Three reasons you want fast lenses
Fast lenses are sexy and that’s why in this article I take the time to explain the use of lenses that open up wide. I will go trough the main three reasons why I find them very helpful.
Because of composition
We’ve all been there, a good looking car but no way to create a composition that draws attention to the subject. Fast lenses can sometimes fix this problem for you, if you know what you’re doing. As fast lenses have the option to open their aperture wide, or the f-stop low for that matter, you can utilize the depth of field for your composition. This crudely translates into what part of the photo is in focus and which is not. Fast lenses can create small parts of the photo in focus (and the rest out of focus as a blur or Bokeh) and with that you immediately draw attention towards the car. There are however more factors that come into play when talking about this focus bit, but we’ll get into that another time. For now just remember: the lower that number behind ‘f’, the better!
Because of filters
Earlier I wrote about the need to use polarizing filters for carspotting and about their downsides. As we don’t all live in sunny places with loads of sunlight to allow for fast shutters speeds at low ISO, the use of these filters can be troublesome for handheld shots. As these filters reduce the light in f-stops by 2 steps, it can cause shutter speeds that long that you can’t get that handheld shot you want. Without upping the ISO. Fast lenses, like the famous 50mm f1.8, can mostly compensate for this downside of the polarizers.
Because of flexibility
You simply don’t always want to shoot with an aperture of f1.8 and with fast lenses you aren’t bound to that limitation as you can always close down to create a bigger depth of field. Where the use of ‘slow’ lenses don’t grant you the ability to open up wider to create a narrower depth of field. The use of fast lenses give you far more flexibility to play with depth of field based compositions and you want to creative flexibility when shooting.
