Hidden Colors by Gry Garness
Understand color theory and take your photos to the next level
If you want a good understanding of colour theory there is a great offer available at www.photowhoa.com which you can claim here – “colour offer“ – this comprehensive guide to colour will help you understand how colour works and how you can use it to improve your photography.
Color is a sensation that occurs in the brain in response to stimulation of the color receptors in the eyes.
But the experience of color varies from person to person and from image to image.
As photographers, having an in-depth knowledge of color is what separates the professionals from the amateurs.
Low light photography is something a lot of us find challenging. The idea of taking photographs when there is little light seems counter intuitive but the truth is that these conditions can actually create some of the most stunning photographs. When shooting in low light there are a couple of questions you should ask yourself,
- Do you have a tripod?
- Is the subject moving?
- Are you trying to capture movement?
- Do you want to use flash?
Let’s look at these individually
Do you Have a Tripod?
A tripod is essential for some low light photos as it allows you to keep the camera steady when using longer shutter speeds. If you don’t have a tripod then you could always increase the ISO sensitivity of your camera to get the faster shutter speed but even at very high ISO in very low light you can still end up with a shutter speed too slow for hand holding your camera.
Is the subject Moving?
If the subject is moving then you may struggle to freeze the motion at lower ISO settings as the shutter speed will be too long. You can increase the ISO to try and freeze the action but again you will be limited by how much light there is and the ISO setting of your camera. If the subject is a person you will need them to sit very still while taking the photograph using a tripod.
To capture this image the camera was set up on a tripod and an ISO of 800 was selected to give me a shutter speed of 1/5sec The couple had to remain very still so no movement showed in the final photo.
Are you trying to Capture Motion?
One of the great things with low light photography is being able to artistically show motion in the picture, when there is not much light the slower shutter speeds required to expose an image mean that it can be easy to show motion in your photograph. This can be great for blurring some aspects of the photo whilst keeping everything else sharp. It’s quite simple as long as you have your camera on a tripod when you take the photo anything that is moving when taken with a slow shutter speed will show as motion and anything that is static will remain sharp. This is how photographers create that silky looking water in landscape shots or the traffic trails or star trails with night photography.
The low light levels in this shot meant a tripod was essential but because the only moving element was the water, I was able to get the blurred effect using a lower ISO and longer shutter speed
Do You Have a Flash?
Using a flash in low light may seem like an obvious choice but flash can ruin the ambience of a shot and I would strongly recommend at least trying to capture the image using the natural light. Of course this is not always possible and flash can be used to great effect when it needs to be. To take a shot without flash try using the widest aperture your camera will allow and a high ISO.
Using on camera flash for this shot would have ruined the ambient lighting, so instead I used a very high ISO of 3200 and a wide aperture of f2.8 which just gave me a fast enough shutter speed of 1/50th of a second to handhold the camera and freeze the movement in the guitarist.
This lens is considered by a lot of canon users as their bread and butter lens, it provides them with a solid reliable works horse that can take incredible tack sharp images. It offers image stabilisation that provides you with 3 stops of correction for camera shake. The lenses auto focus snaps into action and is great for tracking fast moving sports or action. It has an eight blade circular aperture that offers a nice out of focus background for portrait shots. It is constructed with weather seals and highly dust and water resistant.
- Focal length: 70-200mm
- Maximum aperture: 1:2.8
- Lens construction: 23 elements in 18 groups
- Diagonal angle of view: 34 to 12 degrees
- Focus adjustment: Inner focusing system with USM
- Closest focusing distance: 4.3 feet
- Zoom system: Rotating type
- Filter size: 77mm
- Dimensions: 3.4 inches in diameter, 7.8 inches long
- Weight: 3.24 pounds
- Dust and water resistant
Another very popular choice amongst professional photographers, this lens offers a F2.8 aperture which is great for low light and has a very fast autofocus. It doesn’t offer image stabilisation which would be a very nice feature but the F2.8 does mean faster shutter speeds in low light. Combined with the Canon EF 70-200mm F/2.8 lens above you have a very serious bit of kit which is the choice for most wedding photographers. However if price comes into play you may want to consider the Canon EF 24-105mm reviewed below.
