DSLR focus with camera lens and no live view.

[frugal]

Okay, everything I have read about focusing a DSLR involves using the live view to focus on a bright star and using a piece of software such as Backyard EOS to help calculate the FWHM or some other similar metric.

My problem tonight was that the Frame and Focus in BYE was not showing any stars, even when I could see Castor and Pollux through the viewfinder... So If Frame and focus does not display any stars, is there any other way of focusing other than taking a shot, downloading it to the laptop, waiting 20 seconds for it to be processed, adjusting the focus and trying again? I use a plan called FOCUS so that I can delete them all at the end of the night, but tonight there were about 50 of them.

[guyroch]

You do not have to use the imaging plan to focus and wait 20 seconds for the image to download.

Stay in Frame & Focus instead and use the SNAP image button.  In conjonction with the LOOP button (toggle on/off) you will acheive the same... with the big advantage that...

1- snapped image are not saved be default so you will not need to deleted them

2- snapped image are small JPG so way, way faster to download.

Hope this help,

Guylain

[all-on-black]

Could just move to a bright star, focus, then swing to your target..

[frugal]

You do not have to use the imaging plan to focus and wait 20 seconds for the image to download.

Stay in Frame & Focus instead and use the SNAP image button.  In conjonction with the LOOP button (toggle on/off) you will acheive the same... with the big advantage that...

1- snapped image are not saved be default so you will not need to deleted them

2- snapped image are small JPG so way, way faster to download.

Hope this help,

Guylain

Cheers, I will try that next time. I had not realised that was what the SNAP button was for. I had mistakenly assumed it was to take a snapshot of the displayed liveview image and save it (which would have been no use to me as there was nothing on the live view )

[frugal]

Could just move to a bright star, focus, then swing to your target..

The problem was that even pointing to Pollux (mag 1.14) there was nothing in Live View. It was especially frustrating as I could see the stars through the camera eyepiece, so they must have been nice and bright. I guess at 300mm F6 with only 50mm of aperture there was just not enough light getting to the sensor compared to my dark adapted eye.

[frugal]

Guylain, thanks for the help. I made up a simple Y-mask and took the camera and laptop outside to test on the lights from across the valley (not point light sources I know, but a street light from 2 miles away is the closest I am going to get with this cloud cover).

Things I discovered:

• The <<< << < > >> >>> arrows actually focus my Canon lenses. No more messing about with the focus ring and over cooking it.
• The snapshot function works exactly as advertised
• the loop function generates images faster than my poor little laptop can deal with them. I either need to experiment with the Pause between frames or just take multiple shots manually.
• I now understand that the duration controls at the bottom of the live view screen only apply to the Snapshot and not Live View, whereas the ISO setting applies to both. This explains why changing the exposure duration made no change to the image shown on Live View
• Although I can use any angle of arms on my Y-mask, if I want to use the Bahtinov Grabber function I really need to make sure that they are the standard 30 degree angle so that the software can figure out which arm is which.

Time to sacrifice some old ice cream tub lids to make some masks that will not disintegrate the moment they are taken outside

[all-on-black]

The problem was that even pointing to Pollux (mag 1.14) there was nothing in Live View. It was especially frustrating as I could see the stars through the camera eyepiece, so they must have been nice and bright. I guess at 300mm F6 with only 50mm of aperture there was just not enough light getting to the sensor compared to my dark adapted eye.

In that case you need to change your camera settings. You should be able to see that star clearly.

Drop your shutter speed right down, and up your iso, also use the largest aperture your lens will go to at the zoom you want to use. It should be nice and bright allowing you to focus. Then you can swing to your target and adjust settings to suit.

Good luck!

[all-on-black]

The problem was that even pointing to Pollux (mag 1.14) there was nothing in Live View. It was especially frustrating as I could see the stars through the camera eyepiece, so they must have been nice and bright. I guess at 300mm F6 with only 50mm of aperture there was just not enough light getting to the sensor compared to my dark adapted eye.

In that case you need to change your camera settings. You should be able to see that star clearly.

Drop your shutter speed right down, and up your iso, also use the largest aperture your lens will go to at the zoom you want to use. It should be nice and bright allowing you to focus. Then you can swing to your target and adjust settings to suit.

Good luck!

[frugal]

Drop your shutter speed right down, and up your iso, also use the largest aperture your lens will go to at the zoom you want to use. It should be nice and bright allowing you to focus. Then you can swing to your target and adjust settings to suit.

