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Which mod should I get?

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#1 rflinn68

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Posted 21 November 2012 - 12:33 PM

I am now seriously considering having my Canon T3 1100D modified by Gary Honis but I'm still wavering over which type to get. The Baader mod, which I understand, will work best with my AT65EDQ refractor. But I also image with a AT8IN reflector. I think most of my H-alpha imaging however will be done with my small refractor on larger objects. The cheapest will definately be the Baader UV/IR, it is $35 cheaper to begin with and I wont need to buy the extra UV/IR filter for imaging with my refractor if I go with a Full Spectrum mod.

I could keep rambling on but I'll just ask the question: Given that I image with both a refractor and a reflector will I be happy with the Baader UV/IR mod or should I get the Full Spectrum mod done and buy the extra UV/IR clip-on filter for use with my 65EDQ?

#2 Peds

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Posted 21 November 2012 - 01:17 PM

I would choose a modification with a UV/IR filter since it allows you to use the camera with all refractive optical systems (lenses, refractors, sct's) and the viewfinder and autofocus remains calibrated.

In fact I did get my Baader UV/IR modification with Hap Griffin years ago and do not regret it! If I were to get a new modification today, I'd probably go for the Astrodon Inside modification, however.

P.

#3 Fred76

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Posted 21 November 2012 - 01:22 PM

Hi!

If you dedicate your dslr for astroimaging, don't go for a mod. Instead, go for a full spectrum defiltering. And add the filter (CLS, Ir Cut...) you need in front of your coma corrector.

If you want to keep your dslr for daylight and astroimaging, an Astrodon mod would be great. The Baader is just a change of the "blue" filter (Ir absorb) by a clear glass to restore the light path.

#4 Peds

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Posted 21 November 2012 - 01:28 PM

Hi!

If you dedicate your dslr for astroimaging, don't go for a mod. Instead, go for a full spectrum defiltering. And add the filter (CLS, Ir Cut...) you need in front of your coma corrector.

If you want to keep your dslr for daylight and astroimaging, an Astrodon mod would be great. The Baader is just a change of the "blue" filter (Ir absorb) by a clear glass to restore the light path.


The Baader filter is not a clear glass filter! It is a UV/IR filter. If you decide to use DSLR lenses, refractors, sct's to take astropics in the future, you'll need the UV/IR filter, so it's better to just get it over with and put it in from the start. As an added bonus, you'll be able to use the DSLR for daytime pictures.

P.

#5 Fred76

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Posted 21 November 2012 - 03:41 PM

Peds, I have the spectral curve of the Baader filter : it is "almost" a clear glass. What it does is to restore the optical light path. The Baader mod is done by replacingthe Canon's Ir absorb internal filter (the blueish one) by the Baader filter, and letting the front filter (the one that has a piezzo on some EOS). By doing so you don't loose focus in the view finder or AF.

The Canon's front filter is an Uv/Ir reject filter that let the H-alpha pass. It cuts the Ir above 665-670 nm approx.

The Astrodon mod is made by replacing both Canon's filter by the Astrodon filter. It is thick to be close to the sum of both Canon's filters thickness to restore the light path. It is a real Uv/Ir filter.



Fred

#6 rflinn68

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Posted 21 November 2012 - 03:47 PM

This is about the Baader UV/IR from Garys website....Baader UV/IR filter: The Baader UV/IR filter replacement is a much milder UV-IR-Cut filter than the original Canon IR Cut filter and it allows the H-Alpha wavelength to pass for deep sky. It also blocks higher infrared wavelengths that cause poor focus and bloated stars with refractor telescopes and camera lenses. Because the Baader replacement filter is the same thickness as the original Canon IR cut filter, the camera's autofocus feature and optical viewfinder will continue to work as in the original un-modified camera.

Will it work just as well for me as the Full Spectrum mod? I dont care anything about taking infrared daytime pictures.

