I bought a used Canon EOS-1D Mark IV along with a Canon 17-40mm wide-angle zoom. When I use the lens, the picture is extremely flushed, too much light. But when I use the standard 50mm lens that also came with the camera the photos look good.
Is there a setting for the 17-40mm that I need to make?
Based on your very minimal post, it's impossible to know what the problem is; or even how much you know about photography. I'm going to start by assuming you're a complete beginner; if this is too insulting, well, you need to post more info.
When taking pictures, it's up to you to control the exposure; i.e. how much light hits the sensor during the exposure. You can do this by controlling the aperture and shutter speed. You can also control the sensor's sensitivity to light, which is called the ISO.
You can do this by putting the camera into aperture or shutter priority mode, or you can use a program mode. In any of these modes, the camera will make its best guess to get the exposure right. But it can easily be misled by different scenes; for example a photo of a snow scene may come out too dark. So you need to know how to compensate for this to get good exposure. You can also use manual mode, where you control everything directly.
If you're not already comfortable with this, there are many resources online which can teach you the basics of photography.
If you want more help from this forum, I suggest posting *way* more details. For example, some example pictures, and for each picture:
Hope this helps.
If the camera is exposing properly with the 50mm lens but not with the 17-40mm lens it is possible there is a problem with the zoom lens.
Reset the camera to factory settings, clear all custom functions and then set the camera to Program mode. Take a photo with both lenses outdoors in good light. Report back what happens.
Take a normal photo with the 50mm, and then switch to the 17-40mm without changing any camera settings and take a second photo. Just take off the prime, and replace it with the zoom. Repeat these steps a couple of times, capturing 2-3 shots with each lens.
If the prime photos are consistently good, while the zoom photos are consistently poor, then it is almost a certainty that there is an issue with the zoom. If it is used, return it for a refund.
I don't see any strange camera settings that would affect exposure. What I do see is that you are in a sunny condition, so the "Sunny 16" guidance should apply.
You were in Program mode. In P mode the camera will select a shutter speed (generally 1.5 to 2 times focal length to avoid motion blur due to shake) and then try and get the lowest possible ISO f/stop combination, favoring a low ISO to avoid noise.
The ISO is 100. So the f/stop should be around f/16. I believe the aperture is stuck/sticking close to wide open.
Either take a photo in Av set to f/16 or just set the camera to f/16, press the DoF preview button and look into the lens. Is the aperture closing down?
I uploaded 4 pictures: 2 made with the 50mm lens and the other 2 using the 17-40mm zoom lens. All were taken on the "P" mode and AF focus setting. You can clearly see the "flushed" photos using the 17-40mm lens. As I mentioned before, when I use "shutter priority" instead of "P" mode, I can get the zoom lens to take a good photo.