Will a LP filter on a DSLR lens reduce reds in an astro-modified DSLR ?

[Spaced Out]

Hi All

Just thinking of trying some landscapey astro stuff with my Canon 600D which is astro-modified. I normally use a 6D for nocturnal landscapey stuff but fancied trying to catch some red nebula in wide WIDE field !

I did a quick test last night on the orion & rosette nebulas with a Samyang 24mm lens. The camera certainly picks them up but it also picks up orange/brown light pollution to the south of me (Newcastle upon Tyne). So, I’m wondering if a LP filter will remove that orange/brown without reducing the red nebula ?

Frustratingly I used to have a LP filter for the same lens but it fell off on a dark night in a field somewhere ! That was before I got the 600D so I never had chance to try it with the astro mod camera.

Thanks in advance for your thoughts.

[MARS1960]

1 hour ago, Spaced Out said:

Hi All

Just thinking of trying some landscapey astro stuff with my Canon 600D which is astro-modified. I normally use a 6D for nocturnal landscapey stuff but fancied trying to catch some red nebula in wide WIDE field !

I did a quick test last night on the orion & rosette nebulas with a Samyang 24mm lens. The camera certainly picks them up but it also picks up orange/brown light pollution to the south of me (Newcastle upon Tyne). So, I’m wondering if a LP filter will remove that orange/brown without reducing the red nebula ?

Frustratingly I used to have a LP filter for the same lens but it fell off on a dark night in a field somewhere ! That was before I got the 600D so I never had chance to try it with the astro mod camera.

Thanks in advance for your thoughts.

Short answer is yes. I used an astronomik CLS CCD clip filter, works a treat.

[david_taurus83]

Yes! It will reduce some of the signal but they are designed to block out a lot of orange from street lights. Your astro modified 600D will be very sensitive to red emission nebula.

[Spaced Out]

Thanks for the replies !

So assuming a LP filter won't affect the red nebula in photos my next question is which filter should I go for ?! Can clip in filters be used with camera lenses ? More importantly can they be used with the Samyang lenses I own ? I'd prefer to get a clip in filter because I could use it with my telescope too, however, if that's a non starter with lenses then I guess I am back to an external filter for the lens.

[MARS1960]

33 minutes ago, Spaced Out said:

Thanks for the replies !

So assuming a LP filter won't affect the red nebula in photos my next question is which filter should I go for ?! Can clip in filters be used with camera lenses ? More importantly can they be used with the Samyang lenses I own ? I'd prefer to get a clip in filter because I could use it with my telescope too, however, if that's a non starter with lenses then I guess I am back to an external filter for the lens.

A clip filter can be used with your scope and EF lenses, yes you can use it with your Samyang, you can't use it with EF-S lenses.

You can get clip in filters for both FF and APS-C.

https://www.astronomik.com/en/clip-filter/clip-filter-canon-aps-c.html

[Stub Mandrel]

I generally use an LP filter for all my imaging aside from Ha. The gain in contrast trumps any loss of sensitivity.

[Spaced Out]

5 minutes ago, Stub Mandrel said:

I generally use an LP filter for all my imaging aside from Ha. The gain in contrast trumps any loss of sensitivity.

Thanks.

I'm lucky to live in an area with fairly dark skies so I've not bothered with any filters yet. However, there is a big orange glow to the south which comes from Ashington and Newcastle (about 30 miles away !). The glow is lower than I normally point the telescope (anything directly south and low in the sky is out) but it’s definitely a pain for doing landscapey stuff.

I may have to invest in a filter just to try out and see if it improves things at all either with the telescope or mucking about with lenses for nightscapes. 

[Spaced Out]

OK, one last question !

My 600D has the 'hot mirror removal' mod, I think this is just removing one filter ? So does that mean I will be fine with a basic CLS filter ? Or might I need the CLS-CCD filter ? Just been reading about CLS and CLS-CCD and now I'm a bit confused tbh ! ?

[Stub Mandrel]

Depends what you want to spend, I was recommended a to get a 2" moon/skyglow filter for about £20 and it works fine. I'm sure the CLS - CCD is superior, but only you can decide if it is worth the extra?

[Spaced Out]

5 minutes ago, Stub Mandrel said:

Depends what you want to spend, I was recommended a to get a 2" moon/skyglow filter for about £20 and it works fine. I'm sure the CLS - CCD is superior, but only you can decide if it is worth the extra?

Thanks. I've decided on a clip filter but unsure which is the best for my camera, I've read about both but it seems unclear which one I should choose based on the camera modification I have, seems there are different types of mods that require different filters ? All I know is that my camera has the 'hot mirror removal' mod.

[fireballxl5]

20 hours ago, Spaced Out said:

OK, one last question !

My 600D has the 'hot mirror removal' mod, I think this is just removing one filter ? So does that mean I will be fine with a basic CLS filter ? Or might I need the CLS-CCD filter ? Just been reading about CLS and CLS-CCD and now I'm a bit confused tbh ! ?

Isn't the only difference between these 2 Astronomik filters the fact that the -CCD version has an IR block to stop this light from from reaching the sensor. CCD's are normally sensitive to IR but this light is usually brought to focus at a different distance compared with RGB and so is normally out of focus on imaging systems that include a refractive element, such as a camera lens or refracting telescope.