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Astrophotography and Sketching >> DSLR & Digital Camera Astro Imaging & Processing

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Mike C
scholastic sledgehammer


Reged: 03/05/08

Loc: Cornwall, UK
Re: Question about canon modification. new [Re: Hap Griffin]
      #5576920 - 12/18/12 08:20 AM

mmalik: LPF-2 removed; LPF-1 still in place. Hope that makes more sense

Hap: I do have the overall red tinge to daylight shots, and am getting good results with emission nebulae imaging, e.g
http://www.flickr.com/photos/28745090@N02/8275392709/in/photostream
http://www.flickr.com/photos/28745090@N02/8268345546/in/photostream/
Note that both of these display the red disks around the bright stars that I believe to be due to IR.

The self-cleaning routine on the camera works when I switch it on and off (or at least it does not display an error message).

Regards,


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Hap Griffin
Vendor (Imaging Infinity)
*****

Reged: 04/15/08

Loc: Sumter, SC
Re: Question about canon modification. new [Re: Mike C]
      #5577216 - 12/18/12 12:15 PM

OK, that sounds pretty definitively that you have LPF#1 still in place and LPF#2 removed. So, evidently LPF#1 by itself is not providing sufficient IR attenuation to prevent star bloating.

Thank you for the additional images with the bright stars. The fact that the bloating is in the red channel is pretty conclusive that the issue is IR related.

Edited by Hap Griffin (12/18/12 12:18 PM)


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vmsguy
sage


Reged: 01/09/07

Loc: West Virginia
Re: Question about canon modification. new [Re: Hap Griffin]
      #5577594 - 12/18/12 05:03 PM


Hi,
I'm the "Brent" that did the stovetop tests.

My T1i and another T1i I modded for my friend Jeff Ball, don't show star bloat. Both are the LPF#1 only mod (LPF#1 filter left in camera, LPF#2 removed with no replacement filter)

I can only speak from my experience, but using my relatively low-end imaging gear (Nikkor lenses), I don't see adverse affects of IR related star bloat. Maybe the Nikkors are well corrected for IR.

Now Jeff, on the otherhand has high-end APO gear that probably corrects well for IR, and his images don't show IR bloat issues either.

So, what does this mean. For me, I'm replacing my T1i with a T3i that I will be modding soon. I will remove LPF#2 and
leave only the LPF#1 in place, but before doing so, I will try to perform additional test of before and after to add more "data" to this discussion.

I may repeat the "stovetop" test, and throw in some additional IR remotes that may be transmitting at different wavelengths. I also have a B+W 486 IR filter, A Baader IR 1.25" filter, and an original Baader BCF filter that I will use in the tests to see what results I get using different IR filters.

I will also take series of star images with the T3i before mod
and repeat using the same setup after mod to see if star bloat is apparent.

For other users with different optical systems, the results may be different, so take that into consideration when I post the results.


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mikotoy
super member


Reged: 06/20/12

Re: Question about canon modification. new [Re: vmsguy]
      #5577763 - 12/18/12 06:53 PM

I'm presuming that it is entirely possible to remove LPF2 and if the star bloat is experienced to go back and install a secondary filter (Astronomik, Baader, Asrtrodon ...etc) at a later time without affecting the camera further?

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mmalik
Post Laureate
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Reged: 01/13/12

Loc: USA
Re: Question about canon modification. new [Re: mikotoy]
      #5577781 - 12/18/12 07:10 PM

Quote:

I'm presuming that it is entirely possible to remove LPF2 and if the star bloat is experienced to go back and install a secondary filter (Astronomik, Baader, Asrtrodon ...etc) at a later time without affecting the camera further?




