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時間:2022-08-16 來源:本站 點擊:258次
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适马正式发布18******

    今日,SIGMA正式发布18-50mm F2.8 DC DN | Contemporary镜头,这是一支小体格机身的“大三元“镜头,专供无反相机使用,兼容APS-C相机适用于L卡口、E卡口。同时这也是一支优秀画质的F2.8大光圈镜头,轻便小巧的构造,是无反相机的理想之选,恒定光圈,适应场景广泛。

F2.8大光圈变焦挂机镜头

    这支用于APS-C传感器的无反相机标准变焦镜头,拥有极致小巧且轻便的造型,可以成为您的理想挂机镜头。

    这支镜头是SIGMA首支APS-C尺寸无反变焦镜头,具有27-75mm的标准全画幅变焦范围,这使得它非常适合拍摄包括风景、肖像、扫街、建筑和活动在内的各类照片和视频。它还可以用于微距特写摄影,因为它的最大放大倍率为1:2.8*1,最近对焦距离仅为302.5px。拥有明亮的F2.8光圈,更容易进行手持微光拍摄,可以在浅景深下拍摄出具有冲击力的效果。

    依靠其步进马达对焦系统,这支镜头的自动对焦快速且安静,这在拍摄视频或快速移动的对象(如儿童和动物)时特别有用。这支镜头小巧、轻便,重量不到300g,是您首支可换镜头和全画幅机身副镜头*2的完美选择,也是在各种拍摄场景下的理想选择。

*1 最近对焦距离和最大放大倍率均为广角端数值。

*2 在全画幅相机上使用时,请切换到APS-C裁剪模式。

[主要特点]

1. 优秀画质的F2.8大光圈镜头

    SIGMA 18-50mm F2.8 DC DN | Contemporary 镜头在35mm全画幅标准下,焦段覆盖27mm-75mm的变焦范围,并在整体变焦范围内拥有F2.8大光圈。这使得摄影师在拍摄肖像和特写时,能够轻松获得理想的虚化效果。它能够拍摄出顺滑而美丽的焦外虚化,有助于承托主题集中焦点。

    这支镜头运用三片高精度玻璃磨铸非球面镜片,尽可能减少了镜片的使用总数,在保持轻量化的情况下实现了卓越的光学质量。另外,通过机身像差校正,进一步消除了畸变和眩光等光学缺陷。这些都是由SIGMA最新光学设计技术实现的,并在SIGMA唯一的工厂“会津”进行制造。

2. 轻便小巧的构造,无反相机的理想之选

    SIGMA 18-50mm F2.8 DC DN | Contemporary 镜头设计非常紧凑,与APS-C无反相机的便携性相匹配。这使得它可以成为一支完美的主力镜头,非常适合日常使用。这支镜头是目前同类产品中最小和最轻的*1,其最大直径为65.4 mm,长度为74.5 mm,重量为290g*2,但仍可以保持F2.8的恒定光圈。

    为了尽可能减轻镜头的重量,SIGMA使用精心挑选的材料来构建镜身。镜头主体使用一种名为耐热复合材料(TSC)的聚碳酸酯制成。它光滑而坚固,更重要的是,它的热稳定系数接近铝的热稳定系数。这确保了在温度变化时,镜头可以保持其使用的稳定性和良好的操作性。SIGMA在一些内部结构中使用了金属材料,使得这些部件在更轻薄的情况下拥有更高的刚性,从而确保镜头能够经得起频繁和长时间的使用。

*1 适用于APS-C相机的AF兼容F2.8恒定光圈变焦镜头(截至2021年10月,来源:SIGMA)

*2 该数据为L卡口数据

3. 恒定光圈,适应场景广泛

    SIGMA 18-50mm F2.8 DC DN | Contemporary 镜头具有快速且近乎静音的自动对焦功能,适合各种拍摄场景,包括在安静环境下拍摄、录制视频和捕捉快速移动的对象等。这是通过使用步进马达作为自动对焦实现的。由于这支镜头小巧且轻便,它可以灵活应用于手持拍摄、稳定仪拍摄、单人视频拍摄、Vlog等等对拍摄机动性要求较高的场景。