#7 Peds

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Posted 21 November 2012 - 04:31 PM

Fred, like I mentioned above and you also mentioned afterwards, the Baader filter cuts the UV and the IR range but allows the h-alpha range (unlike Canon's filter). It is therefore not a clear glass filter.

The Astrodon Inside filter works the same way as the Baader UV/IR filter (cutting the UV and IR spectrum and allowing the h-alpha light to pass through) and both filters are the same thickness as the Canon filter meaning you can still use your viewfinder and autofocus. The Astrodon filter, however, claims to pass 6% less near-IR light than the Baader filter.

This is about the Baader UV/IR from Garys website....Baader UV/IR filter: The Baader UV/IR filter replacement is a much milder UV-IR-Cut filter than the original Canon IR Cut filter and it allows the H-Alpha wavelength to pass for deep sky. It also blocks higher infrared wavelengths that cause poor focus and bloated stars with refractor telescopes and camera lenses. Because the Baader replacement filter is the same thickness as the original Canon IR cut filter, the camera's autofocus feature and optical viewfinder will continue to work as in the original un-modified camera.

Will it work just as well for me as the Full Spectrum mod? I dont care anything about taking infrared daytime pictures.


rflinn68, the Baader UV/IR filter will work the same as the full spectrum mod in practical terms (unless you try to image in the UV/IR range :p). When I meant daytime imaging, I did not mean infrared daytime pictures. You can take normal pictures with your modified cameras by adjusting the white balance.

More info on the Baader UV/IR filter here

P.

#8 Fred76

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Posted 21 November 2012 - 04:33 PM

Rflinn, there are two filters in the original Canon's setup.

The front filter is a UV/IR "wide band" interference filter. It cuts the IR above 665-670 nm but NOT the H-alpha. It is also one of the three elements that uses polarization for the anti-moiré system. On some EOS, a vibrating mechanism is installed on this filter to shake the dust.

The second filter, which has a light blue color, is a tainted glass that absorbs IR above 650 nm. It blocks the H-alpha. It is also the second layer of the antimoiré system.

The third element of the antimoiré system is the protective glass of the sensor. It may have some filtering effect on the light. But one can not remove it.

The Baaderisation of a DSLR is done by keeping the original Canon front filter and replacing the second filter by the Baader one. The Baader filter very slightly cuts the IR above 660 nm to make a stepper slope of the curve (but the difference is mini). It is almost impossible to see the difference betWeen a Baader modded DSLR and a DSLR that only has its second filter removed (and front filter kept).

The Astrodon filter shall be put in the place of the front Canon's filter. The second filter shall be removed.

@Peds : the link you provide is about the "old" Baader filter that was used with the 350D/20D DSLRs. These DSLR don't have the two filters of the next Canon's generation DSLRs. On these cameras, only one filter combines the antimoiré and UV/IR filtering, and the Baader filter was therefore a real IR filter.

Fred

#9 Hap Griffin

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Posted 24 November 2012 - 04:02 PM

Fred, that is not quite correct. I am the north American supplier for Astrodon replacement DSLR filters and it is used in the same manner as the Baader filter...by replacing the rearmost filter and leaving the front filter in place. In fact, the physical dimensions of the Astrodon filter would make it quite impossible to use it to replace the front filter.

#10 Fred76

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Posted 26 November 2012 - 06:08 PM

Thanks Hap, I didn't knew that.

Therefore it confirms that the front filter makes almost all the filtering job and the Astrodon/Baader filters are just here to narrow the slope after 656 nm.

Therefore, for a cheap but still working modd, one can just remove the rearmost filter and not replacing it. That won't be as effective as a Baader or Astrodon, but (at least on Baader modd) it is not easy to see the difference...

