How do I change the f stop on the XL2?

Question

When I change the Iris it changes the f-stop. It also makes the picture brighter or darker. I thought the f-stop changed how blurry things that were out of focus are. I'm wanting to do just that but I don't know how. How can I change the blurriness of out of focus objects on the Canon XL2?

Answer 1

Ok here is the Real answer. Because of the slow native shutter speed of video, and the high light sensitivity of the CCD, normal exposure will almost always require a high f-stop and have a wide depth of field. There are 3 ways to solve this.
1. Use the high speed shutter setting, that reduces the light getting to the CCD and causes the iris to open.
2. Use a ND4 filter to darken the light and force the iris open.
3. Use a filter with a clear center spot that will fog or blur the rest of the picture regardless of distance.

Answer 2

You are correct with how f-stop changes OoF (out of focus) areas, the blurriness. I think the blurriness you are talking about is depth of field. Basically, the more open the aperture is, like f2.8, the more OoF the BG (background) gets. A small aperture like f8 will have high DoF and be sharp throughout most of the plane.
Focal length also plays into DoF but I assure you that this topic is all over the Internet.
Iris, f-stop, aperture all mean the same thing.
I do not mean to be angry but with such a hail almighty camera you have, please know the ins and outs of camcorder techniques to utilize the XL2 to its fulliest potential. You will find lots more help on dvinfo.net under the Canon XL2 Watchdog forum.

Answer 3

The iris is the f-stop. It controls how blurry things are, but more commonly, the brightness, which is what is happening here. To get a shallower depth of field, you'll need to open up as wide as possible, then increase shutter speed, or add an ND filter (this is better). I don't know if the XL2 has negative gain, but if it does, you can do that as well. Alternatively, you could build a DOF adapter http://www.mediachance.com/dvdlab/dof/index2.htm.
However, from what I've seen, as long as you have 24p recording and filmic contrast/gamma, DOF won't really make a huge difference in making your video more filmic. But if you need it for an effect, then obviously it's good to have. Hope this helps!