Recently, i've purchased a modded canon 40D. I found out instead of the regular Baader UV/IR filter replacement, it actually has a Baader BCF filter replacement. The first attached picture is the BCF Filters wavelength. Comparing the BCF filter wavelength chart, and the UV/IR filter chart 2nd image, they both look identical in wavelength.
Ok, so i balanced my colours using custom white balance properly and test the modded cam on daylight images (see pic 3). There is no green to be found with the leaves. I then hold up the Hutech LPS2 filter infront of the camera lense, it looks normal (see pic 4). Does that mean my camera can take IR images as it looks like IR light is passing through?? In your opinion, does pic 3 looks like a typical IR shot without the actual IR lense filter?
Would anyone know whether the Hutech LPS2 filter incorporates IR block also as it looks normal once it is held up infront of the lense?
Any recommendations in what filter i should be looking for to take normal daytime photography?
I have messaged Ted from Hutech, he too believes my camera is somehow letting IR light in. Scott Alder (Tornado33) suggests the Hutech front filter for daytime use but switching back to astro use i have to take the filter back out.
Can any filter guru's out there confirm 100% that my camera is indeed letting IR light? i don't want to spend $289 US to get a UV/IR front filter from Hutech and find out that it doesn't work. Another example is pic 5 and pic 6 where the colour blue in an object normally will turn out purple. Pic 6 was taken with the Hutech LPS2 filter infront of the lense.
Just need to relief my stress and need some help with what kind of camera exactly do i have .
Hi Eric - given the questioning I've put to you on modded Canon's, you would imagine me as the last person to be responding to your post!?!
However, your question has caused more re-reading of the requirements of Astro-imaging with DSLR's so I thought, in the absence (yet) of any other responses to your questions, I'd articulate my thoughts - if only for my own erudition!
As I understand it, modifying these units with UV/IR filters allows for the passing of wider bandwidths of both the infra red and ultra violet light spectrums - clearly demonstrated in the graphs you provide. This complements the sensitivity of the camera's chip's ability to register and record these particular colours' (ie, more of their bandwidths/wavelengths'.)
This is demonstrated by the blue graphics in your first graph - this being what the "normal" unmodded Canon passes of the infra red spectrum - less than the bandwidth of the fuller bandwidth pass of the filter used in a modded camera.
Although the graphs you show do not reveal the ultra violet response, from what is seen of them and extrapolating from the infra red graphs it is reasonable to presume it performs a similar job.
Thus, taking a normal day shot is going to reveal more of the infra red or ultra violet without any external moddifying filters - as your pictures 3 and 5 would seem to attest.
Have no idea what your Hutech LPS2 filter is, but from the logic I am educing it would seem that it is of a similar type to the original Canon internal filter that was removed during modifications.
This would cut the extended bandwidth pass of the modified internal filter and revert it to the response (or closely similar) of that of an unmodified camera - as picture 4 and 6 seem to attest.
I hope you won't take offense at my presumptions, but logically the above seems to hold water!
Sorry, I meant to say the "red" is the normal Canon bandwidth pass - not "blue."
It seems, from the Hutech page, that a clear internal filter in front of the sensor will allow fuller bandwidth pass (naturally) and thus infra red photography.
Your LPS2 filter, if that is one and the same as Hutech's LPSP2 filter, is a selective multi-pass filter for the infra red specrum which may, as I posited before, create photo shots similar to "normal day shots." The graph in the Hutech article shows none of the UV end of the spectrum.
The steep cut-offs at either end of the IR spectrum window is evidently to minimize reflectivity between internal filter and sensor (chip.)
Evidently, these LPSP2 filters come as internal (just behind any lens you may fit to the camera) or as an external filter onto the outside of the lens.
Hi Eric
Those pics do look very similar to my modded camera which has clear ar coated glass so I am thinking some IR light is sneaking in past the 1100 nm area where the filter starts passing IR agin.
One final test is to take a picture of an electric stove element thats heated up to almost but not quite red hot. With my camera if I take such a pic the element glows strongly even though to the eye its still not red hot.
Hutech also have screw on versions of the VLC filter that balances it for normal daylight imaging, in 58mm, 67mm, and 77mm diameters but the one that goes behind the lens would be better if you plan to use other lenses, other advantage is it prevents dust getting in when changing lenses.
I use a screw on UBIR filter http://www.sciencecenter.net/hutech/idas/uibar.jpg
It too lets in some IR past 1100 nm, I should test it with the stove element imaging . I only use it when astro imaging to stop excess IR light, it may stop most, but not all of it.
Scott
As with Darryl, certainly not a guru but I just went through some stuff I've been collecting while researching getting a Hutech modded camera. Only going to tell you stuff you've probably already been through, but your predicament is an interesting one.
