Noisy Images

Digital noise or the grainy texture you sometimes get on your image has long been the woes of many budding photographers. It results in less than pleasing pictures of speckled images rather than the silky smooth ones that you would most of the time, like to see. Little do some photographers of the digital era know, that at once in analog photography, the equivalent phenomenon, called film grain had such a following that it warranted its own field of interpretation.

 

june2005_image02 june2005_image03

Here is a picture of an old man on the street. Not only does converting the picture to black and white gives a “raw” feel to the scene, the effects of film grain helps to emphasis the old man’s desolation.

WHAT IS FILM GRAIN?

In analog or film photography, film grain is a speckled texture you see on the surface of your picture. This is created by clumps of silver halide which are the light sensitive components on your film. Faster films, which are identified by their higher ISO range (ie ISO 400, ISO 800, ISO 1600) are more sensitive to light and form larger silver clumps resulting in a grainier image.

WHAT IS DIGITAL NOISE?

june2005_image04 In digital photography, Digital Noise is the digital equivalent to Film Grain but how they are created is different. The image sensor in a digital camera (CCD or CMOS) converts light into digital information which is stored in the camera’s memory card. Photoelectrons are produced when light hits each individual photosite or pixel on the image sensor. Free electrons are sometimes produced from the heat of the photosites and contaminate the neighboring sensor thus creating digital noise. In the situation of low-lighting, these photosites are affected by electrical signals during the long exposure timing.

Although the effect of digital noise from digital cameras is similar when viewed on a small print, photography purists never regard these two as the same. In fact, digital noise is shunned by many photographers who see this as a poor result of image processing by their digital camera.

 

june2005_image01(d) june2005_image01(a) june2005_image01(b) june2005_image01(c)

Here are a set of pictures with high level of grain effects. The effect of grain adds to the mood to the pictures.

WHY DOES MY CONSUMER DIGITAL CAMERA SUFFER MORE FROM DIGITAL NOISE THAN A DIGITAL SLR CAMERA?

Consumer digital cameras have a smaller image sensor to convert light into digital information. This means that the photosites on the sensor are closer to each other increasing the occurrence of free electrons. A DSLR has a bigger image sensor with more space in between photosites. This lends to a cleaner and smoother looking image.

june2005_image05 This is also another element to consider when you are looking at the latest 8MP digital camera that fits in your front pocket. It does not necessarily mean better quality images but perhaps just higher resolution ones. It may do just as well to get a high quality 3.2MP digital camera with a better output, if you are just going to end up mostly printing 4R prints and the occasional 8R. But, image sensors on digital cameras are improving greatly and I could be proven wrong with many of the new digicam in the market nowadays. Do consider all elements when getting your next digital camera.

WHAT IS THE EFFECT OF FILM GRAIN ON AN IMAGE?

Black and White films in analog photography are the fastest ranging up to ISO1600 and ISO3200. At this level, grain is extremely high. One of the effects it has on the picture is creating a picture that has a lot of mood and atmosphere. This sometimes helps to improve a scene that is otherwise lacking in interesting features.

Grain in a black and white picture also results in a punchier and sometimes a more dramatic picture as it as a shallower contrast range and outlines are more clearly defined. Bear in mind faster films are also less saturated and are not as sharp.

june2005_image06 Faster films or ISO setting allows you to use a faster shutter speed setting in many situations where lighting is low and using your camera’s flash will kill the ambience of the scene.

It is still best to set your camera on the lowest ISO setting most of the time and then add the effect of grain into your picture as you see fit. At least this way, you can adjust any changes that have been applied to your image.

Making Compositional Adjustments

It’s near impossible to say you can go through images which you have just downloaded from your digital camera and every picture is good enough not to require the slightest adjustments. Professional photographers are notorious for taking large quantity of shots and then using just a few perfect ones and more often than never, ending with slight touches of adjustments here and there.

For this purpose, some basic photo adjusting skill and a good eye for a potentially good picture are required. As we have looked at correcting your images in terms of contrast, brightness and toning adjustments in previous issues, this month we will look at compositional adjustments.

CROPPING

Cropping is a method of adjustment which you could be using less as you gradually become better at composing your picture at the point of taking your photograph. This means you should gradually master the skill of knowing what should go in or out of your picture at the point of pressing the shutter button.

Cropping adjustments help to result in defining compositional rules, such as the Rules of Thirds. Another important use of cropping is really to reduce the amount of clutter or empty space in a picture to give it more “focus” in directing the viewer’s eyes towards the main focal point of your image.

