query: Does focal length change when I adjust the focus?
positive_passages.docid: 150402
positive_passages.text: Is it normal for focal length to change while focusing?
negative_passages.docid: 9671
negative_passages.text: Do gravitational lenses have a focus point?
negative_passages.docid: 10820
negative_passages.text: What is the formula for percent of frame filled at a specific distance and focal length?
negative_passages.docid: 129613
negative_passages.text: Why does illuminance stay the same for a given f-stop even when focal length changes?
negative_passages.docid: 109652
negative_passages.text: What is the limiting factor in lens construction when it comes to f-stop values?
negative_passages.docid: 29080
negative_passages.text: How do extension tubes affect focusing distance?
negative_passages.docid: 129196
negative_passages.text: Does crop factor still apply to a vintage film SLR lens?
negative_passages.docid: 113163
negative_passages.text: Why do some lenses focus past infinity?
negative_passages.docid: 134974
negative_passages.text: What is the focal length on your typical cell phone camera?
negative_passages.docid: 124074
negative_passages.text: Does stacking more lens filters decrease overall image quality?
negative_passages.docid: 37632
negative_passages.text: How to compare the focal length of a 50mm prime lens with the default lens of a point and shoot camera?
negative_passages.docid: 145622
negative_passages.text: How do constant aperture zoom lenses work?
negative_passages.docid: 63434
negative_passages.text: Technically, why is the out of focus area blurred more when using a bigger aperture?
negative_passages.docid: 35335
negative_passages.text: What is the relationship between focal length and shutter speed?
negative_passages.docid: 151884
negative_passages.text: How do I set focus range?
negative_passages.docid: 38465
negative_passages.text: Does a Nikon DX lens on a FX camera get subjected to the 1.5X crop factor?
negative_passages.docid: 87866
negative_passages.text: Tracking a shot with focal variation (zoom)