- Focal length: 24-70mm
- Maximum aperture: 1:2.8
- Lens construction: 16 elements in 13 groups
- Diagonal angle of view: 74 to 29 degrees
- Focus adjustment: Front-focusing method
- Closest focusing distance: 1.25 feet
- Zoom system: Rotating type
- Filter size: 77mm
- Dimensions: 3.3 inches in diameter, 4.9 inches long
- Weight: 2.1 pounds
This is my favourite all round lens it offers image stabilisation with 3 stops of correction for camera shake, a constant F4 aperture through the whole focal range and very fast auto focus. The focal length offers is a very useful range and is great for landscape, portraits and weddings amongst other uses. When stopped down the lens is still very sharp and although it is not as fast as the F2.8 zooms the image stabilisation still makes it very useable in low light.
- 24-105mm standard zoom lens with f/4 maximum aperture for Canon EOS SLR cameras
- 1 Super UD glass element and 3 aspherical lenses minimize chromatic aberration and distortion
- Ring-type USM system delivers silent but quick autofocus (AF); full-time manual focus
- Image Stabilizer technology steadies camera shake at up to 3 stops; weighs 23.6 ounces
- Dust- and moisture-resistant
- Dimensions: measures 3.3 inches in diameter and 4.2 inches long
- 1-year warranty
This lens has optics that are comparable to it’s big brother the Canon EF 70-200mm F/2.8 L IS USM reviewed above but with an F/4 constant aperture. It is a lot lighter than it’s big brother so if weight is an issue this may be a serious contender. It is also a lot cheaper and for those on a budget it is still a great lens and with the higher ISO capabilities of the modern DSLRs the loss of the extra stop may not be such an issue as it was in the past. The IS on the lens offers 3 stops of correction for camera shake which comes in very handy for those longer focal lengths and low light shots.
- Focal length: 70-200mm
- Maximum aperture: f/4
- Lens construction: 20 elements in 15 groups
- Diagonal angle of view: 34 to 12 degrees (with full-frame cameras)
- Focus adjustment: AF with full-time manual focus
- Closest focusing distance: 3.94 feet
- Zoom system: 7-group helical zoom (72-degree rotational angle)
- Filter size: 67mm
- Dimensions: 3 inches in diameter, 6.8 inches long
- Weight: 26.8 ounces
This lens is a must have for any canon shooter, it offers a maximum aperture of F/1.8 which is great for low light photography and for very shallow depth of field. At under £100 it is an absolute steel for a lens that offers razor sharp images even when shooting wide open. If you wanted to splash out a little bit more you could also consider the Canon – Lens – 50 mm – f/1.4 USM – Canon EF or if you really have money burning a hole in your pocket you could try the amazing Canon EF 50mm f/1.2L USM Lens.
- Canon EF lens F/1.8 50 mm
- Minimum Focus Range: 45 cm
- Automatic and Manual Focus Adjustment
- 52 mm Filter Size
- Light Weight (130g) and Compact (68×41 mm)
Most digital SLRs have four main modes which include, aperture priority (A or Av), shutter priority (S or Tv), program mode (P) and manual mode (M). There can be others as well but they tend to be automatic or scene selection modes where the camera makes all the decisions for you. For the purpose of this lesson I’ll just cover the four settings that leave some control to the user.
Program mode (P)
The cameras P mode is one step up from fully automatic it’s the one that everyone reaches for when they first start taking things a little more seriously. The camera still makes a lot of decisions for you but you do have some control over the final settings. In P mode you can still choose the ISO sensitivity of the sensor, the metering mode, the focusing points and the white balance. The aperture and shutter speed are all decided by the camera, however you have got the option to apply under or over-exposure using exposure compensation. You can also change the combinations of shutter and aperture settings that the camera chooses to create the same exposure, but the camera will always choose a combination to give what it thinks is the correct exposure based on the metering mode you have selected. This is where you can run into problems for one it can be time consuming constantly jogging through all the combinations and two the camera doesn’t always get it right.
Where I do find P mode useful is when I’m using a flash, flash photography can be particularly tricky to master and sometimes it’s easier just to leave the decision to the camera.
Shutter Priority (S or Tv)
Shutter priority is a partially manual mode, you select the shutter speed of the camera and the camera will automatically choose the aperture for you. The camera’s choice of aperture will depend on the metering mode the user selects to expose the scene. Basically the camera will select an aperture that it thinks will give a correct exposure based on the shutter speed selected by you. Shutter priority is great for situations where you want to have creative control over any motion in your photographs. To capture a fast moving object such as a motorbike or car you can select a fast shutter speed which will make sure you freeze the action without any motion blur, by doing this in shutter priority you only have to worry about the speed setting, the camera will take care of everything else. Alternatively by selecting a slow shutter speed you can choose to show some motion in a photograph such as the silky water you get in some landscape photographs. Slow shutter speeds are also used in night photography and for interesting lighting effects such as traffic trails and star trails.