The problem is that with Backyard EOS you can only adjust the ISO and aperture in the Live View mode. Llive View runs at something like 50 fps and you can not drop that frame rate. This appears to be a limitation of the Canon firmware on the camera itself.

I have now discovered that I can take a series of low resolution snapshots with BYE in the frame and focus mode. This lets me take 2 second or longer images so that I can see the stars and still perform the FWHM and Bahtinov metric analysis.

Sent from my GT-N7000 using Tapatalk

[JayStar]

I am having the same problem so will try some of the suggestions here.  One thing I have noticed is that the <<< << < > >> >>> focus controls do not always appear (in fact never when I am out at night!).  I use a Canon 700d.  Is there some reason / setting that enables the focus controls?  (I am not talking about ASCOM focusers, only the frame and focus controls).  

[Atreta]

JayStart,

Maybe this is a dumb answer, but are you using the lens in AF? i think it has to be in AF for it to work(or the other way around)

i don't use BYEOS for a long time, and tried the focus controls only once with APT.

Frank

[JayStar]

JayStart,

Maybe this is a dumb answer, but are you using the lens in AF? i think it has to be in AF for it to work(or the other way around)

i don't use BYEOS for a long time, and tried the focus controls only once with APT.

Frank

not a dumb answer at all!  i have no idea what i am doing yet!!

i set the camera to M but wonder if there is another setting i am missing.... will check

thanks.

[Atreta]

BTW, my answer only applies if you are using the camera with it's lens.

Frank

[Yoddha]

The lens has to be in AF mode in order to allow control from PC. Once the focusing is done, it has to be switched back to MF

[JayStar]

The lens has to be in AF mode in order to allow control from PC. Once the focusing is done, it has to be switched back to MF

Thank you - how do you set that?

I have the camera dial on 'M'.  My settings say that I have to switch to the AF dial in order to auto focus... and what is confusing me is that with my current settings I get the focusing arrows available sometimes but on other occasions it doesnt give me the option.

I think there may be an issue with this camera and BYE as I have spotted a couple of other things:

1) BULB setting does not work

2) the image quality keeps resetting itself to S1 (even though I have it set as RAW + JPG in the camera and also in the BYE settings)

Maybe because its a newer camera it has not been fully integrated / tested in the latest release...

[hazegood]

The AF/MF switch is on the lens not the camera, the M on the camera dial is for Manual

[JayStar]

The AF/MF switch is on the lens not the camera, the M on the camera dial is for Manual

Ah yes i see it - i am using prime focus method, so no lens.  This has answered the question on why I was not seeing the focus arrows when testing inside with the lens on.

Just need to work out why the arrows do not appear in prime focus when out at night.

cheers. 

[StuartJPP]

As above, there should be a switch on the lens itself that allows manual/automatic focus...MF/AF...as long as it is a Canon compatible EOS lens with AF...

BYEOS to me seems to change the settings way too often and not save/restore them sensibly. Switching from focus to imaging modes is in my mind not clean enough...too fiddly. I'd prefer to be able to set things up in a "profile" style so that you can switch back/forth easily. Too many check boxes to set up...though maybe I don't know how to use it properly. I tend to do things manually anyway...

[Owmuchonomy]

You can use the Canon software EOS UTILITIES to engage live view in manual mode. Just find a decent star, manual mode (not video), crank the ISO up and away you go. It doesn't work on dimmer objects though but you can slew to these after. Works fine on my Mac.

[Atreta]

Ah yes i see it - i am using prime focus method, so no lens.  This has answered the question on why I was not seeing the focus arrows when testing inside with the lens on.

Just need to work out why the arrows do not appear in prime focus when out at night.

cheers. 

It won't appear as you are using the telescope as the lens, so you have to focus manually using the telescope focuser or maybe get some sort of autofocuser.

Frank

[JayStar]

It won't appear as you are using the telescope as the lens, so you have to focus manually using the telescope focuser or maybe get some sort of autofocuser.

Frank

Got it thanks.  Kind of obvious really but starting out it can take a while just to figure out the basics.  You saved me some time there.

Cheers

[dph1nm]

The problem is that with Backyard EOS you can only adjust the ISO and aperture in the Live View mode. Llive View runs at something like 50 fps and you can not drop that frame rate. This appears to be a limitation of the Canon firmware on the camera itself.

As others have said you should be able to see bright stars on the camera screen - but only if you are very near focus. Especially with shorter focal length lenses, the slightest shift out of focus will make the star image vanish.

NigelM