Review: Telesin 6" Dome Port for Gopro

This is a review of the Telesin 6" dome port for Gopro cameras. My use of the dome port in shallow relatively quiet water is probably very different  to your intended use so please keep this in mind when reading on.

Dome ports enable you to get those great split or under/over shots where you can see both under water and above water at the same time. They can add a whole new dimension to your photography and video.

I was excited when I saw these first dome ports come on the market for gopros, but I just couldn't justify the price of the KNEKT KSD 6 or SPL models for my limited use. I explored a few options of building my own as several have done on youtube  and elsewhere online but then put the idea on the backburner for a while.

Recently I discovered online that a much cheaper dome had been produced – the Telesin 6" Dome Port – and despite some mixed reviews on Amazon, I went ahead and ordered one through the Ebay seller dadahkstore. At AUD $115  and about a quarter the cost of the KNEKT dome and handle it seemed like a bargain, considering the acrylic domes alone, without any drilling, handles, backing etc retail for around AUD $60.

To date I've only used the dome on a couple of occasions mainly just to test it, and so far I'm very happy. The Telesin 6" dome port has several limitations compared to the much more expensive models, however for the price and non-professional user, and depending on the intended use, I think it is a great buy.

Here's what I received in the box:

• the dome port with attached backing plate and "gopro" waterproof housing
• a yellow plastic bobber handle with gopro connection and screw
• a microfibre cleaning cloth
• a blue lightweight wrist strap
• an allen key to remove the screws on the dome port if required
• cardboard box with fitted foam insert to protect the dome port*

*Do not throw the box and foam insert out. Like all acrylic, the dome can be very easily scratched, so unless you have a better option available, keep the dome stored in the foam inside the box and be meticulous about sand and dirt.

Different views. Note the curvature of the dome in profile, not quite a full half sphere and the black camera faceplate with red seal. Also note for this photo I have the handle on backwards.

Some details: one of the 12 screws holding the dome port to the backing plate, and  detail of the front lens of the gopro housing. Note the red seal behind the screw in the far left image. Middle image shows rear view of screw from backing plate. Right image shows inside the dome. Note how the camera power on/off button is covered and front camera display  is covered.

I was a little concerned about what actual model of dome port I would get as there are several different images available online. Some with blue, some with black inside the dome. Also some seem to be half spheres in profile, others seem to be less then half spherical in profile so it was a bit of a lottery. Even the Telesin website does not show the difference between versions or the latest model.

What appears to be an older model in many images online. Note the blue camera face plate, very different curvature of the dome (a full half sphere) and the phillips(star head) head screws. Even some of the sellers online have images of different domes so it's hard to be sure exactly what you are buying.

I was concerned about getting reflections off the screws and retaining plate or the Telesin namebrand but to date haven't had any problems. I am still very surprised why the whole inside of the backing plate is not a matt black to ensure no reflections as in the more expensive domes.

First impressions

Considering the price, I was impressed by the build quality – much better than what I could have done myself. Off course some things could be better, but for the price I'm happy.

The "gopro" waterproof housing looks like a new Hero 4 series gopro housing but I have my suspicions it's not. My Gopro Hero 3 fits comfortably inside, but I would thoroughly test the housing underwater without the camera before you use it. The housing is glued onto the dome backing plate so can't easily be replaced. There is a single latch with no safety catch to close the housing and a short string to help you open the latch.

The only attachment point to the bobber handle is the standard gopro like fitting. This is fine and sturdy for just a gopro, but when you stick a big heavy dome port on it, with an enormous amount of resistance and bouyancy in the water, you create a lot of leverage at this point and I have my doubts if it will be durable enough in the surf or rough water. To allow for the camera lens to be in the centre of the dome, the bobber handle is off the centre axis. For my intended use though it's fine.

