Focal Length: 77mm - This is considered a short telephoto focal length on full-frame cameras, offering a narrower field of view compared to standard or wide-angle lenses. It's close to the focal length provided by an 85mm lens, commonly used for portraits, but slightly wider. On APS-C cameras, with a crop factor of approximately 1.5x, this lens would provide an equivalent focal length of around 115.5mm, pushing it more into the telephoto range.

Aperture: The maximum aperture is not specified, but assuming it's a prime lens, it could range from f/1.4 to f/2.8 for higher-end models, providing excellent light-gathering capabilities and the potential for very shallow depth of field. The minimum aperture might range from f/16 to f/22, allowing for greater depth of field in well-lit conditions.

Optical Design: The optical design could vary, but high-quality lenses of this focal length might feature elements such as low dispersion glass and aspherical elements to reduce aberrations and improve clarity, contrast, and color accuracy. Anti-reflective coatings are also common to minimize lens flare and ghosting.

Autofocus: Equipped with an autofocus motor, the lens can quickly and quietly focus on subjects. Higher-end models may include ultrasonic motors (USM) for even faster and near-silent focusing, which is beneficial for both photography and videography.

Image Stabilization: Depending on the brand and model, the lens might include optical image stabilization, which compensates for hand shake and is particularly beneficial at longer focal lengths and in low-light conditions.

Build and Features: The lens body could be constructed from high-quality plastics or metals, with weather-sealing for protection against dust and moisture. It might feature a manual focus ring, and possibly a custom function button or aperture control ring, depending on the manufacturer.

Compatibility: Designed to fit on cameras with the corresponding mount type (e.g., Canon EF, Nikon F, Sony E, etc.). The lens should be compatible with both full-frame and crop-sensor (APS-C) cameras, though its effective focal length will vary on the latter.

Usage: Ideal for portrait photography due to its natural perspective and ability to isolate subjects from the background. Also suitable for certain types of sports, wildlife, or event photography where a slightly longer focal length is beneficial.

Accessories: Typically comes with a lens hood to reduce lens flare and a carrying case for protection. Optional accessories might include filters, extenders, and tripod mounts.

Please note that the specifics can vary significantly between different lens models and manufacturers. If you're looking for information on a specific lens model, please provide the brand and exact model for more detailed information.