【BMD】珍惜生命，远离佳能——关于返厂修理的具体原因【canon】
本帖最后由 无语的人 于 2017-2-26 20:04 编辑消息来自BMD官方论坛：转载请注明来源，谢谢！
Kristian LamBlackmagic Design
Hi guys,
I want to give you an update about this issue.
The cameras are all shimmed and calibrated to 44mm as per the reported focal flange depth of EF mount. I use the term "reported" as Canon does not publish the specifications officially so the exact expected tolerances are not known.
When checked against a collimated cine lens, we expect the Blackmagic Cinema Camera to get accurate focus according to the witness marks on the lens. For example, at focus chart placed 6 ft from the camera sensor plane will be in focus when the witness mark on the lens is at 6 ft.
When I tried the same collimated lens on some 5Ds, 7Ds and even a C300, the witness marks fall short of the expected distance which indicates to me that there's some fair amount of tolerances built into the Canon cameras to cater for still lenses where the tolerances are not as critical as cine lenses.
To address this, we need to put in the same allowances. We have tested this with some of the cameras from customers reporting this and it works.
If you think you're encountering this issue, please contact your local Blackmagic Design support office and we'll sort you out.
简单翻译一下：
这次BMCC有一部分机器要返厂维修，不光是BMD的原因
BMD愣头愣脑把佳能口头上说的：“我们的法兰距是44mm”给当真了，给做到BMCC上去了
BMD把校准过的电影镜头在5D 7D C300等多台机器上进行了测试，均发现跑焦，这说明了一点，
当佳能自己的机器搭配EF镜头时，机身内部会有很大一部分的容差，也就是说，EF头搭配佳能自己的机器才能完美
而对于别的机器，自然会有 有的机器正常，有的机器不正常的问题。（这也能解释为什么腾龙适马图丽的一些头在佳能相机上都会跑焦的原因）
BMD这次真是为佳能背了黑锅，这也就是为什么专业如RED，可以用户自行调节后焦。。。（但是现在没钱买RED啊！！！）
另外附上一位用户的测试数据，他有两台BMCC 还有ZE,尼康,EF，福伦达EF口镜头若干，一个好的转接环和一个便宜货转接环。
这是他的测试结果：
I have tried a number of lenses from Zeiss, Voigtlander, Nikon, Tokina and Canon on two separate BMCCs. My manual focus EF mount lenses from Zeiss and Voigtlander with a hard infinity stop cannot focus to infinity on either BMCC. My Nikon mount manual focus lenses cannot focus to infinity on the BMCC when used with a high quality Rayqual adapter, but do focus to infinity when used with a cheap eBay adapter. My Canon autofocus lenses all focus past infinity by design, and can all achieve infinity focus on the BMCC. All these lenses can focus to infinity on both my Canon 5D mark III and 500D.
Results from 1st BMCC received early January. I tested the infinity focus on the camera and put some files here: http://www.phillipmortimer.com/BMCC/. Follow the link and right click to download them if you are interested. The tall building in the background is the Tokyo Metropolitan Government building which is approximately 5km from my apartment and is my infinity reference.
01 Nikon 28mm f2.8 Ai-S with high quality Rayqual Nikon to EOS adaptor. Furthest focus ~10m.
02 Nikon 28mm f2.8 Ai-S with cheap eBay adaptor which is too thin. Can achieve infinity focus. Indeed you can focus past infinity with this adaptor on both the BMCC and my Canon cameras.
03 Voigtlander 58mm f1.4 Nikon F mount. Rayqual adaptor. Furthest focus ~40m.
04 Voigtlander 58mm f1.4. eBay adaptor. Can achieve infinity focus.
05 Voigtlander 40mm f2. EOS mount version. Furthest focus ~20m.
06 Zeiss 85mm f1.4. EOS mount version. Furthest focus ~70m.
07 Tokina 11-16mm f2.8 at 11mm. EOS mount version. Furthest focus ~2-3m.
As a control, same lenses on other cameras:
08 Tokina 11-16mm f2.8 at 11mm on Canon 5D mark III. Can achieve infinity focus.
09 Voigtlander 40mm f2 on Canon 5D mark III. Can achieve infinity focus.
10 Zeiss 85mm f1.4 on 5D mark III. Can achieve infinity focus.
11 Tokina 11-16mm on 500D. Can achieve infinity focus.
I contacted Blackmagic support in Japan who were fantastic and arranged for the camera to be replaced. I received the replacement camera last week. It has the same problem.
Here are the files for the second camera. http://www.phillipmortimer.com/BMCC2/
01 Zeiss 85mm f1.4 EOS mount version. Furthest focus again about 70m.
02 Voigtlander 40mm f2 EOS mount version. Furthest focus again about 20m.
03 Tokina 11-16mm f2.8 EOS at 11mm EOS mount version. Furthest focus ~1m.
Again, as a control, on my 5D mark III:
04 Zeiss 85mm f1.4 on 5D mark III. Can achieve infinity focus.
05 Voigtlander 40mm f2 on 5D mark III. Can achieve infinity focus.
kr可以手动调节后焦 无语的人 发表于 2013-3-1 11:33 static/image/common/back.gif
另外附上一位用户的测试数据，他有两台BMCC 还有ZE,尼康,EF，福伦达EF口镜头若干，一个好的转接环和一个便宜 ...
这。。。等我吃完饭 最后一句话这么小 你害怕别人看不见啊 哈哈 移花接木。 个人认为，ef版的bmd实在是没什么意思，要买就买mft bmd不给力，跟佳能有毛关系。 bmd不给力，跟佳能有毛关系。 色和尚 发表于 2013-3-1 15:41 static/image/common/back.gif
bmd不给力，跟佳能有毛关系。
ef口的容差是佳能自己搞出来的 这个机器 想说爱你不容易啊！ 我昏，BMD是挺不谨慎的。 应该出尼康口，向red学习 上次看到，说sony 开放了E 卡口的相关资料，我觉得BMD可以学习一下，毕竟价格优势在哪里！不会象佳能，尼康那么不靠谱！ 新产品有问题也正常吧，毕竟也是大厂初尝试，赶紧出m43带电子光圈的机器吧 我还是看看MINI吧 ^17^珍爱生命，远离佳能~ ip333 发表于 2013-3-2 07:44 static/image/common/back.gif
应该出尼康口，向red学习
就是，nikon老头很多，包括AF的D头
这下完了 小机器e口是王道啊。。。。可电子ef可手动任何。。。
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