Panasonic LX7 reference compact for underwater video

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
Panasonic LX7
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.

Pedersen Shrimp with two stacked UCL165AD and intelligent zoom 7.5x The frame height is less than 1cm
Pedersen Shrimp with two stacked UCL165AD and intelligent zoom 7.5x
The frame height is less than 1cm

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.

White Balance on Bianca C 36 meters depth
White Balance on Bianca C 36 meters depth

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.

Lens Marking reflection on Wet mate dome
Lens Marking reflection on Wet mate dome

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.

Inon UWL-H100 Flare on top of the frame
Inon UWL-H100 Flare on top of 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

Wet lenses choices for Panasonic LX7

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.

There is a common misconception that as the camera has a wider lens you don’t need to buy a wet lens for underwater activities. This is also reported in otherwise good articles like this one:

So why is it a bad idea to shoot just with the bare camera and no add-on lenses?

Two key reasons:

  1. Once in water the 84 degrees diagonal of a 24mm equivalent camera reduce to 54 or less because of the water medium
  2. At focal lengths shorter than 35mm pincushion distortion becomes stronger to the point the pictures are awful.
Pincushion Distortion at 24mm with flat port
Pincushion Distortion at 24mm with flat port

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.

Flat Port 35mm
Flat Port 35mm

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.

Flat Port Close Up
Flat Port Close Up

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.

Underwater Photographers

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.

Inon UCL165
Inon UCL165

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.

UWL-H100 28mm
UWL-H100 28mm

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.

Underwater Videographer

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.

LX7 with Nauticam Wet-Mate
LX7 with Nauticam Wet-Mate (do not compare with the Inon Picture this is taken from further away)

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.