Hi Jon.
jon@xxxxxxxxxxxxxx wrote:
> Just to add to what everyone else has said, I was told a vague rule of thumb
> a while back by an old photography friend (who shoots N*k*n - pah !).
> Basically, the slowest shutter speed you can safely hand-hold is the
> reciprocal of the lens length.
>
> For example, with a 50mm lens, don't hand-hold it any slower than 1/50th of
> a second. For a 200mm lens, don't hand-hold any slower than 1/200th of a
> second.
I've heard this rule of thumb before too... The math is easy but I
personally prefer at least 1 stop faster with the shutter than this.
Eg: 50mm = 1/125th. I'm a "hack" so slow shutters don't work for me.
> Also, I haven't seen anyone give a simple explanation of Depth of Field and
> the use of the Aperture yet, so I'll have a go. As simple as I can....
You gave a very good explanation. Good job! One thing I would like to add.
Most prime lenses have a "depth of focus" scale on the focus ring.
On my Zuiko 18mm there is a "Red Dot" on the mounting flange of the lens
that indicates where to mount the lens but listed on either side of the dot
are the various aperture sizes in descending size.
When you focus the lens the "distance to focus" on the focus ring lines up
with the "Red Dot" and you can use the various aperture sizes listed out on
either side of the "Red Dot" to determine how near & far will be in focus. I
find this scale very valuable in low light or when I'm trying to shoot
quickly... I can preset focus distance and then choose an aperture with
enough depth of focus to hide my errors.
It is important to remember that each lens will give different depth of
focus depending on it's construction.
For instance: A Zuiko 18mm/f3.5 set at f16 and focused at 1 meter gives
close focus to 0.5 meters but focuses PAST infinity on far focus. Using this
scale I realized that I could focus the lens closer (.75 meters) and I could
still have EVRYTHING from 0.35 meters to infinity in focus as long as I kept
the aperture at f16.
This might sound complicated but it's really very easy and it will help you
to get to know your lenses and there characteristics.
- Matt Crawley
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