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Daylight IR photography with modified 350D?

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#1 Case

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Posted 30 July 2013 - 10:12 PM

Hi,
I was finally able to get myself a brand new 600D as my main daylight camera, so my trusty old 350D is most likely going to get modified for astrophotography (I've been using it as my astro camera for years, just unnmodified) - I'm planning to do both prime focus and wide angle photography.

However, I've been somehow experimenting with daylight IR photography lately - the old unmodified 350D was kinda usable, even though the exposure times were long-ish and only really handholdable at ISO 1600+ on sunny day. But still, as I mostly shoot landscapes and don't really mind using a tripod, that was sufficient. My new 600D, on the other hand, is pretty much unusable for IR without modding it - its response to IR is so poor it's pretty much out of the question, the exposure times would most likely be minutes at ISO 100.

So, I'm thinking about using the old 350D for both astrophotography and IR. Thing is, I'm also looking for the most cost effective way to do this, since I really can't afford to spend too much on that.

The obvious solution would of course be to replace the IR cut filter with clear glass, which I'd probably have to cut myself, since the commercially available custom made replacement filters are pretty expensive - especially considering that to be able to use the camera for astronomy, I'd have to buy the adittional clip in UV/IR cut filter (Astronomik or Baader). The thing is, my wide angle is EF-S mount, which means I'd be very restricted in regard of wide angle astrophotography. But for the daylight IR photography, this solution would obviously be perfect and much better than what I'm used to now.

So there's the second option - replace the Canon IR cut filter with Baader ACF filter. This would allow me to use my EF-S lens for wide angle astrophotography without any issues. But the question is - how would this solution work for daylight IR photography?

I've seen the Baader frequency response sheet for the ACF, but I kinda doubt it's that accurate - both the original Canon IR cut and Baader ACF show zero response beyond something like 700nm there, but that's obviously not true, since the original Canon IR cut still lets through at least a part of the IR light, otherwise I wouldn't be able to shoot IR with my unmodified 350D at all. So I'm really not sure what is the real IR response of Baader ACF - does it pass some of the IR as well? Is it less than the Canon IR cut? More?

I've tried searching the net for any answers, but couldn't find much. There's this page, which shows the Baader ACF filter response in IR being somehow higher than Canon IR cut, which would be good news for me. There's also a test photo, taken with a 780nm filter, which further confirms the Baader ACF allows more IR through than the original IR cut - I'd never get an exposure time of 1/2s on ISO 400 f/7.1 with 780nm filter on my unmodified 350D, I'd maybe get there on ISO 3200 and f/3.5. But - there's that ugly flare on the left in that image that worries me...

So, my kinda long-winded question is - does anybody have any experience with shooting daylight IR on Baader ACF modified 350D? Would it work at least on the same level as with the unmodified camera? Or is there perhaps something I'm missing which would help me, or some other way I didn't think of? Note that I really want to keep the autofocus working, so the option to simply remove the IR cut filter and do not replace it with anything is pretty much out of the question. (As is modding my brand new 600D, not going there ;) Even though the live view would obviously be of tremendous help in both astrophotography and IR.)

Thanks for any comments or ideas (and sorry for being kinda long-winded, can't really help it, that's just how I am).

#2 mmalik

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Posted 31 July 2013 - 01:06 AM

does anybody have any experience with shooting daylight IR on Baader ACF modified 350D?


Welcome to the forum. I find bit of contradiction in your question; to clarify, typical astro mod with LPF-2 with Baader ACF/BCF will block most of IR (and UV) while it lets through Ha. Read more here....


On the flip site, if you just wanted to do IR imaging you'll need an IR conversion; I found this... tutorial that pretty much goes through the IR conversion. IR filter for Canon here.... Hope this helps. Regards

#3 Falcon-

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Posted 31 July 2013 - 01:40 AM

mmalik: The 350D era camera does not have the LPF-1 LPF-2 filter arrangement, there is only one filter in those cameras.

Case: Welcome to Cloudy Nights!

