What is Aperture?
Aperture refers to the size of the opening in the lens that allows light to pass through the camera. If the opening is big, more light passes through. If the opening is small, less light passes through. In technical terms, the iris of the lens (similar in concept to the iris of your eye) controls the diaphragm which controls the amount of light that passes through the camera. Point and Shoot cameras do the aperture work for you. Setting the aperture relates to DSLR (Digital Single Lens Reflex) cameras.
Aperture is measured in f -stops. F-stops can range from f/1.4 – f/22 and beyond depending on your lens size . Although it may seem counterintuitive, a smaller f-stop number, such as f/2.8 has a wider opening and lets more light into the camera than f/22. Tamron and Sigma make great lenses and often times can be priced cheaper than lenses from canon or Nikon. The best prices I have seen have been on Amazon.
The aperture size is directly related to depth of field. The higher the f/stop (f/16 or f/22) the greater the depth of field.
This means that when you take a picture with f/2.8 , you will have a lot of light focused on your subject but not on your background. Therefore, objects in y our foreground will be sharp but objects in your background will not. Very often in flower photography, photographers tend to use f/2.8 or f/4 to highlight a specific flower or group of flowers and purposefully create an unsharp background so that it doesn’t distract from the subject of the shot.
Conversely, with a higher f/stop such as f/22, you are decreasing the size of the opening in the camera so less light can get through. At the same time, you are increasing your depth of field. Higher f/stops are used in landscape photography or in other instances where you want to see both the foreground and the background clearly. When photographers shoot mountains in the distance they will use a higher f/stop to try to keep everything sharp.
Lenses for DSLRs often vary in price based on the the f-stop variance and distance they can cover. Some are definitely more pricey than others.
A lens with an f/stop of 1.4 or 2.8 is considered a fast lens since it can allow more light into the camera. Since more light can pass through, these types of lenses are great for low light photography situations. When looking to purchase a lens, always concentrate of the maximum aperture (the lowest f/stop number like f/1.4.) The Sigma 30mm f1.4 is a great lens that I use often. The best price I have seen for this lens is $489
Lenses can be sold as either “Fixed” lenses or “zoom” lenses. A fixed lens has an aperture and focal length that does not change. A zoom lens has the ability for you to focus on subjects both near and far with an aperture that will change to satisfy your focal distance.
A Canon EF-S 18-200mm f/3.5-5.6 IS is a Standard Zoom Lens for Canon DSLR Cameras. The lowest price I have seen for this lens has been on Amazon. At 18mm the aperture will be f/3.5. At 200mm the aperture will be f/5.6
When you are searching for a lens, make sure that your lens is compatible with your camera. Sounds intuitive, but if you have a Canon camera or a Nikon, for example, and are buying a Tamron lens, you need to make sure it is a Tamron lens that will work with your make and model.
If you are interested in a Tamron AF 18-270mm f/3.5-6.3 Di II VC PZD LD Aspherical IF Macro Zoom Lens with Built in Motor for Nikon DSLR Cameras, the lowest price I have seen – with a rebate has been $550.
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