Why a faster lens?

Question

Let us say that I wish to photograph with a flash, or if not with a flash on my camera, with an aperture of 16f. Will it make any difference if I use a lens with aperture that can go as far as 1.2f compared with a flash that only can open to 5.6f....?

Answer 1

Why a faster lens? Most flash photography, especially if you aren't using a pro flash which can be filtered or bounced can be quite unflattering especially when photographing faces. Having a large aperture like an aperture of F1.8 can be quite advantageous if there is an ample amount of available light. As I am sure you are aware the larger the aperture i.e F1.2 as you mentioned the more light is allowed into the camera and the faster your shutter speed. If you couple a large aperture with a high ISO film often times you can shoot with very minimal available light.
There are also a lot of other advantages of shooting with a lens that has a large aperture. For one thing having a larger aperture allows you to use faster shutter speeds which thus will stop action better. Also using a larger aperture can have the effect of minimizing your depth of field especially if you are using a lens of 100mm or greater. If you are shooting a portrait and you focus on a persons face using your largest aperture you will in effect be able to drop out any distracting background.

Answer 2

You have to use fast speed film, with the faster aperture settings leave less time to capture an image. You don't say what you are trying to take a picture of. But you have to leave room for moving objects. These will be a blur, if the aperture rate is not adjusted in tune w/ f s. If you your flash is low you will get a picture that will appear greenish (under developed).

Answer 3

Depth of field and the range of the flash unit will be affected by your aperture size.