R7 auto-iso on viewfinder display with flash

[mcsuppes]

I have a Canon R7 with a Neewer Z1-c flash

When I attach the flash to my R7 and look through the viewfinder the display becomes auto-iso even in Manual mode. I can change my iso settings but the viewfinder itself is constantly adjusting iso, which is maddening.

 I’ve tried countless changes in the camera and flash menus to no avail. Is this a bug with Canon and Neewer flash compatibility? I just want to use manual flash without the image exposure constantly shifting. Any help greatly appreciated! 

PS: Another probably unrelated thing is that when the flash is attached my shutter speed is capped at 1/250. Not sure how to correct this either.

[Waddizzle · Accepted solution]

There are numerous posts in these forums from members reporting compatibility issues between Canon cameras and Neewer products.  The Neewer products are [not] fully compatible with Canon gear it would seem.  This is a Neewer problem, not a Canon problem.  Other brands like Godox do not suffer from compatibility issues.

As for your shutter speed being limited to 1/250 goes, you are probably running into the high speed sync limitation on shutter speed.  Download the User Guide for more info.

https://www.usa.canon.com/support/p/eos-r7 

High speed since has no simple explanation.  The Neweer products may not be compatible.