[rollei_list] Re: OT: 35mm Slides from Digital Images
- From: CarlosMFreaza <cmfreaza@xxxxxxxxx>
- To: rollei_list@xxxxxxxxxxxxx
- Date: Tue, 13 Oct 2009 11:50:01 -0300
Elias, it has to do with the image distortion, it is an inevitable
feature of lenses based on gnomonic, rectilinear projection that equal
angle intervals need to be imaged onto a larger image distance towards
the periphery, BTW it has to do with the subject features too. At the
closest focusing distance, shorter the lens focal length, the risk
about image distortion increases even if the lens is perfect about
optical aberrations, the risk diminishes at larger focusing distances
or using lenses with longer focal length, however, talking about
documents reproduction, a focal length too long could produce a no
wanted perspective for the document and then I think you can do a good
work with a standard lens or a short tele, but a 50mm lens still could
produce distortions at the minimal focusing distance, last Carl Zeiss
Camera Lens News has an interesting technical article about
Distortion:
http://www.zeiss.com/C12567A8003B8B6F/EmbedTitelIntern/CLN_33_Distortion_EN/$File/CLN33_Distortion_Article.pdf
Carlos
2009/10/13, Elias Roustom <eroustom@xxxxxxxxxxx>:
> On Oct 13, 2009, at 6:34 AM, CarlosMFreaza wrote:
> > it's better to work with a standard lens or a short tele avoiding the lens
> > minimal focusing distance
> >
>
> Hi Carlos - all you've said on this is familiar to me except the text quoted
> above. How come?
>
> Thanks,
>
> Elias
>
>
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