Re: [Leica] comparison of Hologon and Heliar lenses

["Henning J. Wulff" <henningw@archiphoto.com>]

At 10:12 PM -0400 9/14/99, Marc James Small wrote:
>At 01:39 AM 9/15/1999 GMT, Dan States wrote:
>>
>>First, if Zeiss was so insistent on the constant use of the neutral density
>>graduated filter they should have made it a permanant part of the lens.
>>They did not.
>>
>>Second, any lens that has a single working aperture of f16 will be useless
>>in handheld applications indoors which is the very reason to go with a super
>>wide on 35mm.  This alone makes the Heliar a more workable solution for many
>>photographers.
>>
>
>As to the second, so be it.  Whether this renders the lens useless to you,
>I cannot say.  But, it DOES have an effective aperture of f/16 with the
>graduated filter in place.
>
>As to the first, yes, Zeiss does most strongly recommend the use of the
>graduated filter -- otherwise, you encounter the light fall-off so
>prominent in all of the Heliar shots I've seen to date, and in Godfrey's
>Hologon shots.
>
>I do agree, of course, that the next round of shots should be with the
>Hologon with filter and the Heliar at f/8.  That would be as fair a test as
>could be arranged under these conditions.
>
>Marc

It's really hard to make a completely 'fair' comparison here, as the lenses
are quite different. The Hologon has one effective aperture at which it
performs excellently, but that aperture means it often has to be tripod
mounted, or quite fast film has to be used. The Heliar has a range of
apertures, allowing about 12 times as fast shutter speeds, with more light
falloff.

Should the Heliar then be tested at f/8 with a 100 speed film and the
Hologon c/w center filter with 400 speed film to attain the same shutter
speeds, and practical equivalency? You would then almost certainly have
poorer image quality from the Hologon in most respects, except for eveness
of illumination. For anyone interested in the practical application of
these lenses that would seem to me to be the fairest comparison. Using a
Hologon for 25 years, and now the Heliar for 6 months underlines this for
me.

A lot of shots just weren't possible with the Hologon, usually because it
was too slow. Also, as the stuff I was shooting was often very close, and
required a large depth of field, I was sometimes better off shooting with
the 21SA and stopping down to f/22. The Heliar allows me to control the
depth of field with a 15. Admittedly, not the optimum aperture, but
sometimes it still leads to the preferable result.

With respect to the light falloff, I find that the Heliar can be used very
acceptably with contrasty slide film, whereas the Hologon (I base this
mostly on the 15, as I have a lot more experience with it than with the 16)
really has too much falloff to be used without the filter. The retrofocus
construction of the Heliar reduces the light falloff enough to make this
difference. With negative film the Hologon can often be used successfully
without the center filter.

   *            Henning J. Wulff
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