PHOTOGRAPHY

 Focal Length and types of photographic lenses

  Many photographers talk about focal length a lot because it greatly affects the appearance of the image.

  If used correctly, it can improve your topic. And if used poorly or thoughtlessly, it can negatively tarnish the appearance of your subject. This applies to people, products, buildings, landscapes... anything. So let's take a look at what a focal length is and how to use it.

  Understanding the focal length will help you know which lens to buy and how to use it for a variety of types of photography.

  Make sure you read the entire article, as it will contain some great examples that will help you get the right focal length when taking photos.

Focal Length

   What do we mean by focal length?

  Without getting into an in-depth physics discussion, the focal length is the distance between the optical center of the lens and the camera sensor optical and is measured in millimeters.

  The optical center of the lens You may wonder what this means!! Well, the viewfinder is not, as many think, made of a single piece of glass, but rather a combination of elements and fixtures that help focus light and reduce distortions. The location where all the rays of light converge to form an image is known as the optical center of the lens.

  Now that you know the technical definition of focal length — which, by the way, isn't something you need to remember unless you want to impress optical engineers. What is important to remember, is what we will now see in the following paragraphs.

   Where do you find the focal length on your lens?

  Focal length is a characteristic of lenses, they are named according to the focal length, and you can find this information on the lens nozzle. For example, a 50mm lens has a fixed focal length that does not change 50mm.

  While the 18-55 lens is a telephoto lens, the widest range that this lens can achieve is 18mm, while the largest zoom that it can reach is 55mm.

   What does the focal length tell us about a lens?

  Focal length is used to describe lenses because it tells us something very important: how much a lens can magnify distant subjects.

  However, not all lenses do zoom or zoom, there is a type of lens that has a fixed focal length called prime lenses. Let's know the difference between them and the zoom lenses.

   What is the difference between Prime Lenses and Zoom Lenses?

  Prime Lenses

  A prime lens is a lens with a fixed focal length (also referred to as a “fixed lens”). With this lens, you cannot make your subject appear larger or smaller within the image. The only way to enlarge your goal is to approach it yourself. The only way to make your subject smaller and have more elements in your image is to step back.

  Primary lenses have a specific focal length, such as 50mm. They come in all kinds of sizes and focal lengths. Examples of primary lenses:

• Canon EF 800mm f/5.6L

• Nikon AF-S Nikkor 50mm f/1.8G Lens

• Sony - FE 50mm F1.8 Standard Lens

  Zoom Lenses

  These lenses have a variable focal length. Meaning you can stay where you are and zoom in on something far away that you want to photograph. Some common telephoto lens ranges include. This lens is great for travel because it covers both wide shooting ranges such as landscapes and telephoto ranges for photographing architectural details.

  Examples of zoom lenses:

• Nkr 18-200mm F/3.5-5.6G

• Sigma 70-200mm f / 2.8

• Canon EF 24-70mm f/2.8L II

   How does focal length affect your image?

  1- viewing angle

  We can't talk about focal length without mentioning the field of view (angle) because when you change the focal length, you also change the field of view.

  Before I explain further this point – field of view and angle of view are the same things. Just different ways of saying it.

  First, what is the viewing angle? It is simply the amount of scene your lens can capture. Do you want a wide angle where you can take a picture of the house with the garden around it, or do you want a narrow-angle where you will only take a picture of the house?

  Lenses with a shorter focal length such as 28mm, are called wide-angle lenses because they allow you to get a wide view in a single image. Meaning the subject you want to capture will be small in the photo with many other elements.

 This wide-angle lens is ideal for shooting wide scenes such as landscapes.

 While lenses with long focal lengths such as 300mm are called telephoto lenses, they have a smaller field of view. Meaning your subject will look large or close up in the photo.

  These lenses are commonly used in sports and wildlife photography because they bring the subject closer without having to go close to photographing it.

  For example, if you photograph a dog with the lens set to 85mm, the cat will be far away in the photo with a lot of elements around it.

  But if you set the lens to 200mm, in this case, the dog will be closed up in the image with a few elements surrounding it.

  These images show how the focal length affects the viewing angle, the higher the focal length, the smaller the viewing angle.

  The relationship between focal length and the viewing angle is summarized in the illustration below.

  2- Depth of Field

  Before diving into this effect, let's first give you a simplified definition of depth of field.

  In short, it is how blurry or clear the area around your target is. Meaning the number of scenes you focus on. It is of two types: deep depth of field, and shallow depth of field.

  For example, if you want to photograph your friend and focus on him without paying attention to the background, you will simply make this background blur, and the amount of scene you will focus on is only your friend, this is the narrow depth of field.

  While if you want to photograph a landscape Or a family photo where all of the people's faces need to be clearly visible, here you'll need a deep depth of field, where both the foreground and background are in focus.

