SLR Cameras and Housings

The decision to commit to a digital SLR camera and housing is a daunting one. Financial costs can be considerable and one's aspirations as an up and coming photographer may fail or succeed depending on whether you acquire the right equipment or not. SLR cameras have numerous menus and features, but which ones are useful underwater I'll take you through these features and discuss how they can help or hinder your photography. We also need to keep the camera dry Steve Warren from Ocean Optics in...

Be Aware of Distortion

When using wide angles, the relative size of subjects near and far is distorted. Nearer subjects appear to be larger and closer than they really are, and more distant subjects appear to be smaller and much further away. Wide angle lenses do, in effect, increase the appearance and scale of FIG. 9.3 Distortion is a challenge to avoid and is most prominent towards the corners of the frame. Wreck structures are problematic but when shooting the reef I find more often than not that I get away with...

Prime or Zoom Lenses

There are two types of lenses prime and zoom. A prime lens has a fixed focal length like a 10.5 mm fisheye or a 50 mm macro. A zoom lens has a range of focal lengths, i.e a 12 mm 24 mm or 17 mm 35 mm. In the past a prime lens was always optically superior to a zoom but this is no longer the case. The advanced improvement in lens design has elevated zoom lenses into the same class and it's difficult to tell the difference in optical qualtity when two similar lenses, zoom and prime, are compared...

Diffraction

SLR macro lenses display a minimum aperture setting of f32, which is twice as much depth of field as with f22. So why not use it for macro Many photographers do, but some prefer not to. The reason for this is a physical problem called diffraction. When light passes through the aperture of a lens, light waves are affected by the edges of the diaphragm blades. If you use a small f-stop, like f32, the more distinct the effect becomes, and as the light spreads out it begins to soften the image. The...

Aperture Priority

The photographer chooses the f number and the camera automatically works out the appropriate shutter speed. As the name 'aperture'suggests the emphasis is on the selection of the aperture by the photographer. The majority of underwater photographers favour Aperture priority as they can directly regulate depth of field. A general rule of 'thumb' is to consider the priority of the subject you have chosen. I will take this concept one stage further. Ask yourself this question 'What is my priority...

Crop Sensor vs Full Frame Sensor Which is Right For

After you have determined the implications between a crop and full frame your next move is to determine which suits your needs. For the enthusiastic underwater photographer a smaller 1.5x or 1.6x DX sensor will be ideal. If like me you have kept many lenses from the film era, it might be worth looking into a full frame body. Modern Nikon bodies are compatible with many Nikon lenses. Canon bodies all work with Canon EF lenses. Underwater photographers who aspire to a professional client base,...

New Ideas about InCamera Histogram

When I moved to a digital SLR in 2003 I thought it was very easy to determine the exposure accuracy of my 'in-camera' photographs and judge whether they were correctly exposed or not. I simply evaluated the histogram and highlights feature and made the necessary adjustments. Even in my books, articles and workshops I encouraged other underwater photographers to do the same as me. But in recent years I have come to realise that the histogram highlights exposure indications are not what I thought...

Viewing Angles

Water is much denser than air and light diffuses quickly resulting in soft hazy images over distance. To overcome this you need to reduce the column of water between subject and camera by moving in as close as possible. For example when photographing a Manta Ray overhead you may be close enough to get a sharp image but will only manage to frame a portion of its underbelly. You will need to move further away from the Manta to include its whole body, but then you are shooting through more water...

Golden Rules Law of Thirds

Law Thirds Photography

A basic guideline of composition, and one that is used to create a visually balanced picture, is known as the law of thirds. I place significant importance on this technique. It proposes dividing up the viewfinder into an imaginary grid, using two horizontal and two vertical lines and the focal point is then placed on or near any one of the four intersection points created by the lines. It gives a feeling of tension, energy, balance and harmony, preventing the focal point from occupying the...

Understanding Exposure Compensation

Exposure compensation is a feature of an SLR camera which allows you to adjust the exposure measured by its light meter. Usually this range of adjustment goes from between plus 2 to minus 2 EV in one-third EV 1 3rd increments. This means that you can adjust the exposure measured by the light meter within the camera by forcing it to allow more light in plus exposure compensation or to allow less light in minus exposure compensation . Depending on how your SLR deals with exposure compensation, it...

Viewfinder Dioptre Adjustment Control

Most SLR cameras are equipped with a viewfinder dioptre adjustment control to accommodate individual differences in vision. It's a feature that is often missed I knew of one photographer who was so frustrated with everything appearing blurry and out of focus within the viewfinder they had corrective lenses inserted into their dive mask just to be able to clearly read the shooting information display. When you begin to adjust the dioptre control with a lens fitted to the camera, it's very easy...

The Future

DSLR technology has reached a point where one can legitimately question whether one really needs to keep upgrading. This means that a system bought now might be used for many years. The current popularity of underwater digital photography has led to many new companies setting up to manufacture and sell underwater camera equipment. A concern for the underwater photographer looking to invest in an SLR system must be the Ask around, do your homework, search wetpixel for housing discussions and...

Live View

Several popular SLRs are now equipped with a live view facility. In simply terms, live view on a digital SLR allows you to preview the photo you're about to take using the large LCD on the back of the camera. It's fair to say, however, that this new technology is yet to take off with SLR users both on land and underwater. The main limitation is that the reflex mirror inside the camera needs to be raised in order to expose the image sensor. This effectively disables the auto focus system. As a...

