There are a few enhancements in the Camera App in iOS5. The biggest improvement is now you can use the "Up Volume" button as the shutter button. With an iPhone4, you can hold it and take a photo as you are using a real camera. No more touching the screen. You can also do that with an iPad. However, the volume control for iPad is on the left side instead of on the right side (like the iPhone4), therefore, this feature is not very useful unless you are left-handed.
Another good feature for photographers is the AE (auto-exposure) control. Now you can tell the device where to take the exposure reading. Just tap that area. Here is an image that AE at the sky:
And the same scene but AE at the desk:
You can also lock the exposure setting and then recompose. Just tap and hole for a second on the area that you want to meter. The white grid will flash a few time and then "AE Lock" will be displayed on the bottom of the screen. Now you can recompose with the same exposure. To unlock the AE, just tap anywhere on the screen.
iOS5 also adds a on screen grid option to help your composition. Just tap the options button on top to turn it on or off.
From the look of this screen, I am pretty sure Apple will continue to add more features to the iPhone camera to make it a serious camera.