Yes, that's one school of thought per discussion thus far. Thx


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Hap Griffin
Vendor (Imaging Infinity)
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Reged: 04/15/08

Loc: Sumter, SC
Re: Question about canon modification. new [Re: mmalik]
      #5578029 - 12/18/12 10:25 PM

Note as stated before, the amount of star bloat will be magnified by contrast stretching that is the standard processing procedure in astrophotography. So any A/B test will have to have the processing carefully duplicated so that the final results will have the SAME amount of histogram stretching. I'm suspecting that this may be at least some of the difference why some people are experiencing it and others don't see it...differences in processing. I see many imagers, especially those just starting out, with the low end of the histogram crushed...that is, the dark areas are crushed into a black background. If star bloat is present, it may not come through in these images. In Mike's images, he has processed to preserve the faint detail which will also bring out low level IR related artifacts.

Edited by Hap Griffin (12/18/12 10:30 PM)


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Gary Honis
Vendor-DSLR Mods


Reged: 12/15/04

Re: Question about canon modification. new [Re: Hap Griffin]
      #5578271 - 12/19/12 01:25 AM

I agree with Hap's comments. When I first started imaging with a Full Spectrum modified 300D in 2004, I wasn't using a UV/IR cut filter when imaging with a ShortTube 80 refractor. I was very happy with my images until someone commented that my stars seemed bloated. I added a 2" Baader UV/IR cut filter and I got tighter stars. I don't know how much I was loosing in image detail.

I have done many tests over time showing that the original Canon front filter of the newer two-filter models by itself does not fully block infrared. A still image test comparing the front filter only of a 1000D (XS)camera to a Baader BCF-1 DSLR replacement filter is HERE.

Today, I posted a YouTube video using a Full Spectrum modified camera to demonstrate how much more infrared light the original front filter passes than in a Baader (or Astrodon) modified camera. The YouTube video is HERE.

The front filter does not have a sharp cutoff at 700nm like the Baader or Astrodon filters. Baader has the transmission curve of the Baader BCF filter posted HERE. In the FILES section of DSLRmodifications there is a spectral curve by Ken Harrison that shows the front filter of a 1000D (XS) passes infrared above 700nm.

If you are imaging with a reflector, SCT or RC at prime and using a "front filter only" modified camera you should not have star bloat. Once you add a lens such as a reducer or barlow you will and would need to add an IR blocking filter.


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Hap Griffin
Vendor (Imaging Infinity)
*****

Reged: 04/15/08

Loc: Sumter, SC
Re: Question about canon modification. new [Re: Gary Honis]
      #5578625 - 12/19/12 09:35 AM

Thanks for the input, Gary.

Those of us who are offering filter modifications are not trying to sell an extra filter that customers don't need (except in very special cases) but a solution to the IR problem that has been demonstrated clearly by the test images shown in this thread. If you feel that the Canon LPF#1 by itself provides all the IR blocking that you need, that's fine and it's your choice. In my experienced opinion after having worked with television camera optics for 34 years, performing over 800 Canon DSLR modifications and having my DSLR astro images published in books and magazines, I feel that the most versatile modification that will ensure that your Canon DSLR can be used with any telescope you will ever get without resorting to external filters, is one that replaces LPF#2 with a true astronomical UV/IR filter.

Edited by Hap Griffin (12/19/12 09:38 AM)


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Hap Griffin
Vendor (Imaging Infinity)
*****

Reged: 04/15/08

Loc: Sumter, SC
Re: Question about canon modification. new [Re: Hap Griffin]
      #5578632 - 12/19/12 09:42 AM

Actually, Gary, my experience with imaging through a Schmidt-Cassagrain (Meade 10" LX-200) is that the front corrector plate being refractive in nature does indeed cause star bloat without effective IR filtering.

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Gary Honis
Vendor-DSLR Mods


Reged: 12/15/04

Re: Question about canon modification. new [Re: Hap Griffin]
      #5578691 - 12/19/12 10:28 AM

Thanks Hap,

I have been telling my customers that even though SCTs have a corrector lens up front, it is a weak lens and does a good job of focusing both infrared and visible (RGB) light to the same point. Also, that the Celestron SCTs are especially good in this regard since their correctors are a little thinner than those of Meade SCTs. Samir Kharusi on this page:

http://www.samirkharusi.net/spectrograph.html

..says this...

