If you're using Canon's latest full-frame offering to shoot video, you'll be pleased to hear that the 5D Mark IV is slated for a major firmware upgrade in the coming weeks that should vastly increase its video capabilities. There is a drawback for some owners, however.
One of the main criticisms of the 5D Mark IV thus far has been its 1.78x crop factor when filming in 4K. Canon Rumors is reporting an upcoming firmware update that is expected to introduce C-Log to the camera will also change this, introducing a 1.27x crop factor for DCI 4K and 1.29x for UHD, with no change in frame rates and output remaining at 8-bit. Nonetheless, the 1:1 4K sampling mode (1.78x) will remain an option.
Furthermore, full-sensor 3K modes at 60 fps and 24 fps (HDR) will be added, which the FullHD 1080p mode will take advantage of for improved perceived resolution. Lastly, the XF-AFC file format will be introduced with two options: 120 Mbps (4:2:0) and 200 Mbps (4:2:2).
The drawback is that the decrease in crop factor means an increase in sensor sampling area and an increase in generated heat from additional processor load. Newer batches of the camera have an improved heatsink design, but earlier models may need to be sent to Canon for service or they may experience overheating warnings with the new firmware. There's no word yet on if Canon will charge for this service.
Remember that this is still a rumor, but if true, it could indicate a major shift in the 5D Mark IV's position in the video world.
[via Canon Rumors]