underwater photography what i've learned so farpaul.naishfamily.net/underwater...

Underwater PhotographyWhat I've Learned So Far

Paul Naish, PADI Advanced DiverJanuary 8, 2013http://paul.naishfamily.net

I've been on about 25 dives over four years taking underwater pictures. I didn't take the PADI Underwater Photography course until 2011 and the personal course from Cathy Church in 2012. The Advanced designation is something my wife and I got so we can dive deeper and gain additional diving experiences. A standard underwater diver is allowed to dive to 18m/60ft while an advanced can go to 30m/100. Deeper is not necessary for good pictures. If you do take a scuba class at a resort I recommend you do so from a PADI or NAUI certified dive shop.

Journey to Another World!

My wife Brenda and I decided to get certified for our 25 Wedding Anniversary. Underwater diving is like visiting a foreign world. The benefit over snorkelling is to stay under the water and explore a wider range. Snorkelling to me now is like looking in the window as opposed to going into the store. This one of my favourite pictures on Brenda taken in Peter Island by Armando Jenik, a professional photographer who joined us on one our dives in the British Virgin Islands in 2008.

Being under the water provides many different perspectives than simply looking down. As you look up and about you see new images under outcrops and ledges.

Much of the marine life is also very small and you need to look for it. This little, I think Goby, was living in a shell on a brain coral. Its head was only about the width of two pin heads. This also means that if you are taking pictures of small things you need a good number of mega-pixels to capture the detail and a camera that allows zooming to review sharpness.

There also can be more diversity per square meter in the ocean and anywhere on land. In an active coral reef there are different types of life in every nook and cranny.

New Freedoms & Challenges Weightless Positioning for Shots

http://beforeyoubackpack.com/wp-content/uploads/2010/08/mountain.jpg

Y

X

http://www.divingchristmas.com/wp-content/uploads/2008/04/perpendicular-wall-dive.jpg

One of the additional freedoms, as well as challenges is the full 3 dimensions of movement. There is no gravity holding you in a position. On land if you see an interesting picture in the middle canyon, you have to be able to find a way to climb down. Underwater, you simply descend. If there is something in the middle of a large garden you can't get the picture without trampling the flowers to get to in. Underwater, you simply hover over the flower bed. However, such hovering requires a lot of practice in buoyancy control. Especially if you have to stay in the same position for an extended period of time.

Water's Affect on Colour

On land we are used to dealing with outdoor light that includes reflections off objects, different colours at sunrise and sunset and overcast lighting. Underwater, we have the same however because of the density and clarity of the water, we have other challenges.

Total Distance Light Must Travel

On land we normally don't pay attention to the path light follows unless the reflection causes a colour shift. Underwater, the distance light has travel, both naturally and with flashes, is cumulative on both the amount of light the camera receives as well as the change in colours you can expect.

Colour Loss By Distance Light Must Travel

Water is a substance which is 800 times denser than air. As soon as light enters the water, it interacts with the water molecules and suspended particles to cause loss of light, colour changes, diffusion, loss of contrast and other effects. A photo taken under water at one metre distance is not unlike a telephoto above water at 800 metres distance, both looking bluish while lacking contrast. The way light changes under water is responsible for the typical under water 'atmosphere' and it offers creative possibilities not found on land. This chapter shows how light changes as it enters the water. It also discusses techniques to reduce unwanted scatter in photographs and how to restore colour.

http://www.adorama.com/alc/article/13245 At eighty feet in depth, these schooling fish at left have lost their colour under ambient light in the shot at left. Right: Artificial light in underwater photography adds the wonderful colours back into the subject. Lens: 15mm fisheye

Bringing Back Colour

Custom White Balance

Filters(Best for landscapes)

Internal/External Flashes and Strobes

There are several ways to bring back the colour but keep in mind the proper technique is affected by the depth and path length of the light. If you will be taking pictures at the same depth and light using manual white balance and/or a colour chart can help. If you are taking a landscape picture, filters to compensate for loss of spectrum can be used. The best approach in my opinion is to light up the subject with an external flash or strobe. Remember, the colour information lost in the picture cannot be artificially replaced.

Red Filter

No Filter

Here is an example of a picture I took with no attempt to bring back the colour. Note the shift to left of the red channel and the loss of any information in the midtone or high end.

Red Filter

No Filter Red Filter

Compare this with a picture taken at a similar depth where I used a red filter on the camera. Both pictures taken about 20 feet down.

