Rodney Campbell's Blog

Time to try something a little different.

I setup my tripod at my bedroom window and took some shots facing approximately east away from the setting sun during sunset, twilight and dusk. All of these shots are untouched from the out of camera RAW images (no white balance correction, no tone or colour correction) – just the standard Nikon RAW profile then resized and sharpened – so the colours you see are as the camera captured them.

This first shot is at 7:24PM – there was still quite a bit of ambient light around as the sun had not yet set so even at an aperture of f/32 the shutter speed was still faster than one second.

0.6 sec at f/32, ISO 200, 250mm equiv

The second shot is at 7:27PM – still ambient light around but the sun is falling below the horizon now.

0.8 sec at f/32, ISO 200, 200mm equiv

The third shot is 7:42PM – the sun has well and truly set and now we have to use much longer shutter speeds to gather enough light.

13 sec at f/32, ISO 200, 300mm equiv

The fourth shot is at 7:55PM – we are out to 30 second shutter speeds now at f/16. To the naked eye the sky was basically dark but the faint rays from twilight are providing those deep purpley blue hues in the sky. I’m having to manually focus now as there isn’t enough light to auto focus. I believe this is my favourite shot of the bunch.

30 sec at f/16, ISO 200, 225mm equiv

The last shot is at 8:15PM and it’s well and truly black outside. There is no colour in the sky now just the lights from the city buildings. I had to go fully manual now – manual focus and full manual exposure.

30 sec at f/14, ISO 200, 300mm equiv

I was fortunate to be able to borrow a colleagues Sigma 10-20mm F4-5.6 EX DC HSM Lens for an hour or two so that I could get a feel for what an Ultra-Wide lens would be like on my Nikon D90.

I went to Hyde Park (very close to my work in the city) during lunch and took a few shots.

This is inside the Anzac War Memorial looking up towards the ceiling at maximum wide (10mm).

1/160 sec at f/4, ISO 200, 15mm equiv

Outside the memorial I took a sequence of approximately 50% overlapped shots (10 of them) with the camera vertically oriented so that I could stitch them together into a 360 degree panorama. I’ve locked the Aperture at f/11. Ideally I would have used a tripod (which I didn’t have at the time) so I’ve done this handheld – the result however is pretty good considering.

f/11, ISO 360, 15mm equiv

Camera Shooting/Exposure Modes

Most digital camera’s have multiple Automatic Modes including:

• a full auto mode (where the camera sets everything based on algorithms which attempt to guess what you’re trying to do – you’ll almost always get a ‘correctly exposed’ photograph but it might not be what you creatively expected)
• multiple ‘scene’ modes (like Portrait, Landscape, Sports, Close-Up, Night Portrait and so on)

Some digital camera’s also have Four Advanced (Manual) Modes:

• P (Program Mode) – Camera automatically adjusts both Aperture and Shutter Speed for correct exposure but allows you to cycle through the different combinations of the two (usually also disables auto flash)
• A (Av) (Aperture Priority Mode) – You choose Aperture and camera selects Shutter Speed for correct exposure
• S (Tv) (Shutter Priority Mode) – You choose Shutter Speed and camera selects Aperture for correct exposure
• M (Manual Mode) – You set and control both Aperture and Shutter Speed

The greatest level of creative control is achieved by use of the advanced manual modes and whilst I wouldn’t advocate a novice user jump straight into Manual exposure mode I’d seriously recommend any users wishing to take their photography to the next level consider appropriate use of Aperture and Shutter priority modes. I personally leave my camera in Aperture priority mode by default (mainly because for the majority of the photos I take I like to be able to control the Depth of Field).

Lens Focal Length

There are basically two main types of Digital SLR camera’s:

• Full Frame (where the image sensor is physically the same size as 35mm film) – basically for the professional photographer
• and Crop Sensor (also called APS-C (Nikon calls it DX)) – in this case the sensor is physically smaller than 35mm film by a certain ‘crop factor’

The practical upshot of a smaller sensor is that there is an ‘effective’ multiplying of the lens focal length (Nikon/Sony/Pentax 1.5x, Canon 1.6x) for 35mm lenses attached to the camera. For example a standard 50mm lens attached to a Nikon 1.5x crop sensor camera acts like a 75mm (i.e. 1.5 times 50mm) lens attached to a full frame camera. The further upshot of this is it is “easier” to get more telephoto lengths on a APS-C DSLR but “harder” to get wider angles.

