Together, the unit of observation and the level of analysis help define the population of a research enterprise. It is distinct from unit of observation in that the former refers to a more or less integrated set of relationships while the latter refers to the distinct unit from which data have been or will be gathered. Level of analysis is used in the social sciences to point to the location, size, or scale of a research target. But while stabilization is nice to have for general and moderately close-up shooting, it’s of negligible benefit for extreme close-ups.Location, size, or scale of a research target These are more effective for close-up shooting, as they correct for vertical/horizontal shift in the camera as well as the more usual vibration or ‘wobble’ associated with handheld photography. Some, like the Canon EF 100mm f/2.8L Macro IS USM and the latest edition of the Tamron SP 90mm f/2.8 Di VC USD Macro, have ‘hybrid’ stabilizers. Increasingly, macro prime lenses nowadays feature image stabilization. The optical quality at very narrow apertures is also important, as you’re likely to have to use narrow apertures to gain even a little depth of field. A smoothly operating manual focus ring with plenty of rotational travel helps to enable very precise adjustments. Given that macro prime lenses also work well for portraiture and general short telephoto shooting, a fast, accurate and quiet autofocus system is good to have.įor extreme close-ups, however, you’re more likely to focus manually, due to the tiny depth of field (which we’ll come to in the next section). To maintain this, most current macro lenses have internal focusing mechanisms, so that the front element of the lens neither rotates nor extends, and doesn’t encroach on the subject at short focus settings.Īutofocus is an important factor for most photographers these days. The distance between the front of the lens and the subject will typically be around 14cm, which feels very natural for close-up shooting. They’re a manageable size and weight, affordable to buy, and have a convenient minimum focus distance of around 30cm. At the other end of the scale, 150mm and 180mm macro prime lenses have minimum focus distances of around 38cm and 47cm respectively, giving you plenty of breathing space, but they tend to be expensive.Īll things considered, macro lenses with a focal length of between 90mm and 105mm are the most popularĪll things considered, macro lenses with a focal length of between 90mm and 105mm are most popular. That’s less than 1.5 inches, and uncomfortably close for many types of macro photography, especially if you’re trying to shoot bugs and other small wildlife.įor intimate subjects, you'll want a lens with a decent working distanceĮven for inanimate objects, the closeness of the lens will often cast a shadow over what you’re shooting, blocking out ambient light. This is towards the rear of the camera body and, once you take into account the depth of the body and the length of the lens, the front of the Nikon 40mm lens extends to a mere 3.5cm from the subject. That might sound reasonable, but the focusing distance is always measured from the ‘focal plane’ of the camera, corresponding to the active surface of the image sensor. Macro lenses with a longer focal length have a correspondingly longer minimum focusing distance, putting more working space between you and what you’re shooting when you need to maximize magnification.įor example, the Nikon AF-S DX 40mm f/2.8G Micro lens (Nikon uses ‘Micro’ instead of macro in its lens classifications) has a minimum focusing distance of 16cm. Instead, it’s all about the minimum focusing distance. Unlike when buying regular lenses, it’s not really about wide-angle coverage or telephoto reach. Focal lengthĪ crucial consideration when choosing a macro lens is the focal length. They’re generally not much larger, heavier or more expensive, and you’ll avoid any heartache if you upgrade to a full-frame camera body in the future. However, you’re often better off buying a full-frame compatible macro lens. There are several macro prime lenses on the market that are designed exclusively for APS-C format cameras. It’s a similar effect to the way that crop-sensor cameras boost the effective telephoto reach of a lens. There’s a bonus if you’re using an APS-C format camera with a 1.5x or 1.6x crop factor, as you’ll fill more of the image frame with smaller objects, giving greater ‘effective’ magnification. As we’ve mentioned, a 1.0x magnification factor reproduces an object at full life size on a camera’s sensor.
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