|
For English version, please scroll down. ARRI大画幅摄影机系统常见问题解答欲知详细信息，请您点击“阅读原文”了解， 或复制以下链接至浏览器： http://www./largeformat/index_zh.html 浏览详情。 如果本文未能解答您的疑问，请前往ARRI论坛 https://www./forum/ 提出.
问: ALEXA LF支持哪些录制分辨率？ 答: 在LF片门全开模式下，整个影像传感器都是有效成像区域，录制分辨率为4448 x 3096（原生4.5K）。在LF 16:9影像传感器模式下有三种选项：首先是原生3840 x 2160（UHD）；其次是在机内从3840 x 2160下采样到ProRes 16:9 2K（2048 x 1152）；第三种是在机内从3840 x 2160下采样到ProRes 16:9 HD（1920 x 1080）。如果您不需要较高分辨率，希望降低数据码率，就可以采用这些下采样方式。LF 2.39:1影像传感器模式也支持用完整影像传感器区域录制4448 x 1856（原生4.5K）。 问: ALEXA LF是否符合Netflix的发行要求？ 答: 这台摄影机的分辨率已经超越4K，因此应该是支持Netflix的。 问: ALEXA LF使用SxS存储卡时支持哪些录制帧率？ 答: 使用SxS PRO 存储卡时的最大录制帧率 问: 能不能在ALEXA LF上使用我自己的画框线？ 答: 可以。除了机身内建的默认画框线，您也可以利用在线工具ARRI画框线生成器自由创作画框线。 问: ALEXA LF能不能录制MXF/ARRIRAW？ 答: 不能。目前ALEXA LF只能录制传统的ARRIRAW（.ari），也就是ALEXA Classic、ALEXA XT和ALEXA SXT系列摄影机通用的格式。 问: 为什么不再支持XR Capture Drive、CFast 2.0存储卡或者小容量的SxS PRO存储卡？ 答: 因为ALEXA LF的数据码率较高，继续使用既慢容量又小的存储媒介没有任何意义。同时，我们也希望简化系统的复杂程度，缩短测试时间。 问: ALEXA LF有没有内建ARRI画面风格库？ 答: 暂时没有，未来会通过ALEXA LF的软件升级包提供。 问: 监看画面可不可以放大？ 答: 暂不支持，但ALEXA LF的第一次软件升级将带来类似ALEXA 65上的那种缩放和放大功能。 问: ALEXA LF的外形有多大？ 答: ALEXA LF比ALEXA 65小得多，只比ALEXA SXT W长、宽各多出12 mm。 问: 机身前面的三个螺丝是做什么用的？ 答: 这些螺丝与用户的日常使用无关。在摄影机制造过程中，我们要精确调整影像传感器的平面，使它与镜头卡口平面完美平行。这三个螺丝并不是用于调整的，更像是用于封口的螺帽，内部也没有与产品维护有关的零部件。 问: ARRI会推出一款ALEXA LF Mini吗？ 答: 我们会就可行性进行观察，但现在还不知道。不管结果如何，考虑到如此高的数据码率，制造ALEXA LF Mini的难度不会低。
问: 为什么要使用一种新的镜头卡口？ 答: 更大的影像传感器需要用更大的镜头卡口来优化镜头设计。与参数相同但采用直径较小的PL卡口的镜头相比，使用LPL卡口可以让全画幅镜头做得更小、更轻，光圈更大。传统的PL卡口无法发挥现代全画幅镜头的设计优势，因为它的直径是根据Super 35影像传感器确定的，它的法兰距长度也必须照顾到采用反光镜快门的胶片摄影机。 问: 为什么LPL镜头卡口的法兰距不小于44 mm？ 答: 这是为了兼容现有的ALEXA摄影机。 问: LPL镜头卡口能够使用在其它ARRI摄影机上吗？ 答: 可以。目前有两种版本的LPL镜头卡口：“ALEXA LPL镜头卡口”用在ALEXA Classic、XT、SXT和LF摄影机上；“ALEXA Mini LPL镜头卡口”是用在ALEXA Mini和AMIRA上的，不过，它的LBUS接口在AMIRA上不起作用。 问: LPL镜头卡口能够用在其它厂牌的摄影机上吗？ 答: 如果对方愿意，我们可以为其它厂牌的摄影机提供LPL卡口的使用授权。 问: LPL镜头卡口能够用在其它厂牌的镜头上吗？ 答: 如果对方愿意，我们可以为其它厂牌的镜头提供LPL卡口的使用授权。 问: 我能不能在ALEXA LF上直接使用现在的54 mm PL镜头卡口？ 答: 可以，现有的PL镜头卡口可以匹配ALEXA LF。然而在测试中，我们发现将LPL镜头卡口和PL-LPL转接环搭配起来，比单独使用PL镜头卡口更能够提高画面四个角落的通光量，因此我们建议始终将二者搭配使用。 问: 为什么LPL镜头卡口上只有一组LDS触点？ 答: LPL镜头只在12点钟位置有LDS触点，它们接收LDS-2和/i信号。在LPL镜头卡口上，PL-LPL转接环有两种安装方式：12点钟位置或3点钟位置。两种安装方式都支持LDS-1和/i。
