lenses

It would probably be hard to miss the fact that some photojournalists often carry two cameras, and sometimes more than two cameras, when covering various types of events, whether political, sports, or otherwise. Photojournalists often carry multiple cameras for a variety of reasons. One important reason is to have cameras setup in advance to be able to photograph subjects at a variety of distances from the photographer. Also, there isn't any single lens with the features and capabilities to handle every potential situation. 

Beyond focus length and maximum aperture, one of many factors a photograph must consider is that every lens has a - minimum focus distance - a limitation that impacts lens choice for various types of photographic situations. Significantly, lens price is not a determining factor when it comes to the minimum focus distance aspect of lens features. Nearly always, the minimum focus distance is a limitation of the geometry and light physics of the lens itself. In other words, it is extremely difficult to create a lens that provides both a wide maximum aperture, a long maximum focal length, and a short minimum focus distance. For example, the $1,849.95 MSRP Nikon AF VR Zoom-NIKKOR 80-400mm f/4.5-5.6D ED lens has a minimum focus distance of 7.5 feet. The similar, slightly more expensive, Nikon AF-S NIKKOR 80-400mm f/4.5-5.6 G ED VR, with Vibration Reduction (Image Stabilization) added,  has a minimum focus distance of 5.74 feet. The nearly equivalent Canon lens, the $1,699.00 MSRP Canon EF 100-400mm f/4.5-5.6L IS USM, has a minimum focus distance of 5.9 feet. In all these instances, the photographer cannot photograph subjects - in focus - at less than six (6) to seven (7) feet when using these lenses, and none of them is a "budget" lens. None of these lenses, which all include zoom capabilities, is a "wide open" lens with an extremely large maximum aperture either. 

So, the next time you see a photojournalist at any type of event, who requests their subject back up, that photographer is telling the truth when stating that it isn't and/or wasn't possible to obtain focus on a particular subject during a event because the subject, or subjects, were too close to the photographer for the photographer's lens to be able to obtain focus on that subject. There are many trade offs with regard to choice of equipment for event photography. It could be that a photographer made the calculated decision to "pack light", since each full frame DSLR camera and full frame zoom telephoto camera lens together may weigh between four (4) and six (6) pounds each, or more, in addition to any other gear the photographer may need to carry during an event shoot that may last hours, and which might even involve various types of dangers, including crowd violence, police violence, and even violent assault directed specifically at photojournalists.