Shoot on 35mm – develop negative – digital scan to hard drives at 4K – laser scan to 35mm screening print.
This is a very efficient workflow. The film, once scanned to hard drives, can be edited online and any digital effects, titles or credits can all be added digitally. It can then be scanned back out to a 35mm print.
This is a very expensive workflow and will rely entirely on using professional post-production facilities. This is way beyond the budgets of most short films.
16. LENSES AND FILTERS
The type of lenses with which you choose to make your film has a direct effect on the quality of the image you will be able to record. The higher the quality of the lenses, the clearer and sharper the image you will be recording.
One of the major factors in films’ quality and style is the lenses designed for and used with the cameras. However, extremely high-quality cine lenses are no longer just available to people shooting on 16mm or 35mm. High-end video cameras have for some time come with the possibility of interchangeable lenses that allow the user to potentially attach a range of lenses, which means that many of the classic film techniques that require specific lenses can now be achieved on video.
LENS BASICS
Different types of lenses serve different purposes and attaching a different size or type of lens to a film or video camera will give you a different sized image. So, for example, if you set up a camera ten metres from a subject, you could attach different sized lenses, allowing you to create close ups or wide shots without ever moving the camera from its fixed position. This is an important principle to remember. Moving a camera from where it is set up is potentially time-consuming, but by using prime lenses or a zoom lens you can obtain a variety of different types of shot from the same camera position, saving valuable hours and creating a more dynamic variety of shots.
Lenses also change the characteristics of the image, for example wide lenses can give an extreme or subtle curvature to an image also referred to as barrelling, while long lenses can make an image appear flatter. Not simply a byproduct of certain types of lens, this distortion can be used creatively when both choosing a lens for a particular shot and also when cutting between shots created with different lenses during editing.
Lenses function by combining various curved glass elements that can be moved in increments to achieve a sharp, focused image. They also contain an iris that can be adjusted to different sizes or apertures to control the amount of light that passes through it.
LENS TYPES
Focal length
Lenses come in different focal lengths and these focal lengths are referred to in millimetres, so for example 18mm, 50mm, 75mm etc. Each focal length produces a different size of image and perspective.
Different formats require specific ranges of focal lengths, for example a 35mm film camera requires a range of focal lengths designed especially for it. While video formats will have a much smaller image size often recording on to CCD chips seven times smaller than a 35mm film image, so they will have a range of focal lengths based on that.
Even though focal lengths of lenses vary enormously between formats due to image size, the type of image they produce can still be compared, so for example looking through a 35mm film camera with a 50mm lens attached will give you a very similar image as looking through a video camera with a 5.5mm lens attached.
Normal lenses
If you imagine that the focal lengths of any format range from short to long and give you a variety of perspectives, then the mid focal range is what is called normal perspective, because it is the most similar to the perspective of the human eye and so produces a realistic image. Medium focal range lenses give little distortion and are therefore a general-purpose lens for any scenario.
Normal lenses will normally be of these focal lengths, according to format:
35mm film: 50mm lens
S16 film: 25mm lens
DV: 5.5mm
Wide-angle lenses
Wide-angle lenses are lenses with shorter focal lengths. They provide a more extreme perspective, creating a wider frame by pushing the perspective further back than where the camera itself is actually placed. They are frequently used for creating an impression of greater space and the distortion they produce can make actors or props appear larger than they actually are. Extreme wide-angle lenses or fish-eye lenses will produce a very noticeable distortion that is often used for visual effect.
Wide-angle lenses will normally be of these focal lengths, according to format:
35mm film: 9.5 downwards
S16 film: 6.5 downwards
DV: 3.4 downwards
Telephoto lenses
Telephoto lenses are lenses with longer focal lengths. Long lenses produce a close perspective with a smaller frame that brings you closer to the subject than where the camera is physically placed. Telephoto lenses produce a very flat, tight image and can be used for close ups to shoot subjects from greater distances. The disadvantage of telephoto lenses is that they magnify movement, shake or wobble, while controlling the camera will appear much more severe when using a long lens.
Telephoto lenses will normally be of these focal lengths, according to format:
35mm film: 135mm
S16 film: 50mm
DV: 20mm
Prime lenses
Prime lenses are lenses with a fixed focal length. These focal lengths are normally combined into sets of lenses that will cover everything that you would conventionally need for filming a scene. Sets of lenses will range from short to long lengths covering intervals in between; by using a combination of prime lenses in a conventional set, it’s possible to create a dynamic range of shot perspectives. Although a zoom lens may cover the focal lengths of prime lenses, primes normally produce higher-quality images and are faster, so can be used with less light. Sets of prime lenses will normally consist of these focal lengths according to format:
35mm film: 18mm, 25mm, 50mm, 85mm
S16 film: 9.5mm, 12mm, 16mm, 25mm
DV: see video lens adapter
Figure 33. Set of super speed Zeiss Prime lenses. Image courtesy of Arri Group.
