Novice Questions! Please help

[tcompton2]

Ok, I am new to photography in general. I have a few questions.

When is it a good idea to raise the ISO? What lighting conditions should this be changed in?

At what aperature should be used most? What affects does a high/low f-stop have on images.

IF it is night time....and say u want to take a picture of the moon and a landscape with a few lights...my pictures are always blurry where the light is... what settings should be used?


THANKS!!

 

[Mr. Baz]

Originally posted by tcompton2
Ok, I am new to photography in general. I have a few questions.

When is it a good idea to raise the ISO? What lighting conditions should this be changed in?

At what aperature should be used most? What affects does a high/low f-stop have on images.

IF it is night time....and say u want to take a picture of the moon and a landscape with a few lights...my pictures are always blurry where the light is... what settings should be used?
THANKS!!

ISO setting is dependent one what you're shooting for.
WIth a nice quality camera, any setting up to ISO400 is pretty good. Anything above that, you have to start worrying about grain/ISO noise.

Higher number, the smaller the aperature, less light let in, sharper image, and deeper depth of field.
Lower number, the larger the aperature, more light in, not as sharp, and a shallower depth of field.

At night time, you want a higher ISO(400 or 800), lower f-stop, a tripod, and a slower shutter speed. If nothing is moving, use a larger fstop, and a longer shutter speed for better focus.

 

[Sean]

I use 400ISO film for indoor shooting, without studio lighting. I use it either with ambiant sunlight, or tungsten lighting, with a filter. I use for prints primarly 100ISO film. Its a true fine grain, good color film. Esentially The ISO of a film indicated the sensitivity to light it has. The higher the ISO the shorter time kes to expose the film. One trade off with the faster film is the grain on the film is larger, and easier to see.

Apature is the area of the diaphram inside your lens. Its also a mathmatical ratio. Let me explain.

f=Focal Lenght. So if your f-stop is f/2 and you focal lenght is 50mm then the diamater of the diaphram is f/2 = 50/2 = 25mm. So as you can see the ratio is 50/25 = 2. Ok so lets look at the standard set of f-stops.

1.4
2.0
2.8
4
5.6
8
11
16
22

OK now each full stop is either double the amount of light that enters, or halfs the amount of light that enters the lens. Now you are saying 2.0 to 2.8 isn't half. Well here is where it gets tricky. Lets remember that apature is the AREA of the circle that is formed by the diaphram. So area is defined at pi X radius{2}. Pi for this purpose will be 3.1415926535897932384626433832795 and {2} will be defined as squared (why because that what it is on the Windows Calculator!)


So the area of f/2 is 490.9 Square mm [pi X (25/2){2}]. Ok so if we take a look at f/2.8 we see that the area of this f-stop is 250.2 [pi X (17.85/2){2}. This is about 1/2 the area of the stop previous. Because the blades on the diaphrams can vary a little, it doesn't necessarly produce a full 1/2 of the amount of light, so its essentially halfing for doubling.

This is how we determine what the full f-stops are. These areas are always different when using lenses with different focal lenghts. That is why f-stops are respresented as a mathmatical equation. f/2 is eaier then giving the specific area for each focal lenght.

I hope that explains apature for you. Mr. Baz's information about the differences in the different apatures is good information to know. Keep it in mind while shooting.

Moon shooting I know requires a tripod, and a dark sky. In city shots of the moon usally are blured from the ambiant sky lighting. Ever wondered why it was so dark in the country at night. less ambiant light. Depth of field is very important with moon shots. I suggest a telescope with a camera adapter for really nice shots. I will eventually try this out when I can find someone that can lend me his/her telescope, and mount. Happy shoooting.

Cheers,

 

[Mr. Baz]

Originally posted by Eigtball

Moon shooting I know requires a tripod, and a dark sky. In city shots of the moon usally are blured from the ambiant sky lighting. Ever wondered why it was so dark in the country at night. less ambiant light. Depth of field is very important with moon shots. I suggest a telescope with a camera adapter for really nice shots. I will eventually try this out when I can find someone that can lend me his/her telescope, and mount. Happy shoooting.

Cheers,

Yeah, moon shooting MUST be done with a tripod. Just don't leave it on a REALLY long shutter speed. I don't know if it was from me brumping the ground the tripod was on (grass) or if it was from the earth moving....but I got a motion-blurred moon shot.

 

[jliechty]

When you shoot the moon at night, you have to decide if you want a well-exposed moon, or a well-exposed scene around the moon. Since the moon reflects light, you'll find that it actually requires a much shorter exposure than you might otherwise think. I seem to recall using something on the order of f/8 at 125 on ISO 100 transparency film to get a decent exposure that preserved detail in the highlights of the moon. Go much slower than that, and you'll blow out the moon entirely (at least with transparency film).

 

[PurdueDood]

At night time, you want a higher ISO(400 or 800), lower f-stop, a tripod, and a slower shutter speed. If nothing is moving, use a larger fstop, and a longer shutter speed for better focus. [/B]

If nothing is moving and you're using a tripod, then lower your ISO to 50 (assuming digital) and lose the ISO noise/grain. Why you would use an ISO 400-800 for a night shot, I'm not understanding... Sure, your ISO 400, F5.6 @ 5 seconds would yield o.k. shot, but a ISO 50, F5.6 @ 8 seconds would be 10x better.


-PD