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Old Jun 28, 2008, 9:24 AM   #11
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OK... First of all thanks for all the help and advice so far... I'm probably more of a wide angle person on landscapes, but like detail in macro (yes I'm a bit of a contradiction!)... anyway here's all the key data I find can in the EXIF info - hope it's enough!

for the first picture (yellow):

Exposure time: 1/200"

F number: F4

Aperture Value: 4AV

Max aperture value: F2.2

Shutter speed: 7.66 TV

Focal length: 12.69mm



For the second picture (red):

Exposure time: 1/125"

F number: F4

Aperture Value: 4AV

Max aperture value: F2.51

Shutter speed:6.97 TV

Focal length: 17.59mm



For the third picture (blue):

Exposure time: 1/500"

F number: F4

Aperture Value: 4AV

Max aperture value: F2.99

Shutter speed:8.97 TV

Focal length: 28.81mm



Does that help with regard to what lens capability I need?

Nicky
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Old Jun 28, 2008, 12:53 PM   #12
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All three of the photos you posted were shot using an aperture of f/4.0 on a lens with a maximum aperture of from f/2.0 (at it's shortest focal length) to f/3.0 (at it's longest focal length.

Using the DOF Calculator at http://www.dofmaster.com/dofjs.html, I figure that on a Canon 450D, with a lens of an equivalent focal length, you'd need to use an aperture of f/12.7 to get the same depth of field. (That's more than 3 fullf-stops![suP]*[/suP]) As a result of the much smaller aperture, and presuming the same ISO setting,you'd need to use shutter speeds of 1/20", 1/12", and 1/50" (round numbers), respectively, to reproduce the three shots you posted.

Certainly, the 450D will perform better at higher ISO settings than the G3, and using a higher ISO setting will allow you to use shutter speeds that are more appropriate for handheld shooting without reducing image quality. But either an IS lens or a tripod would help.

So a Canon 450D with the kit IS lens would work well for reproducing two of the three photos you posted, but for the third, you'd need a longer lens.

And you might need to get used to longer shutter speeds.

[suP]*[/suP] I knew that a dSLR offered the potential for a much smaller depth of field than a P&S, but I never actually knew how much. That's a lot!
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Old Jun 28, 2008, 3:06 PM   #13
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Very nice photos, btw.
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Old Jun 28, 2008, 3:25 PM   #14
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Thanks - both for the advice and the complement!!!
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Old Jun 29, 2008, 6:54 AM   #15
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BTW, your G3 has an extraordinarily large aperture for a P&S camera. You might want to keep it around for indoor/low light situations where the XSi's kit lens would be too dim.
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