Digital SLR cameras filming technique
On 16 Dec 2011
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Aperture besides can be used to control of the depth of field, can also affect the image quality. We know, the greater the aperture, means that have more light through a lens can participate in imaging. But this brings about a problem: because there and less like lens ball etc various reasons, through the lens of the light "quality" and through the lens of the edge "quality" is not the same light. The greater the aperture, it means that there is more to the light from the edge by participating in imaging lens, it is directly causes the imaging quality of decline, performance for lower resolution, dark corner or is the dispersion, etc. But, if we could bring the aperture contraction some, so, only the lens that part of the middle light can through the aperture, the edge of the lens that "quality is bad" ray is blocked. So, as appropriate, shrinkage after aperture, in addition to the resolution will improve beyond, like lens dark corner, dispersion, etc can all be mitigated imaging quality also can get further improvements. So, does the small aperture contraction, the image quality is better? And not so, because, aperture is too small, means that light to the small hole. In the light of the hole is too small, through the light too little, also go against high quality imaging, even in extreme cases, the light will happen diffraction phenomenon, which can reduce the resolution performance. So, imaging for the quality, aperture is not smaller may be more beautiful. Neither the bigger the better, also is not smaller may be more beautiful, so, the aperture of the lens that there must be a best imaging aperture. So, at present the digital SLRS lens, best aperture is? Roughly speaking, for all the picture lens, best aperture in the F8 F11 or general to the left. And for APS-C digital SLR special lens (for example the nikon, Canon EF the DX lens-S, SONY DT camera lens), the best aperture in the F8 usually left. And for the lens used 4/3 system, such as the Olympus ZUIKODIGI-TAL and panasonic/measurement card lens, its best imaging aperture more often, in F5.6-F8 between. In addition to explanation is, not all of the lens aperture to F5.6 contraction in more than to get excellent optical quality. Otherwise, the large aperture lenses will be completely meaningless. In fact, many large aperture high-quality lens, usually only a two gears aperture contraction would get excellent optical quality. For example nikon classic "people like" AFNikkor85mmF1. 4 D, aperture will shrink to F2 above can get the good performance. Instead, the quality of the general lens, often will shrink to F8 aperture. Consequently, in the indoor or dark places, the shooting will be much limited. Can choose to focus while convenient, but in all of these to focus of focus capabilities are not completely the same. Generally speaking, the farther away from the scene by to focus, focus ability weaker. So can get such a conclusion: the central the point must be the most powerful focus. Especially in light faint, or is not what the contrast between the background, the central focus of often can lock focus, and the other is to focus is only "pull the bellows". So digital SLR to still have a kind of focus mode: the central point focusing. That is, the central focus of fixed for that. If set to the central point of focus, does that mean must be placed in the picture taken object is the central? That is not to composition will be waking? The worry is reasonable, but can use some advanced skills to make up for this fault, here are two measures available for reference. One, first will be placed in the picture taken object, then half the shot, at this time the chance to lock in focus. Then, half the shot not to put (this step is key), to move the camera, to change the composition, such, the focus of the picture will still be located in just on the object, at this time to press the shutter, you will get accurate focus, but different composition image. Secondly, the use of automatic focus lock button. Digital SLRS has a button to call AF-L, is automatic focus lock. Also, first will be placed in the picture taken object, then half press the shutter, focus after the completion of the press AF-L button, the camera can also will focus lock, by this time can easily change the composition, and then press the shutter finished making. Adopting the two to should pay attention to. First, to keep the stability of the focal plane, that is, change the composition, usually can only move the camera around, and don't movement. It is simple, and move the camera is equal to the camera, and was taken to change the distance of the object, the focus has to be inaccurate. Second, generally speaking, if the press shutter half way to lock focus, must pay attention to in this case, the exposure data are usually locked. That is, change after composition shutter, the camera is not to the chart. That brings us another problem, if change after too much brightness difference composition environment, it can cause the exposure of the inaccurate, should try to avoid that. ____________ http://www.chargerbatteryshop.co.uk/ http://www.gobatteryonline.com/ Go to Category Digital Cameras | Previous Page |
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