apertures
- Thread starter taff63
- Start date
lawrie29
Balloons! Yay!
- Messages
- 5,051
- Name
- Lawrie
- Edit My Images
- Yes
The aperture is the size of the hole in the lens. This is an adjustable feature on many cameras. By changing the size of the hole, you change how much light enters the camera which affect shutter speed. It also affect the Depth of Field, the size of the area that is in focus. The larger the hole the more light, so a faster shutter speed can be used, and the smaller the DOF is. the smaller the hole, the less light enters the camera, so a longer shutter speed may be needed, however the larger the DOF.
I'm sure someone will have a better answer shortly though...
I'm sure someone will have a better answer shortly though...
- Messages
- 753
- Name
- Graham
- Edit My Images
- No
That's pretty much it in a nut shell.
They're measured in 'f' numbers, which is the relative aperture and is an industry standard. It means that you get the same light intensity from f/8 on an 8mm lens as you would on a 600mm lens, even though the effective aperture on the 600mm lens will be much, much larger. The smaller the f/no., the larger the effective aperture.
You can go very in-depth about why a smaller f/no (so larger aperture) will lead to a shorter DoF, but to be honest you don't really need to know why, you just need to know that it does. It's handy for selective focus, and is also very important for reciprocity when it comes to your exposures.
They're measured in 'f' numbers, which is the relative aperture and is an industry standard. It means that you get the same light intensity from f/8 on an 8mm lens as you would on a 600mm lens, even though the effective aperture on the 600mm lens will be much, much larger. The smaller the f/no., the larger the effective aperture.
You can go very in-depth about why a smaller f/no (so larger aperture) will lead to a shorter DoF, but to be honest you don't really need to know why, you just need to know that it does. It's handy for selective focus, and is also very important for reciprocity when it comes to your exposures.
Please proof read your post.:bonk:
When talking about apertures many posts quote the diameter for a certain F stop. This may lead to a bit of confusion. I prefer using the area for calculating the light loss. Take for instance the diameter for a 50mm lens at F8. the diameter is 6.25mm. The area being 30.67sq mm. Now use a 100mm lens ,the diameter being 12.50mm Twice the 50mm setting. BUT 4 times the the area 122.7 sq mm. Why do we allow 4 times the light through for twice the focal length,the answer is inverse square law. A 200mm lens area is 490.8 sq mm 16 tims the amount of light.
- Messages
- 4,367
- Name
- Steve
- Edit My Images
- Yes
And the rest of that statement doesn't :shrug:
- Messages
- 623
- Name
- Tony
- Edit My Images
- Yes
**PLEASE NOTE THIS IS NOT MY WORK, THIS IS FROM A HANDOUT, AND MR JAMES OLIVER STONE HAS DONE THE HARD WORK ON PRODUCING THIS, NOT ME.**
Aperture controls the amount of light that can enter a lens. It also controls the DoF (depth of field)
The same principle appiles to aperture as it does to ISO, and shutter speed. Each time you increase or decrease the aperture by one full stop, you increase or decrease the light by a full stop.
aperture is measured in stops:
f1, f1.4, f2, f2.6, f4, f5.6, f8, f11, f16, f22, f32
When shooting portraits a shallow DoF is more pleaseing to the eye, when shooting landscapes, f11 or f16 and a tripod are you best friends, and the shallower the DoF (or larger the aperture are) the harder it is to focus.
Aperture controls the amount of light that can enter a lens. It also controls the DoF (depth of field)
The same principle appiles to aperture as it does to ISO, and shutter speed. Each time you increase or decrease the aperture by one full stop, you increase or decrease the light by a full stop.
aperture is measured in stops:
f1, f1.4, f2, f2.6, f4, f5.6, f8, f11, f16, f22, f32
When shooting portraits a shallow DoF is more pleaseing to the eye, when shooting landscapes, f11 or f16 and a tripod are you best friends, and the shallower the DoF (or larger the aperture are) the harder it is to focus.
Last edited:
- Messages
- 9,005
- Name
- Paul
- Edit My Images
- No
What's wrong with the post? It makes complete sense and provides an intelligible answer to the question, unlike yours which would confuse the hell out of anyone!
Slight correction there "aperture controls the amount of light that passes through a lens" Also the focussing is no harder for small or large aperture. Also very poor grammar. Wondered when you would get your pennorth in Bud