    为使这支镜头可以在各种拍摄条件下进行使用,SIGMA设计的镜头最近对焦距离为302.5px,放大倍率为1:2.8*,这也是特写镜头的理想选择。

* 最近对焦距离和最大放大倍率均为广角端数值。

    这支镜头可以搭配“口袋全画幅”SIGMA fp相机,总重量只有712g。它还可以作为全画幅相机(在裁切模式下使用)的副镜头使用,以减轻其重量。

    SIGMA 18-50mm F2.8 DC DN | Contemporary 镜头集小巧、轻便、高性能和大光圈于一身,支持多种拍摄场景,从入门级的无反相机到视频拍摄,再到与全画幅相机进行组合,随心所欲。

与APS-C格式全画幅相机结合使用的镜头示例

[镜头规格和特征]

·镜头结构:10组13片镜片结构,内含1片SLD 镜片和3片非球面镜片

· 采用内部对焦机构

· 支持各项机身高速对焦模式

· 步进马达系统

· 支持机身像差校正

* 该功能仅在支持相机上可用,校正功能可能因相机型号而异。

· 支持自动对焦、手动对焦以及全时手动对焦(DMF)

· 超级多层镀膜

· 花瓣式镜头遮光罩(LH582-02)

· 卡口处防尘防滴溅结构

· 兼容SIGMA USB DOCK UD-11(另售/仅适用于L卡口)

· 最大程度减少鬼影和眩光

· 每个镜头均通过SIGMA专有MTF测量系统

· 7片圆形光圈叶片

· 高精度、高耐久的黄铜卡口

· 全日本制造

陕西省增加1例本土确诊病例:为西安海外工作人员防护酒店餐厅工作专班组员******

  12月8日0时-12月9日7时,增加汇报当地确诊病例1例。

  12月8日0-24时,增加汇报海外键入确诊病例1例、没有症状的感染者1例,没有症状的感染者消除密切接触1例。

  截止到12月9日7时,总计汇报当地确诊病例264例,在院2例、康复259例、身亡3例。

  截止到12月8日24时,总计汇报海外键入确诊病例451例,康复440例、在院11例。总计汇报海外键入没有症状的感染者425例,变为确诊病例52例、消除密切接触361例、尚在密切接触的没有症状的感染者12例。

  当地确诊病例:向某,男,21岁,为西安市灞桥区海外工作人员隔离酒店餐厅工作专班组员。向某承担为隔离工作人员外卖送餐、搜集废弃物和消杀工作,并分別于12月5日、12月8日担负海外键入核酸检测呈阳性旅客屋子的消毒每日任务。12月8日在隔离酒店餐厅全部领导小组工作员按我国规定开展隔天一次核酸检测中,向某的单取样本核酸检测結果为呈阳性,12月9日1时经西安市市疾控中心复查結果为呈阳性。12月9日5时,经地市级专家团专家会诊,确诊为新冠肺炎确诊病例(轻形)。基本具体分析,向某感柒缘故为领导小组工作员间断性职业暴露而致,现阶段向某已被装运至医保定点医院隔离医治,西安已对该隔离酒店餐厅领导小组工作员就地隔离监管,其它工作已经进行中。

  海外键入确诊病例:林某,男,33岁,新疆省籍,为12月4日由塔吉克斯坦伊斯兰堡至西安市PK854飞机航班旅客。该飞机航班抵达西安市咸阳国际机场后,飞机航班所有工作人员贯彻落实中国海关检验检疫、核酸检测、点到点装运等闭环对策,无山西省内自主活动轨迹。隔离期内核酸检测結果呈阳性,经地市级专家团专家会诊,确诊为新冠肺炎确诊病例,现阶段在医保定点医院隔离医治。

  海外键入没有症状的感染者:女,26岁,外国籍,为12月7日由首尔至西安市KE9807飞机航班旅客。该飞机航班抵达西安市咸阳国际机场后,飞机航班所有工作人员贯彻落实中国海关检验检疫、核酸检测、点到点装运等闭环对策,无山西省内自主活动轨迹。核酸检测結果呈阳性,经地市级专家团专家会诊,确诊为新冠肺炎没有症状的感染者,现阶段在医保定点医院隔离密切接触。



来源于:山西省卫健委。

编缉:曹静。

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Tanzania's Serengeti wins Africa's leading national park award******

DAR ES SALAAM, Oct. 21 (Xinhua) -- The World Travel Awards (WTA) has declared Tanzania's Serengeti as the 2021 Africa's leading national park, the Tanzania National Parks (TANAPA) said in a statement on Thursday.

