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Hutech now offers Canon digital SLR cameras
which have been spectrum enhanced to make full
use of the bandwidth of the Canon CMOS sensor
through the use of custom designed filters.
New models include the consumer level 10-megapixel XTi (400D)
and the pro 8-megapixel 30D.
Older models have included the 6-megapixel
Digital Rebel (300D) and 8-megapixel Digital
Rebel XT (350D), as well as the professional level
8-megapixel 20D.
Standard Canon cameras, like
most modern digital cameras, incorporate
IR-cutoff filters which also cut into the deep
red end of the visible spectrum, greatly reducing
response to a scientifically important part of
the visible and IR spectrum.
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Also now available as a spectrum-enhanced
DSLR is the full-frame (35mm format),
12 megapixel
Canon 5D
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These enhanced cameras are brand-new units,
enhanced for scientific/engineering
applications such as astrophotography or
general near infrared photography. A Hutech
warranty covers the original camera and
enhancement for 12 months.

Canon Rebel XT body with standard accessories.
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XTi (400D)
30D
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Enhancement Options
Two basic options are available at the time of
order:
- Canon IR filter replaced with enhanced H-alpha filter
- Canon IR filter replaced with clear (IR-pass) filter
Enhanced Filters
The Hutech enhanced filters consist of a
permanently mounted rear
filter (RF) which replaces the standard Canon
IR filter, mounted close to the imaging sensor.
The second part of the enhanced filter set
consists of an optional front filter (FF) in a holder
mounted in front of the camera's viewing
mirror. This filter may be easily changed by
the user.
Rear Filter Details
The rear filter (RF) exactly matches the
light path of the standard Canon IR cutoff filter that it
replaces (two filters in the case of the 400D),
enabling the camera's autofocus (AF)
to work properly. Options are a Clear filter,
or astronomical bandpass filter. Both filters are
fully anti-reflection (AR) multicoated and have
been designed by IDAS, utilizing the
UFP and IGAD
technologies to insure undegraded and
extremely durable optical performance.
- Clear filter
- This passes
all bands (including IR) and includes a
fully multi-coated anti-reflection (AR)
coating effective between 380 and 1000
nm. This allows the user to fully
utilize the sensor's sensitivity into the
IR band, but requires an IR blocking filter to be
inserted at the front-mounted position
for most "normal" use.
- Astronomical filter
- This UV/IR
blocking filter allows the astronomically
important H-alpha to be
recorded, and is the most cost-effective
way to adapt the Canon digital cameras
for astronomical use but does not allow
for IR photography. It features a very
sharp cutoff at the band edges to insure
that reflections between the filter and
image sensor are minimized.
An additional filter in the
front-filter position or the camera's
custom white-balance function may be used
to achieve proper color balance for
non-astronomical photography.
Front Filter Details
The front filters are mounted in a holder
which goes between the camera's lens
bayonet and the viewing mirror.
These may be quickly and easily
inserted or removed from the camera
body as required by the user.
Front-mounted
filters do not affect the camera's autofocus
operation but, when installed, preclude the use
of Canon EF-S lenses or some lenses designed
for APS-C sized sensors. These filters also
affect the closest focusing distance for each
lens. An alternative is to use a conventional
front-of-the-lens type screw-in filter. VLC
filters are available in 58, 67, and 77 mm
sizes.
These filters need not be specified and ordered
at the time of purchase of an enhanced camera.
Astronomical Applications:
| Filter |
Thickness (mm) |
Description |
| LPS-P2** |
1.05 |
Same as IDAS
LPS-P2
externally mounted filters
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| LPS-V3** |
1.05 |
Nebula enhancement filter passing comet C2,
H-alpha,
H-beta, and OIII lines while blocking
light pollution sources, yet allows for
natural color balance corrections.
A separate UV/IR
blocking filter or LPS filter is recommended
for complete cutoff of the UV and IR regions.
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| UIBAR* |
1.05 |
Same as the rear-mounted UV/IR blocking filter.
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| H-alpha* |
1.05 |
Bandpass is 8 nm FWHM, with a unique flat topped
and off-centered passband to accomodate off-axis
targets. A separate UV/IR
blocking filter or LPS filter is recommended
for complete cutoff of the UV and IR regions.
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| HEUIB** |
1.40 |
This is a daylight-balanced filter which still
allows for H-alpha transmission. This allows the
Canon 20D auto-white-balance (AWB) and internal
color balance adjustment feature to be used
for normal daylight photos. When used with the
300D, the custom white balance (CWB) must be used
for daylight photos.
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* IDAS filters incorporating
UFP and IGAD features.
** IDAS filters incorporating
MBT, UFP, and IGAD features.
Daylight Photography:
| Filter |
Thickness (mm) |
Description |
| HEUIB** |
1.40 |
This is a daylight-balanced filter which still
allows for H-alpha transmission. This allows the
Canon 20D auto-white-balance (AWB) and internal
color balance adjustment feature to be used
for normal daylight photos. When used with the
300D, the custom white balance (CWB) must be used
for daylight photos.
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| VLC |
1.00 |
This is a daylight-balanced filter which
matches the Canon original filter and thus
allows all internal automatic color balancing
functions to work properly.
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| VLC |
NA |
Conventionally mounted VLC filters (as
described above) for mounting in front of
camera lenses, available in 58mm, 67mm, and 77mm
diameters.
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** IDAS filter incorporating
MBT, UFP, and IGAD features.
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FAQ's answered:
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Can I use EOS010 (no filter) with my
refractor?
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For use with refractors, configuration
EOS011, EOS012, or EOS010 may be used.
In the case of EOS010 (no filter)
a separate IR blocker or IDAS LPS filter
should be mounted
in the telescope's optical path.
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Why should I get a knife-edge focuser option
for my Canon astro-camera?
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For night sky photography, the
knife-edge focuser has long been
acknowledged as the method of choice to
consistently achieve sharpest focus for
film photography without depending on the
observer's visual acuity.
For digital cameras,
it is possible to take test photos and examine
the result immediately for best focus
either manually or with third-party
computer software. But this requires
having a computer with your imaging
system, complicating setup and adding
fragile, power-hungry equipment to the
imaging system as well as adding data
transfer delays. This is not a problem
for permanent observatory setups but a
negative for portable imaging. In this
case the knife-edge focuser is the
recommended accessory for simplicity
and to assure consistently sharp photos.
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