The first Canon RF 70-200mm f/4L IS USM shipment appears to have been delayed
By Canon Rumors | December 8, 2020 | Canon Lens News
When Canon officially announced the Canon RF 70-200mm f/4L IS USM and the Canon RF 50mm f/1.8 STM, both lenses were scheduled to be available in early to mid-December. While the RF 50mm f/1.8 STM has begun shipping, we’re still waiting on the RF 70-200mm f/4L IS USM.
It now appears the first shipment of the new lens will not happen until January 28, 2021, according to many retailers, including Adorama. There is no word on why the delay, it’s just a sign of the times I think.
By Canon Rumors | December 8, 2020 | Canon Lens News
When Canon officially announced the Canon RF 70-200mm f/4L IS USM and the Canon RF 50mm f/1.8 STM, both lenses were scheduled to be available in early to mid-December. While the RF 50mm f/1.8 STM has begun shipping, we’re still waiting on the RF 70-200mm f/4L IS USM.
It now appears the first shipment of the new lens will not happen until January 28, 2021, according to many retailers, including Adorama. There is no word on why the delay, it’s just a sign of the times I think.
SIGMA to start producing RF mount lenses in 2021
By Canon Rumors | December 8, 2020
Nikon Rumors is reporting that SIGMA will begin producing lenses for the RF and Z mounts some time in 2021.
By Canon Rumors | December 8, 2020
Nikon Rumors is reporting that SIGMA will begin producing lenses for the RF and Z mounts some time in 2021.
Forwarded from 小摄影师的幻想罢了
尼康如何使用一套复杂的拨杆-弹簧系统 通过一个直流马达同时完成反光镜动作+光圈收放：
①：反光镜动作拨杆
②：光圈拨杆释放预备
③：光圈动作拨杆
④：反光镜上的拨杆
各位可能发现了尼康不仅光圈环之类旋转方向和佳能是反着的，连机身内的反光镜动作+闪光灯电容布置位置都是反着的。当然这个不是重点，我们接下来来看它如何动作：
首先，直流马达驱动一个带有拨杆的齿轮（齿轮在两个拨杆下面的凹槽中定位与运动），使反光镜拨杆①离开预备位，将辅助光圈拨杆释放的②顶入预备位置，此时②通过弹簧带动①向左拨起反光板与副反光板，准备曝光。③则暂时被光圈动作机构卡住，弹簧进入张紧状态，准备动作。
随后，光圈限位机构按机身设定将③释放到指定位置，③的另一端即是你在机身F卡口内见到的那个拨杆，由其拨动镜头上的光圈打开到指定大小，快门打开、关闭，曝光结束。
接下来，直流马达反向旋转，将①与②复位，③与反光镜则在各自弹簧的辅助下归位，准备进行下一次测光与曝光。
因为这一套机构的东西实在太多了，各种力全压在那一个转轴上，因此可靠性着实存疑。我手里的这个就是因为转轴断掉导致整个动作机构全部卡死，无法进行任何拍摄，和佳能的祖传飞反光板有类似的味道。
①：反光镜动作拨杆
②：光圈拨杆释放预备
③：光圈动作拨杆
④：反光镜上的拨杆
各位可能发现了尼康不仅光圈环之类旋转方向和佳能是反着的，连机身内的反光镜动作+闪光灯电容布置位置都是反着的。当然这个不是重点，我们接下来来看它如何动作：
首先，直流马达驱动一个带有拨杆的齿轮（齿轮在两个拨杆下面的凹槽中定位与运动），使反光镜拨杆①离开预备位，将辅助光圈拨杆释放的②顶入预备位置，此时②通过弹簧带动①向左拨起反光板与副反光板，准备曝光。③则暂时被光圈动作机构卡住，弹簧进入张紧状态，准备动作。
随后，光圈限位机构按机身设定将③释放到指定位置，③的另一端即是你在机身F卡口内见到的那个拨杆，由其拨动镜头上的光圈打开到指定大小，快门打开、关闭，曝光结束。
接下来，直流马达反向旋转，将①与②复位，③与反光镜则在各自弹簧的辅助下归位，准备进行下一次测光与曝光。
因为这一套机构的东西实在太多了，各种力全压在那一个转轴上，因此可靠性着实存疑。我手里的这个就是因为转轴断掉导致整个动作机构全部卡死，无法进行任何拍摄，和佳能的祖传飞反光板有类似的味道。