According to this Apple discussion forum post:

As you know, software always controls your iSight. Most apps, including all Apple apps of which I am aware, automatically make the iSight settings for you and do NOT allow you to manipulate them from within the application.

In my own case, I have found that merely adding more light to my work room has allowed the automatic settings to give me adequate iSight images.

However, if you want to take manual control, the iGlasses2 add-on lets you manipulate many of the features that iSight (and many other compatible webcams) offer. Note that iGlasses2 may not work with every applications that can work with your camera.

You can get iGlasses2 here: http://www.ecamm.com/mac/iglasses/

This Apple KB also offers some troubleshooting guidance:

Important: Follow these instructions in order. Test the camera between steps to see if the issue is resolved.

Built-in iSight cameras These steps are for iSight cameras that are built into a computer, such as the iMac G5 (iSight) or later, the MacBook, or MacBook Pro.

1. See if the issue is application-specific. Try another application (iSight works with applications like iChat, PhotoBooth, and iMovie HD 6) to see if the iSight camera exhibits the same behavior in all applications. If it only happens in one application, try reinstalling that application.
2. See if the issue is user-specific. Test your iSight camera in another user account. If the issue only occurs in one user, the issue would be isolated to user settings.
3. Find out if the computer recognizes the iSight Check System Profiler (in the Utilities folder, inside the Applications folder). Under the USB header, check to see if the iSight camera is detected.
4. Reset SMC or PMU Reset your computer's SMC or PMU, and then check System Profiler again. (SMC reset instructions for iMac G5 (iSight), Intel-based iMacs; PMU reset instructions for MacBook and MacBook Pro.)

If your built-in iSight camera is still not behaving correctly after trying all these steps, you may need to contact Apple or an Apple-Authorized Service Provider for service.

In short, you can try adding an app to offer access to the controls or do a bit of troubleshooting on you MBP to confirm if this issue occurs on other applications or for other users. Worst case, bring your MBP in for servicing.

Note: Fixed typo.

It's possible you have installed, or someone else has installed, a system utility to capture the image from the iSight when opened. This is often something an anti-theft application might do, in order to track down the user of a stolen laptop.

One combination of utilities that can do this sort of thing is "sleepwatcher"

You might check to see if there is a file at

/etc/rc.awake

or an invisible file in your home directory called

.sleep

If so, sleepwatcher is installed.