What Lens do I Need?

April 14, 2017

 

 

You’ve just bought your shiny new camera body and now need to kit it out with some tasty glass but there are too many choices out there. We’re here to help you decide what lens will be best for you!

 

The Basics of Lenses

 

There are a lot of different factors to consider when buying your lens but there are two main ones you should really be looking at. The first is the focal length; this is measured in mm (millimeters) and determines how much magnification a lens will give you. The lower the number in mm the wider the lens or the more you can fit into the image and the higher the number the more zoomed in or magnified the lens will be and the less you can fit into the frame.

The second factor is the aperture or the amount of light the lens can let through to the camera. The aperture is measured in something called F stops (or sometimes T stops, but we’ll cover that in a later blog) and the basic rule of the F stop is to remember the lower the number, the wider the aperture or the more the light is being let through the lens. So an F stop of f/1.8 will let more light through than say f/8. The other big thing with F stops is the lower the F stop, the more bokeh is produced or the more out of focus the back ground will be. This is a very desired look for video production.

 

Prime vs Zoom

 

There are two major types of lenses that you can find on the market, prime lenses and zoom lenses. A prime lens will not give you any ability to change the focal length or zoom in on a subject and is fixed to one field of view. Whereas a zoom lens will allow you to quickly change how an image looks by changing the focal length.

 

Now, from the above a zoom lens can seem very attractive to many, but the main thing to consider is that generally prime lenses will outperform zoom lenses in quality in regards to sharpness and clarity as the glass inside does not move and is designed for one specific focal length. On the other hand a zoom lens must adhere to multiple focal lengths and therefore requires the glass inside to move and often lowers the quality of the final image. But this is not to say that there are not fantastic zoom lenses.

The other main thing to consider is that a prime lens will often let much more light through the lens. For example, they will often have an F stop of f/1.8 or f/1.4 and can even go as low as f/0.9 which is letting through a lot of light and giving you a razor thin depth of field. Zoom lenses on the other hand often fall as low as f/4 or f/2.8 but very few high end models can go as low as f/1.8.

When choosing between prime and zoom lenses it is often a choice of quality against convenience. We like to use a set of very fast f/1.4 cinema prime lenses as we believe this gives us the greatest quality for the final image we output. But we do also have some very high quality zooms in our camera kit such as a 70-200 f/2.8 and a 24-70 f/4 which give us good enough apertures to use in more situations and very nice focal lengths for run and gun style shoots such as when shooting weddings or documentaries.

 

 

Remember your Sensor Size

 

Before I carry on and discuss the different types of lens, you must remember to consider the crop factor of your sensor. For example, if you read our last blog and have been inspired by the amazing Panasonic GH5, you will know it has a very small sensor that requires you to multiply you focal length by 2. Meaning that a 50mm lens on that camera is actually a 100mm lens. An APS-C camera will generally have a 1.5x crop factor (or 1.6x on Canon cameras) meaning a 35mm lens is equal to a 52mm lens (or 58mm on Canon). These simple pieces of maths can really change how your lens works with your camera so always remember to check the size of your cameras sensor before committing to any lens.

If you have a full frame camera like the Canon 6D then you won’t need to worry as all the focal lengths translate directly to the full frame 35mm format, this means your 50mm lens is always going to be 50mm.

 

Types of lenses

 

As we’ve said, the lenses come in many different focal lengths and each one has a different effect on the image it produces.

 

Fish eye (12mm and below)

A fish eye lens will give you probably the most unique look to an image out of all the lenses. It will firstly give you a circle image rather than a rectangle image as it often is too wide to cover all of your cameras sensor. As it is so wide, it also has an extremely distorted look and feel to it. This means that the straight lines in your image such as buildings often appear to be curved. We don’t often use these lenses here, but if you’re shooting skateboard videos, I’d say it should be the first lens you need.

 

Ultra-Wide (12mm – 20mm)

Ultra-wide lenses are great for fitting a lot into your frame, so if you are either really strapped for space or need to get a grand wide shot of landscape, this should be your go to choice. We recently shot a short film that took place in a tiny cottage and used a 14mm lens on a super 35mm sensor recently which gave us roughly a 21mm lens and worked out great, making it look much bigger without too much distortion in the image.

 

Wide Angle (24mm-35mm)

Wide angle lenses are a perfect edition to the camera bag because of their versatility. I personally like the look of a wide image as you are still able to get some sort of narrow depth of field while still being able to use space in your shots, with the two of these together really allowing you to isolate a subject and make it stand out. These are often best used for shots on gimbals and glide-cams as they pick up minimal shake when moving with them. Wide angle lenses also push out the background from a subject, so make everything look much further away from you than they actually are.

The great thing about this focal length is that it is often included in many kit lenses that come with cameras, for example a lot of Micro 4/3 lenses are 12mm wide making them 24mm, APSC kit lenses are 18mm at the wide, meaning they are about 27mm and full frame kit lenses are 24mm wide. So which ever type of camera you chose, this is often included.

 

Standard (35mm – 85mm)

Standard lenses are the most important lenses to have in your arsenal. They give you the closest look to what your eye can see, which is roughly 50mm translated. A 35mm lens will give you something a little wider allowing you to play with distortion and an 85mm will give you a little more telephoto, pulling in the background and giving you a very claustrophobic feel to your image. These lenses are great for portraits as they offer minimal distortion to your subject and again, a very similar view to what your eye can produce. If you are choosing your first lens, we always recommend a lens that covers this focal range, whether it is a prime or a zoom lens. Having a standard focal length will give you the most flexible lens in all situations.

 

Telephoto (100mm and above)

Telephoto is one of our preferred focal lengths for video production as it can often allow us to take a step back from the action in front of us and let us record from afar. This is due to the large magnification that these lenses give you.

If you are recording wildlife or sports then we always suggest these lenses, they are also very useful when recording any macro or close up work. But we also use them in normal recording too as it allows us to compress the background completely and create a really out of focus background to the image, pushing a greater focus onto the subject.

 

So that’s our breakdown of the different types of lenses you may encounter when you are looking for new glass. Remember the best lens is always the one most suited to your needs, there is never one stand out lens we can recommend for anyone as everyone's needs are very different. But we hope this quick guide has helped you in choosing your next lens.

 

Happy shooting!

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