  Now that you know the meaning of depth of field, you might be wondering what it has to do with focal length?

   The focal length of the lens has a significant effect on depth of field, lenses with a long focal length (zoom) give a shallow or narrow field, focusing on distant objects and bringing them closer without paying attention to the surrounding elements.

  While lenses with a short focal length (telephoto) have a greater depth of field allowing them to have a wider range of subjects in focus.

  For example, if we photograph a subject with a 50mm lens, we will get an image with a deep depth of field, and the more we increase the focal length in the sense of bringing the subject closer, the smaller the depth of field will be as shown in the images below.

  3- Perspective

  Many people think that focal length affects perspective, lenses with a short focal length like 28mm widen perspective, resulting in more space between the subjects in the image, and the background of your subject looking farther away than it actually is. In contrast, a lens with a long focal length such as a 200mm lens will do the opposite, making the background of your subject appear close to the subject.

  This is a mistake! In fact, the focal length of a lens alone does not affect perspective; Instead, the perspective changes as the focal length and camera position change.

  This type of photography is used to add many effects to your photos, such as optical illusions.

  Perspective distortion by changing the focal length and position of the camera, it works well when photographing people's faces.

   4- Image shake:

  This is the noise that occurs as a result of the vibration of the shutter-release button being pressed, which leads to a decrease in image quality.

  When using a lens with a long focal length and a narrow perspective, the lens or the camera is more sensitive to the slightest movement, image shake can be prevented using a tripod.

   What's the relationship between focal length and camera sensor?

  For those who don't know what a sensor is; It's simply a device inside a camera that takes light to form an image.

  It divides cameras into two types:

• Crop Sensor cameras, Full Frame Sensor cameras.

• Crop sensor cameras, as the name implies, have a smaller (or cropped) sensor than their full-frame sensor counterparts.

   What does all this have to do with length or focal length?

  Let's use an example to clarify this issue.

  We took two photos of the same subject, with the same 50mm lens, and also from the same distance, the only thing we changed was the type of camera, where we took the first photo with a Full Frame camera, and the other with a Crop Sensor camera. The result is as follows:

  We note that the house in the Crop Sensor image is zoomed in compared to the same house in the Full Frame Sensor image, even though both images were taken from the same distance and with the same lens.

  I think you've come to a conclusion!

  Yes! A Full Frame camera that captures the subject you want to shoot with the focal length you selected, for example, you put an 85mm lens on a Full Frame camera, you will get a picture with a focal length of 85mm that does not change. Whereas if you put the same 85mm lens on a camera with a cropping sensor, it would zoom in on the subject. This zoom made by the camera is the so-called Crop Factor. I will explain this point further:

  For example APS-C, Nikon APS-C means that the camera has a cropping sensor, and the crop factor of this camera is 1.5x.

   When we put a 50mm lens on this camera, this focal length will be increased by 1.5x (meaning your subject will be zoomed in at 1.5x scale), so we will multiply 50mm by 1.5, so we will have a focal length of 75mm. (50mm X 1.5 = 75mm)

  In simple terms, a 50mm lens will "behave" like a 75mm lens on a camera (Crop Sensor or APS-C), while the same 50mm lens will "behave" like a 50mm lens on a full-frame sensor camera. Nothing changes.

  If you want to buy a camera, and you are confused between a Crop Sensor camera or a Full Frame Sensor camera and do not know the difference between them and what are the disadvantages and advantages of each of them, please feel free to visit our article on this topic at this link.

   Focal length comparison in camera lenses

  There are many groups of camera lenses, and therefore many focal lengths, let's discover some of them:

  Ultra-wide lens (focal length 8mm to 24mm)

   These lenses are special items, as they create a viewing angle so wide that shooting with them looks unnatural. This is because it is trying to capture as much of the scene as your eyes can see.

  These lenses are called fisheyes, they can be used to take a picture of up to 180° around the lens, and in the end, you will get an image with significantly distorted dimensions.

  This lens may seem useless to you, but on the contrary, it is very useful for shooting in narrow fields or places, because it enables you to include many elements in your image without having to move away from the subject.

  These lenses are also used in photography of events and buildings.

  These lenses are not suitable for portraits, because they distort perspective to the point that the features of the face can look unnatural.

  Wide lens (focal length 24mm to 35mm)

  With a lens of this size, distortion is reduced and the image looks more natural, which means everything is in focus unless your subject is very close to the camera. However, the image taken may have spatial distortion, but it is less than the very wide lens.

  Medium lens (focal length 35mm to 70mm)

  Suitable for almost any type of photography, these lenses are versatile, from portraits to landscapes, as they give approximate images of what the human eye sees.

