tunable filters, portable spectrophotometer

[Saeideh Gorji]

Hi,

I have a question about tunable filters, they have special aperture
size, I want to know if its aperture size is for example 1"; it can
only be used with a camera with the similar or smaller aperture?

Another question, is there any portable spectrophotometer which can
support multi aperture shapes? For instance, it can be used for
measuring the spectral of curved objects?

At last, could you please recommend me a portable spectrophotometer
for measuring powder?

[Danny Rich]

Any filter has an intrinsic f/# below which, its bandpass characteristics
change. What ever optics you place in front of the filter will need to be
matched to that f/# - regardless of the size of the aperture. One way to do
this might be to use a Galelian telescope as a relay lens taking a small
beam at one f/# and broadening the beam and generating a wider beam with a
very high f/#. You will need to consult a textbook on optical design and
the specifications of the filter you have in mind to do this right.

Almost all portable spectrocolorimeters have multiple sample presentation
devices. I have seen some for meauring the color of soft drink and beer
cans, rolls of textiles and yarns, presses for measuring powders and loose
threads. Hunter Associates Laboratory has specialized in the QC of unusual
materials. I would start there.

Danny Rich

"Saeideh Gorji" <gor...@yahoo.com> wrote in message
news:15913898-9e82-4ebd...@e34g2000vbm.googlegroups.com...

[Saeideh Gorji]

On Sep 17, 10:42 pm, "Danny Rich" <Danny.R...@verizon.net> wrote:
> Any filter has an intrinsic f/# below which, its bandpass characteristics
> change.  What ever optics you place in front of the filter will need to be
> matched to that f/# - regardless of the size of the aperture.  One way to do
> this might be to use a Galelian telescope as a relay lens taking a small
> beam at one f/# and broadening the beam and generating a wider beam with a
> very high f/#.  You will need to consult a textbook on optical design and
> the specifications of the filter you have in mind to do this right.
>
> Almost all portable spectrocolorimeters have multiple sample presentation
> devices.  I have seen some for meauring the color of soft drink and beer
> cans, rolls of textiles and yarns, presses for measuring powders and loose
> threads.  Hunter Associates Laboratory has specialized in the QC of unusual
> materials.  I would start there.
>
> Danny Rich
>

> "Saeideh Gorji" <gorj...@yahoo.com> wrote in message

>
> news:15913898-9e82-4ebd...@e34g2000vbm.googlegroups.com...
>
>
>
> > Hi,
>
> > I have a question about tunable filters, they have special aperture
> > size, I want to know if its aperture size is for example 1"; it can
> > only be used with a camera with the similar or smaller aperture?
>
> > Another question, is there any portable spectrophotometer which can
> > support multi aperture shapes? For instance, it can be used for
> > measuring the spectral of curved objects?
>
> > At last, could you please recommend me a portable spectrophotometer

> > for measuring powder?- Hide quoted text -
>
> - Show quoted text -

Danny

Thanks a lot.