BEFORE

may2005_image01

Although the image above is perfectly fine as a snapshot of your subjects in their surrounding, it can be improved as a portrait by cropping out distracting elements surrounding the focal point of your image.

AFTER

may2005_image02

By cropping out the distracting plants on the right side of the picture and the empty space on the left side of your subject, you have effectively brought the focus strongly on your subjects.

BEFORE

may2005_image03

This image of our Prime Minister’s office was taken perfectly symmetrical but suffers from poor composition. The empty space at the bottom of the picture does not contribute in any way to the aesthetics of the picture.

AFTER

may2005_image04

Cropping away the empty space greatly improves the composition of the image. Stronger emphasis is given to the centre of the building. Leaving behind a small part of the path helps to lead the eye of the viewer into the picture.

PERSPECTIVE CORRECTION

The problem of distorted perspective is most common in architectural photography. This happens when you are taking a picture of a building from a low angle. Exaggerated perspectives are sometimes done on purpose (this is done by using a wide angle lens and shooting from very near the structure).

may2005_image05

The perspective of this building was purposely exaggerated to accentuate the grand façade of the building.

However, if the distortion is slight but clear enough to be noticeable, the building may seem to be leaning backwards. If the edges of the building are close to the edge of your image, the distortion would be emphasized more in relation.

Some digital cameras come with a built-in perspective correction feature. It is still better to correct perspectives on your computer which allows for a better control of the correction and final image quality.

BEFORE

may2005_image06

The distorted perspective of this image shows this building, especially the clock tower on the right, leaning backwards.

AFTER

may2005_image07

After perspective adjustment, the entire building should look perfectly upright. This creates a more pleasing final composition.

CORRECTING YOUR HORIZON

Holding your camera straight and perfectly horizontal is seldom an issue if you have both feet planted on a flat surface and two hands to correctly hold your camera. If the situation you are in is contrary to the above or if you are so intently focused on your subject that you fail to shoot a perfectly horizontal horizon; your picture may seem to slope to one side. Your viewer’s attention to detail may be quite acute to notice such imperfections.

BEFORE

may2005_image08

In this picture, although the line of the horizon is not clearly seen, the sloped horizon is evident from looking at the slanted structures in the picture.

AFTER

may2005_image09

Adjust the horizon level of your picture using the structures in your picture as a guide. In this example, the minaret of the mosque serves this purpose)

Note: It’s also quite acceptable at times to shoot with unique angles to give your picture a sense of motion and dynamism. No harm in being creative and trying this out.

Interesting Fact

Lines in an image sometimes create interesting optical illusions. At times, you may not even realize the first time you look at an image. Take note of this the next time you come across similar images.

may2005_image10

may2005_image11

Take some time to look through your images and see how each of these can be improved by making the above compositional adjustments. You would be surprised as some of these adjustments are minor but makes for a great improvement in the final outcome of your image.

Using Filters

Do you sometimes wonder why a professionally taken picture can look so full of impact? Sometimes you would realize a picture may have colours are “so bright” or a sunset that almost feels “warm” or a sky that is so “clear” and “blue” or even a portrait shot looks so “gentle” and “soft”.

A lot of times, the secret here is the clever use of filters. In analog (film) photography, a lens filter is attached to the front of a lens. Light passing into the camera is affected by the filter and this creates different effects in the final image.

In digital cameras, the built-in image processor mimics traditional filters to create the effects you would normally get. However, D-SLR cameras still uses physical filters as this allows for greater control of the effects of the filters.

If you are using a camera with threaded lens or a DSLR, here are several descriptions of some common photography filters that you can use to create interesting effects

UV Filter

If you use a SLR camera or a camera with threaded lens, a UV filter will be almost essential to keep on your camera all the time. It is a colourless filter and its purpose is to keep out ultraviolet light in the atmosphere and reducing atmospheric haze to capture images clearer.

