Thread-topic: [filmscanners] Re: film and scanning vs digital photography
Your math is good; I got 26.2 degrees off vertical. But I don't know the
significance of that angle with respect to the sensor "tunnels". It sounds
like a rather large angle to me.
Regarding the issue of (individual) lens-specific info being passed from the
lens to the image file, for Olympus (from their web site):
"Each Zuiko Digital Specific Lens also contains its own CPU to further
solidify a richly colored, clear image. These "smart" lenses transfer data
specific to the lens being used to the system's software to correct
potential distortions and aberrations that occur in all lenses. Pin
cushioning, barrel distortion, shading and other unwelcome phenomena can be
eliminated with the single touch of a button in software."
Berry
On 7/5/07 2:50 AM, "David J. Littleboy" <davidjl@gol.com> wrote:
>
> From: "Arthur Entlich" <artistik@shaw.ca>
>>>>>>>>>>>>
>
> Well, that actually raises another issue. Silicon will probably never
> be as thin as film emulsion, and that is a problem. It is why lenses
> required redesigning, because light that arrives at an obtuse angle to
> the CCD/CMOS/whatever sensor has to travel through a fairly thick and
> changing thickness of sensor cover. This leads to problems with color
> fringing, distortion, light falloff, defraction, and other aberrations
> of light which are pretty much avoided due to the very thin nature of
> photo emulsions.
> <<<<<<<<<<<<<<<<
>
> I don't buy it.
>
> I'm too cheap to buy a film EOS and test myself, but everything I've seen
> indicates that FF digital is simply better than 35mm film for wide angle
> work. (1) The angles aren't all that steep. The shortest flange-to-sensor
> distance in the APS-C and larger dSLR world is 44mm, so the steepest angle
> is about 27 degrees off vertical (63 degrees from the sensor)* when stopped
> down. (2) The dome-shaped microlenses means that light falloff is slightly
> less with a digital sensor than film for the same lens. And (3) the flatness
> means you don't get killed by the fact that depth of focus gets narrower
> with shorter focal lengths.
>
> In real life, the superwides I own are rather iffy lenses and need to be
> stopped down to f/11 (17-40) or f/16 (Stigma 12-24) for the corners to
> sharpen up. But they make nice sharp 12x18 prints. (At 12mm, it's quite hard
> to persuade the Stigma to cough up sharp corners. I'm still working on it.)
>
> The coke can and cigarette butts in the shadows are rendered fairly well in
> the following.
>
> (click original for a 6MP
> version)
>
> *: Someone check my math here: the diagonal is sqrt(12^2 + 18^2) = sqrt(144
> + 324) = 22mm, so that's tan^-1(0.5) = 26.6 degrees.
>
> David J. Littleboy
> davidjl@gol.com
> Tokyo, Japan
>
>
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