Variable aperture is a key concept in zoom lenses that impacts the quality and versatility of your photography. This guide breaks down what variable aperture means, how it functions, and what it implies for your images, with examples from popular lens manufacturers.
What does Variable Aperture mean?
Variable aperture in a lens means the widest possible aperture changes as you zoom. This is a design feature that keeps lenses affordable and light but comes with trade-offs in light intake and depth of field.
How Variable Aperture Functions
As you zoom in with a variable aperture lens, the maximum aperture typically gets smaller. This design choice balances cost and portability against the consistent light-gathering ability of more expensive lenses.
Examples of Lenses with Variable Aperture
Fujifilm XC 50-230mm f/4.5-6.7 OIS II
With the Fujifilm XC 50-230mm lens, you'll notice a maximum aperture of f/4.5 at 50mm, which narrows to f/6.7 as you extend the zoom to 230mm, affecting exposure and depth of field.
Sigma 17-50mm f/2.8-4 DC OS HSM
This Sigma lens starts with a wide aperture of f/2.8 at 17mm, ideal for low light. At the telephoto end, 50mm, the aperture reduces to f/4, which changes the exposure settings required.
Nikon AF-S DX 55-200mm f/4-5.6 G ED VR
This Nikon lens is a classic example of variable aperture in action. At the wider end of its zoom range (55mm), its maximum aperture is f/4. However, as you zoom in to 200mm, the maximum aperture narrows to f/5.6. This means that if you're shooting in a low-light scenario, you'll need to account for the reduced light intake at 200mm compared to 55mm.
Canon EF-S 18-135mm f/3.5-5.6 IS STM
Canon's versatile zoom lens, suitable for a range of scenarios from wide-angle to telephoto, also exhibits variable aperture. At 18mm, its widest focal length, the lens has a maximum aperture of f/3.5. But as you zoom in towards 135mm, the aperture decreases to a maximum of f/5.6.
Sony 16-50mm f/3.5-5.6 OSS
Designed for Sony's mirrorless cameras, this compact zoom lens provides flexibility for photographers on the go. At its widest setting of 16mm, it offers an aperture of f/3.5. As you zoom in to its telephoto end at 50mm, the maximum aperture becomes f/5.6.
Understanding the Impact of Variable Aperture
Variable aperture can affect your shooting in several ways, from the amount of light entering the lens to the depth of field in your images. Recognizing these effects can help you make better decisions on exposure and artistic expression.
Grasping the variable aperture is vital for photographers who use zoom lenses. It guides you in choosing the right settings across your lens's focal length range and ensures you're prepared for how aperture variation affects your photos. No matter the brand—Fujifilm,