问: 我能在ALEXA LF上使用变形镜头吗？ 答: 可以，在ALEXA LF上使用Super 35或全画幅变形镜头都十分简单。ALEXA LF的取景器和监看输出信号都能够以目前的变形宽银幕压缩系数（1.25x、1.3x、1.5x和2x）拉伸还原画面。全画幅变形镜头使用LF片门全开影像传感器模式（左图）。Super 35变形镜头使用LF 16:9影像传感器模式，它的画面高度与Super 35 ALEXA使用6:5变形宽银幕影像传感器模式时完全一样，后期裁掉两侧的画面（右图）。 问: 我能在ALEXA LF上使用PL卡口镜头吗？ 答: 可以。将PL-LPL转接环安装到LPL卡口上，就可以使用所有的Super 35或全画幅PL卡口镜头了。每一台ALEXA LF都标配了这款转接环，让您在现场迅速切换PL和LPL卡口镜头。 问: 在ALEXA LF上怎么使用Super 35镜头？ 答: 有许多种方式，这里介绍三种最常见的用法： 1. 使用画面扩展器 您可以加入一种画面扩展器，以光学方式放大画面来覆盖LF片门全开影像传感器模式的整个成像区域，球面镜头和Super 35变形镜头都支持这种方式。不过，您需要留意几个问题：
2. 后期裁切Super 35成像区域 如果使用LPL镜头卡口搭配PL-LPL转接环，那么Super 35拍摄的画面是支持后期裁切的，不管是变形镜头还是球面镜头效果都很不错。使用变形镜头时，在LF 16:9影像传感器模式中，画面高度正好与ALEXA Super 35 6:5影像传感器模式的完全一样（见左图）。ALEXA LF 16:9录制的分辨率是3840 x 2160，ALEXA S35 6:5是2578 x 2160。如果使用球面镜头，您可以选择LF 2.39:1影像传感器模式，它最高支持150 fps（右图），这种模式的成像区域大小能够容纳ALEXA Super 35 3.2K和ALEXA Super 35 2.8K。大多数ARRI Super 35镜头的像圈都能够覆盖3.2K，但某些第三方厂牌的Super 35镜头无法做到，但所有的Super 35镜头覆盖2.8K是没有问题的。 3. 利用Ultra Prime和Master Prime镜头的照度圈
镜头制造商所保证的光学品质是指镜头成像圈内的画质，在镜头的整个照度圈内都有光线射入，但成像圈之外的部分就难以保证画质了，但ARRI镜头的成像圈和照度圈都非常大。因为以往有些用户在胶片摄影机上拍摄Super35格式时会忘记把取景器遮片从N35换成S35（N35画幅比S35小）。在这种情况下，为了保证实际画幅上的成像品质，我们把的镜头成像圈和照度圈做得非常大，比其它大部分厂牌的Super35镜头都大。
在测试中我们发现，Master Prime 35镜头的照度圈在焦距较长时能够覆盖LF 16:9影像传感器模式（UHD - 3840 x 2160）。因此，制作团队可以大部分采用Master Prime拍摄，遇到广角画面时也许借助一两支Signature Prime镜头来拍。请注意，MP 35/LF 16:9组合的水平视角和MP 26/S35 2.8K组合（转换系数1.33x）的一样。Ultra Prime镜头也是这个原理，事实上，最近有一部德国的Netflix剧集《暗黑》就是用ALEXA 65和Ultra Prime镜头拍的。 问: 我能在ALEXA LF上使用Leica M镜头吗？ 答: 目前不可以。如果需求量高，我们会专门开发一个Leica M镜头卡口。 问: 其它厂牌的全画幅相机镜头能不能用？ 答: 有可能，但我们需要先做评估。
ARRI发布大画幅摄影机系统 (0.12 mb) https://100-assets./arri_assets/lf_assets/downloads/cn/ARRI%E5%8F%91%E5%B8%83%E5%A4%A7%E7%94%BB%E5%B9%85%E6%91%84%E5%BD%B1%E6%9C%BA%E7%B3%BB%E7%BB%9F.pdf ARRI大画幅摄影机系统_官方新闻图片 (5.7 mb) https://100-assets./arri_assets/lf_assets/downloads/cn/ARRI%E5%A4%A7%E7%94%BB%E5%B9%85%E6%91%84%E5%BD%B1%E6%9C%BA%E7%B3%BB%E7%BB%9F_%E5%AE%98%E6%96%B9%E6%96%B0%E9%97%BB%E5%9B%BE%E7%89%87.zip
ARRI Large-format Camera System Frequently Asked QuestionsFor more information and details, Please click 'read more'， or, visit the offical webpage link: http://www./largeformat/index_zh.html. If you have a question not listed here, please ask in the ARRI Forum https://www./forum/.
