Lenses, Camera's and f-stops.
Greetings all,
I bought a Tamron 90mm f2.8 marco lens on wednesday.
Not had much time to play with it as yet. Tomorrow:clap (Working on Saterday sucks!:cry )
When I did have it on the camera (D50) in AP, I could not get the apature to go down to 2.8. If I remember correctly it was 3.2 (Might be wrong though. was late)
Is this a fault with the lens or just does not do what it says on the tin?:dunno
One thing I could get the camera to say was f65. I did not know you could go this high other than with pin hole.
At f65 the exposure was 2 seconds, spot metering, pointed straight at a lamp.
Third question: (And last:help )
Assume I have an exposure time of 1 second at f2.8. How would you work out what the time required is if you increase to say f3.2? Inversly, adjusting the shutter, by how much must you change the apature?:dunno
Cheers,
Crispin
p.s.
In the office on saterday but not _really_ working. shhhh:rolleyes
I bought a Tamron 90mm f2.8 marco lens on wednesday.
Not had much time to play with it as yet. Tomorrow:clap (Working on Saterday sucks!:cry )
When I did have it on the camera (D50) in AP, I could not get the apature to go down to 2.8. If I remember correctly it was 3.2 (Might be wrong though. was late)
Is this a fault with the lens or just does not do what it says on the tin?:dunno
One thing I could get the camera to say was f65. I did not know you could go this high other than with pin hole.
At f65 the exposure was 2 seconds, spot metering, pointed straight at a lamp.
Third question: (And last:help )
Assume I have an exposure time of 1 second at f2.8. How would you work out what the time required is if you increase to say f3.2? Inversly, adjusting the shutter, by how much must you change the apature?:dunno
Cheers,
Crispin
p.s.
In the office on saterday but not _really_ working. shhhh:rolleyes
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