Lens vs. camera apertures

By: biho 5707 days ago
I understood from the lens reviews that if for example the maximum aperture of a lens is f/3.5-5.6, we still can achieve higher f numbers via the camera aperture control but we cannot have an apperture greater than f/3.5. Do I understand this point right? I was confused to see pictures taken with D40 at f/8 beyond the kit lens range.
By: johnriley 5706 days ago
You are correct that the widest (maximum) aperture in this case would be f3.5 at the wide angle end. It would be f5.6 at the telephoto end of the zoom.

The aperture can be closed down to much smaller values to restrict the amount of light entering the camera. Small apertures also give greater depth of field. The smallest aperture on a lens of this type is oftem f22, but that would be at the wide angle end. At the telephoto end it might be f28 or f32.

I think you have mistaken the f3.5-5.6 as meaning that was the range of apertures available, but it actually refers to the maximum aperture of the lens that, with this lens design, changes as you zoom.

There are some lenses that have a constant aperture value, such as the SMC Pentax-DA 12-24mm f4. But the lens still stops down to f22.

Hope that has cleared it up for you.

John

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