Lens length, aperture, and sharpness.?

Question: Lens length, aperture, and sharpness!.!?

Ok, I have a 75 - 300mm lens that I use and am having a bit of trouble making sense of how the aperture affects the sharpness of my photos when zoomed out to 300mm!.

Can someone please explain this to me or point me toward a good online explanation!?Www@QuestionHome@Com

Best Answer - Chosen by Asker:

The biggest thing aperture will affect when it comes to the photo is depth of field!. However, using a couple stops lower will generally result in a sharper image!. So, if your 75-300 lens is 3!.5 - 5!.6, and you're zoomed out to 300mm, stopping down to F11 or something will give you a slightly sharper image!. Just don't stop down too much, or diffraction starts screwing everything up!.Www@QuestionHome@Com

The EF 75-300mm is a budget lens which obviously has some limitations in regards to image quality (especially the 300mm end), so you may have some trouble getting sharp images!.

From one review!.!.!."The Canon EF 75-300mm f/4-5!.6 III USM Lens is soft wide open at all focal lengths!. Sharpness decreases as it zooms from 70mm to 300mm!. However, the corners are softest at 70 and getting better by 300!."

There are (or were ) two versions of this lens!. The reviews below will give you some idea of which aperture works best with any particular focal length!.!.!.and which focal length gives the sharper image!.

Don't forget that this lens is very slow at the tele end, so instead of handholding it!.!.!.you may have better results using a tripod!.Www@QuestionHome@Com