Need help with focusing using live view

[Run45]

Hi

I am getting quite confused how to use my canon 100d to manually focus on bright stars using live view. One night I got it working but tonight I had no luck. Not sure what I did differently. High ISO setting, bulb mode , autofocus off.

I think I saw simulation exposure setting displayed when it was working but not today.. no luck today though..  so annoying because I am finally at a dark.site.  it's like exp. sim. is off but can't find a way to force it in..checked all the online guides but can not spot my mistake.. will try tomorrow again.Thanx for any suggestions 

 

[Atreta]

  with camera lens and also with scope i find easier to focus on double stars, like gacrux,   when the dimmer one seems ok (like a point of light)  i take a test shot to check it.  you could also download a copy of APT and use it's focus tools,(fwhm)  they're very handy and it's a great software. 

[cjdawson]

Instead of bulb mode, set an exposure time.   I think that might have an effect.

Of course, when you come to take the actual shots don't forget to turn bulb mode on again.

[Alien 13]

As above, I normally set on 20-30 seconds to get liveview to kick in another useful tip if you are doing Lunar shots and want the live view image to match the actual exposure is to use a "chipped" T adapter this allows you to play with the F number rather than the default 0 with no lens attached.

Alan

[Run45]

Forgot to mention: just trying to shoot summer triangle and milkyway using standard 18-55mm lens that came with canon 100 d. When I could get the live view to display something a couple of days ago, I was focusing on Arcuturus but tried and failed with Altair yesterday..the display just stayed black whatever exposure or ISO I selected. 

As I said I member exposure sim being displayed before. But did not see that yesterday.shoud exposure sim kick in automatically..is it possible that I disabled it somehow.. don't have manual with me.

Thanx again for any suggestions 

 

[Run45]

Double checked my settings. Manual mode selected and autofocus switched off.. bu still had cont. AF selected in camera menu .. wondering if that causes the problem.. need to test tonight.

[The Admiral]

I don't have your camera, but for what it is worth I've been caught out before because I'd forgotten to whack up the ISO setting. Use MANUAL exposure settings and as mentioned above, set a long exposure time. Also I'd have thought that you need to set the camera to 'work without lens' (see user manual for that). I don't think AF settings would make a difference.

Ian

[SteveNickolls]

Hi Run45,

I've just begun trying out piggybacking my Canon 600D on my refractor to take wide-ish shots of the night sky and have become conscious of a number of points in the process that help make or break things. Without trying to teach you to suck eggs having your finder and camera well aligned to the view through the telescope makes finding a star to focus on easier. I have a Skywatcher mount so after carrying out a careful 2 star alignment I will slew to a very bright star, Vega, Deneb etc to focus the camera. I always let the mount settle down a few minutes and ensure the star I have slewed to remains in the centre of the eyepiece FOV. Unless you are using BYEOS the actual focus position is down to your decision making and personal choice. Until you are almost in focus you probably won't see much of the star in 'Live View'. I then increase the view through x5 to x10 for focusing. Focus can be delicate to achieve and I often move the lens in and out of focus a few times to judge best what I consider is the focus point. Once focused don't replace any lens cap or change the lens setting as this will cause movement of the lens position and your focus. I have my camera lens on manual setting 'M', no autofocus, lens IS off, exposure usually ISO 1600 or 800, and 30 seconds exposure for starters changing to Bulb when actually imaging. Hope this helps.

Best of luck with your imaging.

Cheers,
Steve

[Run45]

Thanx for all the comments. Tried live view during daytime without settings changes and it behaved as expected 

..will try my luck this night again

[Alien 13]

The exposure simulation can be enabled/disabled in the "live view shoot" menu it will only work with exposures up to 30 seconds and as mentioned by Steve you will only see stars if the focus is close, zooming in +5 or +10 does seem to also brighten up the image and number of stars you can see.

Alan

[MARS1960]

You could also get the free month trial of BackyardEOS, it has some very useful functions especially for focusing, i liked it so much i bought the premium version for less than £35. 

[happy-kat]

If using the kit lens then in manual mode you must set the aperture, have lens at 18mm and aperture say two or so stops in around f4. Set iso 1600 at least at this stage and 20 second shutter.

I much prefer setting camera to back button focus as well it stops the camera from trying to change focus when you press the shutter button.

[happy-kat]

Day time possible trick set lens 18mm f4 then using autofocus focus on furthest furthest view, quickly chang button to manual focus. Turn camera off. Turning it on again hopefully lens still in same focus point. Give a head start at night with any luck, with a try.

I use dlsr controller and my 7 android tablet to focus our canon.

[Stub Mandrel]

You need exposure simulation + select 30- seconds exposure to get the brightest possible live view image.

[Run45]

Hurray.. all working.i was more patient tonight. Think my focus was way off yesterday for live view...took my first milkyway pictures.. can't wait to see it on big screen.....

Thanx for all the suggestions 

[SteveNickolls]

Hi Run45,

Look forward to seeing your images of the Milky Way :-)

Best of luck in all future sessions.

Cheers,
Steve

[cjdawson]

10 hours ago, Run45 said:

Hurray.. all working.i was more patient tonight. Think my focus was way off yesterday for live view...took my first milkyway pictures.. can't wait to see it on big screen.....

Thanx for all the suggestions 

Photo or it didn't happen!   Post them  up here

[Run45]

Photo...well..prob. in 1 week have time to get picture of camera. hope I get one more night to shoot at a relatively dark site... such a difference to my usual light polluted garden..

[Run45]

ok .. here it is. Attaching one of the raw images that I shot. Not processed at all.  I have approx. 6 similar shots (and other ones with lower iso)  that I could use for stacking but prob. would need some help with that.

(will add a new thread for that if I keep on failing). Currently tried Deep Space Stacker  + Star Tools with mixed results (as I said not related to this original thread so will open a new one soon).

Also managed to get andromeda on (+ some light pollution from nearby village) a different image (attached).

 

 

 

IMG_1657.CR2

IMG_1723.CR2

[cjdawson]

I've just taking a look at both images.   Looks like you've got past the focussing issue.  My very quick look (it's my lunch break) showed me that the stars are pin sharp.  Your Milkyway shot looks fantastic.  The other one has some light pollution - I'm sure that can be removed in post processing, pesky lights getting in the way of our need to dark skies.

[alacant]

Hi. If still no go, bypass the electronics; stick a piece of tape over the contacts on the lens where it meets the mount. Set M on the dial and it will fire every time on the speed you have chosen but with no control over aperture. +1 for APT. Place a piece of paper over the lens with two holes about the diameter of a pencil. In live view zoom you're in focus when the two points of light superimpose. Easier than a Bahtinov for camera lenses I find. HTH.