PROS

• good build quality for the price, cheaper than DIY
• easy to use and assemble
• great results when used at the surface of the water
• white horizontal line on backing plate makes for easy leveling/half-way reference
• foam insert and box is good for storage and transit

CONS

• no access to camera power on/off button when in dome port
• cannot see front camera display when in dome port
• without red LED's turned on, you cannot tell if the camera is on or off
• although I've had no problems yet, I'm concerned that the mounting point is too weak to use in rough conditions and could perhaps break in the surf or if used at any depth.
• if the gopro housing is damaged or develops a leak it would be very difficult to replace
• poor information available on web regarding the actual model/versions available
  

Using the Telesin dome port

One very important point you need to be aware of with this dome is that there is no access to the power button on the camera. This means that you must power on your camera before you put it into the waterproof housing. You cannot view the front display on your camera whilst it is in the housing, so unless you have the red LED's set to flash, then you have no way of knowing if your camera is actually on. If you plan to use the dome for photography, then you must go into your camera settings menu and ensure that the camera is not set to turn off automatically after 60 seconds or so. When taking photos I have just set the camera to timelapse mode so that it takes a photo every second or so and hence it won't turn off. If you are doing video then you need to start recording before you put the camera in the case and leave it running for the whole time you are in the water. It also means that you can't switch between video and photos or any other settings unless you open the back of the housing and remove the camera first. This is a big difference to the KNEKT KSD 6 where you can access the power button and see the display on the front of the gopro whilst it is in the dome port.
 
As expected the dome is very buoyant. I only intend to use it for surface use but did test it briefly down to 2m and it held up ok without leaks, although I held onto the edges of the dome itself and not the handle at that depth as I didn't have great faith in the handle mounting point. For use on the surface in mild conditions the handle was fine, although I wouldn't want waves in the surf to be hitting it. I would like to see the dome with a much more rugged mounting to the handle, preferably to the backing plate and not just the gopro housing, but remember this is a cheap dome!

When raised quickly out of the water, water seems to bead off the dome ok, but for extended use you probably want to spit on it and rub it on the dome – I've heard Rainex is not good to use on acrylics. You need to clean the outside of the dome thoroughly before each session, salty water can quickly dry and leave marks, as can sweaty fingers, sunscreen slicks in the water etc.

A clear white horizontal line on the backing plate makes it easy to judge what is level and halfway in the water and is very useful.

Domes work best in clear water with a light substrate as in this situation there is not a big exposure difference between above and below the surface. Remember your camera will try and balance the overall exposure to an 18% neutral grey. If the water is much darker than the sky, the camera will think the image is underexposed and so expose the image for longer, resulting in blown out skies without detail. With a gopro you have no control over this apart from using external factors such as how much of the image is in the water and how much is out. It comes down to trial, error and experience.

All the photos and video stills below are straight from the camera with no adjustment apart from resizing for the web. The photos were taken by using the gopro in timelapse mode so a photo was taken every second or so.

It's very easy to overexpose the sky and loose detail on split shots. This was taken looking towards the sun. Try to avoid high contrast areas for the best shots.

Taken with the sun on my back, there is much less contrast in the image resulting in better exposure with all detail maintained. Of course the image could be vastly improved with a quick adjustment in photoshop, but all these images are straight from the camera apart from resizing.

Although the metal grid appears razor sharp above the water, it appears slightly out of focus underwater – a result of the virtual image created by the dome being slightly too close for the gopro's focal range. It is not an issue caused by this dome, it is an issue with all domes.

Another example: hand sharp above water but slightly soft below.

Although the water is very clear, it's also dark so the camera calculates to overexpose the image resulting in the blown out sky and loss of all detail. Too much contrast for the camera to handle.

Below are 2 video stills taken from 1080p video on the Gopro Hero 3 using the Telesin dome port in a shallow freshwater stream. There have been no adjustments made for exposure, contrast or colour, the images have only been resized for web use. Note that I deliberately tried to block sky views to allow for a more balanced exposure under the water. The gopro was set to medium view mode. Note that there are some water droplets on the dome port.

Dome Port Theory

There is quite a bit of physics at play when using dome ports for over/under shots due to the way light travels through different mediums (air and water) and the role of refraction in creating a virtual image some distance in front of the underwater part of the dome. That distance is determined by the radius  of the dome and the thickness of the acrylic.

