l*****o
发帖数: 19653 | 1 ccd现在都至少是几百万像素了吧，肯定超过了diffraction limit，所以感光元件的分
辨率真不是问题。。。而且，ccd像素的大小肯定不是由光刻制约的，光刻现在应该正
从65nm向45nm过渡，即便是135nm node，也远远远远小于现在ccd每个cell的尺寸。。。
至于入射光的角度，但凡是超过半米的景物，基本都算是垂直入射吧，而且，防反射膜
也都是根据垂直入射光的波长来设计的。。。
至于镜头的畸变(aberration?), 肯定是有的，毕竟是spherical lens。。。但就我所
知，所有的照相机都是spherical lens，没人搞抛物线的吧，除非想把照相机当光刻机
使用。。。 |
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l*****o
发帖数: 19653 | 2 每个ccd element的尺寸决定了digital resolution，而前端的光学系统有自己的
diffraction limit，正比于波长，反比于aperture size。 ccd的尺寸基本由像素数目
（number of elements)决定的。比如，一平方厘米里如果有1万像素，那么每个像素的
面积就是1万分之一平方厘米，如果是正方形，就是边长为100微米。。。依次类推，如
果是1平方英寸ccd，有500万像素，那么每个像素对应的尺寸大概就是10微米一点儿。
。。
而光学系统的diffraction limit是1.22X波长/D（镜头直径），假设波长600nm，直径
35mm，那么它的diffraction limit大概是0.00025°，假设ccd距离镜头2厘米远，这个
limit就意味着大概5微米的成像尺寸。这是完全理想的情况。加上各种aberrations，
则接近10微米。。。
所以，如果像素高于500万（专业级别的相机基本都远大于），就可以说是超过了
diffraction limit, 其作用，我猜主要是用来经行数字图像处理。。。 |
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b*s
发帖数: 82482 | 3 你说的是像素密度，这个密度（单个像素的大小）跟光学镜头的解像度，which is
really diffraction limited是两个独立元素，你这样说，就像是比较发动机马力和轮
胎的等级。虽然像素密度和镜头联合起来决定光学成像系统的总体性能，但是这两者之
间的联系跟发动机跟轮胎一样，完全不是一码事。
CCD的尺寸是由厂家决定的，单反的CCD像素比point and shoot的像素大得多，跟光学
系统没有什么关系。当然，CCD的选择跟镜头有关系，就如轮胎的选择和发动机是有关
系一样。
你首先混淆了resolution的定义：resolution是一个光学系统能够分开的两个点的最小
距离，跟最终的像素点没有一毛钱的关系。一台光学显微镜的分辨率是300-500 nm，跟
波长跟镜头的数值孔径有关，跟CCD无关。只要所选择的CCD的像素点符合成像面
Nyquist采样率即可
每个ccd element的尺寸决定了digital resolution，而前端的光学系统有自己的
diffraction limit，正比于波长，反比于aperture size。 ccd的尺寸基本由像素数... 阅读全帖 |
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l*****l
发帖数: 5909 | 4 Thurston Moore: Black Metal is music made by pussies of the lowest order,
and we felt it was necessary to investigate this aberrant anti-music
behaviour. We feel like the sound and attitude of black metal is a loss of
self, life, light and desire in a way where it becomes so negative that a
whole new bliss arrives where we become super pussy. |
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p***e
发帖数: 29053 | 5 【 以下文字转载自 PhotoGear 讨论区 】
发信人: xy95242 (XY), 信区: PhotoGear
标 题: Re: 【2013年度总结】拍的很少的一年
发信站: BBS 未名空间站 (Wed Jan 8 11:53:37 2014, 美东)
课程的名字叫Visual Design, 是一个职业风景摄影师教的。一共上了9节，前4节是讲
visual design elements, 包括line, shape, texture, perspective。 中间4节是讲
组合的方法，就是构图，包括Proportion, Rhythm, Dominance, Balance。最后一节是
综合，field trip, 和评片。每节都有作业，评片，和老师的范片。下面是一些笔记
• Rules of Odds: 主要构图元素的总和是奇数。这个老师上课强调了很多遍
• Contrast, Sharpness and Warm Color: 一副图里，人眼首先被吸引的是
图片中对比度最高，最清晰和最温暖的部分
• White... 阅读全帖 |
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a**e
发帖数: 427 | 6 Yes, you can approximate part of the curve as linear, but cannot extrapolate
the value to beyond 100%. The exact curve should be the Fourier transform
of the diffraction/aberration pattern from a point light source. |
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d*****0
发帖数: 68029 | 7 丐友们可以参考一下。
18mm
K18/3.5 is an excellent rectilinear lens; it is quite large and bulky though
. It's correction of spherical and coma aberrations seems far better than
that of A20/2.8, and it is surprisingly sharp edge to edge. Its coma wings
are also smaller than those of K24/2.8, K28/2, or K30/2.8. Yoshihiko
Takinami also notes that the corner resolution of K18/3.5 is higher than
that of A20/2.8, and the only defect of K18/3.5 seems to be the lack of
normal or UV filter though it has four filte |
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x****c
