Aperture – variable or fixed?


Let’s talk a bit more about photography and lenses in particular.

In the last few posts we talked about photography, cameras and lenses. Today, I want to expand on that. A bit more on lenses, apertures to be exact.

When purchasing a lens one of the decisions to make is to decide whether you’re happy with a lens with a variable aperture i.e. an aperture that changes as the focal length changes. Not all zoom lenses have variable apertures, many professional zoom lenses have an aperture that doesn’t change.

A variable aperture is one of the signs of cheaper lenses (cheaper doesn’t mean bad) and sometimes you’d be fine with a variable aperture. So what if the aperture changes as you zoom in? For example, a lens that I use is an EF-S 17-85mm F4-5.6, so the aperture at 17mm is F4 and as you zoom in to around 35mm it changes to F4.5 and then to 5.6. Besides I think that with these focal lengths you don’t really use small apertures anyway. The best results are achieved with apertures F6.7-8 and more.

I hope this gives you some idea on lenses and apertures. You need to decide and you may have a different opinion from mine. That is fine.


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