Aperture question (1 Viewer)

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BackGardenMoths

Well-known member

• Feb 21, 2011

• #1

Hi, I hope someone can advise me please. I've started to use my new Canon 100-400mm lens with an EOS 500D body. The lens says it maximum aperture is 4, however when I try the comera in aperture prority mode I can't seem to reduce the setting below 5.6. Can anyone advice me on what might be happening. I'm very new to bird photography.

Thanks

Simon

 

postcardcv

Super Moderator

Staff member

Supporter

• Feb 21, 2011

• #2

the lens has a variable max aperture depending on the focal lenght (f4.5 at 100mm going to f5.6 at 400mm), so I guess you're shooting at the long end when you're unable to get wider than f5.6.

 

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Huntso

Well-known member

• Feb 21, 2011

• #3

At what length does it change I wonder?

Had a shorter variable aperture zoom before and it changed very quickly once away from the minimum length.

 

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BackGardenMoths

Well-known member

• Feb 21, 2011

• #4

Hi, thanks for the reply. Yep, I was shooting at 400mm so that explains that. Good to know.