The list below indicates some typical categories of lens focal lengths and some of the typical characteristics of those lengths (the numbers in brackets indicate the focal length required when used on a 1.6x or 1.5x crop sensor camera – like my Nikon D90 which is a 1.5x crop sensor):

• Normal: 50mm (30-35mm) – this focal length is typical of what you’d see with standard human vision
• Wide-Angle: 24-35mm (15-24mm) – more depth of field, wider field of view, perspective distortion, better handholding (slower shutter speed); however softer corners, vignetting & distortion can be issues
• Telephoto: 70-300mm (45-200mm) – narrower field of view, shallower depth of field, compresses the apparent distance between objects
• Ultra-Wide: 12-24mm (8-16mm)
• Super-Telephoto: 300-600mm (200-400mm)
• Macro: for macro and close-up photography, closer focusing distance & more magnification
• Fisheye: special purpose lens, uncorrected for distortion, produces circular 180 degree images
• Image Stabilisation/Vibration Reduction: attempts to counteract the effects of motion or vibration when handholding the camera/lens to get sharper images, especially useful for lower shutter speeds (low light) and/or longer focal lengths, current technology can achieve up to 4 stops of effective stabilisation

Tip: most beginning photographers think of wide angle, telephoto and zoom lenses as a method for either bringing faraway things up close (telephoto) or fit as much stuff into the frame as possible (wide angle). What many miss is the effect these focal length choices have on the creative aspect of the image.

The following image sequence illustrates this effect. In this case I have my daughter (the “subject” of the photo) standing still and for this entire sequence of photos I’m attempting to keep the “subject” framed the same.

What I am doing is starting at the most wide angle setting on my 18-200mm ultrazoom lens (27mm effective focal length) and then physically moving away from my subject whilst zooming in to keep the same framing until I reach the most telephoto end of my zoom (300mm effective focal length). I’ve taken five shots spread out over this range.

I’ve also kept the Aperture constant (f/13) (which would normally give you a fairly large depth of field) across these shots so any depth of field effects are simply due to the change in focal length and not aperture.

This first image is at a medium wide angle (27mm) – and I’m standing as close as I can (about half a metre) and still autofocus (this isn’t a macro lens). This lens doesn’t go wide enough to dramatically show the effect (I wish I had a 11-16mm ultrawide lens! and got up really!! close). You can however see some of the effects of wide angle perspective distortion – the closer things are to the lens the more spread out and distorted they will be. This is usually not a flattering focal length for portraiture since it often stretches and distorts the face and often makes the nose much more pronounced and wider – sometimes however this look when taken to the extreme can be used to creative effect – if that is the desired result. You can also see lots of the (distracting) background (the wider angle takes more of it in and keeps it in focus) and the branch behind her head looks reasonably far away and the row of trees in the background spread way away in the distance.

1/60 sec at f/13, ISO 360, 27mm equiv

The second images is at the “normal” focal length of 50mm. That branch behind her head looks much closer now but the row of trees still stretch away in the distance. There is still lots of distracting background even if it is slightly out of focus.

1/60 sec at f/13, ISO 280, 50mm equiv

The third shot is at a “typical” portrait focal length of 105mm. The objects from front to back in the photo are now starting to look a bit more compressed – the branch behind her head is very close and the row of trees behind look a lot closer. Also even though we are shooting at an aperture of f/13 (which would normally give a very large depth of field and back to front sharpness) we can see the effects of this focal length starting to blur out the background making my subject start to pop off the page.

1/60 sec at f/13, ISO 250, 105mm equiv

The fourth image is at a focal length of 200mm. Personally I prefer focal lengths a little longer like this for a much more pleasing look to the portrait (subject). That distracting background is starting to vanish both from the restricted field of view and the soft blurring.

