IR/UV filter

[LewisM]

Instead of modding my Canon 40D with the Baader replacement filter, could I simply use the Baader Canon T ring with the in-built IR/UV filter? I don't want to permanently mod the camera, and would use it on my NEVER TO BE MODDED 5D MKII also.

Thanks.

[rustigsmed]

Hi, I have literally just posted my canon 600d off for full spectrum conversion. My understanding is that what you are talking will result in having 2 ir/uv cut off filters (rather than 1 - or none!) that would not provide any benefit.
You can mod the camera by removing the ir cutoff and replacing with a baader filter which allow more Ha through or by simply replacing with clear glass (full spectrum) you van then use the astronomik eos clip in filters to control cut off such as restoring the original balance or for astrowork the clip in eos cls ccd (I think you have a refractor?).

Hope this helps!

[Merlin66]

I repeat:
On the Canon DSLR >400D there are two filters:
A colour correction filter- which is normally removed for improved Ha transmission
and the front anti-alias filter which also acts as a UV-IR cut filter. This is normally retained.
If you remove the colour correction filter with no replacement it works 100% for astro with the scope etc, but slightly compromises the auto focus with standard lenses.
The CC can be replaced with plain glass (1mm thick). Some modders use the more easily available Baader UV-IR replacement ( not for the UV-IR cut but the price!!)
I use the clip-in CL Astronomics filter (only works with the EF lenses) to allow me to get good focus and use the modded camera with std lenses and an objective grating.
Hope this helps.