anat
sage
Reged: 06/03/04
Posts: 236
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I modified my 450D without any UV/IR cut filter on the CMOS chip. The original filter was simply removed because I would like to use it for IR photography with the Hoya R72 filter.
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Astro-physics 155EDT
Borg 60ED
Losmandy G11 Gemini
Hypermodded Canon 450D
LVI SmartGuider
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Freddy WILLEMS
Carpal Tunnel
Reged: 11/13/05
Posts: 2535
Loc: Hawaii, Honolulu
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Neat, any results ?
Is the (auto)focus still ok?
Freddy
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Freddy
Meade 14" LX200 GPS UHTC GPS on permanent pier
Celestron C 14" Peltier cooled for planetary imaging.
Meade 10" LX200 & TITAN 50:1 mount Gemini 'go to'
Meade 127 mm f/9 APO & TITAN 50:1 mount Gemini 'go to'
W/O 102 mm f/7 APO doublet
Orion 80 mm f/7 ED
DFK 21AU04.AS
ToUcam 840 II pro
Canon 10D Unmoddified
Canon 40D Hutech moddified
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anat
sage
Reged: 06/03/04
Posts: 236
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I compare these three filters to see how strong the spectral cutoff is. They are
- IDAS 48mm UVIR cutoff filter
- Baader DSLR filter for 350D
- Baader DSLR filter for 400D/450D
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Astro-physics 155EDT
Borg 60ED
Losmandy G11 Gemini
Hypermodded Canon 450D
LVI SmartGuider
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anat
sage
Reged: 06/03/04
Posts: 236
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This picture is taken by the 450D with the Hoya R72 filter. Infrared is allowed to pass only. Exposure conditions are
1.3 sec, f/4.5, ISO 400, 18-55mm lens.
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Astro-physics 155EDT
Borg 60ED
Losmandy G11 Gemini
Hypermodded Canon 450D
LVI SmartGuider
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Samir Kharusi
scholastic sledgehammer
Reged: 06/14/05
Posts: 977
Loc: Oman
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Quote:
I modified my 450D without any UV/IR cut filter on the CMOS chip. The original filter was simply removed because I would like to use it for IR photography with the Hoya R72 filter.
Depending on your lens selections you may wish to cut a Wratten 89B gel and use it behind the lens (cheaper than a Hutech IR-pass pop-in filter). The 89B behaves similarly to the Hoya R72. It works great even with ultrawides with bulging front elements. Pity you did not include a clear glass cover on your sensor, otherwise your autofocus would still work, useful for telephotos. Nevertheless LiveView should make quick work of focusing for landscapes, etc (non-sport or birding) and getting the exposure right. Nice combo. My 20D does not have LiveView and framing becomes a challenge for teles, since I can't see anything through the viewfinder!
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Bored? Peruse my website:
http://www.samirkharusi.net/
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anat
sage
Reged: 06/03/04
Posts: 236
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The IDAS filter is held in front of the lens. You can see that the lower part is darker. IR is blocked by the IDAS filter.
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Astro-physics 155EDT
Borg 60ED
Losmandy G11 Gemini
Hypermodded Canon 450D
LVI SmartGuider
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anat
sage
Reged: 06/03/04
Posts: 236
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This is the result for the Baader 350D filter. The result looks similar. Note my two fingers holding the filter.
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Astro-physics 155EDT
Borg 60ED
Losmandy G11 Gemini
Hypermodded Canon 450D
LVI SmartGuider
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anat
sage
Reged: 06/03/04
Posts: 236
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This is the result for the original filter removed from 450D. The filter was broken during the modification. It allows a little IR to pass.
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Astro-physics 155EDT
Borg 60ED
Losmandy G11 Gemini
Hypermodded Canon 450D
LVI SmartGuider
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anat
sage
Reged: 06/03/04
Posts: 236
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This is the result for the Baader 450D UV/IR cut filter. I hold the filter in front of the lens. It seems that the filter doesn't block IR as much as the 350D or IDAS filters. Note that I cleaned the 450D filter by 95% ethyl alcohol once. It may be possible that the cleaning removed all the UV/IR coating. But considering the modern coating process, it is less likely to occur.