#11 Gary Honis

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Posted 27 November 2012 - 11:46 AM

Hi Fred,

The early Baader DSLR replacement filters labeled "400 BCF" were weak infrared blocking filters. The later Baader DSLR replacement filters "BCF 1" provide more infrared blocking. My guess is that you are referring to the older Baader DSLR filter? My infrared test results of the current Baader "BCF 1" DSLR replacement filter is HERE.

If you remove LPF#2 and rely on the original front filter(LPF#1) only, you will not be blocking infrared fully and star bloat will result if imaging with lens systems.

Below is a side by side comparison. An animated GIF file is HERE.

Attached Files



#12 vmsguy

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Posted 27 November 2012 - 12:06 PM

Hi Gary,

The new BCF-1 filters definitely block much more IR than
the original ones. I still have an original BCF 400 that
I don't plan on using because I didn't want the extra glass
for a dedicated astrocam, with little or no IR blocking benefits.

I wonder if they would swap my "vintage" one for a new one ;)

Brent

#13 Gary Honis

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Posted 27 November 2012 - 12:38 PM

Hi Gary,


......I wonder if they would swap my "vintage" one for a new one ;)

Brent


Hi Brent,

You could always ask..especially if it wasn't opened. Still, the vintage filter does block IR and when used in conjunction with the front filter produces great astro images, as evidenced by the many fine astro images captured with Baader modified cameras over the years and still in operation.

Most of the modification requests I get now are for Full Spectrum modified cameras (75%) with the Astronomik MC Clear Glass replacement. It is so easy now to add UV/IR filtering with clip and lens thread-on filters if needed. There is also the benefit of removing the anti-aliasing filtering of the front filter.

#14 Hap Griffin

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Posted 28 November 2012 - 12:19 PM

Be sure that when you are deciding if you need a replacement IR filter you consider ALL the parts in your imaging chain that could be refractive in nature. Refractive optics have natural chromatic abberation that will cause bloated star images with any IR light going through them. These parts are not just limited to lenses, but include corrector plates on SCT's, field flatteners, focal reducers, etc that are built into some scopes that you might think may operate with mirror's only.

#15 Fred76

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Posted 30 November 2012 - 06:17 AM

Hi!

I found back the spectral curves of the 40D/400D/1000D series DSLR with associated Astrodon and Baader filters.

Spectrums of the LPF#1, Astrodon and Baader filters (for 40D/400D/1000D DSLRs) have been measured for Astreos by Alphanov with an Oceanoptics HR4400 CG UVNIR spectrometer.

I don't know the exact ref of the Baader BCF filter tested (whether it is an early or late one), but from the filter curves, I guess it should be an early one. The late one should show a curve close to the Astrodon curve... but still very very close to what we get by just using the LPF#1 filter alone.

Posted Image

As you can see, the difference is minimal (less than 0.5% in Ir) on the 3 configurations : LPF#1 alone, LPF#1+Astrodon or LPF#1+Baader. The difference is in the range 690-710 nm and is very minor : this is probably what Gary is demonstrating on his Ir LEDs photo test.

By modding your DSLR, you will capture 3x more Ha compared to the unmodded DSLR.

Fred

#16 nofxrx

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Posted 10 December 2012 - 12:54 PM

Hi!

I found back the spectral curves of the 40D/400D/1000D series DSLR with associated Astrodon and Baader filters.

Spectrums of the LPF#1, Astrodon and Baader filters (for 40D/400D/1000D DSLRs) have been measured for Astreos by Alphanov with an Oceanoptics HR4400 CG UVNIR spectrometer.

I don't know the exact ref of the Baader BCF filter tested (whether it is an early or late one), but from the filter curves, I guess it should be an early one. The late one should show a curve close to the Astrodon curve... but still very very close to what we get by just using the LPF#1 filter alone.

Posted Image

As you can see, the difference is minimal (less than 0.5% in Ir) on the 3 configurations : LPF#1 alone, LPF#1+Astrodon or LPF#1+Baader. The difference is in the range 690-710 nm and is very minor : this is probably what Gary is demonstrating on his Ir LEDs photo test.

