A74非堆疊式cmos性能可能到盡頭了

DPREVIEW：Despite the higher resolution, the a7 IV can still shoot at 10 frames per second. However, it can only do so in the lossy compressed format if you want to shoot Raw. The a7 IV has a lossless compression option, for when you need maximum processing flexibility, but the burst rate drops to around 6 fps if you use it. Sony says the camera's buffer depth allows over 800 Raw+JPEG images (or over 1000 JPEGs), but this is in the uncompressed Raw format, which again shoots at around 6 fps.

M4在使用無失真壓縮/無壓縮14bitRAW時的連拍速度只有6張/每秒，比之前的R4還差，更沒有R3/M3的水準。發佈會上的800張Raw+JPEG也是在6fps下測出來的，結合CFe卡槽的速度，所以緩存根本沒有大太多，是因為CMOS讀出速度慢了所以才可以拍得更久。

DPREVIEW：Our first look at the rolling shutter rates suggest this isn't an especially fast sensor. 14-bit readout of the whole sensor for stills takes around 1/15 sec (~66ms), which is around seventeen times longer than the super-fast a1 takes to read out its sensor. This means silent shutter mode is likely to result in significant distortion with moving subjects.Full-width 4K video takes around 26.5ms, which is comparable with the other models in its class. It's likely the camera is dropping to 12-bit readout for video mode, but the process of combining pixels should reduce noise and hence prevent DR dropping to ~12EV. 60p footage has rolling shutter rate of around 12.8ms, which is low enough to avoid distortion of all but the fastest movement.

Sensor讀出14bit 66ms，12bit 26.5ms(估計)。m3 imx410的Sensor 14bit讀出速度是52ms，12bit 24ms，也就是a7m4的使用電子快門果凍效應比m3的還要大一些。

MON: 由3寸92萬點(640*480)變成102萬點(720*480)，266ppi升至288ppi

個人認為，4k 60要CROP，連拍性能提升不到，都是這塊sensor的問題，老實說我寧可用回低像素的底，把這些痛點解決再說

不過相對於A74的失望
A7r5只要山a74的對焦移植過去便能成為新一代神機，價格倒是也可能升到3899美金就是