunaken and not in Lembeh where you can get up to 10 people on the same spot whilst in Bunaken I was on my own twice.
I hope you found those tips useful and good luck with your next mandarin dive!
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.
Inon introduced a new close up lens in February of this year the UCL100. So why did Inon come up with this after the very successful UCL165 series? Probably some pressure from products like Subsee that produce better quality images than the Inon lenses and more and more lenses with similar performance to the existing Inon lenses. So what is different about the UCL100? First of all this lens is heavy 243/269 grams in the LD/M67 version in air that become 130/151 grams in water double than the UCL165. The lens is made of 3 elements instead of two and is very similar to a Subsee this is more evident taking a look at the lens on land.
This shot is taken with the bare port at 50mm.
This is the same shot at the same working distance using the UCL100 note the magnification.
The lens behaves like a magnifying glass exactly as the Subsee, Inon has made some effort to try to reduce vignetting, this picture is taken on land at 28mm.
Note a little dark bottom right corner, the lens in fact vignettes at 24mm this is due to the huge size of the LX7 lens and may not happen with other cameras.
Here we can see the rear of the lens from the Fix adapter side. The lens sits very close to the glass port.
I have opted for a bayonet version of this lens as I will use the fix as m67 adapter if I had to dive with the wet mate.
If you are a photographer I would definitely recommend the LD bayonet version over the M67 as it is easier to remove and attach in water.
There are some other very interesting characteristics of this lens. Usually a diopter works only around a certain working distance for a given zoom so the issue with such a powerful close up lens is that if we are far away from the working distance the lens is not usable.
The UCL100 instead is quite flexible and has a huge swing of working distances for a given focal length as in the table below.
All values are in mm.
So the lens keeps working well far away the nominal 100mm and due to the construction also gives a magnifying effect this means that it is possible to take this lens in water as the only close up lens and there will not be too much of a limitation if for some reason we can’t get that close to the subject. A swing of 40mm at telephoto end is excellent and this becomes 70mm at 70mm zoom and 110 at 50mm.
What about image quality most of you will know by now how specific I am when it comes to aberrations, this is a crop of an image taken with the UCL165
You can see the yellow and purple halo around the zero.
This is a detail of the same ruler in water with the UCL100
The image is a bit soft because of the aperture used but absolutely free of any fringing that is astounding for this level of magnification, the quality of the image is same as Subsee.
This lens comes with a lens front and back cover, the front lens is a clip with lanyard. The UCL100 can also be stacked with other M67 lenses if you need more!!!
With the LX7 the UCL100 achieves a reproduction ratio of 1.1:1 compared to the 1.4:1 of an Inon UCL165. The limitation of the zoom of the LX7 shows a bit here as even the Sony RX100 gets nearly a 1:1 with this lens but the strength of the focus of the LX7 are second to no other camera in this segment so I look forward to using this lens on some really small stuff.
The UCL100 is priced at $282 in US and £275 in UK versus $225/£210 of Subsee so why would you bother getting this lens from Inon instead? I think the main selling point of this lens in addition to the image quality and magnification power is the fact that the lens operates until wide end and has a very wide range of working distances so you are not stuck just around the 100mm nominal focal lenght. This allows use of the full zoom from wide to tele that in video is especially important. For pictures I am not so sure the additional cost is justified as stills are usually at full telephoto end.
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.