If anyone has any questions, I'll try to re-visit it and clean things up. I hope this all makes sense - I wrote it in small chunks over several hours from my mobile device. This would be an indication of the same sort of thing as on the other end, just in reverse - the blades are only able to close to a certain physical diameter, but that diameter yields a different f-number depending on the focal length of the lens. You may also find that the minimum (smallest opening, though that's the highest number) aperture also changes as you zoom - perhaps f/22 at the wide end of its range, and f/32 on the telephoto side of things. The aperture can still close down from that point, though. So, on your lens, the listing of f/3.5-f/5.6 is an indication of how wide the aperture is when all the way open. the all-the-way-open setting of the aperture blades) aperture, which actually does change the aperture diameter as you zoom, even when wide open (even your lens, when set to a non-wide-open aperture like f/8, will change its aperture diameter). Some zoom lenses, especially "fast" and/or high-end ones, have a "constant" maximum (or "wide open", i.e. With many zoom lenses, including yours, the default way of operating is to do this when your aperture is set to be all the way open. So, with a zoom lens, you get an interesting thing going on: if you leave the aperture blades in their same physical position, and zoom in or out, this has the effect of changing the f-number, without changing the actual aperture diameter. This also means that the same f-number on a different focal length lens will have a different opening diameter - while f/8 was 12.5mm for a 100mm lens, that same diameter will be f/4 on a 50mm lens, or f/2 on a 25mm lens. At f/8, the opening has a diameter of 12.5mm, etc. The number is actually an expression of the ratio between the focal length of the lens ("f") and the diameter of the opening - so, for example, f/4 on a 100mm lens means that the diameter of the aperture's opening (possibly redundant phrase, but in this case I mean the mechanical blades as the "aperture", which thus does have an opening) is 25mm. The "over" is often left out of speech (one might just say "eff five point six"), but it is quite relevant. You may notice I write these all as "eff over" something.
The way photographers indicate how open or closed the aperture is is with an f-number. The opening, or aperture, can be opened and closed (in a roughly circular configuration - though it may actually be a pentagon or an octagon or other shapes, depending on the construction of the specific lens in question). What is it an opening in? Well, inside the lens, there are a set of metal "blades", whic overlap each other.
In the world of photography, though, the word aperture is usually used to refer to a very specific opening inside a camera's lens. "An aperture" is a phrase that could be used to describe any opening. The word aperture literally just means opening. I think this question may benefit from an answer that goes a little further back to basics than the answers I see so far.
0 kommentar(er)