From my limited understanding, the virtual image underwater is created approximately on a plane which lies 4 times the radius of the dome in front of the backing plate/camera lens position. For a 6" dome (ie with a radius of 3") that means that the virtual image is created approximately 12 inches in front of the camera. This is closer than the gopro is able to focus so the underwater part of the image never looks quite as sharp as the above water parts. DSLR photographers using expensive large domes are able to refocus their cameras and the position of their lenses to allow for this virtual image, however, being a fixed focus camera, on the gopro this is not possible. The smaller the radius of the dome, the closer the virtual image is created and this seems to explain why the curved lens housing on the early model gopros was never able to obtain sharp focus underwater.

Here are some links to interesting articles on dome port theory.

An old article from Stephen Frink but still very relevant and a good read.

Scroll half way down here for a good short summary 

and here for a very technical explanation of dome port theory  

I will post some video shot with the dome port here and on my Youtube channel at a later date.

Summary 

Provided you are a casual user and aware of some of the limitations and workarounds, the Telesin 6" gopro dome port is great value for the price. It will add a new dimension to your photography and video, and provided  you use it in nice clear water, will reward you with some great images. For what I intend to use it for, it suits me very well and I'm happy with my purchase.


 

Welcome to Knee-deep: shallow water video and photography with the gopro

There are numerous excellent blogs and websites on underwater video and photography, but very few explore the real shallows. A whole new world awaits underwater, and you don't need to go the the Great Barrier Reef or the Maldives to find it, you can find wonderful life and beautiful scenes in your local streams, lakes and rockpools and often without even getting wet! I first discovered this world when I bought one of the early model Gopro Hero action cameras, and have since developed a keen interest in underwater video and freshwater fish. Through this blog I hope to share some of my experiences in the shallows and some tips and tricks I have learned along the way when it comes to using small cameras in these environments. If you are a diver you may find some information here of value, however, be aware that at depth you encounter a range of new issues with light, colour, pressure etc that you will not find in the shallows.

What do I mean by shallow water? 

Shallow water can be any body of water you can fit your camera into; that may be just a few centimetres deep down to a few metres. Much of the video I do is done by wading no more than knee-deep into a stream and placing my camera, at other times it's just reaching down with my arm and putting the camera down. The point is you don't have to even get wet to explore and document the underwater world with your camera. Of course you can also throw on a mask and snorkel to help you film and position your camera, even in knee-deep water you'll be surprised by what lives there and the play of light and colour.

But why? 

There are myriad reasons as to why you might want to film in the shallows; perhaps you want to document your local creek or river system for a school project, may be you are a native fish enthusiast and you want to see what fish and other creatures live in your local catchment by using a BRUV (Baited Remote Underwater Video) at various sites, or you just want to get some nice creative footage of an underwater world that is readily accessible but rarely accessed. Whatever the reasons, it's a great way to spend time relaxing in the outdoors and learn a bit along the way. I think of it like fishing with a camera, except you never know what you've caught until you get home and download the footage.

What gear will I need to get started?

Underwater video is no longer solely the domain of those with thick wallets and expensive cameras. You can get started with a reasonable camera setup for around AUD$150 (eg SJ4000 action camera with a memory card) and create great quality video of your natural environment to share with friends. Although these small cameras will never compete with high end broadcast units, the quality of the video that can be gained with them is amazing and they have become an integral part of many TV productions. Small action cameras are light, durable, affordable and you can get them into places you just can't put bigger cameras; you can also take risks with them that you wouldn't take with more expensive units.

All you need to get started is a camera, memory card, a computer and some editing software.

Cameras

There are a range of small action cameras on the market most modelled on the market leading Gopros. The cameras that I use are listed below, and the comments relate to how I use them underwater, not to other uses:

• Gopro Hero HD: this was my first action cam and although now 5 years old is still one of my favourites. In good light it produces great footage and seems to be able to focus on closer objects than the newer models – a big plus in the type of video I do. At first it was fraught with focus problems underwater because of the curved lens on the case, but when I replaced the case with a flat lens housing from eye-of-mine it resolved the focus issues. Newer model Gopros came with a flat-lens waterproof housing so no longer experience underwater focus problems.

