Hi Tanya,
sounds like your friend's friend's imagination has been hamstrung.
However, you will find it worthwhile to understand about hyperfocal
distance. The best way would probably be to find a decent book which
explains it, as it is really one of those subjects that is best
explained with some diagrams. However, nothing ventured...
When you take a picture there is a closest point to the camera and a
furthest point which are both 'acceptably sharp'. The distance between
these points is the depth of field.
'Acceptably sharp' depends on various factors such as print size and
viewing distance, but is not particularly important at the moment.
Most older prime lenses, including Pentax ones, have a depth of field
scale on them. This consists of some f-stop markings either side of a
line on the lens barrel, usually something like 16 11 8 4 | 4 8 11 16.
There will also be some marks for the missing f-stops, and often a red
mark, which is an infra-red focussing index, which you can safely ignore.
Using a 50mm lens, if you set your aperture to f/8, for example, and focus
at 1 metre, you can read off from the depth of field scale where the nearest
and furthest acceptably sharp points are - look at the distances of the 2 '8's.
It should be about 0.9 to 1.2 metres, approx.
Now focus on infinity. The nearest point in focus will be about 8 metres. The
furthest point will be 'infinity and beyond!' (Copyright Capt. B.
Lightyear). So you're 'wasting' depth of field by focusing on infinity.
Now refocus so that the centre of the infinity symbol (a supine 8) is
aligned at the f/8 mark on the depth of field scale. Check the nearest
point of acceptable sharpness by reading off the distance aligned to
the other f/8 mark - it should be something close to 4 metres. You're
now focused at the hyperfocal distance for f/8 and you've saved some 4
metres of acceptable sharpness at the near end.
If you repeat at the smallest aperture setting, say f/16, you'll see
that everything from about 1.8 metres to infinity is sharp.
Many landscape photographers use this technique to maximise the depth
of field in their photographs. It doesn't make it a 'rule' for taking
landscapes. It's a technique that is also used a lot by street
photographers of the Henri Cartier-Bresson type. He almost invariably
set his 50mm lens to f/11, and prefocused on 5 metres. It has also
given rise to one of the cliches of photography from the days of the
Speed Graphic press camera - 'f/8 and be there'. Press photographers
set their apertures to f/8 to get a good compromise between a
handholdable shutter speed and enough depth of field to make focusing
less critical.
It's up to you to decide what is a good or bad landscape, not some drongo
you've never met hidden away in the outback pretending to be a very Minor White.
Hope this helps.
---
Bob
mailto:[EMAIL PROTECTED]
Sunday, April 15, 2001, 6:45:39 AM, you wrote:
> she claimed that she had this friend who was
> an "expert" on landscape photography, which I basically know ZILCH about.
> She claimed that his number one tip was to shoot EVERYTHING in landscape
> photography at f22 to ensure maximum depth of field. Ok, so here is my
> question, (and please forgive me if I am wwaaaaay off track here), but when
> you are shooting, say a lake, or a beach scene at 6.30 at night and you need
> more light, doesn't it make sense to shoot as wide open as possible? The
> lady I spoke to argued the point of depth of field with me, but unless I am
> reeeeally mistaken, I thought that the theory behind a lens which focuses at
> "infinity" meant that after your subject is a certain distance away from the
> lens (eg. 8 metres on my Vivitar 28/2) the focusing switches to infinity
> which basically means that everything is in focus anyways? I mean, if that
> is not the case, than what is the use of having a "fast lens" when only a
> miniscule amount of your shot will be in focus?
-
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