Why does aperture change my light?

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Keith
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I must be missing something. I was doing a close up in macro auto focus and F2.8 and F8 were completely different results lighter and darker.

I thought ISO and shutter speed were the two settings that altered light?
 
Think you need to read up on what aperture means. - Sorry to be blunt.

Have a look on the web for the exposure triangle.

Exposure
 
Hi Keith, as you can see on the diagram below, they all have an impact on the exposure. If you're shooting in manual then you'll need to slow the shutter down as you narrow the aperture to get the same exposure as you would with a wider aperture.

triangle.png
 
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I must be missing something. I was doing a close up in macro auto focus and F2.8 and F8 were completely different results lighter and darker.

I thought ISO and shutter speed were the two settings that altered light?
You changed your exposure value by 3 full stops, so yes, that's going to affect the EV of the image.

It's called the exposure triangle for a reason; ie there are three elements that combine to produce the EV.
 
Think you need to read up on what aperture means.

This.

We talk of the exposure triangle: shutter speed, aperture and sensitivity (ASA/ISO/Film speed)

If you fix sensitivity and use a shorter exposure then you need a larger aperture to let light through.
If you fix sensitivity and use a smaller aperture to let light through then you need a longer exposure.
If you fix aperture and sutter speed then you need to adjust the sensitivity to match.
Etc.

A larger aperture has a smaller number - related to the effective size of the hole divided by the focal length.
 
I must be missing something. I was doing a close up in macro auto focus and F2.8 and F8 were completely different results lighter and darker.

I thought ISO and shutter speed were the two settings that altered light?

Keep an eye on the aperture, shutter and ISO settings Keith. If your camera has auto ISO it might be an idea to see how you get on with auto ISO selected but also keep in mind that higher ISO's can give more noise. If you don't like auto ISO you can always increase it manually to get the exposure you want with your selected aperture and shutter settings.

Also, many people tend to manually focus when doing macro as with AF the camera will focus on something but that something might not be the best choice. What you could do is use AF to get you near and then fine adjust with manual focus.

Actually... another little project for you could be to use all the ISO settings and see at what point the image starts to be affected by noise too much.

Good luck with it :D
 
Hi Keith, as you can see on the diagram below, they all have an impact on the exposure. If you're shooting in manual then you'll need to slow the shutter down as you narrow the aperture to get the same exposure as you would with a wider aperture.

triangle.png
Thanks for that, I thought aperture was all about focus distance, and there was me thinking I had learnt the triangle 1
 
Keep an eye on the aperture, shutter and ISO settings Keith. If your camera has auto ISO it might be an idea to see how you get on with auto ISO selected but also keep in mind that higher ISO's can give more noise. If you don't like auto ISO you can always increase it manually to get the exposure you want with your selected aperture and shutter settings.

Also, many people tend to manually focus when doing macro as with AF the camera will focus on something but that something might not be the best choice. What you could do is use AF to get you near and then fine adjust with manual focus.

Actually... another little project for you could be to use all the ISO settings and see at what point the image starts to be affected by noise too much.

Good luck with it :D
Thanks Alan
 
Thanks for that, I thought aperture was all about focus distance, and there was me thinking I had learnt the triangle 1

The aperture is the hole that lets the light in. A wide aperture, a low f number like f1.4 is bigger than f8 and will let the light in faster allowing a faster shutter speed / lower ISO. It also gives you less depth of field.

If you have a wide aperture lens the best thing you can do is experiment... like taking a series of pictures at different apertures and seeing the results. Oh, hang on... have a look at this...


Keep at it Keith. You seem to be making great and fast progress so I'm sure you'll soon to on top of just about everything :D
 
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The aperture is the hole that lets the light in. A wide aperture, a low f number like f1.4 is bigger than f8 and will let the light in faster allowing a faster shutter speed / lower ISO. It also gives you less depth of field.

If you have a wide aperture lens the best thing you can do is experiment... like taking a series of pictures at different apertures and seeing the results. Oh, hang on... have a look at this...


Keep at it Keith. You seem to be making great and fast progress so I'm sure you'll soon to on top of just about everything :D
Thanks Alan, there's not a lot of aperture adjustment on my little camera, but it still needs to be understood. Somehow I managed to get things the wrong way around and thought F2.8 was best for landscapes and scenery ! Much appreciated.
 
Thanks Alan, there's not a lot of aperture adjustment on my little camera, but it still needs to be understood. Somehow I managed to get things the wrong way around and thought F2.8 was best for landscapes and scenery ! Much appreciated.

It's your choice Keith.

Some people think that landscape should mean wide focal length lenses and small apertures (big f numbers) with everything in the depth front to back but there are also people who like long lens landscape and even wide aperture shallow depth landscape.

You should try it all and see what you like :D
 
It's your choice Keith.

Some people think that landscape should mean wide focal length lenses and small apertures (big f numbers) with everything in the depth front to back but there are also people who like long lens landscape and even wide aperture shallow depth landscape.

You should try it all and see what you like :D
That's good advice, thanks Alan.
 
My Pie chart alternative to the triangle - may, or may not, be helpful :)
 
My Pie chart alternative to the triangle - may, or may not, be helpful :)
Thanks Kev, much appreciated.
 
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