Photography talk. Moderated by @alexbaldwin and @maxvoltar.
Everything you need to know about cinema lensesAugust 20, 2021 at 4:05am
In photography as well as in cinema, the lens is a vital part of the camera because it is through it that the light passes.
Here is an article that explains how it works and the important points to consider.
The aperture A cine lens has an adjustable aperture system. The larger the aperture, the more light you will have entering the camera and therefore the more your photo or shot will be exposed.
The goal is to find the best aperture so that there is enough light on one side so that the image is not under exposed, but on the other side not too much so that it is not over exposed.
For example, if you are shooting a low light scene such as during a sunset, you will need to open your cinema lens so that there is enough light coming through.
On the other hand, if you are shooting at the zenith, there will be a lot of light and you will have to reduce your aperture.
Depending on your lens you will have a range of choice of aperture that will be between 1 and 32.
For example, here is the aperture range of my lens which offers the following values: [ 2,8 ; 3,2 ; 3,5 ; 4 ; 4,5 ; 5 ; 5,6 ; 6,3 ; 7,1 ; 8 ; 9 ; 10 ; 11 ; 12 ; 13 ; 14 ; 15 ; 16 ; 17 ; 18 ; 19 ; 20 ; 21 ; 22 ]
You should know that the lower your value, the more light your cinema lens will take. Conversely, the higher the value, the less light your lens will absorb.
The aperture also affects the depth of field or size of the area of focus. Thus, the lower your aperture value (so a lot of light coming through) the shallower the depth of field. Conversely, the larger your aperture value, the greater your depth of field.
When choosing your lens, it is better to choose those with low aperture values. I advise you not to take a cine lens whose first value of its range is an aperture that is greater than 3.2 because you risk in some situations, to have scenes too under exposed.
The focal length The other very important element of the lens is the focal length.
There are lenses with fixed focal lengths that have only one value and lenses with variable focal lengths (zoom) that vary in general between values such as [24-70] or [70-200] or [16-24] etc..
The larger the focal length, the longer the distance we will see but the smaller the angle of vision.
Conversely, the shorter the focal length, the less you will see at a distance but the greater the angle of vision.
Well come on, an example is worth 1000 words!
The depth of field, in addition to depending on the aperture, also depends on the length of your focal length. The longer your focal length, the shallower your depth of field. On the contrary, the shorter your focal length, the greater your depth of field.
This is why it is easier to make camera movements with a short focal length than with a long focal length, because your area of focus is larger.
The sharpness It depends on both the sensor of the camera and the lens. The better the sharpness, the more detailed the image. Thus, with a lens with good sharpness, you can on a close-up of a face see extremely accurately the details of the skin. The sharpness is calculated in lines/mm.
The focusing ring The focus ring allows you to focus your image manually, that is to say to choose the sharp part of your image. If you make a camera movement and the point changes, you will have to move the ring to find the point.
Some cinema lenses like the DZOfilm Vespid and Zeiss CP 2 have a larger focusing ring that allows you to focus more precisely and is very useful if your point is going to change several times in the same shot because of camera movement.
I hope this article has helped you understand these concepts. Don't hesitate to react in the comments to ask for clarifications or simply to say what you thought of this article, it's always a pleasure.
August 20, 2021 at 8:45am