Zoom lenses
Unlike prime lenses that are fixed at a particular focal length, zoom lenses allow you to move between ranges of focal lengths and can be used either at a fixed length or by moving between them, to create a zoom shot. Zoom lenses have the obvious advantage that they don’t constantly need to be changed. However, due to their nature, they aren’t capable of producing the same quality as using prime lenses; they are often slower-speed lenses than primes, so need more light to shoot with.
FOCUS
Whether you are using low or high-quality lenses, it’s critical to ensure that the focus is as sharp as you can possibly achieve. Video cameras will often provide an auto focus function, but this is not suitable for the needs of most filmmakers, so manually focusing the camera is the preferred option. This can either be adjusted by eye, or by measuring. Eye focusing is fast, but not very precise. Due to the size of viewfinders, it is often hard to distinguish whether what you are seeing is sharp or not.
Some prosumer video cameras offer a function that will highlight the focused area of the frame with red lines, which can help tell you when things have gone out of focus, but the task of focusing the camera while following the action can still remain difficult.
Measuring the distances is the most precise way of achieving a crisp image. Most professional film lenses are designed to be used in this way. The lenses are marked with calibrated distances at which they will focus. So setting the lens marking to 2.8m means that the focus will be precisely at that distance from the lens. When using higher-resolution formats and professional quality lenses, there is more opportunity to achieve a super-sharp image; although this is an obvious advantage, the downside is that any image that isn’t correctly focused will be much more noticeable and appear softer. This is why, on professional shoots, it’s standard procedure to measure the distance to the subject and s
et the lens focus manually. Normally the focus puller attaches a tape measure to the top of the camera and measures off to a point, or range of points if the camera or subject is going to move. These measurements are then marked on the follow focus, so that the lens can be adjusted between them fluidly during the shot, ensuring that the focus is maintained at all times.
Although all professional lenses will be calibrated with focus distances, different focal lengths will only be able to focus within certain ranges. Beyond these ranges, the lenses will reach an infinity marking which appears as an eight turned on its side; anything beyond this point will be in focus, but not as sharp as within the distance markings.
Figure 34. Camera assistant measuring off the focus.
APERTURE
Exposure is the other critical function of lenses. The amount of exposure is controlled by the degree to which the iris of the lens is opened. The size of this aperture determines how much light is let through. This is calibrated on the lens in numbers that are referred to as stops. On stills camera lenses these are known as F-numbers or stops, but, to differentiate, film lenses are marked with T-stops. The lower the T-stop the wider the iris is open and the more light is let in. The higher the T-stop, the smaller the aperture and the less light is let in. Conventional T-stops will run from a low figure such as T 2.0 to T 22. How low the lowest T-stop figure is depends on the speed of the lens (see lens speed).
Setting the right aperture is imperative to producing a well-exposed image, and is dependent on the speed of stock (when shooting on film) and the amount of light available. This is set either by an ‘in camera’ light meter, or more accurately with a handheld light meter. The aperture setting has an influence on the lens’s ability to focus (see depth of field).
Depth of field (DOF)
Depth of field is one of the most important aspects of lenses and formats. Everyone will be familiar with shots in films where only a certain object will be in focus, or the profile of a face, while the rest of the image remains out of focus. This technique is used widely and creatively throughout filmmaking, and allows the director to draw the audience’s attention to particular details and aspects of an image. This is achieved by creating a shallow depth of field.
Figure 35. Shots making use of shallow depth of field achieved with the Brevis 35 adapter on HDV format, shot by Denis Wood. www.cinevate.com
Depth of field is the distance covered by a lens that will be in focus. If you focus a lens on an object three metres away then there will be a distance either side of that object which will also be in focus. How great or small those distances are will be determined by the aperture setting on the camera. The lower the T-stop the shallower the depth of field becomes. So for instance with a low T-stop aperture setting, focusing on the object three metres away might give a depth of field of ten centimetres either side of the object, but with a high t-stop aperture setting, it may focus a metre either side. Depth of field therefore requires large apertures and is also dependent on the image size of the format. Video formats have a lot of depth of field due to their small image size, which is why it is difficult (see video adapters) to create the same shallow depth of field that you can achieve with film formats such as S16 and 35mm.
