OK thought I'd have another go at doing some "hip shots" today and see if I had any more luck.
I was finding that a lot of my shots has a slight tilt to the right of about 2 degrees. This is caused by me accidentally tilting the camera slightly to the left.
Luckily Rawtherapee has a handy straightening tool to correct non straight shots - I have to be very careful as the tool will crop away some of the shot as part of the process.
The GRD IV has a good manual focus function and I set focus to about 2.5 metres when shooting from the hip.
Relying on autofocus would not really work as the shutter needs to fire the instant the shutter button is pressed and using autofocus can add a delay of about 0.2 seconds with the GRD4. This is still fast compared with other compact cameras where you can wait the best part of a second to lock focus, but zero seconds is better than 0.2 seconds.
Shooting from the hip can mean that you end up with quite a lot of similar looking photos, so it's not ideal as the only method of taking street photos.
It can be used indoors, but remember the aperture will tend to be more open if you shoot in program mode so less depth of field to play with when focussing
I think I'm definitely liking the square format for this type of street photography