Live view - screen white out

[FWM891]

Hi - I'm just trying out BYN (which works better than ControlMyNikon for DSUSB connection) but when trying to frame and focus with Liveview all I get is a white screen - looked through the help pages but couldn't see a sollution?

Francis

[FWM891]

Thanks Rick,

 

Also noticed under settings (in the opening screen Dither/Daylight/Setting - top right) that there is a tick box for Liveview maximum sensitivity - I have that checked?

 

Will have a play and see what happens

 

Francis

[admin]

It's over exposed probably.  Which camera do you have?  I can't help you without knowing your camera model, they are not equal

 

Regards,

[FWM891]

Hi Guylain,

 

Camera D3s - if anything it should be under exposed as it was on the scope pointing at a dark sky. I've tried it on the same scope again this morning, first of all setting the camera to give me a clean exposure via the normal capture route.

Then went to focus and framing used same setting in snap shot then tried liveview - got an image this time so I really don't know why it went to a white screen before under dark conditions...

 

Camera activation was via shoestring DSUSB in each case with the relevant box selecting DSUSB in BYN.

 

The only difference would be in the exposure/iso setting for the two situations. For dark conditions I set at 800 iso and bulb, daylight this morning 200iso 1/250th second

 

Will try again under dark conditions to replicate things.

 

Thanks for the prompt response. Francis

[astroman133]

Francis,

 

In Frame & Focus, when LiveView is active, very short exposures are quickly downloaded from the camera to the PC. Changing the exposure and ISO do not change the frame rate.  They only act as brightness controls. You may need to change a setting in the camera to enable this.  In the Canon world it is called "Exposure Simulation".  Because the computer is not controlling the shutter for LiveView Frame and Focus as for a long BULB exposure the DSUSB cable should not be used, however it is OK to keep it connected.

 

I would suggest that you put a lens on your camera and connect it to your computer in a semi-dark room (there is no need to waste dark sky time for this) and put BYN in Frame and Focus mode. Set the aperture to a high value, like f/22, set the ISO to 800 and the exposure to the shortest Tv value that the camera supports, like 1/4000 sec.  What you see on the BYN screen will be very dark, but as you increase the exposure you should eventually start to see the LiveView image getting brighter.  As you keep getting longer you will get to a point where LiveView stops getting brighter.  For Canon cameras that time is about 2 seconds. That is where you should set the exposure to maximize LiveView brightness for nighttime prime focus focusing. 

 

NOTE: because the actual LiveView exposures are short (if the LiveView frame rate is 20 frames per second, then the exposure of each frame MUST be less than 1/20th of a second), even at their brightest they will be pretty dim.  Once you have aimed the scope at a very bright star, say Vega, and set the exposure to your experimental value if you do not see Vega, then you can set BYE for the maximum ISO value to brighten the display further, but don't forget to set it back down before imaging as you will see a lot of noise.

 

I hope this helps.