If you’re already at the camera’s lowest ISO and maximum mechanical shutter speed, exposure compensation alone won’t solve the problem if there simply isn’t a fast enough shutter speed available.

To keep shooting at f/1.7 in bright daylight, your main options are:

• use an ND filter to cut the light
• switch to electronic shutter if your camera allows a faster top speed there
• shoot in lower light or create shade

An ND filter is the usual solution when you want a wide aperture for shallow depth of field in bright conditions.

Negative exposure compensation does not directly reduce sharpness at the focus point. It just tells the camera to make the image darker. But if you’re already at the shutter-speed limit, the camera may still be unable to expose correctly without reducing light some other way.

So the best fix is usually an ND filter, with electronic shutter as another possible option if your camera supports a higher maximum shutter speed in that mode.