新闻中心当前位置:首页-新闻中心
    “恒定光圈”以及各类形状光晕拍摄技巧
    2015/6/9 11:12:43
    “恒定光圈”的作用
    The function of constant aperture
    光圈基本上能影响两个方面- (1)景深和(2)进光量,如果在改变焦距(zoom)时未能保持光圈值,这样便有机会未能保持浅景深,而且因为光圈变少,进光量随之减少,那么快门必定会变慢或者ISO需要提高来保持曝光正常(请参考照片的形成一文),快门一旦超过了”安全快门”,那么便很容易导至震动和相片模糊,而ISO的提高便会做成讯噪(Noise)的出现,令相片不平滑。因此一支拥有”恒定光圈”的镜头能令摄影师更容易控制相片的曝光和景深,集中处理其他事情如采光和构图等。
    高考摄影培训www.dysypx.com/
    Aperture basically can influence two aspects - (1) depth of field and (2) into the amount of light, if at the time of changing the focal length (zoom) failed to keep the aperture value so that they have the opportunity to failed to maintain the shallow depth of field and because fewer aperture, light decreases, then the shutter will slow down or were ISO need to improve to keep normal exposure (please refer to photo the formation of a text), shutter, once more than the "safety shutter", then easily lead to shock and blurred pictures, and the improvement of ISO will make the emergence of signal to noise (noise), order of the photo is not smooth. So a have "constant aperture" lens can makes the photographer photo exposure, and depth of field can be controlled easily. Other things such as lighting and composition.
    为什么不是所有镜头也有”恒定光圈”?
    Why not all lenses have a constant aperture?
    “恒定光圈”的镜头结构比较复杂,而且成本不轻,所以厂商大多因应市场而求来推出一部份拥有”恒定光圈”的镜头,话虽如此,现在DSLR的价格也很平民化,一些拥有”恒定光圈”的镜头也不太贵了,如Tamron的A16型号(SP AF17-50mm F/2.8 XR Di-II LD ASPHERICAL [IF])拥有恒定f/2.8光圈,价钱只是港币3千余元,实在超值!
    "Constant aperture lens structure is complicated, and the cost is not light, so most manufacturers because of the market for to launch a part has" constant aperture lens. Even so, now DSLR, prices are also very common, some have "constant aperture of the lens is not too expensive, e.g. has constant f / 2.8 aperture by Tamron a16 types (SP AF17-50mm f / 2.8 XR Di-II LD ASPHERICAL [IF]), the price is HK $3 thousand yuan, really value!
    光晕拍摄所需要的材料是:不透光的卡纸一张,小刀,铅笔之类的工具,电脑一台!原理其实就是控制失焦时入射光线的形状,所以摄影培训学校只需要用不透光的影纸挡着入射光,留出比光圈小的形状就可以了!我用EMS的信封切的,上面的小柄是防止卡在镜头口抠不出来这是具体尺寸,镜头口径一般写在镜头上如果没有就自己量一下吧!最大光圈=焦距/F值就是说,如果你的镜头是50mm F/1.4的话,最大光圈就是50/1.4=35.7mm大家做图的时候可以用尺规,我取巧一点,在PS新建一个A4画了出来,然后打印后就在图案后面用软质铅笔(就是4B以上)涂满,用圆珠笔拓印到卡纸上然后就可以用刻刀和剪刀裁剪成你们所需要的形状了,使用的时候吧卡纸放在镜头前面,镜头最好先装UV,然后将卡纸紧贴UV就可以了裸镜的话在装拆卡纸时候可能会对镜片伤害较大。
    The halo shooting materials needed: opaque cardboard, a pencil, a knife, a tool such as a computer! Principle is in fact the shape of the incident light when the focus is missing, so photography training school only need to use the impact of the film is not only transparent to the incident light, leaving a smaller shape than the aperture can be! I use EMS envelope cut, the above small handle is to prevent the card in the lens mouth can not dig this is the specific size, lens caliber generally written in the lens if you do not have to measure it! Lens in close to the shape (that is, behind the pattern is 50/1.4=35.7mm F/1.4 the lens focal length maximum aperture = f value that is to say, if you are the 50mm, maximum aperture you do figure can be used with ruler and compass, I tricky point in Photoshop and create a A4 drawing out, and then printed in soft pencil 4B above) painted with ball pen rubbing to the card and then you can use a knife and scissors cut into what you need, use the cardboard placed in front of the lens, the lens is best to UV is installed, then the jammed paper UV can be naked in the mirror assembly and disassembly cardboard climate may be of greater harm.