query: Is the Canon EF 24-105mm f/4L IS USM lens parfocal or not?
positive_passages.docid: 149630
positive_passages.text: Why do photo cameras lose focus when you zoom, when movie or TV cameras keep it?
negative_passages.docid: 116792
negative_passages.text: Is there a single lens suited for flying birds, mountains, and close-up portraits?
negative_passages.docid: 4389
negative_passages.text: How can a lens with a single focal length focus on more than one plane?
negative_passages.docid: 136611
negative_passages.text: Why choose an 80-200mm over an 18-200mm lens?
negative_passages.docid: 152115
negative_passages.text: Can I convert binocular zoom to equivalent lens focal length?
negative_passages.docid: 87632
negative_passages.text: How do I find the thread diameter of my lens?
negative_passages.docid: 57370
negative_passages.text: What are the limitations of a typical kit lens as a general purpose lens?
negative_passages.docid: 8552
negative_passages.text: Which focal-length lens is usually used for portrait photography, and why?
negative_passages.docid: 135149
negative_passages.text: How do camera body motors compare to in-lens motors for focusing?
negative_passages.docid: 46184
negative_passages.text: What should I consider when purchasing a macro lens?
negative_passages.docid: 21744
negative_passages.text: Focal length of an ellipse and related results
negative_passages.docid: 52368
negative_passages.text: Does the diameter of the aperture increase with increases in the focal length with constant F-number(F-stops)?
negative_passages.docid: 80997
negative_passages.text: What advantages does manual mode have over aperture priority mode?
negative_passages.docid: 133059
negative_passages.text: How to select lenses for outdoor sports photography?
negative_passages.docid: 34665
negative_passages.text: What image-quality characteristics make a lens good or bad?
negative_passages.docid: 12460
negative_passages.text: Why prefer the 18-55mm and 55-250mm lenses vs 18-200mm?
negative_passages.docid: 62822
negative_passages.text: How can lens cause consistent front or back focus?