Using a slow shutter speed allowed me to get the milky water effect in this landscape photograph
A fast shutter speed helps freeze action such as the horse jumping in this photo
Aperture Priority (P or Pv)
This is probably the mode that I use the most, it gives you control over the aperture of the camera which in turn gives you control over the depth of field. The depth of field is a great tool for photographers as it controls how much of an image is in focus and therefore has a huge impact on the final look of the photograph. The aperture is basically a diaphragm inside the cameras lens which opens and closes depending on the settings you select. The larger the aperture the smaller the depth of field (less in focus) and the smaller the aperture the larger the depth of field (more will be in focus). To confuse things a little bit a small aperture means a higher f number on the camera and a large aperture means a smaller f number. F-Number, also known as a focal ratio, is the ratio of the diameter of the lens aperture to the length of the lens. The more you open up the lens (smaller f number) the more light gets into the camera and so the faster the shutter speed you can use. If you close down the aperture (higher f number) you reduce the amount of light coming into the camera and so you will need a longer shutter speed to achieve the same exposure.
Enough technical stuff how does it work in practice? A good example of when to use a shallow depth of field (large aperture or small f number) would be in portrait photography when you want to isolate the subject from the background. By focusing on the your subject and choosing an aperture of say f4 or less you can keep the subject nicely in focus whilst throwing the background out of focus which will draw your attention to the subject.
For landscape work large depth of field can give you an image which is in focus from the from the foreground to the background creating a scene which is nice and sharp to look at. To successfully achieve this you could experiment using apertures of f 16 or greater and focus about 1/3 of the way into the scene you want to capture. For more information on this you can google hyperfocal distance, I won’t get into that here but it is worth looking up if you want to find out more about what is going on.
The reason I find aperture priority the most useful setting is because a lot of the time it is the depth of field that want to control in my photographs and with modern metering systems I find the camera more often than not gets the exposure right without me having to worry about the shutter speed. There are times when the camera doesn’t always get it right and this is when I would switch to manual mode.
Large apertures (low f number) help isolate your subjects from the background creating a shallow depth of field.
Scenes like this can be captured using a small aperture (high f number) to create a large depth of field keeping everything sharp from front to back.
Manual Mode (M)
This is the mode that most beginners stay well clear of but actually it’s not that scary. In this mode you have control over all the settings of the camera, the camera makes no decisions for you, so if you take a photo that’s under or overexposed it’s all your own fault!! So how do you know when the exposure it correct? That’s easy you use can either use the cameras built in meter or you can use a handheld light meter. Most of the time you will probably use the camera’s meter and to do this you just need to adjust the shutter speed and aperture setting until the meter shows the correct exposure. The exposure meter can be seen through the viewfinder of the camera and shows a scale from –2 to +2 with 0 in the middle, the 0 is where the camera thinks the correct exposure should be. All you need to do is set the aperture and shutter speed until this scale is set at zero, anything above or below will overexpose or underexpose the image according to the cameras calculations.
So when would you want to use manual mode? When you set the camera in manual mode nothing changes unless you change it, so once a combination of shutter and aperture have been set the camera will continue to use these settings for all the photographs until you decide to change them. This is great for scenes where the lighting is fixed such as studio setups etc. It’s also great when the lighting can fool the cameras meter such as strong backlighting or high contrast scenes where the dynamic range of the camera is being stretched too far. For these scenes you can choose what part of the photograph should be correctly exposed and set the camera accordingly.
The great thing about digital photography is the immediate results you get, you have nothing to lose with trying things out and experimentation is the key. So next time you’re out, turn off that auto mode and try playing with some of the modes above and you’ll be amazed at how much more creative you can be when you’re the one making the decisions!
Dodging and burning is a great technique which can be used when creating black and white images, what this does is allow you to selectively darken and lighten areas within a photo. There are lots of methods which can be used to dodge and burn including just using the photoshop dodge and burn tools. However the method that works best for me is to use a non-destructive method that involves creating a separate layer over the original layer. The advantage of this method is that if at any point you want to revert back to the original photograph all you have to do is turn off the layer effect.
