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CLS or CLS-CCD filter with hot mirror removal astro modified DSLR


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I'm considering getting a CLS clip filter to help with light pollution on longer exposures, on my modded EOS1000D.
 
It's had a hot mirror removal astro modification which, as I understand it, means the IR filter has been removed, so not a full spectrum mod.
 
Now, a lot of what I read says that the CLS CCD filter is what's needed for a 'modded DSLR'. However, for this specific mod, I'm wondering whether it should be the CLS version only, as I don't need the IR cut of the CCD version.
 
Am I making any sense here? Could someone advise please?
 
Thanks, Brendan
Edited by BrendanC
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The CLS CCD will probably cut IR better than the standard IR filter, and so would be more beneficial.  I’m guessing the CCD version is dearer?

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No idea, that's why I'm asking!

My DSLR has had the IR filter removed. So, why would I need a CLS CCD to cut IR? That's where I'm confused - a lot of people say the CLS-CCD is better for a modded camera, but I don't understand why I'd need the IR filter if I already have the IR filter removed.

Edited by BrendanC
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38 minutes ago, BrendanC said:

No idea, that's why I'm asking!

My DSLR has had the IR filter removed. So, why would I need a CLS CCD to cut IR? That's where I'm confused - a lot of people say the CLS-CCD is better for a modded camera, but I don't understand why I'd need the IR filter if I already have the IR filter removed.

You STILL need to cut above 700nm (IR radiation) or stars bloat. [You removed the IR filter that starts to cut from below 650 (visible, red, Ha) and continued to cut above 700]

Edited by tooth_dr
This isn’t correct LPF-1 not removed.
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But I’m confused about your first post!  I thought it will have still have some IR cut remaining otherwise it will be full spectrum? My modified 1000d still had one filter in place which meant it still had some IR cut?

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OK, I guess I'm showing my ignorance here about exactly what the astro mod involved!

I bought it modded, as a hot mirror removal, which I thought meant the filter had been removed.

So, I was confused about whether I should get a CLS or CLS-CCD filter.

I get that CLS filters the light pollution.

But I'm thinking the CCD filter is for full-spectrum modded DSLRs, not IR-cut modded DSLRs... and that's where my understanding ends.

If you think CLS-CCD is the way to go, could you explain why?

Edited by BrendanC
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6 minutes ago, BrendanC said:

OK, I guess I'm showing my ignorance here about exactly what the astro mod involved!

I bought it modded, as a hot mirror removal, which I thought meant the filter had been removed.

So, I was confused about whether I should get a CLS or CLS-CCD filter.

I get that CLS filters the light pollution.

But I'm thinking the CCD filter is for full-spectrum modded DSLRs, not IR-cut modded DSLRs... and that's where my understanding ends.

If you think CLS-CCD is the way to go, could you explain why?

You have a camera with LPF-2 filter removed   This leaves LPF-1 which is the IR block. You don’t need to buy the CCD version in this case.  It won’t do any harm if you do, but won’t benefit you (unless the IR cut of LPF-1 is poor).  The only reason you may want to buy it is a) cheaper b) for resale - would suit owner of any modification be it LPF-2 or full spectrum. 

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Here's where I'm confused: 

"the only difference between the two filters is that the CCD version has IR cut, which you don’t need on an a unmodified Camera, but you also don’t need on a modified camera either unless you have the full spectrum mod which removes both filters in the camera, the “normal” Astro mod leaves one of the filters in the camera which has excellent IR cut, so hence why the CCD version is not needed with the normal Astro mod...the CCD version is really for a CCD Camera that Has nothing in front of the sensor."

From here: https://stargazerslounge.com/topic/307670-cls-or-cls-ccd-for-unmodified-500d/?tab=comments&fbclid=IwAR2m8ebSHJi9yYpnYDWb9LTG3QZYtl-9eUsBlEG4Zssdt4LI8MrZzacrlhU#comment-3364531

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1 minute ago, BrendanC said:

Here's where I'm confused: 

"the only difference between the two filters is that the CCD version has IR cut, which you don’t need on an a unmodified Camera, but you also don’t need on a modified camera either unless you have the full spectrum mod which removes both filters in the camera, the “normal” Astro mod leaves one of the filters in the camera which has excellent IR cut, so hence why the CCD version is not needed with the normal Astro mod...the CCD version is really for a CCD Camera that Has nothing in front of the sensor."

That makes perfect sense and supports why you don’t need the CCD version. 

Edited by tooth_dr
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Ah, posted before I saw your reply!

So, I need the CLS version, right? Not CLS CCD?

In which case, AstroBackyard is a tad misleading: The CLS-CCD filter improves the visibility of deep sky objects while blocking out a great deal of city glow.  This version is suitable for modified DSLRs because of the built-in UV/IR block filter.  This produces smaller, sharper stars.

From here: https://astrobackyard.com/canon-astrophotography-filter/

Thanks for helping out. :)

Edited by BrendanC
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9 minutes ago, BrendanC said:

Ah, posted before I saw your reply!

So, I need the CLS version, right? Not CLS CCD?