Unfortunately I do not see an easy way out for you here... the Baader UV/IR is designed to block the IR you are looking for in daylight. With *luck* it may end up only blocking ~90% instead of near 100% - but alas that is not exactly ideal.

The proper solution is, as you already guessed, a clear-glass mod, then use lens-front IR-pass filters for daylight and either clip-in or lens-front astro-UV/IR-block filters for AP work. That is a minimum of 3 filters (the internal clear glass, the IR-pass and the UV/IR-cut). If you want/need to avoid clip-in filters you may be able to get a 2" (m48) filter and use step-down rings to mount them to the front of your wide lens (depending on the lens)

So assuming you already have an IR-pass filter then Astronomik offers:
- €55.00 for the internal clear filter
- €89.00 for the 2" IR-Block filter
- €??.?? for step-down rings to go from your lens's filter size to M48 size

#4 mmalik

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Posted 31 July 2013 - 01:51 AM

The 350D era camera does not have the LPF-1 LPF-2 filter arrangement, there is only one filter in those cameras.


I tried being legally correct by saying ACF/BCF :), ACF being one filter solution.

#5 Gary BEAL

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Posted 31 July 2013 - 04:05 AM

Maybe a touch off your intended subject, but I got a 550D full spectrum modified by Brent, and use it for everything. Daylight I/R is a breeze, simply awesome, with an I/R filter on the front of the lens.
Astro use means I use an Astronomik IR/UV clip in, but I could quite easily use the IDAS L/P filter on the front of the field flattener (2") if I felt so inclined.
I/R daylight terrestrial though, simple, just use LiveView, uh oh, does the 350D have LV? Sorry, not sure.
Someone else will have some answers here, I'm stuck.
Gary

#6 Case

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Posted 05 August 2013 - 09:03 PM

Thanks for the responses.

I understand that IR and astrophoto do not mix well, and as I've said, I'm not looking for the ideal solution - as far as IR photo goes, I'm perfectly content with what my camera offers unmodified, it's quite enough for me. I understand that if I've just used the clear glass mod, it would make my camera perfect for IR photography and allowed me to handhold at ISO 100. But I don't really need that (I might change my mind later, if IR keeps my interest, but right now I don't really care about handheld IR).

I'm pretty much just trying to find out how the unmodified 350D IR performance compares with Baader ACF IR performance. In theory (and according to official Baader transmission graphs), neither should transmit any IR at all - but in reality, with the original Canon IR filter, that's not the case, it still transmit a "workable" amount of IR. So I'm wondering how the Baader ACF fares.

Gary BEAL: Nope, 350D doesn't have Live view.

#7 Falcon-

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Posted 06 August 2013 - 03:17 AM

I found this site that has actually measured the transmission of the Baader filter and the stock 350D filter. Looks like the Baader should be better for IR even down past the "cut off" point then the stock filter.

#8 Case

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Posted 06 August 2013 - 02:10 PM

Falcon: Thanks, but see my original post (quoted below).

I've tried searching the net for any answers, but couldn't find much. There's this page, which shows the Baader ACF filter response in IR being somehow higher than Canon IR cut, which would be good news for me. There's also a test photo, taken with a 780nm filter, which further confirms the Baader ACF allows more IR through than the original IR cut - I'd never get an exposure time of 1/2s on ISO 400 f/7.1 with 780nm filter on my unmodified 350D, I'd maybe get there on ISO 3200 and f/3.5. But - there's that ugly flare on the left in that image that worries me...


I was kinda hoping someone here might still be using 350D with Baader ACF and would be able to try or even have experience with IR photo, but it seems that most people (not only here) already moved well beyond using the old 350D... :( Not that I blame them, I would do the same if I could.

#9 Falcon-

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Posted 06 August 2013 - 03:35 PM

:foreheadslap: That's what I get for posting at 1am I guess...

I actually *do* still use a 350D w/ baader UV/IR but I do not have an IR-pass filter I just have no experience with that side of things :(

#10 Case

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Posted 06 August 2013 - 04:13 PM

Yeah, well, I guess that's the other problem, not everyone has an IR pass filter ;)






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