"Another common remark is that refractive optics need to be used with a UV/IR Blocker; true, but the corollary that SCTs also do because of their corrector plates is not true. The corrector plates are very weak "lenses" and in actual usage resolution is not impaired to any noticeable extent. In fact I got sharper images in planetary webcamming with no UV/IR blocker than with. Ditto with trying to image the 6 stars in the Trapezium or the zillions in M13 using the modded 20D. Do your own testing. The IR does allow you to use very short exposures, important in hi-res imaging, and you should not throw it away by blindly following weighty pronouncements by the Wise."

I have a 10" Meade LX200, so I could do some testing, but I haven't imaged with it in a very long time. Many have been buying the new HD versions of SCTs and with their extra lens elements, I would expect an IR blocking filter is needed. I'd rather be imaging than testing.


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Hap Griffin
Vendor (Imaging Infinity)
*****

Reged: 04/15/08

Loc: Sumter, SC
Re: Question about canon modification. new [Re: Gary Honis]
      #5578755 - 12/19/12 11:21 AM

That's how I found out way back in 2003 what IR bloat was...by imaging with a 300D with the filter removed through my LX-200 and seeing red rings around all the brighter stars. Adding in a Baader UV/IR filter cured it. I can only attribute it to the corrector plate since no other refractive elements were in the system.

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LeCarl
super member


Reged: 03/16/11

Re: Question about canon modification. new [Re: Aboy]
      #5579071 - 12/19/12 02:43 PM

Quote:

Quote:

Just to say to don't forget about the distance for focusing on focusing,
Aboy wants to use his nikons lens with an adapter... full spectrum, (no glass/LPF-1) will not work, focussing distance will not be good








Yes. I'll use an adapter.. But up to I know it's possible to use it manual, that is in theory.. But I'll find out in real life soon.

Ps. I am learning a lot with this thread




Aboy, I think you get your post stolen,

yes you will see that with lenses, focal distance without glass/filter is important
(don't be surprised if you can't focus) HAHA!

(someone disagree with that???)

Sadly, the people with so much experiences can give you a little advices?

Just received my nikkor 180mm ED F2.8 with canon adapter wow! focus like a charm! woooooo!

Edited by LeCarl (12/20/12 11:10 AM)


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Gary Honis
Vendor-DSLR Mods


Reged: 12/15/04

Re: Question about canon modification. new [Re: LeCarl]
      #5579657 - 12/19/12 09:23 PM

LeCarl,

I do image with a Nikkor 180mm ED F2.8 camera lens using the Nikon to Canon EOS adapter. Some images with the Nikkor lens can be seen HERE. The lens has no problem reaching focus with my Full Spectrum and Baader Modified cameras. My Full Spectrum cameras use an Astronomik MC DSLR clear glass replacement so focus is not an issue. My guess is that if the Full Spectrum modification is one in which both original filters were removed and replaced with nothing, the lens will not reach focus at infinity for stars.

I'm sure you'll enjoy your new lens.


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Gary Honis
Vendor-DSLR Mods


Reged: 12/15/04

Re: Question about canon modification. new [Re: nofxrx]
      #5579834 - 12/19/12 11:31 PM

Quote:

Quote:



Here is an image showing the dual filter system used in 90% of newer models(ALL Canon from the 400D and newer, and most Nikons)





That image does not represent the "dual filter system used in 90% of newer models(ALL Canon from the 400D and newer".

That image shows the frontmost filter as the Infrared Absorption Glass which may be true in the Canon EOS 1D model but that is not the case in the Canon models 400D (Xti), 450D (XSi), 500D (T1i), 550D (T2i), 600D (T3i), 650D (T3i), 1000D (XS), 1100D (T3), 40D, 50D, 60D and 5D Mark II. In those models it is the second filter that is labeled by Canon as the "Infrared Absorption Glass". A list of Canon Filter Diagrams for various Canon models with the correct labels by Canon is HERE.


