[rollei_list] Re: 3.5 Tessar sharpness
- From: Nick Roberts <nickbroberts@xxxxxxxxxxx>
- To: rollei_list@xxxxxxxxxxxxx
- Date: Fri, 23 Dec 2005 23:57:02 +0000 (GMT)
I would absolutely agree that at f8-f11, this lens is
excellent.
Nick
--- Richard Knoppow <dickburk@xxxxxxxxxxxxx> wrote:
>
> ----- Original Message -----
> From: "James Davis" <jamesd@xxxxxxx>
> To: <rollei_list@xxxxxxxxxxxxx>
> Sent: Friday, December 23, 2005 12:47 PM
> Subject: [rollei_list] 3.5 Tessar sharpness
>
>
> > What range of apertures produces optimum sharpness
> on a
> > f/3.5 Tessar as
> > found on a 'flex T?
> >
> > James
> >
> The best range is around f/8 to f/16. Rollei
> limits the
> stops to f/22 to avoid softening from diffraction at
> smaller
> stops. Optimum is probably around f/11 but anything
> from f/8
> on should be pretty sharp all over. The difference
> from
> stopping down will be most apparent in the corners.
> Tessars
> of any version have some residual aberrations there
> which
> disappear on stopping down.
>
> ---
> Richard Knoppow
> Los Angeles, CA, USA
> dickburk@xxxxxxxxxxxxx
>
>
> ---
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