Q: What recording resolutions are available with the ALEXA LF? A: In LF Open Gate sensor mode, the entire sensor at 4448 x 3096 can be recorded (native 4.5K). In LF 16:9 sensor mode there are three options: first, the native 3840 x 2160 (UHD) can be recorded. Second, the camera can downscale 3840 x 2160 to ProRes 16:9 2K (2048 x 1152). Third, the camera can downscale 3840 x 2160 to ProRes 16:9 HD (1920 x 1080). Those downscale options are there if you want to reduce the data rate and have no need for the higher resolutions. In LF 2.39:1 sensor mode, the sensor area of 4448 x 1856 can be recorded (native 4.5K).
Q: Is this camera Netflix compatible? A: Since the camera has a resolution of more than 4K, it should be Netflix compatible. Q: What are the frame rates of the ALEXA LF with SxS cards? A: Maximum frame rates with SxS PRO cards
Q: Can I make my own framelines for the ALEXA LF? A: Yes. In addition to the default framelines built into the camera, there is also the online ARRI Frameline Composer https://www./fileadmin/adapps/frameline_v4/index.php?camera=ALEXA which allows the creation of any frameline your heart desires. Q: Can I record MXF/ARRIRAW with the ALEXA LF? A: No. At this point in time the ALEXA LF records the traditional ARRIRAW (.ari), which is the same format recorded by the ALEXA Classic, ALEXA XT and ALEXA SXT family of cameras. Q: Why do you not support XR Capture Drives, CFast 2.0 cards or the smaller capacity SxS PRO cards anymore? A: This is because the slower and smaller capacity media don’t make sense with the higher data rate of ALEXA LF, and because we wanted to reduce complexity and testing time. Q: Is the ARRI Look Library included in the ALEXA LF? A: Not yet. The Look Library will be part of a future software update for the ALEXA LF. Q: Can I magnify the monitor image? A: Not yet. A zoom and magnify feature very similar to that of the ALEXA 65 will be part of the first software update for the ALEXA LF. Q: What is the size of the ALEXA LF? A: The ALEXA LF is significantly smaller than the ALEXA 65, and only 12 mm longer and wider than the ALEXA SXT W.
Q: What are those three screws in the front of the camera? A: The screws have no relevance for the user. They allow us to adjust the sensor planeness (being perfectly parallel with the lens mount surface) in manufacturing. While these three screws are not the actual adjustments but rather capping screws, there are no user-serviceable parts inside. Q: Will there be an ALEXA LF Mini? A: We are looking into the feasibility of this but we do not know yet; in any case, it would be difficult because of the high data rates.
Q: Why do we need a new lens mount? A: A larger sensor needs a larger lens mount for optimal lens design. The LPL lens mount allows the design of full-frame lenses that are smaller, lighter and have a faster T-stop than equivalent lenses designed for the smaller PL lens mount. The traditional PL mount would compromise modern full-frame lens design; its diameter was based on the Super 35 sensor size and its long flange focal depth was dictated by the fact that film cameras had a mirror shutter. Q: Why is the LPL lens mount flange focal depth not even shorter than 44 mm? A: Because we wanted it to be compatible with existing ALEXA cameras. Q: Can the LPL lens mount be used on other ARRI cameras? A: Yes, there currently are two versions of the LPL lens mount. The 'LPL Lens Mount for ALEXA' can be used on ALEXA Classic, XT, SXT and LF cameras. The 'LPL Lens Mount for ALEXA Mini' can be used on ALEXA Mini and AMIRA. However, the LBUS connector on this mount will not work on an AMIRA. Q: Can the LPL lens mount be used on other manufacturers’ cameras? A: We are licensing the LPL mount to other camera manufacturers if they wish. Q: Can the LPL lens mount be used on other manufacturers’ lenses? A: We are licensing the LPL mount to other lens manufacturers if they wish. Q: Can I attach the existing 54 mm PL lens mount to the ALEXA LF? A: Yes, the existing PL lens mount fits on the ALEXA LF as well. However, in tests we have found that a combination of LPL lens mount and PL-to-LPL adapter lets more light through in the corners than the PL lens mount, so we recommend always using the LPL lens mount with PL-to-LPL adapter.
