09-24-2011, 09:12 AM
[quote name='Rainer' timestamp='1316854867' post='11808']
It really depends, on what detail you're looking at:
- Regarding exposure times at a given ISO-setting, the lens is clearly f/2.8.
- Regarding Depth of field, it behaves like a 400/8 on FF.
- Regarding exposuretimes needed (according to the rule of thumb) you'll find
that the lens behaves like a 400mm on FF ... so, you should use 1/400 for
clear results ... but (see first point) the lens will give you short exposuretimes,
as it is f/2.8 ... a 400/2.8 regarding this point.
Just a thought ... Rainer
[/quote]
Only when you do not use an equivalent ISO setting. ISO is NOT the same ISO anymore as it was with film, when it actually had to do with the sensitivity of the film. Now it is just a user selectable gain in amplification, ON TOP of the amplification the manufacturer already applies to reach said "ISO" value.
So... for digital photography ISO has become meaningless. ISO 100 doe snot mean the same with a Nikon 1 As it means with a Nikon D3. It has lost its importance, has become irrelevant. You can just CHANGE the ISO. With film it had an importance. It just was the film's sensitivity.
So, no, no matter how you look at it, the lens is either a 150mm f2.8 lens, or a 400mm f8 equivalent lens. Just set the appropriate ISO. Or not, if similar exposure times are not necessary/wanted.
It really depends, on what detail you're looking at:
- Regarding exposure times at a given ISO-setting, the lens is clearly f/2.8.
- Regarding Depth of field, it behaves like a 400/8 on FF.
- Regarding exposuretimes needed (according to the rule of thumb) you'll find
that the lens behaves like a 400mm on FF ... so, you should use 1/400 for
clear results ... but (see first point) the lens will give you short exposuretimes,
as it is f/2.8 ... a 400/2.8 regarding this point.
Just a thought ... Rainer
[/quote]
Only when you do not use an equivalent ISO setting. ISO is NOT the same ISO anymore as it was with film, when it actually had to do with the sensitivity of the film. Now it is just a user selectable gain in amplification, ON TOP of the amplification the manufacturer already applies to reach said "ISO" value.
So... for digital photography ISO has become meaningless. ISO 100 doe snot mean the same with a Nikon 1 As it means with a Nikon D3. It has lost its importance, has become irrelevant. You can just CHANGE the ISO. With film it had an importance. It just was the film's sensitivity.
So, no, no matter how you look at it, the lens is either a 150mm f2.8 lens, or a 400mm f8 equivalent lens. Just set the appropriate ISO. Or not, if similar exposure times are not necessary/wanted.