LENS SPEED
The other significant differentiating factor amongst lenses is what’s referred to as their speed. The speed of a lens is the amount of light it can let in at its widest aperture. This is a very important consideration when choosing a lens or set of lenses to shoot with. Slower lenses, which will start with a higher T-stop, mean that they can only be used in conditions where there is at least enough light to reach this first stop. Fast speed lenses, often called super-speed lenses, will have a very low first stop, meaning they are ideal for low-light situations.
Figure 36. Lens aperture T-stops.
Mounts
Different sets of lenses are designed for different formats, but, within those formats, lenses will also have a particular type of mount. Some of these are specific to the make of a type of camera, such as Aaton mount or Panavision mount, which means those lenses can only be attached to a camera with the same mount. There are also universal mounts, such as PL or PV, which can be found on different makes of camera and so any lens with the equivalent mount can be used. It is also possible to find adapters for many common lens mounts. When hiring sets of lenses it’s important to check that the mounts are compatible with the camera.
Video lens adapters
For a long time, one of the major advantages of shooting on film was the quality and behaviour of the lenses involved. Shallow depth of field and general quality of the lenses contributes hugely to the look of film. Video formats due to their comparatively tiny image size and small CCD chips could not benefit from high-quality lenses and the ‘film look’. The first step towards remedying this was the advent of video cameras with interchangeable lenses. However, because of the smaller image size of video, if you simply placed a 35mm film lens on the camera, you would only be using a tiny fraction of the whole lens. This dilemma has recently been solved by the invention of adapters that are designed to enable the use of film lenses with video cameras. They work by projecting the 35mm lens image into a series of prisms that reduce its size to that of the video image. This then means the whole lens is used, and behaves in the same way as if it were on a 35mm camera so you can produce the same shallow depth of field that you can with film. The overall quality that the lenses produce gives amazing quality video images. The adapters are designed to be used with sets of both film and photographic prime lenses.
There are currently several versions on the market:
BREVIS 35
RedRock Micro M2
Mini35 Digital adapter from P+S Technik
MOVIEtube ST or PRO
MATTE BOX
Matte boxes serve two functions. Their primary function is to cover the peripheries of the lens so that light can’t refract into the lens from the sides and ruin exposure settings and image quality. If the matte box isn’t enough within itself, then extension pieces known as French Flags are attached to it.
The second function of matte boxes is to allow filters to be inserted into removable trays that then cover the lens.
FILTERS
Filters perform a variety of functions that will directly affect the images you are capturing. When shooting on film, filters are commonly used in conjunction with certain types of stock or lighting to rectify possible imbalances. Filters can also be used for purely aesthetic reasons on both film and video, allowing you to create a mood or tone or enhance what is already there. The other types of filters widely used in cinematography are neutral density filters and polarising filters.
Neutral density filters, or NDs, are used to filter the amount of light coming into the lens. They come in varying degrees of transparency and are also used in bright light situations to enable wide apertures for shallow depth of field.
Polarisers filter light as well but they filter reflected light from surfaces, for instance reducing glare from windows or reflective surfaces.
FOLLOW FOCUS
A follow focus is used to accurately and smoothly control focus settings. Focusing a lens by hand while operating a camera can be difficult or impossible to do, and is normally performed with a follow focus device that attaches to the camera and is operated not by the DP but by a camera assistant. Using a combination of wheels and gears, the follow focus allows a focus puller or camera operator to make fluid changes in focus. Generally the focus distances will have been measured before the shot allowing the puller to mark them on the follow focus discs and turn the mechanism smoothly between them.
17. LIGHTING
Whichever format and type of camera you decide to shoot on, it’s important to remember that, to fully capitalise on its potential quality, then you need to use it under its optimum conditions. The key factor to creating these conditions is light.
Lighting for either film or video has two major functions, both of which ar
e crucial to creating a quality image.
EXPOSURE
The first is exposure. Whether you are using film or video, you need to create an environment where there is enough light to record a well-exposed image. Both film stock and CCD chips are dependent on receiving an adequate amount of light to produce images. And adequate doesn’t just mean enough light for the camera to pick up an image. Although most cameras, especially video, will be able to record an image in low-light conditions, the quality of that image is going to be very poor. The camera will potentially be able to compensate for the lack of available light by digitally enhancing the image within the camera, but the resulting image is going to be pixelated and lack definition. Similarly with film cameras, using a high-speed film may allow you to film in very poorly lit environments, but unless there is enough light to expose things properly, then again the image quality will suffer and you will end up with a grainy image with no distinct detail.
So when planning your shoot you should ensure that there are high enough light levels for whichever format or camera you are going to use. Natural light may need to be boosted with artificial film lighting and even practical lights, such as domestic lamps, may need to be fitted with brighter photo bulbs until you have raised the light levels to a satisfactory level.
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