# Focal length > The lens property, in millimetres, that sets the angle of view and magnification. Also known as: prime lens, zoom lens. Category: Lighting and optics. Focal length, given in millimetres, determines a lens's angle of view and magnification: short focal lengths are wide, long ones narrow. Prime lenses have one fixed focal length, while zoom lenses cover a range. ## How PhotoRobot uses it PhotoRobot's recommended cameras guide matches lens types to work: zoom lenses for universal robotic arm or tripod use, macro lenses for detail work, and prime lenses with a fixed focal length for multi-camera synchronisation. Its blog notes that most larger products need only a zoom lens of around 40 to 100 mm to keep the product in frame. ## See on photorobot.com - [Recommended cameras and lenses](https://www.photorobot.com/manuals/recommended-cameras) ## Related terms - [Macro photography](https://www.photorobot.com/glossary/macro-photography): Photographing small subjects at close range so that they appear life-size or larger on the sensor. - [Depth of field](https://www.photorobot.com/glossary/depth-of-field): The distance range in front of and behind the focus point that appears acceptably sharp. - [Crop factor](https://www.photorobot.com/glossary#crop-factor): The ratio between full frame and a smaller sensor, used to compare fields of view. - [Aperture](https://www.photorobot.com/glossary/aperture): The adjustable lens opening, given as an f-number; smaller openings give more depth of field. ## Where this term appears on photorobot.com Mentioned on 16 pages. Most relevant: - [Recommended Cameras for PhotoRobot Systems](https://www.photorobot.com/manuals/recommended-cameras): Zoom lens (Universal, robotic arm / tripod use) Macro lens (Macro / detail, close-up photography) Prime lens (Fixed focal, multi-camera synchronization) Zoom Lens (Universal, Robotic Arm / Tripod). - [Jewelry Photography - Behind the Scenes Production](https://www.photorobot.com/blog/jewelry-photography): Using a macro lens with a fixed focal length is essential for jewelry photos. - [Studio Lighting Overview for PhotoRobot Systems](https://www.photorobot.com/manuals/studio-lighting-overview): …focus limits, total depth of field, and the hyperfocal distance for any combination of focal length, aperture, sensor format, and subject distance. - [Understanding Camera Resolution for PhotoRobot Customers](https://www.photorobot.com/manuals/camera-resolution): There was a zoom lens covering 24mm to 105mm in use, with image capture at 77mm at F16 and speed 1/125. - [360° Product Photography - Content Formats and Production](https://www.photorobot.com/blog/360-product-photography): Usually, a zoom lens with 40 - 100mm focal length accomplishes this. - [3D eCommerce - What is it, Why it Matters, and Production](https://www.photorobot.com/blog/3d-ecommerce): Often, a zoom lens with 40 - 100mm focal length achieves this. - [Depth of Field Chart for Studio Photography](https://www.photorobot.com/depth-of-field-chart): Do you need to know if a 35 cm handbag remains fully sharp at f/16? Adjust the sensor, focal length, and unit above the table to recompute every cell. - [What is Automated Image Capture?](https://www.photorobot.com/glossary/what-is-automated-image-capture): It pushes instructions regarding focal length, aperture, ISO, and shutter speed. - [What is Automated Product Imaging?](https://www.photorobot.com/glossary/what-is-automated-product-imaging): The automation software ensures that physical inputs—lighting, camera elevation, and focal length—are strictly controlled. - [Depth of Field Calculator for Studio Photography](https://www.photorobot.com/depth-of-field-calculator): …focus limits, total depth of field, and the hyperfocal distance for any combination of focal length, aperture, sensor format, and subject distance.