Polarising Filter

A polarising filter cuts out reflections by preventing light waves from certain angle from passing through to the camera’s sensor (or film). This means that it also affects the light coming from water particles (i.e. clouds) in the sky at the same time enhancing the image by deepening the colours that comes through. It also is useful in shooting through surface of water and glass which are reflective.

image04

A polarising filter gives you deep, rich and high contrast colours

Neutral Density Filter

A neutral density (ND) filter reduces the amount of light that reaches the camera’s sensor without affecting anything else such as colour. This allows you to create effects such as slow shutter speed. ND filter also come in graduated form which is particularly useful if you want to balance out the amount of lighting coming from the sky, which is generally brighter to light from the ground.

image06 

You can use an ND filter to reduce the amount of light and slow shutter speed to create effects like this

Warming Filter

Sometimes your pictures can look dull on a overcast or cloudy day. Your camera may capture an image that can appear cool. Warming filters help to add a little warmth for a more desirable effect. Sometimes strong warming filters can give that extra touch to a bright sunset.

Cooling Filter

Cooling filters does the opposite of warm filters and are less commonly used for photography. But, it helps to add saturation and impact to a dull sky.

image07 

Blue filter can give you a cool, misty morning feeling

There are also other less common filters such as the Soft-Filter (which is great for portraiture), Intensifying-Filter (to increase individual colour saturation) and Infrared Filters (which enhances the effects of infrared radiation to create surreal light effects especially on green foliages)

image05 

The effects of a starburst filter

Simulating the effects of filter digitally

Here are two post-processing methods you can use on your digital pictures.

Creating a warm sky

1) Open up your picture

image01

2) Create a new Layer and set the blending mode to Multiply

tutorial03

3) From the Tools box select the Gradient tool

4) Change your foreground colour to Orange

tutorial01

5) Select your gradient method as “Foreground to Transparent”

 

6) Drag the gradient from the top of your picture downwards

(adjust the length of this gradient accordingly based on the position of your the sky)

7) Finally, adjust the opacity of the layer to get the desired effect.

tutorial02

You can use this method with blue colour to deepen the colour of the sky.

Softening your portraits

1) Open up your picture

image08

2) Duplicate the existing picture on another layer

3) Adjust the Opacity of the second layer to 50%

tutorial04

4) Click on Filter > Blur > Gaussian Blur

5) Adjust the blurring Radius according to how soft you want the image to be

(as a guide for a 6MP image, set the Radius to 10 pixels)

tutorial05

image09

Filters are quite fun to use. It gives your pictures a fresh outlook. Experiment with different colours and effects. Keep it subtle for a realistic look or go to the extreme for some dynamic effects.

Understanding Histogram

One of the most important features of digital cameras which have changed the experience of taking pictures is the possibility of reviewing your picture at the point of taking a photograph. You are able to see if you have taken a good picture or a bad one and decide whether you should keep it.

However, most of us do not know about an additional feature in our camera that can also help in determining a good picture. This feature is called the histogram.

image01

The histogram shows you the tonal range of your picture, usually depicted as the darkest to the lightest pixels in your picture. Reviewing your picture in such a small LCD on your camera, it can be hard to determine if your picture is of the right contrast level. A histogram can tell you details about your picture’s exposure and whether you need to make any adjustment to the settings on your camera.

A picture that is underexposed will show the following

image02 image03

You can see that most of the details are concentrated on the left side of the histogram showing that there more dark areas in your picture.

A picture that is overexposed will show the following

image04 image05

Here, most of the details are concentrated on the right side of the histogram showing that there are more bright areas in your picture.

In the above cases, what is necessary for you to do is to make the right adjustments such as using flash or to manually increase or decrease exposure level. Most of the time, your camera’s auto exposure feature will correctly make these adjustments unless you are faced with extreme cases.

What do you do if you have already taken the picture?

It’s always best to get a picture just right from the point of pressing the shutter button. But, there are times where you can’t get back the same moment and you end up with a picture that’s not well exposed.

What can you do?

Don’t despair. This is one of the main reasons why there are a number of photo-editing software available to fix the problem.

I’ll use Adobe Photoshop to give you an example of how you can fix your picture. Most good and even basic photo-editing software would have this feature available for you to make adjustments.

Using Levels

For most people the simplest way to adjust the tonal range of a picture is to just use brightness and contrast feature. However, this method leaves you with little control over the results of the adjustments.

Last month, I talked about using an adjustment layer. To recap on this, click on the on the black and white button at the bottom of the Layer box and select Levels.

You will then see a histogram which displays the level of colours for the red, green and blue (RGB) Channels.

If you see empty gaps on either side of the histogram, this means that your picture has low contrast level and could be better with a slight adjustment.

image06 image07

Move the slider on both ends to the edge of the histogram where there are tonal details. You can see the change in your picture instantaneously as the contrast level improves.