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Astro-physics 155EDT
Borg 60ED
Losmandy G11 Gemini
Hypermodded Canon 450D
LVI SmartGuider
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anat
sage
Reged: 06/03/04
Posts: 236
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My conclusion at the moment is that
If the autofocus through the viewfinder is required after the modification for daylight use, the 450D filter is needed. But an additional 2" UV/IR filter may be needed to block some IR.
If the camera is used only for IR and astro photography, the internal filter is not needed. We can use LiveView to get precise focus. And the camera can still reach infinity with the kit lens because the thickness of the IR filter is only 0.57 mm.
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Astro-physics 155EDT
Borg 60ED
Losmandy G11 Gemini
Hypermodded Canon 450D
LVI SmartGuider
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anat
sage
Reged: 06/03/04
Posts: 236
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Quote:
Neat, any results ?
Is the (auto)focus still ok?
Freddy
Freddy
The autofocus doesn't work. But the Liveview is easier to use. With the R72 filter, I cannot see anything in the viewfinder but everything is clear in the liveview 
Anat
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anat
sage
Reged: 06/03/04
Posts: 236
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Quote:
Depending on your lens selections you may wish to cut a Wratten 89B gel and use it behind the lens (cheaper than a Hutech IR-pass pop-in filter). The 89B behaves similarly to the Hoya R72. It works great even with ultrawides with bulging front elements. Pity you did not include a clear glass cover on your sensor, otherwise your autofocus would still work, useful for telephotos. Nevertheless LiveView should make quick work of focusing for landscapes, etc (non-sport or birding) and getting the exposure right. Nice combo. My 20D does not have LiveView and framing becomes a challenge for teles, since I can't see anything through the viewfinder!
Thanks for your suggestion. It is very easy to get a precise focus by LiveView because
1) The liveview is bright (much brighter than the viewfinder)
2) We can zoom to 10x
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Astro-physics 155EDT
Borg 60ED
Losmandy G11 Gemini
Hypermodded Canon 450D
LVI SmartGuider
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Gary Honis
Vendor-DSLR Mods
Reged: 12/15/04
Posts: 220
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Anat,
Congratulations on your successful 450D mod!
One way to keep the Autofocus functioning is to install a clear filter replacement. Lifepixel.com sells clear glass replacements for the 450D, but they are expensive at $180.
Thanks for posting the test results of the various IR filters. When I first modified the 450D I found the Baader DSLR replacement filter to be very clear in appearance. At first, I suspected that I was sent a clear filter by mistake. The instructions that come with the filter say to place the pink coated side in a certain direction, but even with very bright light at different angles, I could not determine which side was coated. My IR test results and discussion of the suspicion at the time are here:
http://ghonis2.ho8.com/rebelmod450d14a.html
Back then I had informed Bob at Alpine Astro of the situation and he said he would ask Baader for the transmission curve of the filter, but I have never seen it.
Baader does have this on their web site about the BCF DSLR filter:
"Mechanical thickness is matched to comply with the effective optical thickness of the original Canon filter, but otherwise it is slightly different, taking the different diffraction indexes of the Canon filter and the Baader substrate into account. High demands are made on proper antireflection coatings to allow highest optical throughput and to prevent internal reflections. The BCF filter has the best VBBAR coating available today."
Still, the 450D Baader DSLR Replacement filter does provide some IR filtering and has been working well with my Astro-tech 127mm triplet.
Another test you could do is take some test images of the IR light from a TV remote control through the various filters.
Gary Honis
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Gary Honis
DSLR Modification Service
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Star surfer8
super member
Reged: 05/15/06
Posts: 493
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Quote:
Thanks for posting the test results of the various IR filters. When I first modified the 450D I found the Baader DSLR replacement filter to be very clear in appearance. At first, I suspected that I was sent a clear filter by mistake. The instructions that come with the filter say to place the pink coated side in a certain direction, but even with very bright light at different angles, I could not determine which side was coated. My IR test results and discussion of the suspicion at the time are here:
Gary,
First thanks for providing the indispensible modification instructions. I used them for modding both my 300D and XS.
