How Fast Should My Lens Be?

If you are still using a point and shoot film orslower at the long end. This is very important,
digital camera, your choice of lens speed is limitedbecause if are going to be shooting at the longer
to the camera. However for those of you whoend of the lens, when shopping for a lens, keep
decided that it is time to move on and upgrade tothis in mind, and you will save yourself some
an interchangeable lens camera, whether itmoney. Let me explain. Take two lenses, one is a
happens to be film, or digital, you are no doubt28-80mm f2.8(short end) / f5.6(long end), and
have been looking at the many lens optionsanother lens, 28-80mm f3.5 / f 5.6. These two
available. Large majority of people switch from ahave an identical range, however the first is
point and shoot to a Single Lens Reflex camera.faster at the short end. This larger aperture does
While overwhelming percentage of people movenot come free. You may end up paying 2 times
to a Digital SLR, Film SLRs are still popular, andas much as the second lens. If you are going to
function essentially the same. So, for the purposebe mostly zooming to the long end of the range,
of this article, the two types will be treated ascompare and price your lens at that end.
one. Lenses are available in so many differentIf you are going to be shooting mostly portraits
combinations, and varieties, that discussing themand other static scenery and plan to use flash, or
all is far beyond the scope of this article.a tripod most of the time, you will not need a
However, they all have one thing in common.very fast lens, because the added speed will likely
They are all broken down into two groups: slow,be of little benefit to you. As such, you will do
and fast. If you are still struggling with choosingjust fine with a F4.0 or slower. Action shooters
your first lens, or just trying to make the rightoften benefit from faster lenses, and if you are
decision, while faced with many choices, this articleplanning to capture sports, animals, and other
should help.moving subjects, a faster lens may help at times.
First of all, the speed of the lens is determined byThe single biggest benefit of a faster lens is the
the size of the opening, known as the aperture.freedom it gives you, when the light is limited. If
The larger the opening the faster the lens isyou are an action shooter, and capture a lot of
considered to be. Typically, lenses marked withaction in dim light, the extra speed will be very
F4, F3.5, F2.8, and smaller are considered fast,helpful, and allow you more hand-held shooting.
while lenses marked with a bigger number areAlways evaluate how much you are going to be
slower. I know this may sound odd, but theshooting in different environments. Action and low
smaller the number the faster the lens. If you arelight shooters will most benefit from lenses with
new to shooting with an SLR camera, you areapertures of F4.0, and larger. If you think low
most likely looking at “zoom” lenses. Mostlight, and action will be very infrequent, and you
zooms today have a variable aperture. This simplyare comparing two similar lenses, choose the
means that at the shortest end, the lens is fasterbudget one, which will likely be just a bit slower.
than at the long end. For example, a typical lens aOften, a price of a zoom lens with just a slightly
28-80mm. This lens zooms from 28mm tosmaller aperture at the long end will be hundreds
80mm, and it is a very good starter lens. Thisor dollars less than a similarly sized zoom with a
type of a lens will typically have a F3.5 apertureslightly larger aperture.
at 28mm (short end), while at 80mm (long end) itMost modern Digital SLRs can really offset the
will be F4.5, or F5.6, which is considerably slowerneed for a fast lens through higher ISO settings,
than the short end. Typically, the faster the lens,something that Film cameras do by using a faster
the more it will cost, and the heavier it will be.film. With Film cameras, you would need to switch
Most casual shooters look for very versatilea roll of film to change the ISO speed. If you use
lenses, and faster lenses certainly offer morea Digital SLR, switching an ISO is easy, and could
flexibility in certain situations.be done at any time. This is a huge benefit, and
Now that we briefly discussed the concept ofreduces a need for the faster lenses. Unless you
speed, lets figure out whether you really need aare planning to make money with your camera
fast lens. The first thing that you have to thinkgear, fastest lenses will not be cost effective.
about is your shooting habits. Everyone isConsider borrowing, or renting a fast lens, in the
different, and very much unique. Some shootrange which will meet your shooting needs, and
landscapes, some only people, others nighttest it in the different environments in which you
scenes, some shoot under water, and so forth.will be shooting. If you are not pushing the limits
Typical casual shooter will likely shoot duringof the lens, chances are, you will be OK with a
daytime, and will likely be shooting portraits,slower, more budget friendly alternative. Make
landscapes, city scenes (during a vacationsure that you know your budget, and how
perhaps), and other fairly undemandingactively you will be involved in photography. If you
environments. If you shoot a lot of photos in dimplan to trade-up your equipment in a few years,
light, like night clubs, restaurants, museums,keep in mind that technology only gets better,
outdoors after dark, and other dim light situations,and making a big investment will make more
a faster lens is definitely a boon. However, yousense if you are going to get a lot of use out of
should always keep in mind that most zoomit.
lenses, while faster at the short end, will be