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Re: [OM] E-1 bokeh?

Subject: Re: [OM] E-1 bokeh?
From: "C.H.Ling-Accura" <chling@xxxxxxxxxxxxx>
Date: Thu, 13 Nov 2003 10:55:01 +0800
DOF is a very complicated issue, if one only use the number it will never
work. I always use "appearance DOF" instead. The DOF of two lenses under
same magnification and aperture may be the same but the appearance DOF could
be very different. Consider a OM 50mm lens and 100mm lens, if you shoot at
five feet and ten feet respectively the DOF and magnification is the same
but the Out-Of-Focus background on the 100mm lens will be much softer. Check
the DOF calculator below:

http://www.shuttercity.com/DOF.cfm

So with E-1 50mm lens you shoot at 10 feet and with the OM Zuiko shoot at
same distance you will get same DOF (if you can use 0.015mm COC on the E-1,
but you can't as the resolution is lower than that) in number but the
appearance DOF will be different.

C.H.Ling

> -----Original Message-----
> From: owner-olympus@xxxxxxxxxxxxxxx
> [mailto:owner-olympus@xxxxxxxxxxxxxxx]On Behalf Of Jeff Keller
> Sent: Thursday, November 13, 2003 10:35 AM
> To: olympus@xxxxxxxxxxxxxxx
> Subject: Re: [OM] E-1 bokeh?
>
>
> The rule of thumb for which I've never understood any proof of, comes from
> comparing 35mm to med fmt to large fmt. The DOF of a normal lens decreases
> as the format increases. So a 50mm digital zuiko should have more
> DOF than a
> 100mm OM zuiko for the same size prints. The handwaving I've seen says the
> difference is relatively small, which I take to mean that a 50mm digital
> Zuiko telephoto will have less DOF than a 50mm OM normal lens. I've never
> seen any numbers just a claim that the format effect is small.
>
> Probably an hour of playing with several of the DOF calculators adjusting
> the circle of confusion to account for the different magnification to get
> the same final print could give a better feel.I don't know how
> accurate the
> various DOF calculators are. The links I have are;
>
> http://www.dudak.baka.com/fovcalc.html
> http://www.fineart-photography.com/dof.html
> http://www.fineart-photography.com/dof.html
> http://www.dof.pcraft.com/dof.html
>
> -jeff


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