What Are Focus Points In Digital Photography

You pick up your camera with a primary objective of taking a picture of your subject. First of all, you’ll want to ensure that your subject is in focus before you take a picture. Conventionally, DSLR cameras a configured in such a way that when you press the shutter button halfway down, the camera locks focus on the subject and when you press the shutter button way down, the image is captured. This method of acquiring focus is a pretty standard method except the camera is otherwise configured.

acquiring_focus
Acquiring Focus

What Are Focus Points?

Let’s assume we’re using the conventional method I mentioned earlier whereby you pick up your camera and press the shutter button half-way down to acquire focus; the moment you look into the viewfinder you’ll see some black dots which become red when the focus is locked (depending on the camera model). These dots are called Focus Points. As photographers, we make use of focus points to draw the attention of the viewer to a part of the scene which we want them to look at. A typical example is the image of my Graphic Tablet sitting next to my laptop on my office desk. The focus was on the pen which threw every other aspect of the scene out of focus.

graphic_tablet
Graphic Tablet

Selecting Focus Points.

When it comes to selecting focus points, we could either let the camera do this for us automatically or we take control of what should be in focus and do it ourselves. Having a camera in Autofocus mode has an obvious disadvantage, which is; the camera may decide to lock focus on a different point within the scene which could be totally different from what we want… Here’s an example.

phone_display
Phone Display

 

I had the camera set on autofocus and wanted the Vimeo thumbnail to be in focus but the camera selected the facebook thumbnail.

So this is a summary of what focus points are in Digital Photography. I tried to make it as simple as possible to understand. Let me know in the comments section if I missed out on any point or If you have thoughts to share.

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The Exposure Triangle: Understanding The Basics

What is The Exposure Triangle?

Before now, we discussed the three primary factors that determine the exposure of a photograph; which are the Aperture, Shutter Speed and ISO. (These factors as stated here have clickable links that would take us to the previous posts where we discussed them in detail just in case we need to refresh our memory).

Now Exposure Triangle is the act of striking a balance between these three variables so as to produce a perfectly exposed image.

APERTURE

The Aperture can be defined as the diameter of the channel through which light passes to get into the image sensor. The Aperture is measured in f-stops. So an Aperture value of f/1.8 has a wide opening while an Aperture value of f/22 has a small opening.

With Aperture comes Depth of Field. The depth of Field here refers to how much of your image is in focus. So shooting with a wider aperture makes less of the image be in sharp focus while shooting with a smaller aperture makes more of the image be in sharp focus.

SHUTTER SPEED

Shutter speed refers to the length of time the shutter is open. So if you’re shooting with a fast shutter speed, for example, 1/1000th of a second, less light gets into the image sensor compared to when you’re shooting with a slow shutter speed of 1/10th of a second which allows more light into the image sensor.

When shooting with a wide aperture, your shutter speed will need to be fast to compensate for the amount of light entering the camera otherwise you’ll most likely end up with an over-exposed image. Same applies if you’re shooting with a small aperture, your shutter speed will need to move slower to enable more light into the camera otherwise you’ll most likely end up with a grossly under-exposed image.

Your shutter speed can also be used to freeze motion. So if you’re taking a photograph of a moving car or a waterfall, using a fast shutter speed freezes the movement. A slower shutter speed will produce a blurry image of the car and a creamy look of the waterfall. These outcomes are not necessarily bad if done creatively.

ISO

This refers to the way your camera interprets light; This is also known as the Image sensor’s sensitivity to light. This sensitivity is measured in figures like 100,200,400,800 etc.

So a camera with a base ISO of 100 means that the best picture quality is to be taken at this setting and this requires enough light and excellent conditions for it to perform. A camera with an ISO setting of 4000 would require less light to take a bright image but this could be at the expense of the quality of the image as there could be the existence of image noise or grainy pixels in the picture.

If you’re taking a photograph in a dimly lit room, you can introduce an external light source like a Speedlite and still operate at a low ISO to ensure the digital noise is kept at it’s barest minimum.