Here are the steps I use
1. Create a new layer (layer>new>layer), change the mode to overlay and select the box to fill the layer with 50% grey.
2. Using the paintbrush select the white brush and paint on the new layer, the areas you want to lighten (dodge) and select the black brush and paint over the areas you want to darken (burn). To vary how much these areas are effected drop the opacity of the brush. A good starting point is about 10% you can then paint over the same area again to increase the effect. Another good thing about using a new layer to make adjustments is that you can tone down the adjustments by adjusting the overall opacity of the layer.
In digital imaging a pixel is the smallest amount of data in any one image. The number of colours that can be shown by any one pixel is determined by the bit depth of the pixel. Most digital images today are either 8bits/channel or 16bits/channel. The list below shows how many colours are in 1 through to 24 bits.
· 1 bpp, 21 = 2 colors (monochrome)
· 2 bpp, 22 = 4 colors
· 3 bpp, 23 = 8 colors
· 8 bpp, 28 = 256 colors
· 16 bpp, 216 = 65,536 colors
· 24 bpp, 224 ? 16.8 million colors
Image resolution in a camera is determined by the number of megapixels the camera has in its sensor. A megapixel is equivalent to 1,000,000 pixels and can be used to show the number of pixels in an image or a camera’s sensor. The more megapixels a camera has, the larger you can print the final image without losing quality. For example a 2MP camera and a 10MP camera can both take excellent photographs and when printed at 6×4 inch it would be hard to tell them apart. However when you start making larger prints say 12×8 inches the 10MP camera will far exceed the quality of print from the 2MP camera. The reason being is that the mega pixel count of a camera tells you the size of the photo in PPI (pixel per inch) from this you can work out the size you can print and still retain a good quality finish. see fig1.
Fig 1. Table showing Estimate of width and height 3:2 camera ratio
|Mega Pixel Count||Image Size on Screen PPI||Print Size (in) at 300dpi|
|2||1736 x 1160||5.78 x 3.86|
|4||2448 x 1632||8.16 x 5.44|
|6||3000 x 2000||10 x 6.67|
|8||3464 x 2312||11.54 x 7.7|
|10||3872 x 2584||12.9 x 8.61|
|12||4288 x 2848||14.29 x 9.49|
The industry standard recognised for good quality prints is 300 dpi (dots per inch) this means that the printer will print the final image with 300 individual dots of ink placed into every one inch line of paper. Using a number less than 300 dpi will result in the image being more pixelated, for example suppose you setup the printer to print at 1 dpi, you would have a printed photograph made up of a series of dots 1 inch in diameter.
Computer monitors have an optimum resolution that they should work at and this varies from monitor to monitor. If the screen has a high resolution set then you can view large image files without having to zoom out from the picture. For example a screen with a resolution of 600×800 will not be able to show an image of resolution 1200×1600 without scrolling or zooming out.
When viewing images on a monitor the accepted resolution is 72 dpi as most computer monitors work at this resolution. However as we have already established if you tried to print at 72 dpi the result would be less than satisfactory. In order to print something from the web first you would have to change the resolution to 300 dpi which would result in a much smaller image.
For example the following image is 8.3 x 12.5 inches at 72 dpi.
If I was to print this image at 72 dpi I would end up with something looking like this.
At 300 DPI the image is clear but a lot smaller
In order to get a good quality print I would need to set the DPI to 300 but this would mean the print size would be 2 x3 inches instead of 8.3 x12.5 inches.
Another reason for web images having a lower resolution is to do with file size, a 72 dpi image will take up a lot less memory than a 300 dpi image of the same dimensions.
The cameras speed setting on modern DSLRs is set using control dials on the camera something similar to those shown in fig 1. In order for the user to select the speed the camera must be set either to manual control or shutter priority. In manual the user has full control over both speed and aperture settings, where as in shutter priority the camera will automatically select the aperture based on it’s calculation of correct exposure.
The shutter speed has no influence over the depth of field of an image, it does however have direct relationship with aperture in controlling the exposure of an image. It can also be used creatively by the photographer to control movement in an image. The faster the shutter speed the easier it is to freeze motion where as slower shutter speeds can be used to show movement or blurring.
