Archived posting to the Leica Users Group, 1997/08/07

[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]

Subject: Re: PROJECT LENS
From: Pascal <cyberdog@ibm.net>
Date: Thu, 7 Aug 97 12:51:33 +0200

>
>When  I  first used my Leica P155 IR projector with 90/2.5 Color-Plan lens,
>the first impression is that, this is the kind of image I have been dreamed
>of  from  projection.  I really enjoy the bokeh of leica M lenses. But, the
>edge  of  the projected image is NOT sharp. I believe is due to the plastic
>mount of Kodachrome slide.
>
>Wonder  would it help if I use a CF projector lens instead of this FF lens?
>Will the usage of CF lens introduce new problem, like the lost of sharpness
>and color saturation? Recommandation please.
>
>
Well, this is precisely the reason why I switched to the Colorplan-P2 CF 
90mm f/2.5. This lens is adjusted so that the whole image of a non-glass 
mounted slide is sharp. I believe that both the ordinary Colorplan and 
the CF version are equal apart from this.

Your problem is not caused by the plastic mount of your Kodachromes. It 
stems from the fact that your slides are not glass-mounted. Because of 
heat from the projector lamp, the slide -which would remain flat between 
the glass in a glass mounted slide- tends to curve a bit. This causes 
sharp center with unsharp edges because the AF and projector lens can 
only project sharp image on one specific point. The CF lens has special 
adjusting capacities build in, so that the whole image is sharp, even if 
the slide becomes curved during projection.

Pascal

- --------------------------------------------
This message was created with Claris Em@iler on a Macintosh PowerBook
- --------------------------------------------