1/60 sec at f/13, ISO 250, 200mm equiv

This last shot is at the most telephoto (300mm) and I’m now standing many metres away. Hardly any of the original background is in the frame now as we have a much narrower field of view. You can clearly see the effects of compression with the branch nearly over her head now (but still out of focus) and the row of trees which were way in the distance now looking pretty close and also nicely out of focus making my subject pop right off the page.

1/60 sec at f/13, ISO 400, 300mm equiv

If you can see what I’ve done here then you can also see that sometimes the vision you have for the image can be best achieved by getting really close to your subject with a wide angle (especially an ultra wide lens) or getting further away from your subject and zooming in more with the telephoto.

Since I upgraded to a D-SLR I have been enthusiastically getting back into what I might call “real” photography rather than just ‘snapshot’ taking with my previous compacts. This has meant taking more care about the craft of photography, visualising the image I want to create and having an idea of my intended end result before taking the shot.

If I was to characterise the types of shots I’ve taken most since rekindling my passion for photography again I’d have to say it has been candid portraits (of children). A couple of fellow parents had asked for some tips on taking better photos (I presume because they liked the shots I’d been taking of our children) and so I offered to run a few impromptu lessons at school.

Since I’ve been putting together a few notes and a rough outline of the sorts of things I was going to discuss I figured I’d share it here as well 🙂 – also by no stretch of the imagination would someone call me a pro photographer – I’m just someone who enjoys photography so I guess you might call me a happy amateur 🙂

This isn’t going to be an in depth tutorial on photography (it’s really just my cliff notes) and nor do I want it to be a detailed technical discussion on every camera setting or how to use the camera and it’s features. What I wanted to do is cover a few fundamental basics and essentially outline a few good “recipes” for taking certain types of shots and cover some basic creative techniques and common pitfalls.

Photographic Basics

Unfortunately even though I said above that I didn’t want to cover too many technical details there are a few fundamental basics with photography which do make it easier to understand some of what will follow…

A photograph is created by focusing light through a lens onto a light sensitive medium (film or digital sensor). Exposure essentially represents the amount of light which is allowed onto the photographic medium – and determines the pictures overall brightness and contrast.

Between the lens and the sensor are two barriers – the aperture and the shutter which together control how much light gets onto the sensor.

The Exposure (exposure value – or EV) is driven by three factors:

• Aperture – an adjustable diaphragm which controls the size of the diameter of the lens opening – specified as a f-stop or f-number (perhaps counter-intuitively the lower the f-number the larger the opening and the more light (fast/wide/larger vs slow/closed/smaller))
  f/1.4, f/2.0, f/2.8, f/4, f/5.6, f/8, f/11, f/16, f/22, f/32, …
• Shutter Speed – length of time the shutter is open allowing light to fall on the sensor (the faster the shutter speed the less light)
  1s, 1/2s, 1/4s, 1/8s, 1/15s, 1/30s, 1/60s, 1/125s, 1/250s, 1/500s, 1/1000s, 1/2000s, 1/4000s, …
• ISO – light sensitivity – with film this was the physical properties of the film – on digital cameras this is a digital function – like a ‘volume’ control on the sensor (the higher the ISO number the more sensitive the sensor and the higher the light reading)
  50, 100, 200, 400, 800, 1600, 3200, 6400, …

A movement of one whole ‘stop’ for any of these parameters along these ranges essentially halves or doubles the amount of light hitting the sensor. If you adjust one of these values by one move (stop) in one direction you also need to adjust one (or both) of the others for a total of one stop in the opposite way to compensate and result in the same exposure (same effective amount of light on the sensor).

Aperture affects Depth of Field (lower f-stop leads to a smaller depth of field)

Shutter Speed affects Motion Blur (slower shutter speed leads to moving objects appearing blurry, very fast shutter speeds freeze motion)

ISO affects Image Noise (higher ISO leads to more more noise especially in darker areas)

Another handheld attempt through my window. The sun had well and truly risen by this stage this morning but the clouds in the sky looked pretty interesting so I shot above the sun and this time I’ve bracketed three shots and tonemapped them into an HDR.

1/250 sec at f/25, ISO 200, 46mm equiv