CONCLUSION

In summary, this is an idea of what the exposure triangle is all about. Effective utilization of these three variables; Aperture, Shutter Speed and ISO to produce a perfectly exposed image. So it’s time to pick up our cameras and get practising. You could share your images in the comments section below or on our community lets all learn.

If you have any questions or contributions to make, kindly share your thoughts in the comments section below.

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ISO : Understanding Exposure in Digital Photography

In today’s editorial, we’ll be looking at ISO as the third primary factor which plays a contributory role in capturing a perfectly exposed image. The first we discussed was Aperture, next we looked at Shutter Speed, and now we’ll be looking at ISO as it relates to Exposure in Digital Photography.

What is ISO?

DSLR Camera sensors have a way of interpreting/responding to light. Their response to light, however, determines how bright or dark the image captured is. This mode or response can be referred to as ISO. ISO is measured in values such as 100,200,400,800 etc and can be controlled automatically or manually via the camera settings.

ISO VALUES EXPLAINED.

Like we mentioned earlier, ISO can be used to control the brightness of an image. The higher ISO values you apply, the brighter your image is. But it gets to a certain value where you begin to notice grains on the image; otherwise known as noise. This noise is acceptable by some photographers while some don’t like it. Personally, I don’t like noise in my images. I love them clear and crisp.

ISO Understanding Exposure in Digital Photography
ISO Understanding Exposure in Digital Photography Aperture f/9 Exposure time 1/160 sec ISO 100, Focal length 50mm

To achieve the highest image quality from your DSLR camera, it’s advisable to stick to the Base ISO. The base ISO here is the lowest ISO value your DSLR camera has. Unfortunately, we can’t always stick to this value at all times due to the conditions in which we’re shooting especially in low-light conditions.

What ISO value is best for you?

Pick up your camera and start experimenting. Set your Aperture to around F4 and your shutter speed to about 1/160th sec and ISO set to your base ISO. Start taking pictures with varying ISO values until you get to a point where the noise/grains are unacceptable. That would then give you an idea of the best acceptable ISO value for you to shoot at using your DSLR camera.

Conclusion

This is just a basic knowledge of ISO as related to Exposure in Digital Photography. We’ll go deeper into how it can be controlled when we discuss the Exposure Triangle.

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SHUTTER SPEED : Understanding Exposure in Digital Photography

The next important factor to be considered while trying to achieve a perfect exposure in digital photography is shutter speed. Like I mentioned earlier, the other two are Aperture and ISO. Firstly, we’ll give a brief introduction to what the shutter is in a DSLR camera, what it comprises of, how it works before we finally go into discussing shutter speed and features associated with it.

What is a shutter in a DSLR camera?

In photography, a shutter is a device that allows light to pass for a pre-determined period, exposing photographic film or a light-sensitive electronic sensor to light in order to capture a permanent image of a scene. The shutter is constructed such that it automatically closes after a certain required time interval. Operation of the shutter is triggered by a button called the shutter button or shutter-release button.

What is a shutter button?

In photography, the shutter button or shutter-release button is a button located mostly on the right-hand side of the DSLR camera body. When the button is pushed, the shutter opens for a pre-defined length of time; allowing light into the image sensor. During this process, an image is captured and the shutter closes afterward.

How does the shutter work in a DSLR camera?

Looking at a typical DSLR camera, the shutter comprises of 3 primary mechanisms; namely the mirror box, the bottom door and the top door. When the shutter button is pressed, the reflex mirror is tilted backward allowing light further into the camera. When the mirror flips upwards/tilts backward, a small door slides open from top to bottom, exposing the image sensor beneath. After that, another door slides down, covering the entire sensor. This process usually varies in time depending on the length of your exposure (shutter speed). After the second door closes, your reflex mirror falls back into place. The doors would then assume their default positions and technically, this process is known as Actuation. A typical DSLR camera can withstand close to 100,000 actuations in its lifetime.

shutter speed-How the shutter operates
How the shutter operates courtesy premiumbeat.com

What is shutter speed?

