{"meta":{"id":"https:\/\/api.iclient.ifeng.com\/ipadtestdoc?aid=ucms_7z9apJDeHIg","type":"doc","o":"1","documentId":"ucms_7z9apJDeHIg"},"body":{"newStatus":"1","documentId":"ucms_7z9apJDeHIg","staticId":"ucms_7z9apJDeHIg","title":"为什么感光度越高噪点也越多?背后原因很无奈,掌握后用好感光度","shareTitle":"为什么感光度越高噪点也越多?背后原因很无奈,掌握后用好感光度","thumbnail":"http:\/\/d.ifengimg.com\/w150_h106_q100\/img1.ugc.ifeng.com\/newugc\/20200823\/14\/wemedia\/b86db267122bea136667579e5d6c01c726d21d7f_size53_w512_h341.jpeg","source":"","author":"","editorcode":"weMedia","editTime":"2020-08-23 14:56:05","updateTime":"2020\/08\/23 14:56:05","wapurl":"http:\/\/\/\/feng.ifeng.com\/c\/7z9apJDeHIg","introduction":"","wwwurl":"http:\/\/\/\/feng.ifeng.com\/c\/7z9apJDeHIg","commentsUrl":"ucms_7z9apJDeHIg","commentCount":0,"text":"
大家常说感光度越高噪点越多,但你知道为什么感光度越高噪点也越多?背后原因到底是啥?<\/p>
其中原因其实很复杂,剖根问底多了解背后的原因才能用好感光度!这里毒法师就详细分享下深层次原因:<\/p>
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1.感光度对画面的影响<\/p>
我们知道,所谓感光度,就是指感光元件(CCD\/CMOS)对光线的敏感程度,用ISO来表示。<\/p>
<\/p>
感光度对我们拍摄的画面有两方面的影响:<\/p>
首先它会影响到画面的亮度,感光度越高,感光元件对光的敏感程度就越高,我们拍摄出来的照片就会越亮;<\/p>
其次,感光度会影响画质,感光度调高不仅照片会变亮,相应的画面噪点也会变多。<\/p>
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2.感光度调节原理<\/p>
那为什么感光度提高噪点会越多?这就不得不说到感光元件。<\/p>
<\/p>
在传统胶卷时代,控制感光度只能通过换不同感光度的胶卷来实现,更换胶卷后,再到相机上设置感光度的地方把感光度调到相应的数值才行。换言之,传统胶卷的感光度是通过改变胶卷的化学成分来改变它对光线的敏感度。<\/p>
<\/p>
而数码相机的感光元件是不能像更换胶卷一样更换的,那怎么实现改变感光度?<\/p>
现在数码相机普遍采用的是电子信号放大增益技术,ISO数值相对应的其实就是电子信号放大增益值(单反摄影控:smmapp)。也就是说,我们通过调节ISO数值控控制感光度,本质上是在改变电子信号放大增益值来实现感光度的变化。<\/p>
<\/p>
3.感光度高噪点多原因<\/p>
我们知道,电子器件总是会产生噪声,主要是由于传感器在成像的过程中,受到同质异谱、同谱异质等因素的影响而产生的,噪声也就是大家所讲的噪点。<\/p>
<\/p>
各个品牌各种型号的相机对噪声的控制能力不尽相同,同一型号的相机也有一定的个体差异,也有些相机有降噪功能(单反摄影控:smmapp),但无论如何,以目前的技术,CCD和CMOS噪声问题是没法完全消除的。<\/p>
<\/p>
所以提高电子信号放大增益值的同时噪声也会被放大。提高感光度,就需要提供更大的增益幅度,也就是在输出影像信号前必须要进行更大的信号放大,这同时也就放大了噪声。<\/p>
<\/p>
4.感光度调节应用<\/p>
感光度在ISO800以下,我们成为低感光度。<\/p>
在这个范围内,画面呈现会相对平滑、细腻。通常来说,控制曝光,不到万不得已一定不要调高感光度。正常情况下拍摄,我们会把感光度设置在400以内,控制曝光会优先调整快门和光圈。<\/p>
<\/p>
感光度在ISO800~6400属于中感光度。<\/p>
在弱光环境下,有时就需要提高感光度。这个范围提高了我们在弱光环境下拍摄的安全系数(单反摄影控:smmapp),也一定程度上降低了手持相机拍摄的难度,不过需要你能够接受一定程度的噪点。<\/p>
<\/p>
高感光度在ISO6400以上则是高感光度。<\/p>
使用高感光度一般是在极端环境下,也就是你对拍摄内容的要求超过了对画质要求, 毕竟有时候能拍到画面总比拍不到好。<\/p>
<\/p>
以上就是感光度越高噪点越多的原因和不同感光度的使用情况,掌握这些,你就能够用好感光度了。<\/p>
毒家摄影指南,让摄影像眨眼一样简单!<\/p>
<\/p>
