http://confocal-microscopy-list.275.s1.nabble.com/Acceptor-Photobleaching-vs-Sensitized-Emission-FRET-results-tp4828946p5632775.html
camera implying a Bayer filter/mask. This effectively increases pixel
_pitch_ by a factor of 2. Please note that it is pixel pitch that is
critical for sampling/resolution issues _not_ pixel size. RGB output
taking place. Fortunately, in monochrome cameras the pitch is often
On 14/10/2010, at 9:53 AM, P. Johannes Helm wrote:
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> Bonsoir, Louis,
>
> that's one of the frequent questions I am being asked by "my" users.
>
> The thing is:
> Your microscope objective and condenser will provide a certain
> resolution,
> officially dependent solely on numerical apertures. In case of a
> transmitted light image, it will be dependent on the numerical
> apertures
> of both, the condenser and the objective (proper Koehler illumination
> assumed). The LATERAL microscope resolution in this case is
>
> d = (1.2 * lambda) / (NA obj + NA cond.)
>
> (at which, in case of day light filter operation, lambda is a somewhat
> undefined thing, assume 500nm and / or use a panchromatic green
> filter to
> reduce wavelength bandwidth).
>
> In case of epi-illumination, the objective will also be the
> condenser, so
> that the denominator reduces to (2*NA obj) though, in some special
> cases,
> you might nevertheless end up with different ray paths for the
> illumination and the detection, anyway, since the illumination ray
> path in
> very special cases is a light cylinder around the "real" objective"
> mirrored onto the preparation (annular illumination).
>
> ("Axial resolution" resp. "depth of field" in the wide field case is a
> complicated and sometimes "debated" issue.)
>
> You might call "d" the size of a "resel" (resolution element). Which
> is
> different from a "pixel" (picture element).
>
> Multiply the size of that resel with the magnification factor of all
> the
> optics between the object and the chip of the camera. If you are
> lucky,
> you have an adjustable zoom optics which allows you to adjust the
> magnfication so that the image on the chip is magnified by a factor,
> which
> makes sure the Nyquist theorem is fulfilled, at least. So: One resel
> imaged onto the chip covers at least 2 pixels of the chip, preferrably
> more (but not too much so that you do not oversample too much,
> loosing a
> lot of light).
>
> There is, in other words, to my mind not a straight forward answer
> to your
> question. Unless you simply like to divide the dimensions of your
> camera
> ship, which you can find in the manual of that camera, by the total
> magnification factor. Then, you have the pixel size in the image,
> although
> this might not really help you unless you compare it to the resel
> size as
> mentioned above.
>
> Best wishes,
>
> Johannes
>
>
>> *****
>> To join, leave or search the confocal microscopy listserv, go to:
>>
http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy>> *****
>>
>> Bonjour à tous,
>>
>> I have a tiff image, 1392 x 1040 - 4.65 um square pixels acquired
>> with a
>> camera interline Sony , 1.4 megapixel, color(7.6mm x 6.2mm array).
>> I use
>> a 40 x objective mounted on a table microscope Leica DME.
>>
>> Can I find the pixel size in hte image?
>>
>> Thanks ,
>>
>> Louis
>>
> --
> P. Johannes Helm, M.Sc. PhD
> Seniorengineer
> CMBN
> University of Oslo
> Institute of Basic Medical Science
> Department of Anatomy
> Postboks 1105 - Blindern
> NO-0317 Oslo
>
> Voice: +47 228 51159
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>
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