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newbie's question on ISO and Depth of Field

 
 
Hoover
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      04-09-2006
If you want to highlight images in the foreground and blur the background,
should the F stop numbers be small or large?
Regarding ISO, in general should ISO be set at 200 for inside photos and
higher ISO's for outside?


 
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Jim
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      04-09-2006

"Hoover" <(E-Mail Removed)> wrote in message
news:J4ZZf.4001$s%6.408@dukeread02...
> If you want to highlight images in the foreground and blur the background,
> should the F stop numbers be small or large?

Small
> Regarding ISO, in general should ISO be set at 200 for inside photos and
> higher ISO's for outside?

No
Jim
>
>



 
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Yomama
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      04-09-2006
Big help

"Jim" <(E-Mail Removed)> wrote in message
news:B8ZZf.575$(E-Mail Removed). ..
>
> "Hoover" <(E-Mail Removed)> wrote in message
> news:J4ZZf.4001$s%6.408@dukeread02...
>> If you want to highlight images in the foreground and blur the
>> background, should the F stop numbers be small or large?

> Small
>> Regarding ISO, in general should ISO be set at 200 for inside photos and
>> higher ISO's for outside?

> No
> Jim
>>
>>

>
>



 
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Mobius
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      04-09-2006
"Hoover" <(E-Mail Removed)> wrote in message
news:J4ZZf.4001$s%6.408@dukeread02...
> If you want to highlight images in the foreground and blur the background,
> should the F stop numbers be small or large?
> Regarding ISO, in general should ISO be set at 200 for inside photos and
> higher ISO's for outside?

I'm somewhat new to many of the terms though I've had some experience so I
can try to answer some of the questions (anyone else please correct me if
I'm wrong here, most of all when to use ISO settings).

The ISO is the film exposer I believe, I know it does effect the amount of
light picked up.

BACKWARDS is actually reverse (think more like golf compared to other
sports, higher number is less).

100 is more outdoor, 200 indoor or outdoor lower lighting, 400 is outdoor at
sunset & low lighting & indoor with low lighting, 800 is for even darker,
1600 is more for night/very dark.

I do know the F-stop arpature setting is also similar. The larger the # the
less light gets into the lense because its the size of the lense when open,
but as the lower number in the fraction (1/f) for the radious.

Fx = 1/x radious = 1/(x^2 or x * x) total light
(just memorize the square roots of numbers which are exponential increases
for 2)

F1.4 (1.41421356...) 1/1.4 radious = 1/2 total light
F2 = 1/2 radious = 1/4 total light
F2.8 = 1/2.8 (2.828427....rounded) radious = 1/8 total light
F4 = 1/4 radious = 1/16 total light
F5.6 (5.656854....) = 1/5.6 radious = 1/32 total light
F8 = 1/8 radious = 1/64 total light
F11 (11.313708...) = 1/11 radious = 1/128 total light
F16 = 1/16 radious = 1/256 total light
F22 (22.62741699796952...) = 1/22 radious = 1/512 total light
F32 = 1/32 radious = 1/1024 total light

Thats the way I read & understood it.


 
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Gisle Hannemyr
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      04-09-2006
"Hoover" <(E-Mail Removed)> writes:
> If you want to highlight images in the foreground and blur the
> background, should the F stop numbers be small or large?


Small. The f-stop number is really expressed as a ratio. That is why
we write it like this: "f/2" - where "f" is the focal length of the
lens. f/2 says that the aperture diameter is half of the focal length
of a lens. So if we are talking about a 50 mm lens f/2 means that the
aperture is 25 mm wide, while f/11 means that it is 4.55 mm wide.

A wider aperture means a more shallow depth of field, so for a
shallow depth of field, you use a small f-stop.

> Regarding ISO, in general should ISO be set at 200 for inside photos
> and higher ISO's for outside?


Asssuming there is less light inside than outside, you do it the
opposite. High ISO for low light/inside, low ISO for much light/
outside.
--
- gisle hannemyr [ gisle{at}hannemyr.no - http://hannemyr.com/photo/ ]
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kctan
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      04-09-2006
There are 3 factors actually for question 1.
1. Small f/number = large aperture
2. Use longer focal length lens, the longest the better
3. Stand close to the subject, as close as possible yet maintain your
required cropping.

They interact so visually do it by taking the 3 factors into consideration.

There is no specific ISO for question 2. Any ISO can take picture both
inside and outside.
But generally, higher ISO is for inside photos when its available light are
too low for lower ISO to perform. Image will be "nosier".


"Hoover" <(E-Mail Removed)> wrote in message
news:J4ZZf.4001$s%6.408@dukeread02...
> If you want to highlight images in the foreground and blur the background,
> should the F stop numbers be small or large?
> Regarding ISO, in general should ISO be set at 200 for inside photos and
> higher ISO's for outside?
>



 
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Neil Ellwood
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      04-09-2006
On Sat, 08 Apr 2006 21:04:44 -0400, Hoover wrote:

> If you want to highlight images in the foreground and blur the background,
> should the F stop numbers be small or large?

Small.
> Regarding ISO, in general should ISO be set at 200 for inside photos and
> higher ISO's for outside?

100 for outside higher for inside - but don't overdo it.
--
Neil
delete 'l' to reply
 
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David Dyer-Bennet
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      04-09-2006
"Hoover" <(E-Mail Removed)> writes:

> If you want to highlight images in the foreground and blur the background,
> should the F stop numbers be small or large?


The number should be small, meaning that the actual aperture in the
lens is large. You're going for shallow dept of field.

> Regarding ISO, in general should ISO be set at 200 for inside photos and
> higher ISO's for outside?


No, the reverse; higher ISO numbers inside (where there's less light
in general), lower ISO numbers outside (where it's brighter in
general).
--
David Dyer-Bennet, <(E-Mail Removed)>, <http://www.dd-b.net/dd-b/>
RKBA: <http://www.dd-b.net/carry/>
Pics: <http://dd-b.lighthunters.net/> <http://www.dd-b.net/dd-b/SnapshotAlbum/>
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m Ransley
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      04-09-2006
With many digital p&s noise is an issue above 100. If I want highest
quality I only use 100iso. Noise is dependant on your camera, most
Panasonic are noisy above the lowest setting, most dslr have great
flexibility from better sensors and noise may not be an issue till near
the maximum iso. dpreview should have a noise iso comment on your
camera or sensor.
You dont say what camera or lens you refer to, on my p&s I cant get out
of focus backgrounds like I can with my A1. P&S are limited in
flexibility.

 
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Don Stauffer
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      04-09-2006
Hoover wrote:
> If you want to highlight images in the foreground and blur the background,
> should the F stop numbers be small or large?
> Regarding ISO, in general should ISO be set at 200 for inside photos and
> higher ISO's for outside?
>
>

Smaller f/stop, which is of course a LARGER aperture. This is the
confusing thing. Large apertures mean shallow depth of field, but large
numbers mean small apertures and vis versa.

High ISO for dim light. Low as possible if there is enough light.
Night outdoors might require high ISO, so it is a bright light/dim light
thing, not an indoors/outdoors.
 
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