In Photography, shutter speed or exposure time is defined as the length of time the shutter remains open allowing light to get to the image sensor; also allowing the camera to take a photograph.

Features associated with shutter speed.

  • Shutter speed controls exposure – It is used to control the brightness of an image. The longer the shutter speed, the brighter the image. This is possible because the shutter is open for a considerable length of time to allow the image sensor to gather more light.
  • Shutter speed is measured in seconds – This could be full seconds (i.e 1 second, 5 seconds, 10 seconds etc) or fractions of a second (i.e 1/500, 1/250, 1/125, 1/60, 1/30, 1/15, 1/8 etc). The larger the denominator, the faster the shutter speed; the lower the denominator the slower the shutter speed. for example; 1/500 is faster than 1/30.
  • Shutter speed is used to freeze movement in an image – By using a very fast shutter speed, motion is frozen. For example, using the featured image above, the image taken at 1/1000 sec freezes motion.
  • Shutter speed is used to capture motion in an image – By using a very slow shutter speed, motion is captured. For example, using the featured image above, the image taken at 1/80 sec captures motion.
  • Shutter speed and focal length – As a rule of thumb, always use shutter speeds with a denominator greater than the focal length. This helps to prevent camera shake especially in situations where image stabilization is absent

Conclusion

So while making things as simple as possible, we’ve been able to analyze the shutter speed as regards to digital photography and how it plays a significant role to achieve a perfect exposure while capturing an image. We have looked at Aperture, Shutter speed, next would be ISO.

Kindly share your thoughts in the comment section below.

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APERTURE : Understanding Exposure in Digital Photography

On our series of demystifying photography, we’ll be looking at one of the three cardinal factors that determine exposure in photography; which is Aperture. The other two are ISO and Shutter speed. Before we go ahead, it’s advisable we have a good knowledge of the structure of a DSLR camera

What Is Aperture

Aperture can be defined as an opening in a lens through which information in form of light travels into the camera body/structure. This could vary in size. The larger it is, the more light that gets into the camera.

Aperture Size

The size of the aperture can be controlled by the Iris. In Digital Photography, the aperture is measured in f-numbers (for example f/8). The f-numbers or f-stops can be used to describe how wide or narrow the aperture is. A smaller f-stop means a larger aperture while a larger f-stop translates to a smaller aperture. This is another area photographers find confusing but once you understand the ideology, it sticks.

Below a graphic representation of Aperture.

Aperture Explained
Aperture Explained

Depth Of Field.

We can hardly discuss Aperture without making reference to Depth of Field. Depth of Field can be defined as the amount of your shot that is in focus. A large Depth of Field means that most of your image would be in focus. This can be produced using a small aperture (large f-number/f-stop) such as f/16.

Large Depth of Field
Large Depth of Field (Large F-number/Small Aperture) F-stop f/13 Exposure time 1/160secs ISO 160

A small or shallow Depth of Field can be seen as an image with only a portion of it in focus while the rest of it remains blurry or fuzzy.

Shallow Depth Of Field
Shallow Depth of Field (Small F-number/Large Aperture) The image was taken at the LetstalkphotographyPH meeting f-stop f/1.8 Exposure Time 1/200 secs, ISO 1600 Focal Length 50mm Subject Distance 2.5m Metering Mode Centre Weighted Average No Flash

DSLR Lenses are manufactured to have specific values on how wide or narrow the aperture can get. The lens specifications usually state the largest f-stop and the smallest f-stop. A lens with a maximum f-stop of f/1.2 is considered to be a fast lens because it allows more light to pass through compared to a lens with a maximum aperture of f/4.0

Here's a brief video produced by Olufemii Tutorials that also explains Aperture

We tried to keep things as simple as possible while explaining Aperture as it relates to Exposure in Digital Photography. Feel free to share your thoughts in the comments section below.

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Understanding Exposure in Digital Photography

As simple as the title of this editorial sounds, many “Professional Photographers” are yet to have a grip on what Exposure in Digital Photography really means. Learning is a continuous process and so This is would be the first in a series of editorials where we’ll be taking an in-depth look at Exposure and how it can be demystified. Kindly attempt to read our introductory Editorials to this series which talks about what photography is and a detailed explanation of the DSLR Camera.

