Shooting RAW will definitly improve things.
However, I offer this advise if you choose to shoot jpegs.
First, never use an ISO over 100 with this camera. You will get considerable noise if you do. The only reason you would up the ISO is in a very low light situation and it is the ONLY way you can shoot the scene. Other than that dont do it
Second, you should learn to use the camera in full manual mode. Set the aperture to F8. Use shutter speed to control your expoure. Your lens will perform better at a constant aperture of F8. Apertures larger (smaller F number) will create a softer image. Apertures smaller (larger F numbers) will cause "diffraction" which is the bouncing of light waves off the edges of the aperture blades. This causes soft images as well. You can however go up or down one or two stops if necessary depending on the lighting situation. More on that in a moment.
Set focus to infinity. Do not use auto focus.
Set the lens setting to F1. This is the correct setting for your lens. It will cause the camera to zoom all the way out and go to infiity focus. You will get a full circle image this way. You shouldnt be shooting drum images with this set up. If you want more quality shoot 4 images instead of 3. The more pixels you have to work with the better your image will be.
Select the proper white balance. Do not use "auto white balance". Use either "direct sun" or "incandescent". If you have mixed lighting like in your example where there is a lot of sun coming in the windows and some incandescent form lights in the room, use "direct sun". If there are no windows like in a bathroom use "incandescent". If you images turn out with a yellow cast you can remove this in photoshop with a color correction or use the "photo filters". Shooting RAW will avoid white balance problems as you can set correct white balance before rendering the images without loosing any quality.
Control your exposure: Using AE lock is correct. AE lock will lock ALL the settings if you are shooting in "auto" mode. Auto mode lets the camera choose the exposure settings. In this mode the camera will most likely select an aperture out of the acceptable range. You just have no control over the exposure settings this way. If you want to meter the scene then switch to auto and look at the shutter/aperture setting the camera has chosen. You can then switch back to manual and set these as suggested or change them to values you want.
If you go to full manual "M" on the camera you can set all these your self and you dont have to use AE lock. You would set the following in the shooting menu
Lens = F1
ISO = 100 , don't use auto.
focus = infinity
zoom = none, ie full circle image
Noise Recuction = off
Sharpening = normal or off.
image adjustmant = normal
contrast = normal
On the CP 5000 you can set up 3 seperate "shooting menus". You shoud set the first one to these settings. This way when you get ready to shoot all you do is select this menu and all the settings are set for you so you dont have to do this every time.
A simple example of shooting a scene:
The room is just like your example. Mixed lighting and a some what low light situation as most interior rooms have.
With the camera set to lens F1 go to manual. Set the aperture at F8. You can now take a few test shots with different shutter speeds. In your example you would probably have to set a shutter speed of around 1/30 or 1/15 to get a good exposure. Or you can set the camera to "aperture priority" which will allow you to select the aperture and the camera sets the shutter speed. If you do this rotate the camera around and you will see that the camera selects a different shutter speed based on where you are pointing which is based on the amount of light the camera is metering at that point. Watch the shutter settings. Point at the darkets part of your scene and then at the