• Gopro Hero 3 Black: I purchased this when it first came out and after initial problems with the memory cards inability to handle the volume of camera data, it turned out to be a great camera. This was sold as a professional model with lots of options including a RAW shooting option. Although I have tried some of these, I generally just stick with 1080p at 30 frames per second. It performs much better in low light than the earlier gopros, but doesn't focus so closely. i often use it with a close-up lens fitted to the the front. This is my standard go to workhorse camera at the moment – if I'm only using one camera then it is this one. Looking back I could have just brought the Silver Hero 3 as I don't use the full range of options. There have been several upgrades of the gopro range since then (3+ and 4) however the prices have increased considerably.

• SJ4000: this is a Chinese copy of the gopro cameras.  I bought it to take a few more risks with as it is much cheaper than the gopros. I was surprised by the quality I got off this camera; again good lighting is a must. I shoot underwater in 1080p at 30fps and it does a good job for the price – it makes a great second or third camera for getting different angles as well. Apparently there are lots of copies of this copy camera on the market, so make sure you get an original SJ4000 if it's what you're after.

• Olympus Tough TG-4: this was a very recent purchase, more for the purpose of it's great macro capabilities and it's tough waterproof qualities. Unfortunately on my first use in water – in only 50 cm of water – it leaked and destroyed the camera! Olympus replaced it but I am yet to develop an overall idea of it's underwater capabilities. I'm unsure how the autofocus will handle the type of work I use it for, although it does have the ability to lock focus in some modes. I'll do a decent review of it at a later stage.

Memory Cards

Don't scrimp on memory cards; beware of cheap deals and fakes on ebay and get the best cards you can afford. The HD video that comes off these small cameras produces a lot of data and cards need to be able to write data very quickly. This is particularly important if you plan on shooting at higher frame rates (> 30fps) or at resolutions higher then 1080p. When the Gopro Hero 3 Black was first released the card  that Gopro themselves recommended (Sandisk Ultra) could not handle the data from higher  resolutions  which resulted in the camera shutting down and locking up. It caused me enormous frustration for several months, and gave the new camera a lemon profile until the problem was properly resolved with a new type of card and firmware updates. The Lexar 633x 32 GB MicroSD card has proved to be very reliable.

Computer

Most computers will be able to handle video editing to various degrees, however some of the gopros can now record in 2.7K and 4K, or lower resolutions at very high frame rates. If you plan to film and edit in resolutions or framerates higher than 1080p at 30fps, then you will need a powerful relatively new computer. I encountered this with my first gopro years ago, unable to watch the footage without first converting it to SD footage, I ended up shelving the gopro for a year or so! My computer now is a more recent  3yr old Macbook Pro but it won't smoothly play 2.7K footage off my gopro, so I continue to record in 1080p.

Editing Software

There is a wide range of editing software on the market, but if you are just starting out try one that is free and easy to use. You can download Gopro Studio here, and you don't have to own a gopro to use it; it will work with files from a variety of different cameras and there are a number of tutorials available online.

A must have program is MPEG Streamclip. In terms of editing it is very basic, and you will need to use another program for titles, sound etc, however it is a real workhorse and is invaluable for quickly trimming rubbish from your files and for exporting them to a wide variety of different formats. It's batch processing function is fantastic. Again there are some good tutorials for using it online.

I currently use Final Cut Pro 7; a professional program although now outdated. When the time comes to get a new computer I'll have to change, that may be Final Cut Pro X or Adobe Premiere.



That's really all you need to get started – the most important thing is that you get started and practice. Throughout the blog, hopefully I'll be able to show you some of the tips and techniques I have learned along the way that will help to improve the quality of your own footage and videos. There is a whole world awaiting in the shallows that remains poorly documented and you and your camera can make a valuable contribution.

Here's an example of a video I shot recently entirely in knee-deep water  in a freshwater stream on Lantau Island in Hong Kong.

 

and one shot entirely without getting wet at all in the Northern Territory of Australia

You can see some other examples of my videos on my Youtube channel