Just getting started in this hobby, I have a mount, but no telescope yet. All of my imaging comes from a Canon 1000D with an EF 75-300mm lens on an Atlas EQ-G.
From what I can gather, there is no way to use the autofocus function on my Canon EF 75-300mm f/5.6 lens. From what I can tell, it appears as though the SDK allows for this since BackyardEOS has the ability to manually tweak the focuser via soft keys in the software.
So based on this, does SGP already have this functionality and I just can’t find it? If not, what would it take to add it as I’m sure that is something that a fair amount of people would love.
What I envision is during any specified autofocus, rather than tweaking an ASCOM focuser, you would send a signal to the camera lens’s focuser.
What I don’t know is if you can leave the hard switch on the lens in AF mode and still image. Whenever I focus using the softkeys in BYE, I have to remember to flip the switch back before an imaging session starts. I don’t know if there’s anyway around that. I don’t know if that’s a limitation of the software or the hardware though.
I guess I’ll let other people here chime in, but I, for one, would love this addition if it’s possible.
Thanks!
Gilbert Shupe
Hi Gilbert,
I suspect the Canon hardware is not able to do autofocus on stars, except maybe very bright one’s. A further bottleneck could be that your built-in autofocus in the camera is not accurate enough for astrophotography. On more expensive Canon 's you can fine tune your autofocus though. My last concern is that the autofocus keeps trying when some clouds are passing by, so you loose your focus point I am afraid.
I think the most simple is to set your focus right once in manual mode and forget it. With a max. 300mm lens it will not shift away with temperature changes I believe,
Clear skies,
Janos
Thanks for the response.
I should clarify though, I’m not actually talking about Canons built-in autofocus logic. Rather, BackyardEOS provides the ability to manually tweak the focuser by pulsing the autofocusers motor.
So I was wondering if it was possible to use SGPs focusing logic to pulse the motor in the same fashion and provide the ability to act as a focuser.
Unfortunately, in my short time I have already seen focus impacted over time. It’s not huge, but within about 8-9 degC temp change, my stars to begin to look a little bloated.
Hi Gilbert,
Now I understand better what are you intending to do. Still I don’t really know how would you power up and connect the PC to the Canon lens, I’m really interested if there is an adapter exist for that when no Canon camera attached.
Clear skies,
Janos
Hi Gilbert,
Reading again you post I see that you have the camera and the lens connected, I’m sorry for the misunderstanding. To move the Canon focusmotor from within SGP is a very tempting idea !
cheers,
Janos
Right? I thought so too. I’m assuming that this means that it currently isn’t supported. I think I’ll wonder over to the feature request forum and put it there!
APT has had this functionality for quite a while now, maybe take a look at that as an alternative.
Cheers
Ian
Sorry, to be clear APT has the ability to control the focus motor on canon lenses so you can tweak focus, AFAIK it doesn’t allow autofocus.