Among others, the two modds you can get from Hutech are the Astro filter or the Clear filter, which did you ask for? From the info I got, the astro passes from around 375 - 710nm and the clear passes from around 350 - 1150nm. When you put the LPSP2 in the path, it should only be passing from around 410 - 695nm.
It would seem feasible that if you had the clear filter modded camera (BCF would indicate that too I guess!)that the pictures you posted would ring true. No LPSP2 filter your collecting all from 350 - 1150nm and with it your only collecting 410 - 700ish.
Is there any chance of getting you to post a pic with no LPSP2 filter and no custom WB, or with a WB that you would use with one of your older modded cameras (1.38, 1.00, 1.23). Out of curiosity, what is the custom balance recommended for the mod you got with the camera (or what did you use)?
The filter in my 30D (since stolen) was the clear one - the red line up the top in the graph I've attached.
I found the best colour correction filter to be the B+W 489. although the 486 was good as well, but these are expensive filters... The 489 has a green tint while the 486 is clear with an UV/IR interference surface and looks very sexy, but gives weird effects at wide angle - below about 20 mm on a 1.6 crop camera like the 30 or 40D. Below about 20 mm, the angle of the light coming in results in green vignetting of the image corners.
Sorry, I meant to say the "red" is the normal Canon bandwidth pass - not "blue."
It seems, from the Hutech page, that a clear internal filter in front of the sensor will allow fuller bandwidth pass (naturally) and thus infra red photography.
Your LPS2 filter, if that is one and the same as Hutech's LPSP2 filter, is a selective multi-pass filter for the infra red specrum which may, as I posited before, create photo shots similar to "normal day shots." The graph in the Hutech article shows none of the UV end of the spectrum.
The steep cut-offs at either end of the IR spectrum window is evidently to minimize reflectivity between internal filter and sensor (chip.)
Evidently, these LPSP2 filters come as internal (just behind any lens you may fit to the camera) or as an external filter onto the outside of the lens.
Hi Darryl. No offense at all, thanks for your input on this. I believe the Baader BCF filter only blocks out UV and certain IR range but not entirely all. From the Baader website apparently, the BCF filter will let in somehow more H-Alpha photons than the UV/IR filter making it more sensitive. This makes sense to the images ive posted. As to my LPS2 filter, yes it is the Hutech LPS2 filter. Adding this does make images look more normal but not 100%. Instead of adding a UV/IR filter, i might as well add the LPS2 front filter if the LPS2 filter also blocks out the IR wavelength.
Hi Eric
Those pics do look very similar to my modded camera which has clear ar coated glass so I am thinking some IR light is sneaking in past the 1100 nm area where the filter starts passing IR agin.
One final test is to take a picture of an electric stove element thats heated up to almost but not quite red hot. With my camera if I take such a pic the element glows strongly even though to the eye its still not red hot.
Hutech also have screw on versions of the VLC filter that balances it for normal daylight imaging, in 58mm, 67mm, and 77mm diameters but the one that goes behind the lens would be better if you plan to use other lenses, other advantage is it prevents dust getting in when changing lenses.
I use a screw on UBIR filter http://www.sciencecenter.net/hutech/idas/uibar.jpg
It too lets in some IR past 1100 nm, I should test it with the stove element imaging . I only use it when astro imaging to stop excess IR light, it may stop most, but not all of it.
Scott
Hi Scott thanks for your input. Im looking into a front filter rather than a lense filter. Heres a shot i just took of the electric stove. Does yours look anything like this? You are right. the glow fully lid up in the image when it is not even fully hot.
Some more graphs that show the UVa end for the LPSP2 and V3
Apologies for my uneducated input to this thread, but what does it all mean? If Eric was to block the visual spectrum, this mod would allow him to image in IR?
I'll try to keep my head down, but this is all very interesting.
Last edited by Escortitis; 31-03-2008 at 12:45 AM.
Reason: naivety
As with Darryl, certainly not a guru but I just went through some stuff I've been collecting while researching getting a Hutech modded camera. Only going to tell you stuff you've probably already been through, but your predicament is an interesting one.
Among others, the two modds you can get from Hutech are the Astro filter or the Clear filter, which did you ask for? From the info I got, the astro passes from around 375 - 710nm and the clear passes from around 350 - 1150nm. When you put the LPSP2 in the path, it should only be passing from around 410 - 695nm.
It would seem feasible that if you had the clear filter modded camera (BCF would indicate that too I guess!)that the pictures you posted would ring true. No LPSP2 filter your collecting all from 350 - 1150nm and with it your only collecting 410 - 700ish.
Is there any chance of getting you to post a pic with no LPSP2 filter and no custom WB, or with a WB that you would use with one of your older modded cameras (1.38, 1.00, 1.23). Out of curiosity, what is the custom balance recommended for the mod you got with the camera (or what did you use)?
