DOF is only dependent on aperture. Hence, the 77 will have larger DOF than the 85 wide
open because the 77 is an 1.8 lens whereas the 85 is 1.4 wide open. This provided that
you keep the image size the same with both lenses.
Otherwise, DOF varies with aperture, focal length, size of the subject, distance
between camera and subject. If you then shot the same subject from the same lacation
with both lenses the 77 will give more DOF due to both shorter focal lenght and
smaller aperture (wide open). The 77 is difficult to focus at infinity in low light
because it focuses well past infinity. You need to establish (in daylight) where on
the helicoid infinity focus is achieved and use that for focusing. The 77 Limited is
sharper than the FA 85 at wide apertures.
P�l
----- Original Message -----
From: "Douglas E Harmon" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Wednesday, May 30, 2001 2:04 AM
Subject: Technical question for those with 77LTD and FA85F1.4
> Hey all,
> I have a technical question regarding these two lenses. I'm sure someone
> has experienced both.
> I would like to know which of these has the longer DOF wide open. I'm
> interested in something a little longer for available light night shooting.
> Basically from the comments I've read, the FA85 F1.4 has a rather short DOF
> optimizied for portraiture. I haven't seen to many comments on the 77LTD's
> DOF length wide open. Any help in this regard is greatly appreciated.
>
> Thanks,
> Douglas E Harmon
> [EMAIL PROTECTED]
> http://personal.mia.bellsouth.net/~genius91/
>
>
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