(单反摄影控:smmapp;《毒家摄影指南》原创内容,未经授权严禁任何形式的转载,严禁篡改和盗用,违者追究法律责任!)<\/p>","img":[{"url":"http:\/\/d.ifengimg.com\/mw640_q100\/x0.ifengimg.com\/res\/2020\/8A6D31992710E4CCDF14A7B32DE36AE07C0E7953_size72_w640_h960.jpeg","size":{"width":"640","height":"960"}},{"url":"http:\/\/d.ifengimg.com\/mw640_q100\/x0.ifengimg.com\/res\/2020\/06A1F12AD243F5D272A34106B5E46A6093553BE2_size34_w640_h424.jpeg","size":{"width":"640","height":"424"}},{"url":"http:\/\/d.ifengimg.com\/mw640_q100\/x0.ifengimg.com\/res\/2020\/90F259CAD3002F18F335F6C0AE94091B750DD4C9_size32_w640_h424.jpeg","size":{"width":"640","height":"424"}},{"url":"http:\/\/d.ifengimg.com\/mw640_q100\/x0.ifengimg.com\/res\/2020\/769029D78D17654CEC7D3089C0917E9568F7294F_size34_w640_h424.jpeg","size":{"width":"640","height":"424"}},{"url":"http:\/\/d.ifengimg.com\/mw640_q100\/x0.ifengimg.com\/res\/2020\/C8F60D113E5407B96425101191DAACE47E9D965C_size107_w640_h960.jpeg","size":{"width":"640","height":"960"}},{"url":"http:\/\/d.ifengimg.com\/mw640_q100\/x0.ifengimg.com\/res\/2020\/964CA3E0682EE7C4D9B39F835D8F5356C31C24A2_size42_w425_h638.jpeg","size":{"width":"425","height":"638"}},{"url":"http:\/\/d.ifengimg.com\/mw640_q100\/x0.ifengimg.com\/res\/2020\/35F6E02C38B6A0EDF0B345D7BC04136B16A2978B_size35_w640_h424.jpeg","size":{"width":"640","height":"424"}},{"url":"http:\/\/d.ifengimg.com\/mw640_q100\/x0.ifengimg.com\/res\/2020\/4D2E9309AD21C5B9E212B078A43F944418A5D969_size97_w640_h960.jpeg","size":{"width":"640","height":"960"}},{"url":"http:\/\/d.ifengimg.com\/mw640_q100\/x0.ifengimg.com\/res\/2020\/907FD4D67D1217D24113B4743D28565E90411F6D_size52_w640_h960.jpeg","size":{"width":"640","height":"960"}},{"url":"http:\/\/d.ifengimg.com\/mw640_q100\/x0.ifengimg.com\/res\/2020\/31F4400384C3143E89D6759A4A889226FB3E4FEC_size63_w640_h960.jpeg","size":{"width":"640","height":"960"}},{"url":"http:\/\/d.ifengimg.com\/mw640_q100\/x0.ifengimg.com\/res\/2020\/C36C3910421C26D9EC99816B30EA6BC5F9B9AE3F_size40_w640_h427.jpeg","size":{"width":"640","height":"427"}},{"url":"http:\/\/d.ifengimg.com\/mw640_q100\/x0.ifengimg.com\/res\/2020\/382C5D5D51071A07042ABFD5500D4B5CBF1D7ED4_size42_w640_h427.jpeg","size":{"width":"640","height":"427"}},{"url":"https:\/\/x0.ifengimg.com\/res\/2020\/F3185CB4E48FC1189985FCE066D7F3DEB7351DC4_size1681_w640_h156.gif","size":{"width":"640","height":"156"},"resizedImg":"http:\/\/d.ifengimg.com\/mw640_q100_ext\/x0.ifengimg.com\/res\/2020\/F3185CB4E48FC1189985FCE066D7F3DEB7351DC4_size1681_w640_h156.gif"}],"summary":"大家常说感光度越高噪点越多,但你知道为什么感光度越高噪点也越多?背后原因到底是啥?其中原因其实很复杂,剖根问底多了解背后的原因才能用好感光度!这里毒法师就详细分","sharesummary":"大家常说感光度越高噪点越多,但你知道为什么感光度越高噪点也越多?背后原因到底是啥?其中原因其实很复杂,剖根问底多了解背后的原因才能用好感光度!这里毒法师就详细分","commentType":"0","wemediaEAccountId":"773327","showclient":"0","shareurl":"https:\/\/ishare.ifeng.com\/c\/s\/v002AQM8NCMK3eq4YJajsg0jUisqJOzOiGXtwet9UHFepxg__","praise":"0","like_num":"0"}}