发帖数: 25662 | 8 ☆─────────────────────────────────────☆
daye520 (打入老鼠会中层) 于 (Sun May 23 16:03:15 2010, 美东) 提到:
丐友们可以参考一下。
18mm
K18/3.5 is an excellent rectilinear lens; it is quite large and bulky though
. It's correction of spherical and coma aberrations seems far better than
that of A20/2.8, and it is surprisingly sharp edge to edge. Its coma wings
are also smaller than those of K24/2.8, K28/2, or K30/2.8. Yoshihiko
Takinami also notes that the corner resolution of K18/3.5 is higher than
that of A20/2.8, |
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c********y
发帖数: 30813 | 9 photozone的色差就别拿来说了，就是一个joke.
举个例子：ZE100/2的色散
http://www.photozone.de/canon_eos_ff/508-zeiss100f2eosff?start=1
结果非常好啊，PZ是这么说的：
“Chromatic aberrations (color shadows at harsh contrast transitions) are
extremely well controlled and not field relevant anymore. ”
今天FM上有人贴出来的样片：
所有的用过这个头的都知道f/2下的色散有点厉害，PZ还能说出extremely well
controled 这种自己打自己嘴巴的话。 |
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a***n
发帖数: 1500 | 10 could be residual spherical aberrations, technically that is..
焦，
，安
申请 |
|
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s*****g
发帖数: 5159 | 12 Zen-Ray has aberration, too. Not serious, but there is. |
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p********e
发帖数: 16048 | 13 how often will zen ray renew its products?
nikon and zeiss renew once every 10 years....
Zen-Ray has aberration, too. Not serious, but there is. |
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t****e
发帖数: 4821 | 14 看焦外貌似和佳能 85L 还是有一定差距，感觉尼康这个焦外脏兮兮的。
http://www.lenstip.com/264.1-Lens_review-Nikon_Nikkor_AF-S_85_mm_f_1.4G_Introduction.html
Pros:
* high build quality,
* splendid image quality in the frame centre,
* very good image quality on the edge of the frame, even on full frame,
* slight lateral chromatic aberration,
* negligible distortion,
* well-corrected coma in the corners of APS-C/DX sensor,
* sensationally corrected astigmatism,
* slight vignetting on APS-C/DX senso |
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a*****s
发帖数: 2663 | 15 It seems to be strong longitudinal chromatic aberration system. No more
wavefont coding. Looks promising for cellphones, webcams. |
|
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C*F
发帖数: 2513 | 17 （ZZ）
Advantages:
* robust and exceptionally compact design,
* very good image quality at the center of the frame,
* well corrected chromatic aberration
* decent image quality in bright light,
* negligible astigmatism.
Disadvantages:
* monstrous distortion,
* a lot of vignetting,
* image quality at the edge of the frame could be improved.
大畸变，烂边角，广角头的问题它都沾上了。。。 |
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b********r
发帖数: 1380 | 18 不是镜头边角成像变形（distortion/aberration)？很多镜头边角都有这个问题吧 |
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P*********g
发帖数: 1336 | 19 怎么看紫边啊？是镜头的Aberration吗？ |
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c********y
发帖数: 30813 | 20 quote:
"That is already insanely good, but the camera then applies an aperture-
specific focus correction to account for focus shift. The Hexar's lens is
optimized for wide-open operation; its spherical aberration causes the focus
point to shift as the apertures get smaller. The Hexar calculates this
error and corrects as its goes. Too bad AF SLRs don't have this feature."