Understanding ISO

At times it can be impossible to achieve the desired aperture or shutter speed to take a photograph. This usually occurs in low light situations where you need to use a large aperture, but, because it's getting dark, you have no other choice than to use a slow shutter speed. This shutter speed required may well be too long to hand hold the camera without causing camera shake and fuzzy pictures. In these situations this is where the sensitivity of your camera sensor comes into play by...

Snells Window

Snell Window Image Surface

'Snell's window' was named after the Dutch mathematician, Willebrod Van Roigen Snell, who lived between 1580 and 1662. A professor of mathematics at Leiden University, he discovered the law of refraction known today as Snell's law. In underwater photography, Snell's window is portrayed as an arc or half-circle through which the sky is visible. The area around the circle is a reflection fig. 6.29 I took this image below the diveboat at about 20 m. The visibility was sandy and I knew that a...

Choosing a Wide Angle Wet Lens

Wide angle lenses to choose from include Inon UWL105 AD lens, UN PWC-01 and Epoque DCL-20, which all provide a coverage of about 100 degrees underwater, equivalent to a 20 mm lens on a 35 mm SLR. Shoot using the camera's widest zoom setting to yield the sharpest possible image. The fisheye lens is perhaps the most versatile of all wide angle lenses and for compacts can cover 165 degrees underwater. This super wide angle lends itself to Forced perspective images with point of interest in the...

Loss of Light and Loss of Colour

Loss Colour Underwater

Topics concerning the difficulty of light and colour loss underwater have become so hackneyed in recent years that it is a challenge to grab the attention of an audience. Let's face it, most of you have seen and heard it many times before, both in pictures and words Light and colour are absorbed at depth, blar, blar, etc, etc. However, my experience in reality is that although these basics are common place, sometimes they don't really 'sink in'. That is, until one is comparing one's underwater...

How Aperture and Shutter Speed Work Together

In photography, the term Exposure Value EV is commonly referred to as a move, either up or down, of one 'stop'. The difference between each aperture setting is one stop or one EV, i.e. f8 and f11 is a difference of one 'stop' or one EV. The difference in shutter speed between 1 125th sec and 1 250th sec is one stop one EV. You will see that both f numbers and shutter speeds are sequenced in a series of 2 1 ratios, and this is where the two work in harmony with each other. A setting of f8, at 1...

Developing a Workflow System by Stuart Gibson

What do you do with your photographs once they're on your computer How do you organise them Instead of paying 'lip-service' to a number of imaging options, in order to be seen as fair and impartial I've decided to take the liberty of recommending just one particular program to you. It's called Adobe Photoshop Lightroom 2. It's designed specifically for photographers and in my opinion it's nothing short of outstanding. During a Maldives workshop I noticed that Stuart had a very easy and...

Exceptions to Crop Factor Full Frame Sensors

Full Frame Crop Factor

The exception to this rule is a series of full frame cameras made by both Nikon and Canon whose sensor is the same size as a 35 mm negative from a film camera . Black - Full Frame l Red - 1.3x Crop Factor Yellow - 1.5x Crop Factor Green - 1.6x Crop Factor Black - Full Frame l Red - 1.3x Crop Factor Yellow - 1.5x Crop Factor Green - 1.6x Crop Factor Canon's range of full frame sensor digital cameras to date are Nikon's range of full frame sensor cameras to date are Further discussion concerning...

RAW and JPEG

Both RAW and JPEG files appear similar when downloaded from the camera. JPEG files have received some processing at the moment of image capture and they usually look better than RAW files, which can often appear quite dull and flat. Newcomers to digital photography are often quite disturbed the first time they see their RAW files looking so lacklustre, but one must remember that this is the effect of retaining all the data in an unprocessed format. It is a fact that the majority of professional...

RAW v JPEG

There has always been debate about the merits of shooting either RAW or JPEG, not just for underwater but over the entire photographic spectrum. A large majority of digital enthusiasts see the RAW format as the professionals approach to photography and this is regularly born out by current trends in digital photography magazines and Internet forums. If I was looking to advise someone on the pros and cons of shooting either RAW or JPEG underwater I would be looking to ask that person questions...

White Balance Settings

Auto Also known as AWB is perhaps the most popular setting as it uses thousands of algorithms programmed into your camera to best work out the white balance for your particular photograph wherever you may be. Auto setting as been developed over the years. Since the third edition of this book was published, and for underwater use, I use 'Auto WB' 70 of the time for the other 30 I use Preset White Balance. Daylight Has a symbol of the sun and is close to the colour temperature of traditional film...

Understanding White Balance and Colour Temperature

We have all taken photographs where the colours of the scene are totally false. You download it onto the computer and it has a garish colour cast. The reasons behind this will be connected to the white balance function on your digital camera. All light has a specific colour associated to it, which is measured in degrees Kelvin K . Take for example sunlight. Throughout the day the colour temperature of sunlight differs because of its position in the sky and the surrounding atmospheric...

Digital Compact Cameras by Mark Koekemoer

Compact cameras have fast become a standard accessory amongst divers. Whether it's your first compact, upgrading from an existing model or down-sizing from an SLR, Mark will help you make a more informed decision. This chapter also includes a 'compact photo gallery' a 12 month 2008 2009 photo project by my wife Sylvia, using a straightforward, no add on's point and shoot compact camera. 'I don't know how well I should be doing ' Is a frequent question from newcomers, and this is the idea behind...