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mmalik
Post Laureate
*****

Reged: 01/13/12

Loc: USA
Re: Question about canon modification. new [Re: Gary Honis]
      #5580125 - 12/20/12 06:34 AM

Quote:

If you are imaging with a reflector, SCT or RC at prime and using a "front filter only" modified camera you should not have star bloat.




Gary, are you implying that there will be star bloat with a refractor at prime focus and using "LPF-1 only" modified camera?


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Gary Honis
Vendor-DSLR Mods


Reged: 12/15/04

Re: Question about canon modification. new [Re: mmalik]
      #5580415 - 12/20/12 10:46 AM

Quote:

Gary, are you implying that there will be star bloat with a refractor at prime focus and using "LPF-1 only" modified camera?




Refractor telescopes and camera lenses are lens optical systems and much work and expense goes into focusing visible light (R,G, & B) to the same focus point. Starizona has a good "basics" explanation of how achromatics and well corrected apo refractors focus visible light HERE.

How well was your refractor or camera lens designed to focus infrared wavelengths to the same point as visible light? They most likely were not. On some old camera lenses, there was a red dot to indicate how much of a focus offset was needed from the visible light focus marks for those doing infrared photography using an infrared pass filter, such as the popular 720nm Hoya R72. 720nm is not that far away from the 700nm cutoff of Astro UV/IR blocking filters and the focus point of infrared at that wavelength can be quite different than for visible light in refractors and camera lenses.

You can easily check that using a Full Spectrum camera and the liveview display. What you will see is that if focus is moved in one direction, the infrared energy will be going out of focus as the visible light is coming into focus. This results in some level of star bloat and poor image resolution because there is no focus point at which both visible (R,G, & B) wavelengths and infrared wavelengths are both in focus. The resulting image is a compromise.


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Hap Griffin
Vendor (Imaging Infinity)
*****

Reged: 04/15/08

Loc: Sumter, SC
Re: Question about canon modification. new [Re: Gary Honis]
      #5581229 - 12/20/12 06:30 PM

Good description. Also, thanks for the convenient reference of the various Canon filter diagrams and labels. I have seen them all, but not in one place.

I hope that this thread has cleared up some of the misconceptions about the double filter system used by Canon and the effectiveness (or not) of the front low pass filter used for the dust cleaning function to act as an IR blocker. While it does attenuate IR to some extent, the images and demonstrations here clearly show that it is not nearly as effective at blocking IR as a true astronomical UV/IR filter.


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nofxrx
Vendor (HyperCams & Mods)
*****

Reged: 07/12/05

Loc: Palm Bay,Florida
Re: Question about canon modification. new [Re: Hap Griffin]
      #5581484 - 12/20/12 09:22 PM

Quote:

Good description. Also, thanks for the convenient reference of the various Canon filter diagrams and labels. I have seen them all, but not in one place.

I hope that this thread has cleared up some of the misconceptions about the double filter system used by Canon and the effectiveness (or not) of the front low pass filter used for the dust cleaning function to act as an IR blocker. While it does attenuate IR to some extent, the images and demonstrations here clearly show that it is not nearly as effective at blocking IR as a true astronomical UV/IR filter.




Agreed, 100%!
BUT
Not everyone NEEDS that "true" Astronomical filter as many have already showed/stated..

SO..what are we left with?
Since it is completely unpractical to 'go for an LPF-1 only setup first, and then wait to see IF you do/do not need the Astro filter, and then send the camera for modification again, we should just recommend the Astro filters, and give the person the choice in saying SOME people do not need it.."??


Now Gary, you tested the newer Baader in that video, right??
BCF-1??