Shutter speeds are set in camera by either halving or doubling the shutter time which is called a stop, this controls the amount of light getting though to the sensor. Doubling the shutter speed doubles the amount of light getting through, were as halving the shutter speed will half the amount of light. If the aperture remains unchanged this will have the effect of over or underexposing the image. Modern cameras now allow you to set half stops or even third stop settings allowing even more control of the camera.
When using shutter priority the camera automatically sets the aperture, this is done depending on the settings of the exposure meter. Modern cameras tend to have a few different settings available including spot metering, centre weighted metering, average metering and matrix metering. Almost all digital cameras take a reflective reading of the scene to calculate the correct exposure. Although modern cameras are pretty accurate they do not always get it right and scenes with very bright or dark subjects can throw the meter, this is when manual mode will give the best results.
A typical shutter speed sequence found on a camera would be as follows 1/1000, 1/500, 1/250, 1/125, 1/60, 1/30, 1/15, 1/8, 1/4, 1/2, 1, 2, 4, 8, 15, and 30secs. Very fast shutter speeds such as 1/1000 of a second can be used to freeze motion of fast moving subjects such as cars, bikes, galloping horses etc. Where as slower shutter speeds of a couple of seconds can be used to show some motion such as moving water, or blowing branches in trees etc. Very slow shutter speeds can also be achieved by using the bulb setting on the camera and this can be used to capture star trails or lightning etc.
Another important decision when selecting shutter speed is to eliminate unintentional camera shake. This can happen when a slow shutter speed is selected and the camera is not supported on a tri-pod the result being a blurry image. To prevent this, the camera either needs to be mounted on a tripod or in some other way supported, or the user must select a high enough shutter speed in camera. The shutter speed required to successfully handhold a camera without camera shake depends on the focal length of lens- the longer the focal length the more magnification and the more chance of blurry images. As a general rule of thumb you can use the 1/focal length rule to calculate the minimum shutter speed to handhold for any given focal length. For example if you are shooting with a 50mm lens you can work on a 1/50 of sec shutter speed to eliminate blur or for a 200mm lens 1/200 sec should be fast enough. This is not a hard fast rule and should be used as a guide only; the actual speed will depend on the user and the conditions.
When parallel rays of light hit a lens, the distance from the centre of the lens to where the rays meet (focal point) is called the focal length.
On older lenses the focal length shown was quite literally the length of the lens, however modern lenses use multiple lens setups which means the actual size of the lens can be considerably shorter and more compact.
In photography lenses come under 3 main categories- you have the wide angle, the normal and the telephoto. The normal lens refers to the lens which gives the closest reproduction of a scene that would be witnessed by the human eye. On a 35mm camera this can be achieved with a 50mm lens or what is sometimes called a normal lens. Anything over 55mm would be considered telephoto where as anything less than 50mm would be considered wide-angle. On a digital cropped sensor camera you have to take into account the multiplication factor of the camera. This can vary but for most digital SLR’s a 28-35mm lens can be considered normal.
Wide Angle Lens
So a wide angle lens is great for taking pictures where you want to show a lot of a scene or need to photograph in close quarters. They work great for landscape, architecture and indoor photography. They do however suffer from distortion and this can be quite obvious especially when photographing close up. They tend not to work well for portrait shots because of this and you can end up with distorted features like the nose and ears. Wide angle lenses also give a good depth of field and even at low apertures you can get relatively sharp images from front to back.
This is a photographers most basic lens and usually has a very low f-number making it ideal for low light photography. Unlike the telephoto which can compress the scene and the wide angle which can distort an image the normal lens creates the most natural view.
This type of lens has a narrow field of view and long focal length, they work well for sports, nature and some types of landscape photography. It has the effect of compressing a scene which can be used very creatively. A lot of portrait photographer find that a 80-105mm telephoto creates the best portrait photographs because of its flattering perspective. Telephotos also have a narrow depth of field and are great for isolating their subject. They are however harder to focus in low light because of their narrow field of vision which takes in less available light.
Zoom vs Prime
Nowadays many of the lenses are zoom lenses offering a range of focal lengths all in one lens. Some of these offer focal lengths right the way from 18mm-200mm in one lens. Although this can be extremely versatile and is great for general purpose, the zoom lenses tend to suffer more from distortion and have less optical quality such as sharpness and contrast than the fast primes available. They also tend not to be as fast so they are not great for low light or very shallow depth of field.