tag:blogger.com,1999:blog-8737967.post1163845264013819559..comments2024-03-27T17:15:58.243+08:00Comments on 弱格吉米言: 何謂光圈?Unknownnoreply@blogger.comBlogger2125tag:blogger.com,1999:blog-8737967.post-87912508193950938902013-05-27T01:39:10.640+08:002013-05-27T01:39:10.640+08:00謝謝您了,r = d/2 已改正。
不過下面這一行我還沒代入 r = d/2,我是用根式化簡也就是...謝謝您了,r = d/2 已改正。<br /><br />不過下面這一行我還沒代入 r = d/2,我是用根式化簡也就是分子分母同乘 sqrt(2) 得到的:<br />R = sqrt(r^2 / 2) = r / sqrt(2) = sqrt(2) * r / 2<br /><br />然後在計算 D 的時候,我的 r 是用 d/2 代入的,但是中間少寫了 * 2。<br />D = R * 2 = sqrt(2) * (d/2) / 2 * 2 = sqrt(2) * d / 2 [其實化簡之後 D 也等於 d/sqrt(2) ]吉米言https://www.blogger.com/profile/03377911270977530663noreply@blogger.comtag:blogger.com,1999:blog-8737967.post-63006811307649185822013-05-24T18:39:28.122+08:002013-05-24T18:39:28.122+08:00你算錯囉
R = D / 2,r = r / 2(應該是r = "d" /2,...你算錯囉<br /><br />R = D / 2,r = r / 2(應該是r = "d" /2,直徑除以二等於半徑)<br /><br />R = sqrt(r^2 / 2) = r / sqrt(2) = sqrt(2) * r / 2 (上面錯,所以這邊也跟著錯囉)<br />最後面應該是<br />R = sqrt(r^2 / 2) = r / sqrt(2) = (d / 2) / sqrt(2)<br /><br />下面我就自己算了<br />D=R*2=(d / 2) / sqrt(2) x 2 = d / sqrt(2)<br />而新的光圈值 A 應該為:(已知:f / d = a)<br />A = f / D = f / [d / sqrt(2)] = f / d * sqrt(2) = a * sqrt(2)<br />所以A = a * sqrt(2)posthttps://www.blogger.com/profile/07814595541313400599noreply@blogger.com