By modding your DSLR, you will capture 3x more Ha compared to the unmodded DSLR.

Fred


Actually, Gary is trying to demonstrate (***AFAIK***) that you NEED a Baader/AstroDon filter for "proper" AP images...which contradicts what your image shows. Which is that there is VERY, VERY, VERY little to NO difference in performance between a system that uses only LPF-1 vs an LPF-1 *and* Baader/AstroDon system.
Which only proves my point, which I have been saying for years, you do NOT need ANY "special" filters for "proper" Astro images(what does that even mean? sorry, dont get me started on that! "proper" means; spend more money because more $=better results?? hardly! lol)

There are TONS of people using an LPF-1 only system that get IDENTICAL images as people using Baader/AstroDon systems..

Said it before, and I will say it again: the ONLY purpose of ANY replacement filter(for LPF-**2**) is to retain AF calibration. Otherwise, leave it out.

Alright, my rant is done ;)

#17 rflinn68

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Posted 20 February 2013 - 09:59 PM

Just noticed this was still out. I ended up having Gary do the Baader mod to my T3 and I couldnt be happier. I've only imaged with my AT65EDQ apo so far and I'm getting some serious star bloating but I figure thats something I need to learn to fix in my processing. Looking forward to imaging with the AT8IN and C8 soon.

#18 Ugmul

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Posted 24 February 2013 - 04:13 PM

I wanted to note that people keep metioning that with full spectrum you lose auto focus and view finder. This is not true, properly done, autofocus and view finder if still fully function with both filters removed from the Camera.

This is done by adjusting the camera sensor after the filters are removed. I have takin amazing daytime photos with the Astromik EOS OWB Clip in filter, and then removed it to take astropics. I also have the Clip in CLS-CCD, so if I move to a refractor, I still get the UV/IR block, but with SCT/Reflectors, the IR block is not nescessary as it is with the refractors.

I did the full mod because with reflectors/sct, I wouldnt need the filter for a dark sight. And if I need the LP filter, it also doubles as the UV/IR Cut filter that I needed to begin with.

#19 Hap Griffin

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Posted 24 February 2013 - 05:05 PM

That isn't true of all cameras. With the older models that dont have adjustable sensor positioning (other than thin shims), there often isn't enough forward play to move the sensor platform forward enough to make up for the lack of filters. Even in the newer models with three adjustment screws, I have found some adjustements from the factory to be close to full forward already, not leaving enough play to adjust to retain auto-focus. The new Astrodon AD40Clear replacement full-spectrum glass accurately retains auto-focus for full spectrum modifications with NO adjustment of the sensor platform required. It exactly replicates the optical thickness of the combination of BOTH the IR and dust cleaner filters. More information in the link on my signature.

#20 mmalik

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Posted 24 February 2013 - 05:13 PM

I couldn’t be happier. I've only imaged with my AT65EDQ apo so far and I'm getting some serious star bloating but I figure that something I need to learn to fix in my processing.


"couldn’t be happier" and "serious star bloating" don't go together :)

#21 rflinn68

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Posted 24 February 2013 - 05:17 PM

I couldn’t be happier. I've only imaged with my AT65EDQ apo so far and I'm getting some serious star bloating but I figure that something I need to learn to fix in my processing.



"couldn’t be happier" and "serious star bloating" don't go together :)


I dont think that has anything to do with the work Gary Honis did for me. Are you saying I chose the wrong guy to perform the mod? I think its more to do with my limited imaging and processing skills.

#22 mmalik

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Posted 24 February 2013 - 05:23 PM

Was kidding...nothing against Gary or you. Thx

#23 rflinn68

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Posted 24 February 2013 - 05:30 PM

Was kidding...nothing against Gary or you. Thx


I hope its ok. I dont guess I would know the difference if it wasnt. This is the first camera I've had modded.






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