http://www.dantestella.com/technical/hexar.html
DOWN |
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H****F
发帖数: 430 | 22 这东西怎么测出来的。。。就测了F2.8还是全部光圈都测了？
lens metric scores 和画面质量还是有区别的。。。
这分数我觉得resolution distortion（0.4%以下人眼不能分辨）都没区别 。
色差校正佳能远好于尼康， vignetting居然用EV做单位。。。
而且这个评测太业余了，什么条件都没给，色差是在什么成像条件下给的？其他的相差
呢？单独拉出几个参数来评个分，就说某家远好于某家，是不是做lens design的时候
直接设置 0色差 0distortion 的constraint， 直接无视MTF最牛逼？
在没有详细lens listing， aberration plot 还有 field plot的情况下评价那是相
当的不客观。。 |
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b***e
发帖数: 15201 | 23 sorry 是看错了
EF 35mm f/1.4L USM Refurbished
Wide-Angle Lens
* Aspherical lens element to correct aberrations
* 35mm focal length
* 1:1.4 maximum aperture
* 63° diagonal angle of view
* 0.3m / 1 ft. closest focusing distance
You Pay: $1,183.20
这个价钱还凑或 |
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N**I
发帖数: 531 | 24 还有NEX-５N的片片，这个夏天属于骚女
。。。
I got a bunch of new info from top sources:
1) Some of them (my sources) saw that you were concerned about the 500 shot
autonomy of the A77. They wanted me to tell you that you are limited with
500 shots only when shooting in LCD mode! If you use the built-in viewfinder
you will be able to take many more pictures!
2) On the A65 and A77 you can enable or disable the automatic lens
correction (Vignetting, Chromatic Aberration and more).
3) It has AF fine tuning! Over 30 le... 阅读全帖 |
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n**b
发帖数: 13203 | 25 不会吧，介绍上说，“Exceptional high contrast, high resolution optics with
minimal aberrations”,而且Pentax的镀膜不是说一绝吗？ |
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G********d
发帖数: 10250 | 26 喷
你真是online expert+armchair photographer啊
不会吧，介绍上说，“Exceptional high contrast, high resolution optics with
minimal aberrations”,而且Pentax的镀膜不是说一绝吗？ |
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b****r
发帖数: 17995 | 27 只听过CA
chromatic aberration
紫边有些镜头还是控制得好得多的
另外后期处理掉也不难 |
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W********g
发帖数: 790 | 28 补上原始链接
http://www.dxomark.com/index.php/News/DxOMark-news/Canon-EF-70-
Wednesday September 21 2011
A couple of days ago, we released the measurements for the Canon EF 70-200mm
f/2.8L IS II USM. With its wide aperture, its image stabilizer and its fast
auto-focus, this telephoto zoom lens is definitely one of the favorite
equipments of sport photographers. It is also ready to face difficult
weather conditions with its solid and watertight build.
Let’s see how it behaves in term of image quality c... 阅读全帖 |
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r******s
发帖数: 3662 | 29 That's a typical sign of lens aberrations. |
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b*******t
发帖数: 33714 | 30 apo一般只是红黄蓝三色spherical aberration的纠正吧，不过也有可见光以外波段的 |
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d******a
发帖数: 32122 | 31 在不用软件调整的前提下，达到了20/1.7软件调整后的画质
dpreview:
The 30mm F2 pancake measures up extremely well in our studio tests. It's
impressively sharp, even at F2, and shows very low distortion, chromatic
aberration and falloff. Overall it gives just as good results as Panasonic's
Lumix G 20mm F1.7 ASPH pancake - but without apparently making any use of
software corrections to get there.
photozone:
30/2:
Panasonic 20/1.7:
MFT: 附件 |
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c********y
发帖数: 30813 | 32 nikon自己说的
http://imaging.nikon.com/lineup/lens/glossary.htm#dc
“AF DC-NIKKOR lenses feature exclusive Nikon Defocus-image Control
technology. This allows photographers to control the degree of spherical
aberration in the foreground or background by rotating the lens' DC ring.
This will create a rounded out-of-focus blur that is ideal for portrait
photography. No other lenses in the world offer this special technique.” |
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b****r
发帖数: 17995 | 33 你意思是紫边经常是Longitudinal Chromatic
Aberrations的？ |
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a********l
发帖数: 39524 | 34 读了佳能的官方产品发布声明，乏善可陈，只看到一个软件中的亮点：
Digital Lens Optimizer – new in Digital Photo Professional v3.11
Digital Lens Optimizer (DLO) precisely imitates lens performance, with a
series of complex mathematical functions replicating each stage of the
journey of light through the optical path. Using this information DLO can
correct a range of typical optical aberrations and loss of resolution
caused
by a camera's low pass filter, by applying an inverse function to each
shot
to take the image nearer to how ... 阅读全帖 |
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n*********n
发帖数: 5605 | 35 哪张？
紫边好像是问题
Chromatic Aberrations (CAs)
Another weakness of the Sony lens is the amount of lateral CAs (color
shadows at harsh contrast transitions). An average width of around 2px at
the image borders is very pronounced especially for a prime lens. |
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l*****s
发帖数: 1754 | 36 to reduce the effect of Longitudinal Chromatic Aberrations, or purple
fringing, you will have to use smaller aperture. let's say stop down to f/4.