The statement signed by TANAPA's senior assistant conservation commissioner for corporate communications, Pascal Shelutete, said Serengeti becomes Africa's leading national park for three consecutive years of 2019, 2020 and 2021.

The statement said other nominees in the 2021 Africa's leading national park include Etosha National Park in Namibia, and Maasai Mara National Reserve in Kenya.

Serengeti National Park is a habitat for a variety of animals, birds and plant species, said the statement.

The statement added that Serengeti is world famous for wildebeest migration and is also renowned for its large lion population. Enditem

New vaccine research needed to tackle emerging COVID******

As the global COVID-19 death toll has passed 5.4 million amid a surge in Omicron cases, an expert from the Imperial College London (ICL) said that research on new vaccines and stronger global collaboration may be needed to tackle emerging COVID-19 variants.。

"The question about whether there's going to be another variant that is even more transmissible and more infectious than Omicron, we don't know yet," Dr. Katrina Pollock, who leads the COVID-19 vaccine project at the ICL, told Xinhua in an online interview on Thursday.。

"I think it's too early to say and that's why we need to have surveillance of these variants and global collaboration so that we can understand what's happening," said the senior clinical research fellow in vaccinology and honorary consultant at the ICL.。

Some two years into the pandemic, the death toll from COVID-19 has topped 5.4 million worldwide, amid a total of 296 million cases recorded, according to the World Health Organization .。

"Different viruses have different rates of making new variants, but they are all governed by the same principle which is that the more easily they are to transmit the more you'll see them," Pollock said.。

"What we're seeing with Omicron is that it's very infectious, and it makes many copies of itself very quickly. That means that we're seeing very, very high infection rates," she said.。

According to WHO data, some 128 countries had reported cases of the Omicron variant as of December 29, 2021.。

New vaccine research。

Asked about whether new vaccines will be needed to tackle highly transmissible new variants, Pollock said that new vaccines may be needed to provide better protection.。

"Certainly, with Delta, we were still seeing high vaccine effectiveness in real world studies against the virus. But it's possible that in the future we may need to change the vaccine, there may be some advantage to have a new strain in the vaccine to provide better protection," she said.。

"What we really need to see is that vaccines are going to help drive down transmission because that's how we get control over the pandemic," she emphasized.。

Early studies showed that more evidence is emerging that the Omicron coronavirus variant is affecting the upper respiratory tract, causing milder symptoms than previous variants.。

Pollock said that significant research and development should also be done on developing new and effective treatments such as antivirals and immune modulating treatments.。

Better phase。

Asked about whether she was optimistic the pandemic could be over this year, Pollock didn't think so.。

"I mean, it would be really wonderful if it were. But we've talked about the new variant and the transmission and the need to get everybody vaccinated. I think this means that we're going to be living with this virus for a while," Pollock said.。

"But we have made great strides and amongst all the tragedy, we also have to have some cause for being positive particularly about vaccination, because it is helping avert what would have been a much worse global disaster if we've not been able to make those vaccines," she said.。

"In a nutshell, I don't think it's going to be over this year. But I think you know, with the research and the coordinated efforts, we may move to a better phase," she added.。

Call for global collaboration。

Asked about the stronger global measures which should be put in place against new variants of COVID-19, she stressed the importance of ensuring access to vaccines and the primary doses to people and controlling transmission instead of just "controlling severe disease and death."

The WHO has set a target for countries to vaccinate 70 percent of their population by mid-2022. However, the organization said in December last year that 98 countries have not yet vaccinated 40 percent of their population, stressing that about 1.4 billion eligible people need to be urgently immunized.。

Pollock highlighted that the most important thing in tackling the pandemic in the long-term was international collaboration.。

"As long as we continue to collaborate globally and to break down those doors with scientists, politicians and public health experts, that incredible collaboration effort that started in 2020, I think if that can continue, then we will move as a global population away from the bad situation that we're in now," she said.。

"The worst scenario would be if people step away from those kinds of collaborative efforts," she stressed.。

美军“闪电航母”停靠日本,又想搞什么事情?

1.杨国福快上市了,我也吃不起麻辣烫了

2.30万元可“买”人才身份?杭州回应将依法处理

3.海南加速推进滞留旅客离岛返程工作

4.安德普泰打造多维整合力 推进皮肤学级行业进步发展

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