Re: Canon's new astrophoto DSLR announced [ 4x5" FILM option? ]

On Sat, 04 Jun 2005 20:13:27 GMT, "David Nakamoto"
<res07oeg@xxxxxxxxxxx> wrote:

>Is it necessary from a strictly technical standpoint to have a sensor the same
>physical size as 35mm film?

Not at all. But a big advantage to a sensor that size is that existing
optics will deliver the same image scale as photographers are used to
with film. People have a sense for what it means to use, for example, a
300mm lens. But if you use that lens on a 20D, it is equivalent to a
480mm lens on a 35mm camera. And a large sensor makes it easier to do
wide angle. To get the equivalent field of a 28mm lens with a 20D, you
need a 17mm lens- pricey.

> Isn't what's important image size and definition,
>and if so, couldn't this be achieved with smaller sensors with more pixel
>density and optics to produce
>an image that fits that sensor?

The point we are at now, with 6-8MP on a 5/8 scale sensor (like the
20D), is about the limit for pixel density. You can add more, smaller
pixels, but the pixel size already at the resolution limit of the
optics, so there is no point. If you want something more like the
resolution of medium format, say 20MP, you need to build a larger
sensor. Not as large as medium format film, but at least as large as a
35mm frame, probably a little larger.

_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com
.

Relevant Pages

  • Re: Low cost image sensor
    ... >>>I have been searching the web for a low cost image sensor. ... >> read to 0.1mm resolution which actually means a minimum of 200 pixels ... resolution of the object and to get that from a 200 pixel device. ... Ideally I would like no moving parts, and no lens. ...
    (comp.arch.embedded)
  • Re: Low cost image sensor
    ... that I probably will need to look at a lens based system. ... Paul Carpenter wrote: ... > vertical resolution only effects the vertical size of the sensor to be ... > resolution of the object and to get that from a 200 pixel device. ...
    (comp.arch.embedded)
  • Re: Noise levels as a function of pixel size
    ... The sensor which will collect ALL the information ... for the limit sensor pitch. ... That would only be valid if the entire gap between the lens and the sensor had a refractive index of 1.6. ... You will also notice that these values also align pretty well with the actual maximum apertures available on typical small pixel digital cameras, so it certainly isn't the order of magnitude out that you claim. ...
    (rec.photo.digital)
  • Re: Canon Response to 5D Dark Corners
    ... different response to angle of incidence than film has. ... is in a real sensor. ... Whether the light comes from a lens, ... Eliminate lens falloff by comparing a shot on film using the same lens. ...
    (rec.photo.digital.slr-systems)
  • Re: Full-frame or 1.5 DSLR?
    ... >>> use the D2X in it's 6.8meg mode which actually REDUCES the sensor ... > 600mm lens, it's not! ... But compared to a FF sensor with the same pixel pitch, ... > has the highest resolution of any DSLR on the market as far as I know. ...
    (rec.photo.digital.slr-systems)