Q: Why is there only one set of LDS contacts on the LPL lens mount? A: LPL lenses will only have LDS contacts at the 12 o’clock position and accept LDS-2 and /i signals. The PL-to-LPL adapter can be mounted in two ways on the LPL lens mount: in the 12 o’clock and in the 3 o’clock position. In both mounting positions, the PL-to-LPL adapter supports LDS-1 and /i.
Q: Can I use anamorphic lenses on the ALEXA LF? A: Yes, the use of anamorphic lenses for Super 35 or for full frame is easy. ALEXA LF can de-squeeze images from all current anamorphic squeeze ratios (1.25x, 1.3x, 1.5x and 2x) on the viewfinder and monitor outputs. For full-frame anamorphic lenses, use the LF Open Gate sensor mode (left image). For Super 35 anamorphic lenses, use the LF 16:9 sensor mode, which has exactly the same height as the 6:5 anamorphic sensor mode on Super 35 ALEXAs, and crop the sides in post (right image).
Q: Can I use PL mount lenses on the ALEXA LF? A: Yes, a PL-to-LPL adapter fits securely into the LPL mount and allows the use of all Super 35 or full-frame PL mount lenses. This adapter ships with each camera and allows fast switching between PL and LPL mount lenses on set.
Q: How can I use Super 35 lenses on the ALEXA LF? A: There are many methods for using Super 35 lenses with the ALEXA LF. Here are three of the most common ones: 1. Using an image expander
You can use a third-party image expander that will optically magnify the image to cover the full sensor in LF Open Gate sensor mode. This works with spherical as well as anamorphic Super 35 lenses. However, you should be aware of a number of issues:
2. Cropping the Super 35 area in post
Using the LPL lens mount and the PL-to-LPL adapter, it is possible to shoot with a Super 35 lens and crop the image in post. This works great for anamorphic and spherical lenses. For anamorphic lenses, the LF 16:9 sensor mode happens to be exactly the same height as the ALEXA Super 35 6:5 sensor mode, which is used for anamorphic lenses (see left image). ALEXA LF 16:9 sensor mode captures 3840 x 2160, and ALEXA S35 6:5 is 2578 x 2160. When working with spherical lenses, you can use the LF 2.39:1 sensor mode, which runs up to 150 fps (right image). Both ALEXA Super 35 3.2K and ALEXA Super 35 2.8K fit within the image area recorded in this sensor mode. While most ARRI Super 35 lenses have an image circle that covers 3.2K, the image circle of some third-party Super 35 lenses does not cover 3.2K, but all Super 35 lenses cover 2.8K. 3. Using the illumination circle of Ultra Primes and Master Primes
Lenses have an image circle within which the manufacturer guarantees the optical quality and an illumination circle where there’s still light, but of undefined quality. Both circles of most ARRI lenses are very large, since we wanted to make sure that if a customer shot Super 35 on a film camera, but had forgotten to switch the lens mount from N35 to S35, they would still get an image. Because of that our lenses have a bigger image circle and a bigger illumination circle than most other Super 35 lenses.
Q: Can I use Leica M lenses on ALEXA LF? A: Not at the moment. We would have to build a special Leica M lens mount, which we will do if there is enough demand. Q: What about other third-party full-frame photo lenses? A: It might be possible, but we would need to evaluate this.
ARRI Large Format Camera System - Press Release (0.05 mb) https://100-assets./arri_assets/lf_assets/downloads/en/20180202_arri_large_format_camera_system_en.pdf ARRI Large Format Camera System - Media Pack (5.7 mb) https://100-assets./arri_assets/lf_assets/downloads/en/20180202_arri_large_format_camera_system_press_pictures.zip
|
|
|