As Shot Photoshop Elements 10 – Auto Levels

No Filter

Caution is needed when the different channels are skewed. It may not be possible to realistically bring the colour back properly. See http://www.dive.snoack.de/tutorials/e_Basics_01.html The picture on the right is when I allowed PS to automatically bring back the levels. A much more pleasing picture but remember your eyes are also seeing the colour shift. If you are not using a flash light you yourself have no idea of what the scene look liked. The middle picture represents what the fish should look like. Much more grey than the blue hues imposed by auto levels.

As taken

One of my favourite pictures of Brenda on the Kittiwake doing her best Kate Winslett impersonation from the Titanic movie. This is in about 35 feet of water and noticed the shift of colour channels in the histogram. No colour correction was utilized here.

Auto Levels – Contrast + Colour

This is the same picture simply put through auto levels and colour. This helps bring out more distinctive colours however, again, what should they be? The ship is actually grey.

Strobe Positioning Paramount to 'Paint with Light'

This is one the pictures I took on my dive with Cathy Church (see http://cc.naishfamily.net) The picture on the right is unadjusted but you can notice the true grey colour of the sea floor as opposed to the bluesih tinge in the adjusted picture. Also notice the two shares of orange of the coral that is directly hit by the strobe and its other side. If the digital image does not have the information, it can't really fill it in. Underwater, you would have not seen the clear grey colour without a flash light.

Other example where Armando is taking a picture of me with our dive master showing Brenda a Sea Cucumber (not good practice to pick up sea life). Notice the colour changes in the sea floor depending on how much of the strobe hit it. Also notice my flesh tone colours in comparison to the dive master.

Except for landscape pictures, the rule for underwater pictures is to get in close. The positioning and number of strobes to use depends on the picture you want. I've only ever worked with one external strobe. This is a Christmas Tree Worm who retreats into the coral when startled. It's about 2 inches tall. This is other aspect, many times in underwater pictures you do not have a sense of scale by simply looking at the picture.

In relation to the previous picture at 80 feet, this is one I took around the same depth in Big Tunnels in the Grand Cayman Island. This, I think, is an immature Squirrel fish but imagine what the reds and oranges would have looked like without the use of a strobe and being in close.

Sometimes you get lucky with a co-operative subject like this Squirrel Fish taken on my dive with Cathy Church.

Backscatter ExamplesBrenda in Decompression Chamber - Kittiwake Wreck

Now that I've shown you the benefit of bringing the light to the subject, another problem that underwater photographers have to overcome is backscatter. This is caused by the reflection of particulate matter between the camera and subject. Think of taking a picture of someone in a snow storm. The picture on the left was taken of Brenda in the recompression chamber of the Kittiwake. Notice the specks cause by dirt and air bubbles. The picture on the right has camera and subject exchanging positions and the use of a strobe. Note how much cleaner it is.

There are two aspects of eliminating or reducing backscattter. Reduce the amount of particulate matter the strobe hits and reduce the profile of the light hitting the material to reduce its reflection. This is why you see external flashes on arms on most underwater cameras.

Camera TypesPoint&Shoot, Full Feature, DSLR

http://www.sealife-cameras.com

http://www.seaandsea.com/

http://usa.canon.com/cusa/consumer/standard_display/underwater_photo

http://www.ikelite.com/

Specialized Traditional

After Market for Traditional

With digital, underwater cameras have become more affordable and flexible. When you research cameras you will normally see them separated by P&S, full and DSLR. I've added another dimension between specialized and traditional. I do this because many specialized cameras can also be a good land secondary camera. The SeaLife camera shown here was used by one of dive companions on a recent trip and took great pictures on land and in the water. The specialized cameras many times will also have features needed for underwater. I'd recommend going to a dive shop if you want to buy a camera for underwater use.

Getting Started with Underwater Photography

� Doesn't have to be complicated or expensive

� Snorkel or Scuba?

− Casual snaps or planned picture taking

� Use primary camera or secondary?

� Research features you think you may want

− Live Preview; External flash capability; zoom review; separate RGB histograms; shutter delay; manual white balance .

� Educate yourself on histograms and white balances.

� Courses? Most are focused on Scuba UW Photography but can be relative to snorkelling

− http://www.uwphotographyguide.com/underwater-photography-guide

So, if you go south and snorkel, consider a secondary camera that you can use for underwater pictures to get started. An important aspect is to consider features you many want to grow into. Also, if you do have a secondary P&S, there are a lot of water housings but can be costly. There are also aspects of basic photography like understanding white balance and histograms that will help with underwater photography. If you are using a strobe, many times you do not need to look at individual channels.

Thank You

Scuba Diving on your bucket list? Try Scuba 2000's free Wednesday night introduction in their 86F poolhttp://scuba2000.com/index.php/training/learn-to-dive.html

underwater photography what i've learned so farpaul.naishfamily.net/underwater...

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