Canon 550d

[stevewell]

Hi all,

I'm looking at getting a modified canon 550d for astrophotography on my Skywatcher 190MN and wondered if anyone else has the same setup or if anyone knows if this would be a good move?

[paulk]

The 550D is a great camera all round, do it and you'll be pleased

[Mr Noble]

Can I ask what this talk of "modded" means please.

[badboybubby]

Can I ask what this talk of "modded" means please.

I believe they remove the infa red filter, but it renders the camera useless for 'normal' use.

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[Gina]

Let's see if I can retype my reply without it disappearing again just before posting...

Yes, DSLR cameras have an IR blocking filter immediately in front of the image sensor. This both corrects for the extra red sensitivity of the sensor and makes it similar to the human eye and blocks wavelengths from the deep red through the infra-red. Now most deep sky objects emit deep red light which this filter reduces. So to make DSLRs better for AP this filter is removed. Cameras in which this has been done are called "modded" (modified). Sometimes the filter is replaced by a more suitable one or plain glass. Often though nothing is put back to replace the filter.

[Mr Noble]

Thanks for the help Gina, a great explanation.

Are there any mods that can switch between "normal" and "non-IR" modes? I'd not really want to buy a DSLR and have it modded so it can then only be used for AP.

[Gina]

If you replace the filter with a piece of glass or filter of the same thickness, that will avoid the problem of auto-focus not working. Without a replacement the focal plane is moved and focus is lost for standard lenses. The other problem is the changed colour balance - I think colour correcting filters are available. You can do a lot to correct it with the white balance control too, I gather.

This is from what I've read - I haven't yet modded my DSLR so no personal experience as yet. For myself, I'm not interested in using my Canon for normal photography - I bought it especially for AP. I have a Sony DSLR for terrestrial photography. Each is great for it's own use in my personal opinion.

[Mr Noble]

Do you think it's 'really' necessary to have the camera modded if you only intend to take the odd AP pictures. Surely having a slightly weaker red spectrum is not a massive issue. Can't you pump up the reds in photoshop after taking the pictures?

[Yoddha]

Hi all,

I'm looking at getting a modified canon 550d for astrophotography on my Skywatcher 190MN and wondered if anyone else has the same setup or if anyone knows if this would be a good move?

Hi Steve,

I have 190MN, but so far had only one imaging session with it. This winter the weather here doesn't allow to travel to dark sites In my signature you can find few images with 1000D and not well collimated scope. My 550D still waits for first light... Not a much help, but this is the info I have.

[badboybubby]

Do you think it's 'really' necessary to have the camera modded if you only intend to take the odd AP pictures. Surely having a slightly weaker red spectrum is not a massive issue. Can't you pump up the reds in photoshop after taking the pictures?

I took the following picture (this is the compressed jpg version) using my unmodded eos450d, this was taken as a first attempt using an az goto mount which isnt really suitable to ap. I'm sure with longer exposures on a better mount I could do a lot better without 'modding' although I appreciate if i want the extra detail I'll probably have to bit the bullet and either mod my eso450d or buy a dedicated cooled CCD.

[jfox61]

Astronomiser - Automated Astronomy and AstroImaging Solutions

This may be of some help to anyone thinking of modding. Will give you some idea of whether to go for replacement or removal of the filter depending on your model.

[Gina]

Good link One thing I can point out is that the 1100D does not have auto-cleaning so there is no piezoelectric device on the front filter. This is one of the things Canon have cut out to reduce the cost. It is considered by many people as a rather poor cleaning device as it only dislodges relatively loose dust which is collected on a sticky pad below.

Interesting point about the front filter with the new information. If you are not interested in the specialised aspect of NIR AP it will be worth keeping the front filter as it now seems it provides the sharp IR and UV cutoff required for AP removing the need for a separate (external) IR/UV cut filter. Very great care is needed to remove this filter to avoid damaging it as too much stress is not good even if you don't actually break it. In fact I've read that some people recommend not to put the original back due to this stress damage.

Personally, I intend to remove mine rather than put it back as I think I might be interested in NIR AP. Also, in case someone reading this hasn't read some of my previous posts, I use the 1100D for AP exclusively. I have another DSLR for other photography. And I already have a CLS-CCD clip in filter.