Definition of Exposure in Digital Photography

Exposure could be seen as how bright or dark your image would be. It’s imperative that we capture our images with the perfect exposure; meaning it shouldn’t be too dark or too bright.

For us to capture a perfect exposure, we must correctly and creatively combine the three cardinal factors which play a contributing role towards achieving a well-exposed image. They are Aperture, Shutter Speed, and ISO. A simple guide to achieving a perfect exposure is the use of the exposure meter. This could be seen when you look into the viewfinder of your camera.

Light meter scale as seen inside the viewfinder
Light meter scale as seen inside the viewfinder

If it tends towards the right, there’s a tendency for the image to be over-exposed; if it tends towards the left, there’s a tendency for the image to be under-exposed. Having the mark at the at the dead center tends to give a perfectly exposed image. The outcome may vary under certain situations but it’s good we have this as our guiding principle.

We’ll be looking at the three cardinal factors {Aperture, Shutter Speed and ISO} and how they individually and collectively {Exposure Triangle} contribute towards producing a perfectly exposed Image.

Did you find this tutorial helpful, please share your thoughts in the comment section below?

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The DSLR Camera

The term DSLR is an acronym which stands for Digital Single-Lens Reflex. So a DSLR Camera is a digital camera that combines the mechanics of a single-lens reflex camera with a Digital Imaging sensor; as opposed to a photographic film.

The primary difference between the DSLR and the non-reflex single-lens digital camera is that the viewfinder of a DSLR presents an image that is almost equal to what’s captured by the camera’s sensor and not being captured by the camera’s image sensor and displayed on a digital screen.

  1. Lens
  2. Reflex Mirror
  3. Shutter
  4. Image Sensor
  5. Focusing Screen
  6. Condenser Lens
  7. Pentaprism
  8. Eyepiece/Viewfinder

OPERATIONAL DYNAMICS OF DSLR CAMERA’S

The Eyepiece/Viewfinder <8> is situated at the back of the camera. When you look through it, what you see is a reflection of information that has passed through the lens <1>; which means there’s a 100% chance of capturing what you see.

Information in form of light passes through the lens <1> and hits the Reflex Mirror <2> which is positioned at a 45 degrees angle inside the camera structure. This light is then directed vertically to a chamber called the Pentaprism <7>. This light is again re-directed by two mirrors into the viewfinder <8>.

When you take a picture by pressing the shutter button, the Reflex Mirror <2> bends backward, allowing light into the camera. The Shutter <3> remains open for as long as it’s been programmed to. This enables information to get to the Image Sensor <4> which then records the image and then the Shutter <3> closes and reflex Mirror <2> returns to its original position of 45 degrees thereby re-directing light back to the viewfinder <8>.

Once the process ends, the camera then processes information from the Image Sensor (4) and converts it into a pre-defined image format and writes it onto the memory card. This process takes less than a second and in most cases, some DSLR Camera’s can replicate this process of writing images more than 10 times within a second.

This is at best a summary of how your DSLR Camera works.

For an expanded view of how it works, you could follow this link and read more on Wikipedia

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What Is Photography

Photography can be defined as the art, process or job of taking and processing pictures with a camera.

Merriam – Webster dictionary defines photography as the art or process of producing images by the action of radiant energy and especially light on a sensitive surface (as film or an optical sensor).

The journey begins in the mind. You, first of all, create a mental picture of what you want and then create it physically with the tools (camera) you have in your hand.

Photography doesn’t just start and end by taking sharp and well-exposed pictures. Also having the best of tools doesn’t also guarantee excellent results. Just like any art, it requires a tool. In this case, the tool is the Camera. To use any tool effectively, it also requires skill/technical know-how to create outstanding results.

Unskilled attempts at photography results in a boring outcome. As a beginner, one may be thrilled by picture clarity and exposure; but as you advance, you start paying attention to details, the kind of images you create and what they stand for.

