What does “Super Fast Lens” Mean?
The term “Super Fast Lens” actually refers to the speed with which the shutter opens and closes to capture a viable photo image of the photography subject. Whether it is a wiggly small child, sitting for his first portrait, or a goalee on your kid’s soccer team reaching over her head as she leaps up in the air to catch the soccor ball and return it to the field of play; these action shots mandate a super fast lens speed for use with a DSLR Camera.
In order to attain a super fast lens speed, we need to understand how the camera system operates and how certain settings: like “Aperture”, “ISO”, “Exposure” and “Shutter Speed”, each work to assure a super fast lens speed.
Aperture
When we refer to “Lens Speed”, we are really talking about the aperture – or maximum diameter of a photographic lens. First, let me explain that there is a simple math trick to remember when discussing aperture formulation. F/1.2 allows a larger amount of light to pass through the camera to the viewfinder, than an f/3.5
Apertures typically range, anywhere from 0.5 to 8.5 – the larger the opening or the diameter of the aperture – translates to a low number, such as f/1.0 – and the smaller of aperture diameters – are expressed as numbers which are higher on the scale, such as f/6.0. An aperture diameter simply explains the amount of light which will be allowed into the camera, through the lens, during the shutter clicks.
Aperture also affect the distance or “depth of field” in which the photograph stays in clear focus, when the shutter is clicked. Depth of field is the entire image on the photograph which is in clear focus, detailed and has a sharp outline to its imagery.
Shutter Speed
When a shutter button is depressed, the shutter opens, and when the shutter button is released, the shutter’s “click” means the shutter has closed. The timing between the opening and closing of the shutter is called the shutter speed.
The diameter of the lens and the setting you choose to lock in the aperture to, means how much light is going to be allowed through the lens, through the pentaprism mirror system to the viewfinder, between the shutter clicks. Shutter speed is measured in seconds and fractions of seconds, such as 1/8000 (meaning 1/8000th of one second).
ISO
Traditional SLR cameras use film, which determines the speed of the shutter, the exposure (amount of light allowed in) and the focal length of the picture. The focal length of the picture is the distance at which the camera should be from the subject, in order to be expressed in a photograph with great detail, sharp lines, no blurry movement, and no noise or grainy features to the image.
For a DSLR camera, since there is no film, we measure the process of the focus in to infinity (distance), the shutter click (exposure & speed) and the aperture (amount of light) – as an ISO Speed. A traditional 35 mm in film, still is represented by the same numerical term, but as an ISO equivalent.
The lower an ISO Setting, like ISO 100, the sharper and more detailed are the features for a low speed, low light, DSLR Camera, with a 35mm lens. The higher an ISO Setting, like ISO 800, would be used for action shots, such as a soccor game in play when the player has lept into the air to make a high kick of the ball. Using an ISO setting of 800 in low light conditions for a distance of 35 mm, with low exposure, would produce an image that appeared to be full of static or (noise) with a grainy appearance.
Exposure
Now, the amount of time can be controlled during the shutter click operation, simply by ensuring that the camera mode is set to “Manual”, so that you can lock-in manual settings which you elect to produce a sharper, detailed and vivid photograph.
The way we control the expsoure timing is determined by how long we continue to depress the shutter button, without releasing the pressure on the button. This is called “Exposure Timing”.
Auto Focus or Manual Focus
Normally a DSLR Camera automaticallu focuses in on each picture, you view through the viewfinder, as the camera mode is set to “Autofocus” (A). However, once the outdoor or indoor natural lighting conditions change, we are forced to reset the camera mode to “Manual Focus” or (M), so that we can correct for mother-nature.
Is it also useful to change the camera mode to M, when we want to shoot with a faster speed! Now some cameras also have an “Infinity Focus” mode (I), in which the camera measures out across the image’s horizon to infinity. Some cameras also have a “Pan Focus” mode (P). The mode enables the camera to lock-in on the closest focus, and ensure than everything else beyond that point is reasonably sharp and in detail. If you are a new user to DSLR Cameras, we suggest you train with each mode, by focusing your camera across a wide open landscape and practice sharpening the image by adjusting the setting dials.
Top 4 things you need to know about Lens & Speed
| 1 | At this time, DSLR Cameras which have a LIVE VIEW option, does not mean that the image you see through the viewfinder, will exactly represent the exposure (how light or how dark) the picture will be when it is printed out. You either need to auto focus, or if you are in low light conditions, set the aperture aprrox between f/2.8 to f/4.2 to ensure eough light is allowed in to the camera’s image. |
| 2 | Lenses are connected to DSLR Cameras through a mount (connector). Only lenses which are made with the same mount-type can be attached together. It is critical to take the camera with you when you shop for lenses. |
| 3 | Available Apertures are limited by the numbering on the attached Lens. Available Shutter speeds or ISO speeds are controlled by the settings on the camera’s body. |
| 4 | A lens may be referred to as “fast” or “slow” depending on its maximum aperture compared to other lenses of similar focal length designed for a similar film format. Lens speed given by the minimum f-number, or alternatively maximum aperture diameter or maximum numerical aperture, is a useful quantitative way to compare similar lenses. |
Taking Care of your Special Lenses
Moisture is the enemy of camera equipment. Remember to continually and gently use your softy lens cloth to keep the lens dry and the camera free of moisture, dust or other particles. With the quality, popularity and relative simplicity of DSLR cameras today and the number of specialty lenses available, even beginners can create magnificent shots of any given subject. Using DSLR camera equipment enables the photography buff to take crystal clear photos, with even exposure, capturing vivid and colorful scenery and perfect natural lighting, every time!
One of the greatest things about owning DSLR Camera is that you can change the lenses as often as necessary for different project shoots. During those lens changes, however, there is a risk of dust falling “onto the sensor.” In fact, the CMOS or CCD sensor is covered by a color filter or a clear glass plate, so really the dust has fallen on something that is covering the sensor. Nonetheless, you want to be very careful at this point, because if anything near the sensor is scratched, the camera needs to go in for professional service!
Remember, all digital lenses are made of GLASS! The sharpness and clarity of your photo images, greatly depends on each lens (including the entire camera body) being squeaky clean and free of any dust, sand, or other particles. The most important tool, every photographer should carry in his/her camera kit is a softy lens cleaning cloth. I am not talking about a washcloth from your closet, or even a paper towel. You need to keep a small and inexpensive camera lens cleaning cloth with your camera kit, at all times!
Don’t use Windex either. Take the time to pick up Camera Cleaning fluid at any camera shop or electronics store. Keep it and new soft lens cloths on your kit and clean your equipment, each event at which you are shooting. Just like in any other business atmosphere, you need to keep your tools clean and ready for the next period of operation.
Taking the time to care for your camera equipment and keep your camera kit full and ready for operation, will ensure a long useful life for your photography equipment!
