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[OM] lipstick on a pig?

Subject: [OM] lipstick on a pig?
From: "William Sommerwerck" <grizzledgeezer@xxxxxxxxxxx>
Date: Wed, 6 Sep 2006 03:48:38 -0700
>> I checked Adorama's listing for Canon digital-specific lenses for their
>> APS-C sensor cameras. The comparable lens, a 10-22mm zoom, is $690.
>> Not $1690 -- $690. The closest 35mm lens is the Canon 16-35mm, for $1400.

> You've got the wrong word in there, "comparable". Leaving aside all
> other construction and optical qualities, the focal lengths aren't
> comparable. Using the horizontal angle covered, rather than the useless
> diagonal FOV used in specs,

The diagonal angle has been the standard for decades. Olympus (and other
companies making digital cameras with aspect ratios other than 3:2)
conveniently ignore this.

The 2x factor Olympus claimed is for the horizontal dimension of the 4/3
sensor (18mm), but the actual diagonal angle covered is less than it would
be if the sensor had a 3/2 aspect ratio.

> and adjusting to 35mm FL equivalents for the FOVs, the ZD is 14.5-29 mm
> and the Canyon is 16-35 mm. 1.5 mm doesn't sound like much, but it is a
> significant % difference down in this range and makes a big difference in
> angle covered and in design/manufacturing costs.

You're being pointlessly picky. I was looking for a comparable lens for a
rough comparison, and the Canon is indeed comparable. That 1.5mm difference
does not, per se, translate into a $1000 difference in lens price.



> Think about it, William. A 20 mm lens for a Leica rangefinder and a
> 20 mm lens for a Leica reflex. The body of the rangefinder is much
> thinner because there is no mirror box and the rear element of its
> 20mm goes through the lens mount into the body to get even closer to
> the film. Same focal length and same format. One is much farther from
> the film plane and the light rays from the rear element have to be
> more parallel from the more distant lens.

They do? Then how can the angle of view be the same? And why, then, would
special lenses be required for digital cameras, as the problem has already
been reduced or elminiated for film cameras?

Note that retrofocus designs are desirable even in cameras without a mirror,
because they partly reduce cos^4 effects.

I don't believe most things until I understand them. And this is a point I
still don't understand. I want to see a clear explanation of it -- not a lot
of vague hand-waving about how "obvious" it all is.


> I have a source that tells that E K has a produced a
> very high end 39Mp sensor. Could that be the next E-3?
> I doubt it but ya never know

39Mp on a 13.5 x 18 mm sensor? Not likely! It's probably for a medium-format
camera.



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