Don't see why you should get to have all the fun!
Good luck mate and enjoy your new camera.
George
Thanks George. My main purpose to get a modded DSLR so i can still take terrestial shot and play around with it. the modded 40D is not from hutech. It had the original filter taken out and was replaced with a baader BCF filter. i have no idea what's the difference between the baader BCF filter and the baader UV/IR filter but from test images as mentioned at the start, it certainly doesn't look like it blocks the IR range. Hutech invents their own range of UV/IR's, LPS2 filter etc etc.
Here are two shots. the first one was taken using AWB without any filters. The 2nd one is using CWB without any filters. The way i do CWB is use a white lense cap under sunlight and take a shot of it then use that image for CWB.
The filter in my 30D (since stolen) was the clear one - the red line up the top in the graph I've attached.
I found the best colour correction filter to be the B+W 489. although the 486 was good as well, but these are expensive filters... The 489 has a green tint while the 486 is clear with an UV/IR interference surface and looks very sexy, but gives weird effects at wide angle - below about 20 mm on a 1.6 crop camera like the 30 or 40D. Below about 20 mm, the angle of the light coming in results in green vignetting of the image corners.
Thanks Suzy for your input on this. So that means my camera lets in the long IR but blocks the short/medium wavelength? By adding a typical IR rejection filter, this will block the long IR wavelength and makes no difference with the short/medium IR wavelength?
Sorry to hear about your 30d ouch that will hurt alot. In conclusion of your test images, i think the B+W 486 image (the 2nd one) has the best colour balance.
great recommendation too suzy and the filtershop is australian also.
Looking at the Baader BCF filter in my 40d, at 1100nm (where IR range starts at around 715nm - 1100+), it increases all the way to around 1140nm at 80% then drops the IR from 1140nm down to 1160nm at 43% which then shoots back up at 1200nm + at 70% !!! this is where the IR light is coming from.
Adding the LPS2 filter infront of it, at 1050nm it increases the IR to 72% then does a major drop at 1125nm at around 7%. then goes back up at 1125nm. That "bump" in the curve helps to cut down a slight amount of IR light with the LPS2 filter but it doesn't cut the IR light fully hence that is why it slightly works with the LPS2 filter but not 100%.
Overall, between 1100nm and 1200nm is the IR range i need to cut to make my images normal again. The baader UV/IR filter graph as seen here http://www.alpineastro.com/filters/uv_ir_cut_specs.htm cuts the 1100nm/1200nm range.
arhhhhh im beginning to get it after looking at it a few more times and a bit of research.
Eric,
Don't know if it helps you, but you can get local glass UV-IR filters ( 1.6mm thick) from ROSCO is Sydney.
I got one when visiting last month to build into a solar ERF. It cuts ALL the IR light above 700nm.
Last edited by Merlin66; 31-03-2008 at 08:16 PM.
Reason: spelling!
Hi Ken, thanks for your reply. As mentioned in my pm, don't have any equipment to cut it into a radius of 2" or rings to fit it . thanks for your concern anyway.
As some of you may have already know, I have now decided to get a Hutech Daylight front filter. This filter is the closest thing to make the camera back to stock 40D again much better than adding a UV/IR filter or LPS2 filter. They don't go cheap, im sourcing around atm. Also adding the hutech daylight filter, no CWB is needed just leave it on AWB as well and "ALL" the automatic modes such as sport, macro, landscape etc can be used!! im rapped when i heard this.
Before, none of my modified cameras can use any of the automatic modes as you can't do CWB in it. From the sound of things, this filter is a must have for modified DSLR users who still want to use their cameera's for daylight use. Not bragging or anything but having a 40D dedicated for astro use only is kind of a waste even though i'm overly passionate about astrophotography.
The Hutech VLC-FF1 Daylight front filter arrived today. As expected, it made my camera back to normal operation as if it never had been modded before!
It clips on fits snuggly into the 40D between the body and the lense. Also, amazingly like no modded camera, all my manual and automatic dial functions such as macro, sport mode etc works perfectly without the need to use any custom white balancing.
This is a great filter and a must have if you really want to turn your modded camera back to stock for daylight use.
forgot to add, the Hutech VLC-FF1 Daylight does not block the H-Alpha range. It can be used for astroimaging. Im not too sure with OIII's or SII's but definitely doesnt block HA.
.
)that the pictures you posted would ring true. No LPSP2 filter your collecting all from 350 - 1150nm and with it your only collecting 410 - 700ish. 
ouch that will hurt alot. In conclusion of your test images, i think the B+W 486 image (the 2nd one) has the best colour balance.
Ummm......thanks, I think!
