"Frame and focus" preview too dark to use on certain Nikons

[catherineryanhyde]

I'm using BYN 2.1.2, premium edition, with several D810As. There's one older camera I haven't used for a couple of years because I can't get a decent live view with it, which makes it hard to recal and get my framing just right. I figured it was a problem with the camera--and it may well be. But as of last night my newest D810A developed the same problem. Using the brightest star possible, I could occasionally see a faint outline of it, but so faint that I couldn't follow it when it moved. I changed the ISO to 1600, which usually does the trick, but it made very little difference, if any. Meanwhile I could take a short exposure and capture the star with normal clarity near the center of the frame. The cameras are not cheap and it seemed worth at least asking if anyone else has had this issue. Is it possible that setting got changed on the camera, or in my BYN window? Any thoughts would be welcome. 

[astroman133]

Were you in Manual shooting mode? What was the shutter speed setting?

[catherineryanhyde]

Yes, Manual, and the shutter was set to several seconds. Should have been more than enough light.

[astroman133]

I am not a Nikon owner, but with my Canon, choosing a shutter setting that is longer than 2 seconds has no effect with regard to brightening the image. You could test the behavior of your Nikon cameras with BYN with a lens on the camera in a darkened room. Just set the ISO to say, 800, and start with a short shutter speed. Then start lengthening it to see the brightening affect on the LiveView image. With your Nikons you may have to pause LiveView then change the exposure and resume LiveView in order to see the effect.

If that is working then perhaps what you are seeing is normal behavior, due to the very short true exposure duration. With a frame rate of 15-20 fps, the true exposure is in the range of 20-30 milliseconds. Even with maximum brightening, only the brightest stars will be visible in an unstretched LiveView image.

In the BYE settings, there is a setting, in the LiveView settings group called Maximum Sensitivity. Have you tried setting this?

[catherineryanhyde]

49 minutes ago, astroman133 said:

I am not a Nikon owner, but with my Canon, choosing a shutter setting that is longer than 2 seconds has no effect with regard to brightening the image. You could test the behavior of your Nikon cameras with BYN with a lens on the camera in a darkened room. Just set the ISO to say, 800, and start with a short shutter speed. Then start lengthening it to see the brightening affect on the LiveView image. With your Nikons you may have to pause LiveView then change the exposure and resume LiveView in order to see the effect.

If that is working then perhaps what you are seeing is normal behavior, due to the very short true exposure duration. With a frame rate of 15-20 fps, the true exposure is in the range of 20-30 milliseconds. Even with maximum brightening, only the brightest stars will be visible in an unstretched LiveView image.

In the BYE settings, there is a setting, in the LiveView settings group called Maximum Sensitivity. Have you tried setting this?

No, I haven't tried the Maximum Sensitivity setting, and I will. As to the previous thoughts, I frame and focus on the same settings every night. So my inability to see the stars was quite different and sudden. In any case, I appreciate you weighing in with your thoughts.  

[admin]

Very few older models support what is called "exposure simulation" in the Canon world. For canon, you need to set the shutter speed to 2 seconds or less (not bulb). I'm not sure if the 810a was one of those Nikon models that supported it though,