hand pick in lightroom to correct purple/green fringing is really time
consuming. correct 1 or 2 photos are fine, but if you shot 200 photos with
it, it is going to be nightmare. |
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|
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p********e
发帖数: 16048 | 39 这不是不错么
没有完全合焦的地方有紫边也是正常 即便是apo |
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f**s
发帖数: 968 | 41 链接在此：
http://www.kenrockwell.com/tech/8mm-f35.htm
8mm f/3.5 Fisheye
Pro-Optic, Samyang, Rokinon, Bower &c. (2009-)
© 2010 KenRockwell.com. All rights reserved.
Intro Specs Performance Compared Recommendations
8mm f/3.5 Fisheye, Pro-Optic Nikon AI-s version. enlarge. ($290, Korean, no
filters, 13.8 oz./391g). This one came from this link to it at Adorama (also
specifically in Nikon, Canon EOS, Pentax/Samsung and Minolta Maxxum/Sony
mounts). It also comes branded as Bower, also specif... 阅读全帖 |
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w**7
发帖数: 5258 | 43 Bokeh 很漂亮
Aberration 好杯具 |
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w**7
发帖数: 5258 | 44 胃镜也是一种镜头哦
Sharpness
Aberrations
Bokeh
... |
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w****e
发帖数: 2210 | 45 Here’s a complete list of all 68 improvements the X100S has over the X100.
Most of these changes were as a result of the fantastic feedback provided by
X100 users.
1. 16-megapixel sensor, up from 12-megapixel
2. X-Trans CMOS II sensor eliminates need for Optical Low Pass Filter
2. The resolution has improved to match Full Frame domain sensors
3. The Signal to Noise ratio improved to be on a par with Full Frame domain
sensors
4. Phase detection pixels allow 0.07 sec Auto focus
6. 1080p 60fps full... 阅读全帖 |
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w****e
发帖数: 2210 | 46 Take a look at the list of ALL 51 improvements the X20 has over the X10,
1. 2/3-inch X-Trans CMOS II sensor without optical low pass filters improves
resolution to as much as a 4/3″ sensor.
2. S/N ratio improved to level similar to Full frame sensors.
3. Phase detection AF allows for AF speeds as low as 0.04secs (compared to
X10 0.16secs).
4. 1080p HD video @ 60fps (X10 1080p HD video @ 30fps).
5. Phase detection Autofocus also works during movie recording.
6. Face detection works during movie r... 阅读全帖 |
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x****y
发帖数: 1853 | 48 I don'think you can separate color from contrast, because the contrast
between color is due to the lens transmitting various wavelengths
differently, on top of other factors, such as stray reflected light inside
the lens, chromatic aberration, and light transmission through the glass-air
gap, all of which contribute to the loss of contrast and desaturation in
color, and all can be improved with better lens design.
You can argue that you may fix all these in post processing (which I doubt)
, but... 阅读全帖 |
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m***i
发帖数: 2480 | 49 那叫Chromatic aberration 也是镜头指标之一 |
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x*****2
发帖数: 1683 | 50 课程的名字叫Visual Design, 是一个职业风景摄影师教的。一共上了9节，前4节是讲
visual design elements, 包括line, shape, texture, perspective。 中间4节是讲
组合的方法，就是构图，包括Proportion, Rhythm, Dominance, Balance。最后一节是
综合，field trip, 和评片。每节都有作业，评片，和老师的范片。下面是一些笔记
• Rules of Odds: 主要构图元素的总和是奇数。这个老师上课强调了很多遍
• Contrast, Sharpness and Warm Color: 一副图里，人眼首先被吸引的是
图片中对比度最高，最清晰和最温暖的部分
• White Balance: 偏色没关系，白平衡是主观滴，但是如果偏色应该是有意
而为
• Leading line: 就是导引线之类的
• Curve: 曲线是构图非常有效的元素，一个图里包含曲线或者只有曲线，这
个图会Strong很多
... 阅读全帖 |
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