Because I did the same test, but with a Full Spectrum 5D2, and tested the newer BCF-1 and it was PERFECTLY BLACK, which is EXACTLY what the tests should show(as your's did as well)..but only WITH LPF-1 with it..otherwise a LITTLE IR still gets through..
BUT, the older Baader, the one from your other test that still showed some(IMHO a lot) IR getting through, that filter is NOT as effective, and I think this is where people have gotten the idea that there is not point to the Baader since the OLD Baader (FBCF-400D) performs a LOT like LPF-1...
So, with the new BCF-1 filter, I think we have a clear winner, and HOPEFULLY an end to the confusion as to which mod is best, the techno jargon, etc

I am still waiting for the new 5D Mark II filter...I think they discontinued it and are making a new one for it as well...hopefully, it will be the same as the BCF-1!
That would be so great and would open the door for a LOT of other models, particularly Nikon, since the 5D2 filter fits nearly every Nikon model made(even their APS-C models! they use VERY large filters)..

I should have my Canon/Baader Filter Test video up this weekend, along with written tutorials for:
Canon 5D Mark II/III
Canon 1D Mark III/IV
Canon 60D/7D
Nikon D3
Nikon D200/300/300s
Nikon D5100/5200/3100/3200
Nikon D700
Nikon D600
Nikon D800 (my current camera...and holy cow. nothing compares. period.. sorry Canon fanboys lol (dont worry, I was one myself two months ago ))

Oh wait...I have all the data but NO freakin time to actually put all of this together...
How do you guys find the time to do any of this stuff??lol


Cheers!


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vmsguy
sage


Reged: 01/09/07

Loc: West Virginia
Re: Question about canon modification. new [Re: nofxrx]
      #5581864 - 12/21/12 04:31 AM


I did a few tests tonight on various filters to see
how well they block IR.

I still have a few more to do, in particular when I mod
my T3i, I will perform a similar test that I did on other
common UV/IR filters.

Here is a video showing the tests.
http://www.youtube.com/watch?v=SDVxXkxBXSU

The result that may be important to folks that have
full spectrum mods, is that a Baader 1.25" UV/IR rejection filter, and a B+W 486 filter allow some amount of IR to be transmitted. If these filters in particular are used in the imaging train, then a small amount IR is passed. These are
the only UV/IR filters I own, so I'm not sure how other brands will behave.

I'm curious to see if the LPF#1 has similar characteristics
to the screw in Baader and B+W filters. I hope to do that test this weekend.

Brent (the other Brent)


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mmalik
Post Laureate
*****

Reged: 01/13/12

Loc: USA
Re: Question about canon modification. new [Re: nofxrx]
      #5581967 - 12/21/12 07:32 AM

Quote:

So, with the new BCF-1 filter, I think we have a clear winner, and HOPEFULLY an end to the confusion as to which mod is best...




Per Gary's video and some searching... I did, following "seems" (corrections welcome...) the latest on Baader as LPF-2 replacement:

Baader-BCF (which Gary referred to as BCF1)
•For Canon EOS 7D/40D/50D/60D/400D/450D/500D/550D/600D/1000D/1100D

Baader-BCF2
•For Canon EOS 5D Mark II

In light of this information, few questions come to mind if anyone could answer:

1. What's the availability for Baader BCF1 & BCF2 filters as LPF-2 replacement; hence who among all is offering these NEW Baader mods at this time?

2. Hutech hasn't been discussed in this thread so far; Hutech website... refers to LPF-2 replacement as 'Astronomical Filter'; I am wondering what kind of LPF-2 filter Hutech has been using in the past and/or are going to use in future. In other words, does Hutech fall under Baader umbrella when it comes to LPF-2 replacement or do they use something proprietary?

3. What's on the horizon for Canon EOS 5D Mark III and 6D when it comes to 'latest' Baader as LPF-2 replacement offerings? These seem to be missing in action.

Thx


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