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CentralDS Cooled T3i (CDS-600 II Pro), Bulb Mode and Bias Frames


mr.griggs

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Hi everyone,

 

While the newest version of the cooled/modified T3i (http://www.centralds.net/cam/?product=cds-600d-ii-cds-600d-ii-pro-3) looks generally awesome, I'm concerned about the "bulb mode only" specification and the impact that will have on shooting bias frames.

 

Can anyone with a Canon T3i tell me if it's possible to get subsecond exposure lengths in bulb mode?  Trying to figure out whether I can get around this "bulb only" limitation by bending BackyardEOS to my will. :)

 

Thanks in advance!

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Well, as it turns out I'm an official CentralDS distributor in North America.  I have a few models on order right now.

 

The CDS600D is hard set to M mode.  BYE is able to use TV and AV pictures as well in this mode.  

 

As a result this is a non issue :)

 

Regards,

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I would wonder if it is really true that only BULB exposures can be taken when the modified camera is tethered to a computer and controlled by BYE.  If so, the camera would be fundamentally different from a stock T3i in ways that the Canon SDK would not understand. I would also wonder what other gotchas there might be. One that comes to mind is...How do you control the cooler when BYE is connected to the camera? Can some cooler control app have access to the cooler without needing to disconnect BYE?

 

It appears that the shortest Bulb duration that BYE can shoot is 1 second. 

 

That said, if your dark frames are the same duration as your light frames and you shoot dark flats at the same duration as your flats, and you can get good flats with exposures longer than 1 second, then you shouldn't need bias frames.

 

Being able to cool the camera to a set temperature gives you much more flexibility to shoot your dark frames whenever it is convenient. 

 

I shoot flats at well under 1 second and would need to get a dimmer light source, or a dimmer for my light source, in order to use BYE to control that modified camera for shooting flats and dark flats. A neat idea, though.

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Bulb mode is not a choice on the t3i wheel. See:

 

http://dpinterface.com/reviews/canon-eos-t3i/canon-t3i-top.jpg

 

For BYE I run mine in "M" or manual mode.

Thanks - I didn't know that about the T3i.  I'm currently using a 7D, so that's my frame of reference.

 

I assume, then, that CentralDS means they only left Manual mode enabled.  If that's true, then I suppose I would use "BULB" in the shutter dropdown and select my exposure lengths and then, for bias frames, I would change the shutter speed from "BULB" to 1/4000 (which looks like the shortest it can do).

 

Does that sound right?

 

I would hope that working the CDS-600D with BYE would be seamless; after all, they include a license for it with the camera. :)

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I would wonder if it is really true that only BULB exposures can be taken when the modified camera is tethered to a computer and controlled by BYE.  If so, the camera would be fundamentally different from a stock T3i in ways that the Canon SDK would not understand. I would also wonder what other gotchas there might be. One that comes to mind is...How do you control the cooler when BYE is connected to the camera? Can some cooler control app have access to the cooler without needing to disconnect BYE?

 

It appears that the shortest Bulb duration that BYE can shoot is 1 second. 

 

That said, if your dark frames are the same duration as your light frames and you shoot dark flats at the same duration as your flats, and you can get good flats with exposures longer than 1 second, then you shouldn't need bias frames.

 

Being able to cool the camera to a set temperature gives you much more flexibility to shoot your dark frames whenever it is convenient. 

 

I shoot flats at well under 1 second and would need to get a dimmer light source, or a dimmer for my light source, in order to use BYE to control that modified camera for shooting flats and dark flats. A neat idea, though.

As dts350z said, I think they (and I) meant manual and not bulb.

 

They have the temperature controller on a separate interface entirely.  If you don't buy the temperature controller, it's just got an on/off switch and is going to run a certain delta below ambient, so that's not great for generating darks, but your noise should be lower overall.

 

Good advice on the dark flats - I've actually never shot those before!

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Depending on what circuitry they removed, the modified camera may not have the ability to time its own exposures. Hence an externally-controlled BULB exposure may be all that is left.

 

The comment on their web site ... "Shooting mode: Bulb mode only" is confusing because on the T3i BULB is not a shooting mode, like Automatic, Program or Manual.  It is an exposure setting.

 

What I don't know is what happens if you try to take an exposure with a non-Bulb (Tv) duration with BYE. Does it work, or not?  If it doesn't work, how does BYE behave?

 

I would not pull the trigger on purchasing the camera until you understand how it will work!

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Well, as it turns out I'm an official CentralDS distributor in North America.  I have a few models on order right now.

 

The CDS600D is hard set to M mode.  BYE is able to use TV and AV pictures as well in this mode.  

 

As a result this is a non issue :)

 

Regards,

Oh, cool!  I knew you had a relationship based on the free licenses, but that's very neat.

 

You say you have some on order.  Does that mean people can order through you?  Would it have any impact on the delivery timelines?  I think it's about a 4 week turnaround from CentralDS.  I just want to be sure that if I order one, I get it in time to shoot me some Horsehead and Rosette...

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Oh, cool!  I knew you had a relationship based on the free licenses, but that's very neat.

 

You say you have some on order.  Does that mean people can order through you?  Would it have any impact on the delivery timelines?  I think it's about a 4 week turnaround from CentralDS.  I just want to be sure that if I order one, I get it in time to shoot me some Horsehead and Rosette...

 

You bet!

 

I had 2 CDS600D and I sold them both this summer.

 

I have 2 CDS600D with clear filter installed on order

! have 1 CDS600D PRO II with IR/IV filter installed on order

I have 1 CDS600D PRO II MONO on order.

 

I should be getting them in about 2-3 weeks.

 

I'm currently working on the e-commerce store front.  I have big plans for O'Telescope becoming a full on-line telescope store.

 

Regards,

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Guylain,

Have you had any opportunity to actually Shoot with these CDS600's??  There's been rather little in the Astronomy Magazines (US/CDN/UK at least) other than a couple of "Puff Pieces" that were hardly more than Transposed Advertising Copy...

 

And as for Operation, it obviously loses any Auto-Focus capability, but what about BYE-driven Manual Lens Focusing??  What of LiveView, since they list "Movie" amongst the "Removed Features"??

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