I had the same suspicion when I received my sample of the Baader filter from Alpine a few weeks ago. Mine did not come with instructions so I had no idea about the pink coated side having to be in a certain direction, though like you I couldn't tell if there was a coating even under bright lights. I have already installed the filter but have yet to use it for astrowork since it has been cloudy and I had been on vaca for the holidays. I had sent an email to Baader about the possibility that I got a clear glass filter by mistake but they reassured me it was not. Now I have to send another email about the pink coated side issue. My mod of the XS went so well, I would just hate to have to take it apart again due to reversal of the "pink side" which I couldn't diffrentiate in the first place.
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Tom
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Star surfer8
super member
Reged: 05/15/06
Posts: 493
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Gary,
Can you post a terrestrial pic using your 450D with just the Baader replacement filter? Thanks.
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Tom
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Gary Honis
Vendor-DSLR Mods
Reged: 12/15/04
Posts: 220
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Tom,
Not sure what you have in mind but I have a terrestrial photo of a mountain top house at nearly 2 miles distance taken through a 127mm AT Triplet Refractor posted here (half-way down on page):
http://ghonis2.ho8.com/astrotech127mm.html
If you need a different test image, let me know.
Gary
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Gary Honis
DSLR Modification Service
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Star surfer8
super member
Reged: 05/15/06
Posts: 493
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Gary,
Did you take that pic with just the Baader replacement filter installed and no other filter in the imaging train? Did you use AWB or custom WB? Again thanks.
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Tom
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Gary Honis
Vendor-DSLR Mods
Reged: 12/15/04
Posts: 220
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Tom,
No other filter in the imaging train. I just corrected the color balance in software (Photoshop). You can see how pink the image was on the liveview screen.
Gary
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Gary Honis
DSLR Modification Service
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Lord Beowulf
professor emeritus
Reged: 10/13/08
Posts: 670
Loc: Cedar Park, TX
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FYI, I just finished my 450D mod today and have an interesting before-and-after measurement of the filter quality between the stock and Baader filter. I took identical shots both before and after the mod on both a black body radiator (soldering iron set to 800°F (427 C)) having a peak wavelength around 4100 nm, and an infrared LED with a wavelength of 940 nm. For reference, the H-Alpha line is at ~656 nm. The black body test was for a 30 second exposure while the LED was for 1/20th of a second. All were taken at 1600 ISO and f/5.6. The difference in IR leakage through the Baader BCF is staggering. The LED image is basically burnt out. I had to step down to about 1/400th of a second to get something even close to the original, and on looking at the full sized print, that still wasn't far enough. I suspect I could have gone another order of magnitude or more before they were equivalent.
I have to say I'm extremely disappointed in having wasted money on a BCF. It doesn't appear to do anything more than glass. It isn't even cut properly to replace the factory filter, since that one has a notch on one corner. I had to chop at the plastic on the frame to get it to fit. 
Beo
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Celestron 8SE w/ Zhumell Focuser, Orion ST-80 & StarShoot AG. 11" NexStar GPS w/ MotoFocus.
CGEM w/ ADM Saddle, Knobs, and SBS Dual Saddles.
Modded Canon 450D & Nikon D90 DSLR w/ various adapters.
Denkmeier PowerxSwitch S2, WO 1.25" & 2" Dielectric Diags.
TV 8, 13, 17 mm Ethos, 1rpd 30 mm, Astro Tech 40 mm, Celestron 1.25" EP & filter kit.
1.25" Filters: TV OIII Filter; Lumicon selector, UHC, H-Beta, & Deep Sky.
f6.3 reducer/corrector & SCT filters.
Various custom carrying cases.
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Samir Kharusi
scholastic sledgehammer
Reged: 06/14/05
Posts: 977
Loc: Oman
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Strange! Either you have clear glass (i.e. not a UV/IR blocker) or your assumed wavelengths are way out, or both. I have used modded DSLRs in spectral measurements (just visit my website below) and frankly, the sensitivity of the Canon sensors peter out to essentially nil by 1000nm and longer. A simple way to verify that you did use a UV/IR blocker: Set Custom White Balance and take a photo of flowers and foliage. If the colors come out OK then the filter blocks IR, if leaves are far too bright and an indeterminate color then you have used clear glass. My experience with Baader is that they deliver what they claim. The BCF is supposed to leak at longer than 1100nm, not (easily?) recordable in Canon DSLRs but block wavelengths between 700nm and 1000nm.
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Bored? Peruse my website:
http://www.samirkharusi.net/
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