wwp@yahoogroups.com:
Re: Canon 70-300mm or Sigma 70-300mm zoom lens
Alexander Balako 2007-Mar-14 19:04:00
> Marketing hype over the use of the magic word
> 'DIGITAL'? How is
> it different from their other FF lenses?
Main difference is in back element coating.
Sensor and film have different reflective abilities.
Sensor is not ?black? body so it reflects light.
Without "Digital" coating back element of the lens may
reflect back to the sensor light which was already
reflected by sensor. "Digital" coating eliminates
secondary reflection. The effect is not always
visible, but I saw examples with very bright spot in
the center of the image produced by secondary
reflection of non digital lenses.
Hope it helps,
Alex
--- "Joel M. Baldwin" <#removed#> wrote:
>
> --On Wednesday, March 14, 2007 10:15 AM +0100 Hans
> Nyberg <#removed#>
> wrote:
> >
> > On Mar 14, 2007, at 6:56 AM, Joel M. Baldwin
> wrote:
> >
> >> DG lenses: Are only for use on Digital non full
> frame cameras.
> >> The Sigmas will not work on the 5D.
> >
> > Sorry that is completely wrong.
> >
> > Sigma DG lenses are specially optimized for
> Digital and they are
> > fully compatible with all cameras also fullframe.
> >
> > Sigma DC lenses are specially made for 1.5 or 1.6
> sensors but they
> > will work on a 5D also.
> > I have the 10-20mm and it works fine on my 5D
> however it does give
> > vignetting of course.
> >
> > Canon does not have anything called DG.
> > Their digitally optimized lenses only for small
> sensors are called EF-
> > S and they do not work on a fullframe.
> >
> > Hans
> >
> > Hans Nyberg
> > Panoramas.dk<http://www.panoramas.dk> Features
> Fullscreen QTVR from
> > the best VR Photographers
> > email: #removed#
>
> My mistake. I didn't realize Sigma had two
> 'Digital' lens lines.
>
> Although I have to wonder what 'Designed to suite
> the special
> characteristics of digital cameras.' means on a full
> frame lens.
> Marketing hype over the use of the magic word
> 'DIGITAL'? How is
> it different from their other FF lenses?
>
> Why would you want to use a vignette producing lens?
> I would think
> a DC or EFS lens would be useless on a 5D.
> ( yes it would produce an image )
> Or are you using them to produce panos where you
> just set the crop
> circle?
>
>
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