佳能单反一向层级分明，我无意中居然发现了1Dx2对闪光灯的支持有不如5D4和6D2的地方，真是奇怪。
5D4和6D2在外接闪光灯的条件下，ISO的自动范围是100-1600，但是1Dx2在外接闪光灯的条件下，ISO的自动范围居然缩小到了100-400！
这太不合理了！
佳能的老法师说说这是咋回事呢？

还有，我是真的觉得这个情况不太合理，拒绝喷子！ 本帖最后由 情商智商双硬伤 于 2017-7-7 09:44 编辑

没什么办法，要么换尼康，要么等5D5。5D5一定可以在闪光灯下自动ISO。

进来学习

其實部磚頭機。太重了。一般拍攝用不到那點速拍功能。。對焦現在無反跟上。。用不到那些功能杠上一塊大磚

噪点感人啊！

人像额头曝光过度为什不减一档。再用闪灯整体补光

Advantages of Live View AF

- In what aspects do the Live View AF surpass the viewfinder AF on the EOS 5D Mark IV?
Kudo: One of the advantages of Live View AF is that it covers 80% x 80% of the screen area during AF shooting. Although the performance of the viewfinder is also excellent with 61 AF points, the area that can be covered by AF is limited. Meanwhile, the biggest advantage of Live View AF is that it offers a wide area for AF, and you can set focus freely on any point within this area without being constrained by the position of the AF points. Yet another advantage of the EOS 5D Mark IV is the use of a touch-screen for features such as Touch Focus and Touch Shutter, which allows for intuitive operation during the shoot.

- Many users have reservations about using Live View AF because of the large AF frame. What are the measures taken on the EOS 5D Mark IV to address this concern?
Kudo: We are aware of the calls for a smaller AF frame. But we have maintained it at the same size after considering its balance with the AF performance. The EOS 5D Mark IV now supports AF shooting while the image is enlarged, and it is also easier to move the AF frame via touch-screen operation. The LCD monitor also boasts a clear display and high definition, so I believe users who have not tried the Live View function before would also find it useful.....

闪光拍摄时提高iso是为了减少灯输出负荷从而缩短回电时间，我确实不明白闪光拍摄时iso400以上有什么实际意义。

- What are the key components that enable mirror control?
Kojima: The key components include the use of a high-torque motor and a new lever mechanism. The mechanism to flip the mirror up and down using a motor and a cam gear is similar to that adopted on the EOS 5DS and EOS 5DS R. However, the EOS 5D Mark IV differs in that a high-torque motor is used to boost the drive and speed control accuracy, based on which the speed is reduced significantly to minimise the vibrations. Meanwhile, the newly-developed lever mechanism effectively suppresses mirror bound, thereby shortening considerably the time needed for the vibration to come to a stop.

Back row, from left)
Kazuki Haraguchi, Megumi Inazumi, Keisuke Kudo, Yasuyuki Watazawa, Takashi Kon, Kiyoshi Tachibana, Yutaka Kojima, Hiroaki Nashizawa

EOS 5D Mark IV Interview with Developers

Is the AF sensor on the EOS 5D Mark IV the same as that used on the EOS-1D X Mark II?
Kojima: Yes, we used the same AF sensor model for both cameras. Other than the parts for securing it to the camera body, the rest of the parts employed are exactly the same as those used on the EOS-1D X Mark II.-

The AF system is significantly different compared to that of the EOS 5D Mark III. Could you tell us how the shooting system has changed?
Kudo: First and foremost, we have made changes to the viewfinder system. By increasing the maximum number of AF points to 61, all of which support a maximum aperture of f/8, not only is the camera capable of capturing even better photos of subjects, the range of photographic possibilities has also widened when shooting with a lens extender. Also, the low light limit has been further lowered to better handle shooting at dimly-lit locations.
The EOS 5D Mark IV now supports the EOS iTR AF system, which detects the shape and colour of the first subject that the camera sets focus on when the subject tracking AF function is used for viewfinder shooting. This enables the camera to perform tracking while switching the AF points. Not only so, advancements have also been made in the tracking performance such as with the updated tracking algorithm.
As for the Live View shooting experience, adopting Dual Pixel CMOS AF has brought about dramatic changes to the Live View shooting style. In particular, the camera is now able to handle a much wider variety of scenes with the higher AF speed.-

Dual Pixel CMOS AF is a technology that was first adopted on the EOS 70D but not on the two EOS 5DS models. What was the reason for introducing it on the EOS 5D Mark IV?
Tachibana: Actually, we had wanted to introduce it on the EOS 5DS series too. However, that would have been rather technically challenging because of the 50.6-megapixel resolution, which is why we eventually did not include it. One of the reasons we adopted it on the EOS 5D Mark IV is because we succeeded in overcoming those technical difficulties.

- I believe the AF system of the EOS 5D Mark IV belongs to the same generation as that of the EOS-1D X Mark II. Is there any area where the EOS 5D Mark IV surpasses the EOS-1D X Mark II in performance?
Kudo: The defining difference between the two models lies in Live View AF rather than viewfinder AF. Both cameras are equipped with Dual Pixel CMOS AF, but the EOS 5D Mark IV allows users to select from the three types of AF: Face detection + Tracking AF, FlexiZone – Multi AF (maximum 63 AF points) and FlexiZone – Single AF. The EOS-1D X Mark II offers only Face detection + Tracking AF and FlexiZone – Single AF.
Also, Servo AF can now be used too for still photography, which helps to enhance the capability of tracking moving objects. Besides, the same Servo AF now comes with an extremely wide array of functions, including a Focus priority mode and a Shooting speed priority mode.
The low light AF performance during Live View shooting supports lighting as dim as EV-4 – the lowest in the entire EOS series and more powerful than the low light limit of EV-3 on the EOS-1D X Mark II when photographing in dimly-lit scenes.

- The low light limit of EV-4 is even better than the low light AF performance of the viewfinder, am I right to say that?
Tachibana: Yes, you are right. The viewfinder image would appear dark too in a dimly-lit scene, and there are occasions where we are unable to identify whether the image is in focus. With the better low light performance of the Dual Pixel CMOS AF on the EOS 5D Mark IV during Live View shooting, it is now easier to establish focus. Also, the Live View image is displayed on the LCD monitor, which allows you to adjust the display for the image to appear brighter than what you actually see. This makes it easier to identify the subject and comes in extremely handy when you are shooting at a very dark location.

我是在佳能官网下载的说明书，然后从说明书截图得到的。

6d2的这个升级还是很有意思的，在av等模式下可以自由iso。请问楼主是在哪看到这些信息的？谢谢。

6D2的程序自动、快门优先、光圈优先、全手动都可以ISO自动100-1600，不仅仅是场景模式，这显然比1Dx2和5D4更高级一些。

6D2还真有点奇怪，1DX II是特殊注明P档可以400～1600，等入手的玩家试机体验

跟推出时间有关系吧。越晚发布的机型，部分功能更成熟，跟定位没有关系。

宽容度也是，1,5,6系基本是越晚推出，宽容度越好。