Jump to content

Canada's top-tier Telescopes & Accessories
Be as specific as possible when reporting issues and *ALWAYS* include the full version number of the application you are using and your exact *CAMERA MODEL*
  • 0

Long Exposures





I an newbie here, have a Orion 80mm telescope and have connected Canon ESXI to it, I can see in frame and focus i can get live view and adjust focus and take shots

when i switch to Imaging mode and use Bulb with 30second exposure i dont get anything, getting blank white screen, what am i doing wrong ?

Link to comment
Share on other sites

  • Answers 11
  • Created
  • Last Reply

11 answers to this question

Recommended Posts

I have never heard of an ESXl camera. I could not find it as a current product on the Canon web site. Are you sure that is the correct model?


What are you shooting a 30 second exposure of? A blank white image is indicative of a totally overexposed picture. It would be what I would expect if you were shooting a 30-second exposure of a daytime scene, for example.


If you hear the shutter open and then close 30 seconds later then BYE is doing its thing. You just need to provide it with a suitable target to image, or adjust the capture parameters (ISO, shutter duration, f/stop) appropriately.

Link to comment
Share on other sites

Got it, One more question, I use frame and focus and derive a optimal Shutter and ISO for a object, but when i use the same Shutter and ISO in Imaging, I dont get good pictures, i need to try a new set of Shutter and ISO in Imaging y trial and error ?

Link to comment
Share on other sites

In LiveView the ISO and shutter speed are the means for adjusting the brightness of the image. The settings that give you the correct brightness for LiveView cannot be used to give you a good still image. The reason is that in LiveView the exposure duration of a LiveView frame is only a few milliseconds long and will not change as a result of you adjusting the exposure duration setting in BYE or on the camera.


Another way to say it is that the frame rate and exposure duration are constant in LiveView and the exposure duration setting becomes merely a brightness control.


When you use your camera and scope on the night sky this will become more apparent. Even when you aim the scope at a bright star like Vega, you will either need to set BYE to Maximum Sensitivity (on the settings screen) or set the Exposure to 2 seconds (not BULB with a duration of 2 seconds, but a Tv value of 2 seconds) and the ISO to the maximum value for your camera to see the star. That is either on the LCD display on the back of the camera or on the PC screen in BYE. This is because the camera is reading out the sensor every few milliseconds in order to update the LiveView display very frequently.


If this is unclear you could look back through the archives of this forum. This topic is revisited fairly often.


I hope this helps.

Link to comment
Share on other sites


Welcome to Nighttime and Astro Photography.

While Camera Sensors and Lenses work the same, all of the Considerations and Priorities are VERY DIFFERENT from Daytime Photography.


Daytime:  Light is Ample and Lenses are very Adjustable and the Sensor Noise is overwhelmed by the Image Signal.  One can Stop-down the Lens significantly and/or use ISO rather indiscriminately to Control the amount of Light and Focus in the Final Image.


Nighttime:  Light is Scarce and Lenses are Fixed or nearly so and the Sensor Noise is one of the critical elements to Avoid.  One only Stops-down the Lens as much as Needed to Control Lens Distortion (no Stop-down possible on a Telescope), and raises the ISO above Unity only when Needed, all other effort is to extend the Exposure Duration long enough to collect sufficient Light to bring out the AP Target (Duration will likely be limited by your Mount Tracking - OR by the Rule-of-600 for a Photographer Tripod).


Using BYE:  Use Frame and Focus (which engages LiveView - causing Serious Heating of the Sensor and therefore uncontrollable Noise) solely to get your Framing and Focusing done.  This Mode is NOT the appropriate place to attempt to determine Exposure Parameters (especially because while LiveView engages "Exposure Simulation", it is rarely an accurate representation because it is a Video Mode not a Shutter-timed Mode).  Once Focused and Framed, move to Imaging Mode.  Determine your Exposure Requirements here using Single "Preview" Shots (Accurately shows Actual Results, AND allows Sensor to Cool-Down from LiveView Frame&Focus usage).


So, for your 450D/XSi:  You'll find that ISO1600 is rather Noisy and ISO800 is much better.  You need to ensure that your Mount is properly Polar Aligned and Tracking - the Focal Length of even the "Fast" Orion Short Tube 80mm at 400mm will cause Star Trails at more than 1 second Exposures on a Fixed Tripod.  You won't be able to use Mirror-Lock unless you have a Serial DSUSB device, but shouldn't need it with a solid T-Adapter connection to the Scope and solid Mount under the Telescope.  You can enable "High-ISO Noise Reduction" unless you want to Stack the Final Images (HINR messes with Stacking).  You'll NEED to Shoot RAW Format, then perform your Stacking/Image Processing and then finally convert to JPG or other Format at the end.


Now, go out there and Enjoy!!

Link to comment
Share on other sites


This topic is now archived and is closed to further replies.

  • Create New...

Important Information

This site uses cookies to offer your a better browsing experience. You can adjust your cookie settings. By closing this banner, scrolling this page, clicking a link or continuing to browse otherwise, you agree to the use of cookies, our Privacy Policy, and our Terms of Use