P+S f/2.8 vs. dslr f/2.8?

Can someone explain the difference in Aperture in a Point & Shoot and a DSLR system? My friend just bought a nice Leica DLUX-3 and was saying that its widest ap. was 2.8. I remember reading how p&s f numbers don't correlate with dslr f numbers. What is the difference? I am wrong, are they the same? Can this produce bokeh like 2.8 on a dslr, certeris paribus?

Thanks

Hopefully next time I see him, I can make more sense.

All is same except Depth of field. A 2.8 PnS lens provides more depth of field compared to dSLR.

farrukh wrote in post #2172691
All is same except Depth of field. A 2.8 PnS lens provides more depth of field compared to dSLR.

And that's because of the different focal lengths and degrees of enlargement of the two. A true 35 mm f/2.8 lens enlarged 10x on either a P&S or a DSLR will have the same visible DoF. But the DLUX has a 6-25 mm lens; you can't get a 6 mm lens for any DSLR unless you can locate the old Nikon 6 mm fisheye. And the DLUX has a much smaller sensor than DSLRs do. So enlargement to get the full frame will be different amounts on the 2 cameras as well.

DOf equivalent examples p&s to slr
f/2.8= f/11
f/4=f/16
f/5.6=f/22
f/8=f/32

So at a given aperture (f/5.6=f/22) p&s could use a shutter speed of 4 stops faster than that of an SLR to achieve .

(taken from Understanding Exposure by Bryan Petterson, love that book!!!)

Jon wrote in post #2172711
And that's because of the different focal lengths and degrees of enlargement of the two. A true 35 mm f/2.8 lens enlarged 10x on either a P&S or a DSLR will have the same visible DoF. But the DLUX has a 6-25 mm lens; you can't get a 6 mm lens for any DSLR unless you can locate the old Nikon 6 mm fisheye. And the DLUX has a much smaller sensor than DSLRs do. So enlargement to get the full frame will be different amounts on the 2 cameras as well.

Yes that is the exact explanation. Thanks for information.