Megapixels vs. Zoom Which is more important?

External Since: Sep 07, 2005 Posts: 36

I'm sorry but you haven't convinced me. My camera has a CCD which is,
according to the specification "1/2.5" inches in size, i.e. around 10mm.
That would give it an area of around 8% of the equivalent piece of 35mm
film. The lens appears to be scaled by approximately the same linear factor.
So the total amount of light falling on the CCD will be around 8% of the
amount falling on the film.
The lens at a given setting and illumination lets a specific amount of light
in. As this light is concentrated/focused on a smaller area the amount of
light per square whatever goes up, not down.

"Rich Wilson" wrote in message

>
> "Chuck" wrote in message
>
> > An example--
> > Oly c8080wz Wide open "f" stop 2.4-2.7 (Zoom lens)
> > Film speed equivilent (settable) 50-100-etc, 400 max useful. (due to
> > noise)
> >
> > 35mm Oly OM-10 film speed - I generally use no slower than 400 for color
> > film, and usually much faster film. Wide open "F" stop 1.5
> >
> > It is true that the light from the lens gets focused on a smaller area
> > with
> > the CCD sensor, since the sensor is smaller than a 35 mm frame.
> > It's also true that the CCD sensor is less sensitive to light than the
> > usual
> > 35mm color film I use, based upon noise.
> >
> > If I use very rough numbers just for talking purposes-- twice the light
> > intensity but 1/4th the sensitivity. (100vs. 400 ASA)
> >
> > This is not really accurate, since the CCD sensor is not 1/2 the size of
> > the
> > 35mm frame.
> > The CCD Sensor is listed as 1/1/8" ?
> > Lens 7.1-35mm equiv to 28-140mm (35mm camera) If I use this as
indicating
> > that the sensor is 1/4 the size of a 35mm frame, the light intensity on
> > the
> > CCD would be 4x when compared to the 35mm. (Same light source, same
lens,
> > same "F" setting.)
>
> Hang on... same lens, same F number with different sizes of film/sensor
> means *different pictures* - so the comparison isn't valid.
>
> > 35 MM Camera uses either a 28mm lens at F2.8, a 50mm at 1.5, or a Zoom
> > 75-140 F2.8
> >
> > Another issue is circle of confusion when it comes to focus.
> >
> > Note: Oly refused to give me specs on depth of field or circle of
> > confusion
> > for the C8080 lens.
> > One reason for the lesser ccd sensitivity is the loss thru a filter on
the
> > front of the ccd.
>
> I'm sorry but you haven't convinced me. My camera has a CCD which is,
> according to the specification "1/2.5" inches in size, i.e. around 10mm.
> That would give it an area of around 8% of the equivalent piece of 35mm
> film. The lens appears to be scaled by approximately the same linear
factor.
> So the total amount of light falling on the CCD will be around 8% of the
> amount falling on the film.
>
> The camera operates, most of the time, at the equivalent of ISO 80. If we
> say that ISO 400 film would give the same image quality, the film is 5
times
> as sensitive as the CCD. But the film is 12.5 times the size of the CCD,
> therefore the CCD has more sensitivity per unit area. Therefore, if you
took
> identical photos with the two cameras, with the same shutter speed, the
> digital one could do it with a smaller physical aperture size and
therefore
> less of a problem with depth of field.
>
> Or, forget all the maths and just flippin' try it! I've just taken a few
> photos of the objects along my desk and to get any sort of noticable depth
> of field effect I had to get really close the the front object - around
12cm
> or so. In normal photography, particularly of distant objects as the OP
> required, depth of field simply isn't an issue with cameras like mine.
>
>

External Since: Aug 25, 2006 Posts: 48

"Chuck" wrote in message

> I'm sorry but you haven't convinced me. My camera has a CCD which is,
> according to the specification "1/2.5" inches in size, i.e. around 10mm.
> That would give it an area of around 8% of the equivalent piece of 35mm
> film. The lens appears to be scaled by approximately the same linear
> factor.
> So the total amount of light falling on the CCD will be around 8% of the
> amount falling on the film.

Sensor Type Designation. Explations of what the 1/2.5" means.
http://www.dpreview.com/learn/?/key=sensor+sizes

> The lens at a given setting and illumination lets a specific amount of
> light
> in. As this light is concentrated/focused on a smaller area the amount of
> light per square whatever goes up, not down.
>
> "Rich Wilson" wrote in message
>
>>
>> "Chuck" wrote in message
>>
>> > An example--
>> > Oly c8080wz Wide open "f" stop 2.4-2.7 (Zoom lens)
>> > Film speed equivilent (settable) 50-100-etc, 400 max useful. (due to
>> > noise)
>> >
>> > 35mm Oly OM-10 film speed - I generally use no slower than 400 for
>> > color
>> > film, and usually much faster film. Wide open "F" stop 1.5
>> >
>> > It is true that the light from the lens gets focused on a smaller area
>> > with
>> > the CCD sensor, since the sensor is smaller than a 35 mm frame.
>> > It's also true that the CCD sensor is less sensitive to light than the
>> > usual
>> > 35mm color film I use, based upon noise.
>> >
>> > If I use very rough numbers just for talking purposes-- twice the
>> > light
>> > intensity but 1/4th the sensitivity. (100vs. 400 ASA)
>> >
>> > This is not really accurate, since the CCD sensor is not 1/2 the size
>> > of
>> > the
>> > 35mm frame.
>> > The CCD Sensor is listed as 1/1/8" ?
>> > Lens 7.1-35mm equiv to 28-140mm (35mm camera) If I use this as
> indicating
>> > that the sensor is 1/4 the size of a 35mm frame, the light intensity on
>> > the
>> > CCD would be 4x when compared to the 35mm. (Same light source, same
> lens,
>> > same "F" setting.)
>>
>> Hang on... same lens, same F number with different sizes of film/sensor
>> means *different pictures* - so the comparison isn't valid.
>>
>> > 35 MM Camera uses either a 28mm lens at F2.8, a 50mm at 1.5, or a Zoom
>> > 75-140 F2.8
>> >
>> > Another issue is circle of confusion when it comes to focus.
>> >
>> > Note: Oly refused to give me specs on depth of field or circle of
>> > confusion
>> > for the C8080 lens.
>> > One reason for the lesser ccd sensitivity is the loss thru a filter on
> the
>> > front of the ccd.
>>
>> I'm sorry but you haven't convinced me. My camera has a CCD which is,
>> according to the specification "1/2.5" inches in size, i.e. around 10mm.
>> That would give it an area of around 8% of the equivalent piece of 35mm
>> film. The lens appears to be scaled by approximately the same linear
> factor.
>> So the total amount of light falling on the CCD will be around 8% of the
>> amount falling on the film.
>>
>> The camera operates, most of the time, at the equivalent of ISO 80. If we
>> say that ISO 400 film would give the same image quality, the film is 5
> times
>> as sensitive as the CCD. But the film is 12.5 times the size of the CCD,
>> therefore the CCD has more sensitivity per unit area. Therefore, if you
> took
>> identical photos with the two cameras, with the same shutter speed, the
>> digital one could do it with a smaller physical aperture size and
> therefore
>> less of a problem with depth of field.
>>
>> Or, forget all the maths and just flippin' try it! I've just taken a few
>> photos of the objects along my desk and to get any sort of noticable
>> depth
>> of field effect I had to get really close the the front object - around
> 12cm
>> or so. In normal photography, particularly of distant objects as the OP
>> required, depth of field simply isn't an issue with cameras like mine.
>>
>>
>
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