International Photographers Association of Los Angeles 洛杉磯國際攝影家協會

We are speculating, since we don't know what kind of camera that took the shot. If this was done on a 4x5 film, then f22 is not small at all. (my hunch says this is film).

Yes, the 光衍射 theory says that a lens performs the worst wide open; however the film (not sure about digital chips) does exactly the opposit -- it records the worst when the lens closes to the minimal. Therefore, in 35mm film days we have a slogan that says: "F8, be there!" -- a compromise of lens and film.

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肖像是个人情感的风光；
风光是天地灵动的肖像...

Yes, and remember the F64 group.

He had +1 EV, so it could not be slide film...

已删。。

Depends where he metered, one slide film metering method says: Meter highlight and add +1 EV. Hehe.

I am not really good at technical stuff, actually.

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肖像是个人情感的风光；
风光是天地灵动的肖像...

What camera?

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肖像是个人情感的风光；
风光是天地灵动的肖像...

Ray兄，
还是一个弥散圈和衍射圈的谁大谁小的问题。大幅机的镜头的弥散圈大，所以衍射问题要到更加小的光圈才能体现，f22是完全不算小的。我给的那个连接有专业阐述。

另外“the 光衍射 theory says that a lens performs the worst wide open”这句话不对，纯粹从衍射看，最大光圈的时候其实反而有最小的衍射，最佳的极限分辨率。最大光圈下图像质量差是因为镜头的色差和球差（Chromatic and Spherical Aberration）等引起的，所以镜头设计需要用到高折射，低色散，非球面镜片等等努力来校正。

At the first, I wrote "a lens performs the BSET wide open", then I thought I remembered it wrong, so I changed it to "worst" -- see I am not good at technical stuff as I said.

Anyway, the point is that film and lens requires the opposit of aperture settings, so we go for F8 on 35mm film cameras. That's what I remember.

Thanks for explaining to us.

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肖像是个人情感的风光；
风光是天地灵动的肖像...

Ray兄，
我只不过正好最近在接触这些光学东西，以前玩乐两年摄影对概念还是模糊的。

Are you sure about this?

I am not a technique person, though.

Yes, I am pretty sure, Sir.

This was many years back when I read it -- it hit my head, because it explains in theory why we choose F8 on 35mm film, so it stuck on me.

Based on that theory, the final system resolution formula as developed by Fujifilm goes something like this:

System resolving power = 1/ (1/(lens res.) + 1/(film res.))

So if you have a lens that's 200/llpmm and a film with 200/llpmm), you will end up with 100/llpmm as a result, which would be really amazing. It's a true compromise where the film and lens meet each other half way in the neighborhood of F8 to get the optimal system resolution.

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肖像是个人情感的风光；
风光是天地灵动的肖像...

开始没看出是什么,以为大树根呢!仔细看WOW!宏大的场面,大地的肌理.就是暗了点...