The Sigma Zoom Master 21-35mm f/3.5-4.0 lens is a versatile zoom lens compatible with Olympus cameras. With a maximum aperture of f/3.5-4.0, it allows for great low-light performance and depth of field control. The lens is designed for zooming, making it perfect for capturing a wide range of subjects. Weighing 454 grams, it is lightweight and easy to carry around. The lens is also multicoated, ensuring high-quality images with minimal glare and reflections.