  These are the most common lenses in both standard lenses (fixed lenses) and zoom lenses.

  A standard non-zoom lens is like 50mm f/1.8. An excellent and inexpensive lens. It provides great results.

  Zoom lens kit also falls into this category. They usually cover a zoom range of 55-18 (on crop sensor cameras) or 70-28 (on full-frame cameras).

  A fixed lens always has better results than zoom lenses, because they are designed for one purpose. You do one well.

  Telephoto lens (focal length 70mm to 300mm or more)

  We often use these lenses to take pictures of distant scenes such as buildings, mountains, or wildlife photography, and they are not suitable for landscape photography, in this case, the depth of field is shallow and narrow (the background is very blurry).

   What camera lens should you use?

  Best camera lens for beginners

  In the beginning, you will definitely need a fixed prime lens,

  A prime lens is the first choice of many photographers, you can capture a wide range of subjects so you can experiment with different areas of photography before purchasing other specialized equipment.

  The 50mm f/1.8 is by far the most popular lens, as it strikes a great balance between field of view and depth of field, and requires no adjustment in focal length to produce a clear image. It's also great for low-light photography.

  Best Portrait Lens

  Capture powerful, powerful portraits, meaning that your photos express the personality of the person you are photographing.

  The best lens for portrait photography is a fixed lens, that is, the focal length does not change

  A quick guide to the best lenses for portrait photography:

• 50mm - Best for photos from the waist up. (If used closely, the face becomes too thin and the nose is too large.)

• 85mm - perfect for knee-up portraits, but also for close-ups to head and shoulders

• 135mm - For shooting head and shoulder photos and headshots. This is also a great focal length for full-length shots with a narrow field of view and background blur.

  In my opinion, an 85mm lens paired with a full-frame camera is the ideal focal length for portrait photography.

  Best lenses for landscape photography

  If you are a beginner, you can use almost any lens as a landscape lens for landscape photography.

  Many new landscape photographers feel as though landscape photos can only be created with a wide-angle lens, for me, the focal length is less important than the quality of the lens glass when it comes to this type of photography.

  If you are a fan of landscape photography, it is better to choose the most high-quality and clear lenses.

  But if you want to specialize in landscape photography, the wider the angle, the more scenery you can include in the photo. Therefore, lengths such as 16mm, 20mm, 24mm, and 28mm are popular choices and are suitable for this type of shooting.

  Best lens for travel photography

  While traveling, you are likely to encounter many kinds of opportunities to take great photographs, from landscapes to close-up portraits and still life. Preparing for all of this while maintaining complete mobility can be a challenge.

  It's a good idea to use a mid-range telephoto lens when traveling. The 24-70mm f/2.8 lens is the go-to lens for travel when luggage is an issue and you simply want to travel light.

  A fast regular prime lens is also a great tool to keep with you when traveling due to its small size and low-light capabilities.

  Best lens for street photography

  Like travel photography, a fast mid-range telephoto lens or a regular fast prime lens is probably your best service on the street. Because you'll want to be able to move around freely, a small lens will always work better.

  Best lens for wedding photography

  Wedding photography is unique in that it includes several types of photography: fashion, portrait, architecture, product, macro, family, and sometimes travel photography.

  To deliver a complete wedding photography business, you will need lenses that allow you to capture every aspect of these aspects with artistic prowess and creativity.

   the best lenses for wedding and event photography:

• 70-200mm f/2.8 telephoto: ideal for portraits and creative background blur.

• 24-70mm f/2.8 standard zoom: the perfect lens ready for anything.

• 16-35mm f/2.8 wide-angle: ideal for reception and group shots.

• 90-100 Macro Lens: For close-ups of rings, table decorations, and a great focal length for head-and-shoulders photos as well.

• f/1.8 35mm: The classic focal length for crisp, wide shots, with a wide aperture to handle low light and deliver gorgeous background blur.

  Best macro lens

  A telephoto lens of at least 200mm is best for macro photography. The focal length of this powerful lens can capture The finer details from afar.

  Best lens for wildlife and sports photography

  These two types share common needs: shooting from a distance, and fast-moving targets.

  You will need a close-up that allows you to keep a large distance between you and the subject you are photographing, while still being able to reach and touch it with the camera. In most cases, the 70-200mm telephoto zoom is the required focal length for most of these applications.

   Conclusion

  The lessons and recommendations in this article are meant to give you a solid foundation of knowledge, so you can start to understand which lenses you might need for your photography and why.

  You already know that your lens is the camera's " eye ". If there is one thing I can recommend if you are just starting out in photography, it is that you invest in a quality lens glass before considering the focal length.

  We hope this article cleared up any confusion you once had about focal length. Once you fully understand it, the technical aspects of photography become easier.

  If you have any questions, ask me in the comments.