[LRflex] Re: article from Amateur photographer
- From: David Young <telyt@xxxxxxxxx>
- To: leicareflex@xxxxxxxxxxxxx
- Date: Thu, 19 Apr 2007 09:41:28 -0700
Roberta wrote:
>Hmmm, I see; Thanks Chris,
> I look to hear from others...
>Roberta
Hi Roberta!
I, too, am unsure just what the reviewer means by "filmic", other
than "film like". However it may have to do with the AA filters.
Anti-aliasing or "low Pass" filters are put in most digital cameras
to prevent moire patterns from being formed by the interaction of
repetitive patterns (roof tiles, for instance) and the geometric
pattern of the pixels. (This does not happen with film, as the
silver halide crystals are in a random pattern.)
Simply put, AA filters work by diffusing the image (making it fuzzy)
and then sharpening the image, afterwards (though while still within
the camera). This restores the edge sharpness to much of the photo,
but also causes the loss of very fine detail, which would be
recorded, had the equivalent shot been made on film. It is simply
blurred out of existence by the filter.
Various makers use differing strengths of AA filters. Canon are
known to use the most 'aggressive' filters, which is also a huge
factor in Canon's famous freedom from "noise". However, it also
causes the largest drop in fine detail.
Nikon is widely reputed to use a much less aggressive AA filter.
Common wisdom (heard mostly from Nikon enthusiasts) is that Brand N
delivers more detail than Canon. Many photographers who have compared
both tell me how much "clearer" or "detailed" the Nikon shots were,
and that is the reason they choose Nikon cameras. OTOH, Nikons
generally show more "noise" than Canons.
Following the model of the MF digital backs for Hasselblad, etc.,
Leica, in both their DMR and M8 do not include an AA filter, at
all. When I moved from the Canon 20D to the DMR, I was blown away
by the difference in clarity of my photos. The improvement in
"clarity" (the fine detail) was stunning. Results much closer to film
that the 2 megapixel difference should ever account for. The trade
off, is more inherent 'noise' than with a Nikon.
Personally, I find the "noise" on the DMR, at ISO 1600 to be
substantially more prevalent than with a similar shot taken with a
Nikon or Canon. However, the resulting noise is still substantially
less than the equivalent "grain" in film at that same ISO. Thus, I
prefer digital at high ISO settings (ISO 400 & above). Film (so long
as we can still get it) retains a huge advantages at lower ISOs.
My Canon 20D shots were very good, and I have 12x18" prints from the
Canon, on my wall, which other list members have accused of being DMR
shots. Still, if you compare the detail of two prints - one from the
DMR and one from the Canon 20D - it is readily apparent which is the
DMR shot.... even though, when seen alone, the 20D shots look very
good. The difference is not in the colours, or in sharpness, but in
the fine detail which is (or is not) reproduced.
My most detailed prints come from film scanned with my Nikon Coolscan
V-ED. At 4000 dpi, it generates a 4000x6000 pixel file, equivalent
to a 24 megabytes sensor!
All of this explains why I use the DMR, despite it's high price,
large size and numerous (& often annoying) foibles.
When Leica can produce a 24 mb camera, without an AA filter, sized
like an R8 (without the DMR) that works as well as the M8, I'll be a
happy camper, indeed!
So, the simple conclusion is that the less aggressive the AA filter,
the more noise is apparent in your photos but with an equivalent gain
in the rendition of fine details. This, of course, assumes that all
other things are equal ... which they are not.
If we accept the above, we may assume that perhaps the Oly use a less
aggressive AA filter than Panasonic & Leica, thus producing more fine
detail (appearing sharper to most folks), though possibly at the
expense of increased "noise". And that may explain the reviewer's
statement that the Oly was more "filmic".
Just my 2 cents worth.
Cheers!
David.
PS: For more, see: http://en.wikipedia.org/wiki/Aliasing and
http://en.wikipedia.org/wiki/Anti-aliasing
---
David Young,
Logan Lake, CANADA
Wildlife Photographs: http://www.telyt.com/
Personal Web-pages: http://www3.telus.net/~telyt
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