2Bdecided wrote:
On 18 Jan, 16:45, Paul Furman wrote:
Do you really need zoom for family photos though?
It seemed very useful, but I don't know. The idea of changing lenses
worries me - I'd break something.
The reason I ask is a
fixed length fast 'prime' lens is really ideal for kids & indoor family
shooting: you can shoot without any flash at all and capture the
ambiance much better and you can get a faster shutter speed for
herky-jerky little kids.
Stuff like this: http://edgehill.net/Misc/misc-photos/nick/pg3pc13
This is something I'm interested in. Let's say a given amount of light
(indoors, night, normal-ish lighting) meant the zoom lens needed ISO
1600 and 1/100th. I have no idea what aperture. The result would be
noisy, of course. What ISO could I come down to with a fast fixed
length lens, still at 1/100th, for a comparably bright picture, with
hopefully much less noise?
Those shots have the shooting data below each. The linked shot is 1/40
second f/1.2 (crazy fast lens) ISO 400.
A kit lens is probably f/3.5 at the wide end. You can get f/2.8 fixed
length (or zoom for high price) and that's about a half a stop. A stop
is a doubling for shutter speed & ISO, so ISO 1600 one stop relieved is
ISO 800 & a half stop is ISO 1200. OK lets make it simpler, assume the
kit lens at f/4 not quite zoomed out all the way, here's a chart of full
aperture stops (strange math):
f/5.6 1/100 ISO 3200
f/4 1/100 ISO 1600
f/2 1/100 ISO 800
f/1.4 1/100 ISO 400
But for indoor light bulbs only, you'll probably struggle to get 1/30
second unless you have really bright lightbulbs:
f/5.6 1/30 ISO 6400
f/4 1/30 ISO 3200
f/2 1/30 ISO 1600
f/1.4 1/30 ISO 800
or:
f/1.4 1/60 ISO 1600
You could get a 35mm f/2 autofocus for a Nikon D80 ($320 lens):
http://www.adorama.com/NK352AFDU.htm...00677506434282
Or a Sigma 30mm f/1.4 for $390 which would work on a D40, Canon, etc.
but it's a fairly bulky lens.
For those, I used mostly manual focus versions on a D200 which probably
wouldn't interest you: 20mm f/2.8 (autofocus), 28mm f/2, 35mm f/2, 35mm
f/1.4, 50mm f/1.2
More examples:
http://edgehill.net/Southwest/12-21-...lestons/pg2pc6