Re: Question about EIR

["Willem-Jan Markerink" <w.j.markerink@xxxxx>]

On  6 Jun 00 at 15:37, Bert P. Krages wrote:

> I have had two problems with EIR.  The first is with sharpness.  I can
> normally get excellent prints up to 11 x 14 from daylight type transparency
> films (e.g., Provia F) but find that EIR gets marginal even at 8 x10.
> Experimentation suggests that my equipment gets the best sharpness at f/16
> but the problem remains.  Is there anything that can be done to improve
> sharpness with EIR?

Yes, finding the best APO lens possible....with the warning that not
all APO means 'IR-corrected' by definition....only Zeiss, Leica and
Mamiya specifically mention IR in their quality description (not
ruling out others which are effectively as good as these).

[the definition of 'APO' is actually a problem in itself....it says that 3 
colors must be focussed in the same plane, but it does not say which 
3 colors, nor how absolute focus is, nor what happens outside these 3 
points]

The fun with this is then also that you might be able to shoot at much better 
quality wide-open than you are doing now stopped down, especially 
with tele's (shortest APO available is a 100mm Zeiss macro lens, 
unless one resorts to high-end enlarger lenses)

Willem (owner of a 350/5.6 Mamiya RB APO for mainly this purpose) Jan




--                 
Bye,

Willem-Jan Markerink

      The desire to understand 
is sometimes far less intelligent than
     the inability to understand

<w.j.markerink@xxxxx>
[note: 'a-one' & 'en-el'!]
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