What is a cameras iris and what does it do?

I'ts called an aperture. It opens and closes (but not all the way, just down to a pinhole size) just like the iris to your eye.



It doesn't just control how much light enters your camera, but the overall sharpness too. A smaller aperture will make pictures sharper from near to far, while a wider aperture can blur the background and/or foreground to isolate the subject that is in focus.

What is a cameras iris and what does it do?
The iris is the brightness of the shot. When it is really sunny, you have to turn the iris down.
Reply:While all of what Ipswhitz says is true, you may find in using older lenses that a very small iris opening can cause flare, pincushion or barrel distortion, and can cause a prismatic effect on bright light causing color separation in extreme light situations, especially when the sun is directly in or just outside the viewscreen.
Reply:Jpshwitz; did a good job on a basic level. This does not mean that I think he is on a basic level, but rather just wanted to explain it basic manor and this is likely what you wanted. However I am going to take it a step farther. I think knowledge is power.



An iris or aperture and an f-stop or not the same, an f-stop is a measurement of the amount of light that hits the film plan (or CCD). An aperture or iris is a device that controls the amount of light. Therefore the f-stop is controlled by the aperture setting on your camera.



The lens aperture diameter determines the deep of field (the area of acceptable focus in an image). The smaller the aperture size (the larger the number Ex: F22) the greater the deep of field. The larger the aperture size (the smaller the number Ex: F2.8) the lesser the deep of field.



A 28mm lens (wide angle) set at F-8 will have a greater deep of field than a 100mm lens (telephoto) set at F-8, therefore it has become a common misconception (even by many professionals) that the length of a lens effects deep of field (length of lens effects perception, it compresses the image as lens gets longer). The truth is that it takes a larger aperture setting (more light coming through the lens) for the same amount of light to reach the film plane (CCD) on the longer lens. Therefore F-8 on a 35mm lens is a smaller aperture than F-8 on the longer 100mm lens. Aperture size controls deep of field and F-Stop settings or lens length do not.

I suggest you get a good book (or search the net) on photography and how a camera works, knowledge will improve your images.



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Reply:it's an opening which can be made smaller or larger so letting in different amounts of light

the larger opening on most lenses has a smaller depth of field than a small opening
Reply:a nice flower
Reply:A camera iris (diaphragm) doesn't effect color perception at all. Color is controlled by 2 things

1) Film

2) Camera Color Balance

- we won't worry about these two things as it doesn't answer your initial question.



The diaphragm of a camera controls the Aperature setting (f stops). Pretty much how much light can come in and how much light can't come in.



By closing the diaphragm and using an aperature setting of say F22 you will let only a small amount of light in. While you shoot at this F-stop, you'll notice that more of your image is in focus. From your foreground to you background. While this is nice, it's nearly impossible to do in low light conditions.



By opening the diaphragm and using an aperature setting of 2.8 you let the most amount of light in feasable for a lense. However, by doing this, you sacrafice detail and pretty much only the subject is in focus.



Different lenses handle aperatures different. A telephoto lense will go from F2.8 (lots of light) to F22 (little bit of light) while a stationary lense may only do F5.6 (a nice roundabout number).