Canon 400D - Researching for best Filter Mod. option

[cpartsenidis]

Hi everyone,

So I'm pretty much ready to start taking my first pictures and wanted to make the final preparations to my kit, which is, to modify my Canon 400D.

After researching the topic, it is clear that the options are Badder, Astrodon and Astronomik's filter clip system.

However I also came across a very interesting website that claims any filter or clear-glass replacement of the Low-Pass filter #2, will do the same job as the more expensive filters mentioned above.

The website's URL is http://hyperdslr-mods.blogspot.gr/2011/06/dual-filter-system-used-by-most-newer.html

At this point, I'd like to hear from others with experience on the topic, to help me decide which way I should go.

Yes, I would like to have the option to use the DSLR at daytime, but this is not a requirement. If I can get best results by using a filter that will not allow me to use the DSLR in daytime, so be it. It's a cheap camera, so I don't mind dedicating it to Astrophotography only.

Do I go for any specific filter from the above vendors or clear glass?

Keep in mind that I'll be doing the modification - don't mind getting my hands 'dirty'

Any advise is much appreciated.

Chris.

[jnc71106]

i'm assuming you will using the 120ED for imaging in which case your going to have to replace the IR filter somewhere in the chain as without it you will get star bloating on your images. so you can either get a replacement IR cut filter like the one from Baader for around £50 they go inside the camera but allow the all important H-Alpha wavelength through or you buy an external filter like the astronomik clip filter with IR cut or a 2" IR cut filter to screw onto the t-adapter for the camera

there are ways around using the camera for daytime use by creating a custom white balance this will take the pink tinge out your images but you may lose the AF function because you have removed the filter

im not an expert but i believe i'm on the right tracks with this post

[JacobvonChorus]

Hello,

As mentioned above, you will need to have a replacement UV/IR filter for astrophotography. You could purchase a UV/IR filter from Baader that physically replaces the original Canon filter. That filter will cost about $90 CDN. The camera could still be used for daytime photography by using a custom white balance but it still won't be perfect. The autofocus will work just fine with that type of modification.

The other option is the clear-glass. I am not sure of the price for that. For astrophotography, a separate UV/IR filter will be needed. A 2" threaded filter will cost about $120 CDN. For daytime use though, a separate filter can be purchased that is equivalent to the original Canon filter which can be clipped into the camera, allowing it to be used normally for daytime use. Another option is to attempt to remove the original Canon filter from the camera intact (very difficult) and glue that into a clip-in frame which can be used for daytime use. With the clear-glass, the autofocus will no longer work. It can be made to work again by adjusting these shims inside of the camera (instructions on-line).

So, if you want to save money and don't really care about daytime photography, then the Baader filter is best. If you want to be able to do normal daytime photography, then the clear glass with additional filters is best but more expensive.

When doing the modification, remember to really take your time, it can be difficult the first time. Also, make sure to use the right type of glue (as I learnt the hard way).

Jacob von Chorus

[cpartsenidis]

I'd like to thank you both Jnc71106 & Jacob for taking the time to reply to my question.

It is without doubt that I'm going to use the DSLR only for Astrophotography. The camera was purchased at the low price of 150euros, so it's going to cost almost as much to purchase the necessary filters to allow daytime use, that I might as well not bother.

With that in mind, can someone point me toward a specific badder filter? Am I looking for a IR cut filter or UV/IR filter from Baader ?

If you can provide a direct link, it would help make things much clearer.

p.s Yes, the 120ED will be used for imaging

Chris.

[Spikey]

IIRC If you want to keep autofocus then you will want to replace the internal filter. If you don't want autofocus and all you want to do is mod the camera for astro use then just remove the filter nearest to the imaging chip, that is all you have to do

[Merlin66]

http://www.teleskop-express.de/shop/index.php?manufacturers_id=5&sort=&XTCsid=9qv8nop0o6pjh9o3st1g3o9ifsuscvfh&filter_id=135

The 400D seems to be the first of the two filter design...

The colour correction filter is the one removed for the enhanced red responce mod.

The remaining Anti-alias/dust filter provides UV-IR cut off.

For astro work only you could remove the CC filter without replacement.

(On my 1000D I have both filters removed for spectroscopy)

[JacobvonChorus]

http://www.alpineastro.com/filters/filters.htm

Do a find on page with this: "DSLR Conversion Filters for Canon EOS cameras"

That is what I used. It is important with a refractor to using the filter as a permanent replacement (what I personally recommend ), as a clip-in filter or a screw-in filter. Otherwise false colour will be worsened.

Jacob von Chorus

[Merlin66]

Jacob,

If only the colour correction filter is removed, there's no difference in performance across the visible spectrum.

If you had chromatic problems before they will still be there...no change.

(I think you may be getting confused with the anti-alias UV-IR filter)

[JacobvonChorus]

The colour correction filter is permanently attached to the UV-IR isn't it? There is the first filter which provides the self-cleaning function, then the filter that was to be removed (the colour correction/UV/IR). Therefore, the Baader filter will provide the UV/IR function but will allow in more of the red spectrum (hydrogen-alpha).

[Merlin66]

Jacob,

No, in the >400D Canons there are actually two separate filter elements:

The colour correction filter - sitting on top of the CCD chip which affects the red responce and

the anti-alias/ dust shake filter closer to the front of the body...which also acts as a UV-IR cut filter.

(I have the spectroscopic transmission curves for each filter if you need them....)

[cpartsenidis]

Merlin is correct.

Canon 400D and above have 2 separate filters in front of the cmos as shown below:

http://www.firewall.cx/pictures/chris/canon-400d-cmos-filter.jpg

The question here Merlin is if I install the suggested badder filter ( http://www.teleskop-express.de/shop/product_info.php/info/p254_BCF-Filter-for-Refitting-Canon-EOS-400D-450D-500D-550D-600D-1000.html ) will I end up loosing the auto-focus ability of the camera?

Does the badder filter fully replace both filters on the 400d ?

[Merlin66]

Basically the Baader filter provides the compensation (in glass thickness) for the CC filter being removed. This should allow full AF control as usual.