What you have done is actually improving the overall contrast of your picture by spreading the colour details over the entire tonal range. This makes for a more pleasing picture to look at.

image08 image09

The middle slider is used to adjust the overall brightness, or gamma level of the picture.

If your picture suffers from a colour cast, either due to poor lighting or a problem with white balancing, you can select the individual colour channel, red, green or blue and move the sliders to make adjustments to correct the colour.

Here are a couple more examples of how pictures can be improved by checking and tweaking the levels in a histogram.

image10 image11

 

image12 image13

Do remember that there may be some cases where it is not necessary to make the above adjustments such as pictures of a grey object, a misty atmosphere or soft colours of a fabric. It may be quite a subjective issue and you have to judge for yourself if it looks fine after the adjustments. Now that you know the basic steps in adjusting your picture levels, try practicing this on your existing pictures. In the next few months we will come across this feature to do some creative digital photo effects.

Essential Black & White

When photography was first invented, there was only black and white. To this day, black and white photography still captures the interests of many not just because of its nostalgic beginnings. Revisit the works of great photographers like Ansell Adams and you will instantly see why black and white images are still amazing and revered.

What we can discover and interpret from black and white pictures are shapes, forms, light and shadows. In a sense, colour does not become a distracting element and is not essential to the impact of the picture.

There are even times where a picture in black and white may look better than it does in colour. It takes a good eye and a bit of visualisation to see a scene in colour.

In analog photography, black and white films are different in terms of film grain, contrast levels, details of shadows and light. Processing black & white may also require some special treatment during the stage of processing the print to produce a good picture.

Processing a Digital B&W Picture

There are a number of ways to convert your picture into black and white. Although your digital camera may have a black and white setting, I would suggest you don’t use this method as the final outcome may not always be what you want and there is no turning back after the in-camera conversion.

Using software like Adobe Photoshop, you can convert your picture simply by using the “Grayscale” or “Desaturate” tool. It’s simple but this method offers little control over the final results of the picture. The method used here is “Channel Mixing”

Here is a tip before you begin: Create an “adjustment layer” rather than directly altering your picture. Changes using this method are not permanent and you can always go back to the layer and adjust the setting. You can access the adjustment layer by simply clicking on the black and white button at the bottom of the Layer box. You can see an example of this in the conversion described below.

Here is the original picture:

feb2005_image_01 

feb2005_tutorial_01 

1) Select a new adjustment layer and select Channel Mixer. As you can see this splits your picture into the 3 colour channels, Red, Green and Blue. Sliding the tabs back and forth alters the mix of colours. But now, we will be working with black and white therefore on with the next step.

feb2005_tutorial_02

2) Click on the box below to choose monochrome. You can see that your picture has turned to Black & White. At this point, tweaking the colour sliders with change the shades of different elements in your picture (based on their original colours). You can try different combinations and select what works best for your picture.

feb2005_image_02

3) Instead of using the brightness and contrast, use “Levels” which. To check the contrast of your picture using levels, simply open up a new adjustment layer, and choose layers.

feb2005_tutorial_03

Look at the two ends of the slider. If there are blank spaces on either end, push the slider to the point where the histogram begins to rise. This simply creates “pure” whites or blacks in your picture.

feb2005_tutorial_04

Most of the time, you will need to do this for your picture but as you become better at evaluating your picture, you may sometimes decide not to alter this simply because your picture look better as it is.

feb2005_image_03 

 

Desaturation vs Channel Mixing

In these two pictures you can see the difference between the desaturation method and monochrome channel mixing. The first picture lacks impact. In the second picture, the correct mix of colours in monochrome setting has given the picture a much needed level of contrast and punch.

feb2005_image_04 feb2005_image_05

Digital Effects

After converting your picture to black and white, you can also add effects to your picture.

1) Adding film grain: You can achieve this by using the “Add Noise” option under the Filter menu. Remember to check the “monochromatic” box at the bottom to create black & white grain.

2) Toning your picture: To tone your picture, again use the adjustment layer and select colour balance this time. Try using a variety of monotone colours. You would be amazed with the effects you can create.

If you have been shooting digitally in colour for a while and feel that your images lack mood, try converting a few to black and white and see how it turns out. You may lease new life into them. I’ll leave you with a few more pictures of subjects that lend themselves well to black & white.

feb2005_image_06 feb2005_image_07 feb2005_image_08  feb2005_image_10 

feb2005_image_09