----- Original Message -----

From: "T P" <tp@nospam.com>

Newsgroups: rec.photo.equipment.35mm

Sent: Tuesday, July 15, 2003 7:59 PM

Subject: Re: Wide Angle AF Nikkor 28mm f/2.8D Autofocus Lens

> "David Ruether" <rpn1@no-junk.cornell.edu> wrote:

[...]

> >The 28mm f2.8 D does show excellent contrast

> >and brilliance, which can make the image look sharper than it really

> >is - but, then, mebbe thet'z awl thet reely cowntz...;-)

> Yes, that is *precisely* what counts!

>

> On a serious note, the human eye does not see resolution nor contrast

> alone. It sees "apparent sharpness".

>

> Apparent sharpness can be defined as the product of resolution and

> contrast, So, for the same resolution as a lower contrast lens, a

> more contrasty lens will appear to give sharper results because it

> *is* sharper - by definition.

>

> I do accept your point about the optical superiority of the 'floating

> group' of the Nikon "Close Range Correction" (CRC) feature in the 28mm

> f/2.8 AIS. The 28mm f/2.8D AF lacks this feature and is therefore

> less sharp when focused close, especially at the edges.

>

> It's also true to say that the 28mm f/2.8 AIS is better at the edges

> at more usual focusing distances, however I believe this is more a

> symptom of the fact that the 28mm f/2.8D AF is not a flat field lens.

> I regard this as a virtue, not a weakness, because the number of

> photographers needing a flat field 28mm f/2.8 autofocus lens must be

> very small indeed.

>

> Probably a high proportion of that very small number are those who

> mainly shoot test charts and brick walls.

>

> ;-)

Or landscapes...;-)

Or architecture...;-)

Or ground-planes...;-)

Or aerials...;-)

Or copy-material...;-)

Give me a well-corrected flat-field lens any day over one that isn't,

even though for center-focus (rfdr, most AF cameras, and MF

cameras focused using only the screen center), a properly curved

field will yield better focus *some of the time* than a flat-focus

lens when the image is recomposed after focus for an off-center

subject shot fairly close...;-)