In which case, AstroBackyard is a tad misleading: The CLS-CCD filter improves the visibility of deep sky objects while blocking out a great deal of city glow.  This version is suitable for modified DSLRs because of the built-in UV/IR block filter.  This produces smaller, sharper stars.

From here: https://astrobackyard.com/canon-astrophotography-filter/

It’s misleading as it doesn’t specify what type of modification. 
 

Have a read here, CLS CCD versus CLS.  You can be sure that IR is cut if you buy the CLS CCD version, rather than relying on the camera LPF-1 filter.  There are mixed views on the LPF-1 filter effectiveness.  If the cost differential is minor why not eliminate that possibility of bloat and just get the CCD version?

 

Edited by tooth_dr
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Yes, that's the problem - he doesn't state what type of mod.

Now, here's the catch - I've already ordered the CLS-CCD filter. Yep, I may as well come clean: everything I read said I should get that one, not just the CLS one, so I ordered it last night. Then, tonight, after a bit of browsing, I started coming across contrary advice and started to worry somewhat.

I've emailed the vendor asking their opinion (and how I stand if I need to return the filter, unopened), and even emailed the guy who did the mod, for their take on it.

Given your advice, I was all set to return it. But are you saying that the CCD might still be beneficial?

All I want, is a filter to lessen the sky-fog from light pollution on longer exposures. I took a look at that page you linked to and honestly, I really don't understand much of it. 

Edited by BrendanC
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15 minutes ago, BrendanC said:

Yes, that's the problem - he doesn't state what type of mod.

Now, here's the catch - I've already ordered the CLS-CCD filter. Yep, I may as well come clean: everything I read said I should get that one, not just the CLS one, so I ordered it last night. Then, tonight, after a bit of browsing, I started coming across contrary advice and started to worry somewhat.

I've emailed the vendor asking their opinion (and how I stand if I need to return the filter, unopened), and even emailed the guy who did the mod, for their take on it.

Given your advice, I was all set to return it. But are you saying that the CCD might still be beneficial?

All I want, is a filter to lessen the sky-fog from light pollution on longer exposures. I took a look at that page you linked to and honestly, I really don't understand much of it. 

Sorry the link was confusing!  I don’t see any detriment or issue with using the CCD version at all, and only potential benefits. Worse case - it’s no different to the non CCD version.  Best case - stars are tighter.  So stick with your choice, it’s not a wrong one. 

5C153E53-C5B6-4341-B13B-F82D16AC62F5.png

A22B3A45-5892-4B30-86A4-3DFA9A6E3BC0.png

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OK, in which case I'll probably stick with it then - not least because the vendor is out of stock with the CLS version. It costs a bit more but then again it's worth it for immediate gratification. 

Thanks again.  :)

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1 hour ago, BrendanC said:

OK, in which case I'll probably stick with it then - not least because the vendor is out of stock with the CLS version. It costs a bit more but then again it's worth it for immediate gratification. 

Thanks again.  :)

Good man Brendan 

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When you have this mod, you have one of the two filters in these cameras removed, they both cut IR but the one that’s removed also blocks much of the Ha, hence why it’s removed, the one left in the camera cuts IR very well, and for that reason is left in the camera, so you will only need the CLS version and NOT the CLS CCD version....if you have both filters removed from the camera as @tooth_dr has pointed out it is a full spectrum mod and IR cut would then be needed.... HTH 👍🏼😀

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I think this needs to be made a "sticky"

The Canon DSLR filters:

There are two built into the camera body:

One, #2 filter, (blue tinted close to the chip) is a colour correction filter which suppresses the red response, to give a "better" colour balance.

The other, #1 filter, is at the front and acts as a UV-IR cut filter as well as an "anti-alias" dust shake element.

The "normal" Mod is to remove #2 filter to enhance the response to Ha wavelengths.

A FULL spectral mod involves removing both filters to provide access across the UV to the NIR. (I use this type of mod for spectroscopy)

 

canon filter mod.jpg

Canon_450D_Spectral_Response.jpg

Edited by Merlin66
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I had exactly that camera and exactly that modification and I can 100% confirm that it will work fine with the non CCD version, you even have a 130PDS which was the same scope as me. 

So you will be fine. Everyone talking about bloat above, he looks to be using a reflector...so what bloat are you expecting? The Coma corrector would not have a big impact. 

Now if you want to use it with a refractor I would get the CCD version just to be sure as the remaining filter will still allow a little more IR through than a conventional IR cut. 

Adam

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4 hours ago, Adam J said:

Now if you want to use it with a refractor I would get the CCD version just to be sure as the remaining filter will still allow a little more IR through than a conventional IR cut.

My point being get the CCD version and then you are covered whatever scope you use with no detriment.

4 hours ago, Adam J said:

Everyone talking about bloat above, he looks to be using a reflector...so what bloat are you expecting? The Coma corrector would not have a big impact. 

Cant seen any mention of a telescope on the thread?  I also had the same camera with the same mod and I had a non-CCD version of the CLS filter 👍🏼

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Thanks all. 

Btw, I think Adam is referring to the kit list in my signature. Great to know someone who had virtually the same kit can advise! :)

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