This is an attempt at defining photography in its simplest terms. Welcome to our journey into the world of photography. We promise to keep things short and simple for easy comprehension.

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Protecting Your Images Online

The need to protect your images online cannot be over-emphasized. This is fast becoming a recurring decimal these days – A situation whereby the established brands steal works from the upcoming artists, publish and take the glory without any form of compensation to the original author. Each day, more and more people are gaining access to the internet. To get noticed, you need to share your works, that’s about the easiest way people can get to notice you and subscribe to your services. When you eventually publish your works, what stops others from taking your work and claiming it’s theirs? Nothing. We can’t prevent them from doing a screenshot or outrightly downloading the image off the internet, but we can make a conscious effort (no matter how small) to keep our images safe.

HOW TO PROTECT OUR IMAGES ONLINE

  • COPYRIGHT PROTECTION

The best form of protection while dealing with copyright infringement is to register your work with the Copyright Commission/Office as it applies in your country. All you need to do is to head over to their office or online portal, create an account, pay the requisite fees and you’re done. The downside of this is that as a photographer or digital content creator, you’ll most likely be releasing content daily and that would cost a lot of money keeping up with the copyright protection of all content produced.

  • AVOID PUBLISHING FULL RESOLUTION IMAGES

If you’re using a Nikon D7100 camera which has a 24MP sensor with a resolution at 6000 x 4000, it’ll be advisable to publish an image size of between 1080px and 1200px on the longest size. In that way, the file size is reduced and the image quality is still retained for online viewing.

  • APPLYING YOUR WATERMARK

Applying watermarks to your images is the most conspicuous and easiest way of protecting your images online. The standard method used by photographers is to either add your name to the bottom/side of the image or better still a small logo. This tells the viewer that the image was created by you and belongs to you. It also doesn’t distract the viewer from appreciating your work. The downside of this is that any thief can easily clone this watermark out and claim ownership of the image.

Another type of watermark that’s usually adopted by those who want full control and protection of their images is to emboss the watermark boldly over the image. This method of watermarking can be seen on sites that hold stock images for sale like Shutterstock. The downside of this is that the watermark distracts the viewer from appreciating the work of art.

  • DIGITALLY SIGN YOUR IMAGES: METADATA

This is an area I’ll advise every photographer to invest some time in. According to the International Press Telecommunication Council (IPTC), Metadata is a set of data that describes or gives information about other data. In this case, Photo metadata is data that gives information about an image. This data can be passed on with the image from one application to another irrespective of the format. Metadata can be stored internally; embedded in the image file in formats like JPEG or TIFF or stored in a sidecar file such as XMP as in RAW files.

The Photo metadata consists of 3 categories,

Administrative: – This covers the identification of the creator, it’sDate of creation and location, contact information of licensors of the image and other technical details.

Descriptive: – This gives information about the visual content such as headline, title, captions and keywords.

Rights: – This covers copyright information and underlying rights in the visual content; including model and property rights and rights usage terms.

I’ll suggest you follow this tutorial closely and ensure this is incorporated in your workflow henceforth.

  • MONITOR USAGE OF YOUR IMAGES VIA GOOGLE ALERTS

If you’re passionate about keeping track of your portfolio online then Google Alerts may just be the most efficient tool to utilise. This service enables you to set up keyword triggers that send email notifications based on the criteria you set up. In this case, your images.

From my research, a random search using a keyword on google can pick up images with that name or with the keyword embedded in the metadata. So as a photographer, you could start by naming your images using a specific prefix or custom naming style. Have the names embedded in the keywords metadata and also in the file name. Then while setting up Google Alerts, put the keyword in a quote; for example ” John Doe” so the search weeds out any false readings and then delivers it’s findings to you daily, weekly or as it happens.

With these simple steps stated clearly above, you can prevent your photography from being used illegally online without your knowledge. Always remember to input your metadata and watermark your images. Sending Google Alerts on a surveillance mission would cost you nothing itsbenefits are huge.