Lens and Focal LengthVafa2020-08-31T10:11:18-06:00
How to Choose a Proper Lens? Or:
Different Lenses for Different Purposes
This topic assumes that you already have an SLR camera and you are comfortable with your cameras settings and its features. Please review “Photography 101” for tips on how to use your SLR camera prior to this lesson.
How to choose proper focal length:
SLR cameras are compatible with different lenses. Regardless of the camera manufacturer you can choose lenses by the same manufacturer or other brands like Sigma, Tokina, Tamran, Zeiss and so on.
There are different factors for each lens. The main one is whether or not the lens is compatible with full frame cameras. Let’s see what full-frame and crop-frame (or simply not full-frame) cameras are. You might think it is about the camera sensor since it is mentioned to “frame”. So, yes, you are right. Full frame cameras are those that come with a full size sensor that is equal to a traditional 35mm film (obviously these lenses are more expensive!) .
Example of full frame cameras are Canon 1D, Canon 5D, Nikon D5 or Nikon 850. Other cameras that are not full frame, have smaller sensors. Smaller frame causes the lens focal length value to get multiplied by a number like 1.5 or 1.4 or 1.6 (depending on how small the frame is). In other words if you attach a 200mm zoom lens to a full frame camera, you get focal length of 200mm, but if you attach it to a cropped frame camera, let say Canon 7D, then the focal length is going to be 200×1.6 = 320mm. This is not always bad! A crop sensor gives you more zoom results which is not necessarily always bad, but different. You can learn more about sensors and the advantages and disadvantages of full frame cameras in other topic on vafa.ca, but for now let’s just consider different lenses compatible with full frame cameras (crop frame cameras are ok with either type, only full frames are picky!).
As an amateur photographer (someone who takes photos for fun) selling them occasionally, you need to cover lenses from 11mm to 200mm. The more professional activities you do the more specialized lenses you will need. For example for birds photography or astrophotography you might need something around 800mmx.
Unfortunately you cannot cover 11mm to 200mm with a single lens, this is why you need at least three lenses to cover the whole range. It could be :
Canon 11-24mm F4 IS USM or Nikon Nikkor AF-S 14-24mm f2.8
Canon EF 24-70mm f2.8L II USM or Nikkor AF-S 24-70mm f2.8 E ED VR
Canon 70-200mm F2.8 IS USM IS or Nikkor AF-S 70-200mm f2.8 E FL ED VR
These are high-end lenses that cover the range from 11mm (14 in Nikon) to 200mm. Of course there are cheaper lenses with the same specification that sometimes still offer similar quality.
Beside these zoom lenses (means you can change the focal length from a min to a max) there are “prime” lenses. Prime lenses only provide you with a single focal length, means you cannot zoom in or out, but they give you the best photo quality. In other words you cannot adjust the framing by changing the zoom ring on your lens, instead you have to move forward or backward to get the subject property framed in your camera. I will talk about them later.
Back to zoom lenses and their ranges, so, here is the question: When do I pick which lens?
The first group of lenses (11-24 or 14-24mm) are “wide” lenses. Means you get to include the most of your scene in your photo. This means you do not have to stand far away in order to capture the whole scene. These lenses are good for real state photography, landscape and architecture photography purposes. These kind of lenses are not recommended for portrait shots. Also not useful for photography of animals (like birds) because they show up so tiny and small in your shot.
Pros and cons:
Wide angle pros:
Focusing is usually faster and easier
They are lighter than other lenses (most of the time)
Depth of Field (DOP) is usually very deep (this one repeats under cons too, depends on what the purpose of photography is)
Wide angle cons:
You have to get close to your subject if you want to capture tiny details
Depth of Field (DOP) is usually too deep (this one repeats under pros too, depends on what the purpose of photography is)
Distortion is more than other lenses (What is distortion? Simply, parallel lines could show up curvy and it happens more as you get closer to the edges of the photo.)
They are more expensive than mid range zoom lenses
The second group of lenses (24-70mm) are called mid range zoom or simply “zoom” lenses. These type of lenses are kind of all-purpose lenses. They are the best for travel. Slightly covering 90% of what you need during a vacation kind of travel or even an adventure travels. Also they are good for portrait photography. When it comes to landscape they are not as good as wide lenses but still cover a lot on their min focal length (24mm).
Pros and Cons:
Mid-range zoom lens pros:
They cover a large range starting around 20mm to 100mm
During travel they cover many different purposes, like portraits, architecture, landscape, events and so on
They are still fast enough when it comes to focusing
You do not have to keep changing the lens for different shots
They usually have narrow Depth of Field which helps a lot with vivid subject and blurry background
Mid-range zoom lens cons:
They are kind of heavy
They are bulky (bigger than prime lenses)
They provide you with bigger aperture than prime lenses, or they are not as fast as prime lenses* (what is Fast Lens?)
The third group of lenses (70mm and more) are called Super Zoom or Telephoto lenses. These kind of lenses give you the opportunity of taking photos of small objects very far away from you. They are fantastic choice for sport or event photography, animal photography, weddings and portrait shots. Also they work great under low light conditions.
Pros and Cons:
Zoom lens pros:
They cover a reasonable range starting around 70mm and more
You do not have to get too close to your subject in order to get the desired details
They are the best option for sport photography, bird photography and astrophotography
They give you a very nice shallow Depth of Field, making the background blurry. Very narrower than other groups of lenses
Zoom lens cons:
They are very heavy. ( when using tripod or monopod make sure lens is attached to tripod not the camera)
They are bulky (bigger than any other lenses)
They are not as fast as other groups when it comes to focusing. That is why they have a switch to narrow down the focus area. (e.g. less than 1 m and full range.)
9 Tips to Remember:
One single lens cannot cover all your photography needs
As beginner or amateur photographer you need to cover the range (roughly) between 11mm to 200mm
You need at least three lenses if you want to use professional lenses to cover the above said range of 11 to 200 mm (One single lens with huge range of 20 to 200 or so on will never give you a reasonable photo quality)
Range 11 to 24 mm (ish) is wide
Range 24 to 70 mm is mid range (or zoom)
Range 70mm + is super zoom
24 to 100 lens is an all-purpose lens, great for travel, landscape, portrait, (some) sport,
Zoom lenses (70mm and more) are great for sport, event, flower and animal photography
This topic is only focusing on “focal length” element of lenses, there are more lens aspects like aperture, focus speed, sharpness, details capturing and more