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5X Zoom on Canon ExSI





I am newbie here, trying out Backyard EOS

I am using a OrionED80TCF with Televue 0.8x Focal reducer on a Canon Exsi

I am using Planetary mode and 5X zoom



Camera supports 10X zoom, why its only 5X zoom in planetary mode

I see resolution of image is just 850*550 and file size is like 300KB, I have set quality as JPG in settings and save to also as JPG

Am i doing somethings wrong or do i need to set higher resolution some where else ?  I see Quality is showing as L


Can i connect a barlow to increase magnification ?  i have a 2" barlow and tried connecting in front of televue focal reducer and i could not get any focus done at all



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The Planetary 5X zoom is really a crop with the image at the actual size. The 10X zoom is a digital zoom that loses data. That is why more (10X rather than 5X) is not better. If this does not make sense, read some of the archived posts for more info.


Planetary is using LiveView data which is JPGs. For still shots you should use RAW, not JPG.  If you use a Barlow, you may need an extension tube to get focus. You would also not want to use both a Barlow and a focal reducer since they counteract each other...The focal reducer lowers the focal ratio and the barlow raises the focal ratio.

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JPG have the same number of pixels as RAW images. The file size of the JPG.images are smaller because they use a smaller color palette.


If the target is too small, even in 5X zoom, then the best way to enlarge it is to use a Barlow to increase the focal length. Good focal length for planetary is in the 4000-5000 mm range.

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even If i use raw, the resolution is the same , why is it?


"RAW" is a File Format, much like "JPG".  It does not actually specify a Resolution, but rather a Treatment (actually lack of In-Camera processing) of the Pixel Data collected from the Sensor.


I would like a much larger resolution at 5X zoom.


The Planetary Imaging Mode is designed to provide a 1:1 Pixel Ratio Image (the BEST POSSIBLE RESOLUTION from a Camera).  It does this by Extracting Frames from the Camera's 5X LiveView data that is actually processed In-Camera specifically for Display on your Back-of-Camera LCD.  THAT is the Limiting Factor on the Image Dimensions.  This Image is "Called" a 5X-ZOOM, but it is actually just "Manufactured" to represent a LiveView level of "Zoom" into the otherwise Compressed Full FOV Display on that LCD.

For Planetary AP Imaging Purposes, we are just "Lucky" that the Canon Engineers decided that the 1:1 Ratio "Full LCD Image" was an "Easy" Image to produce - and Luckier-Yet that the SDK makes it available to Developers like Guylain.  This is because the ONLY Video Pixel Resolution that is usable for Planetary AP Imaging is that 1:1 Pixel Resolution.

AND, for Planetary Imaging,  a 800x600 Pixel Field is actually "Rather Large" compared to what many of the CCD Planetary Imagers produce.



If i use imaging mode, I cant see Live view and also 5X zoom ?


These are 3 separate Imaging Modes - each with a different purpose.  The "LiveView" mode is the "Framing&Focus" mode intended for just that Focusing purpose.  Similarly, the "5x Zoom" Mode is the Planetary Imaging mode - for that Planetary AP Imaging Purpose (no good for DSO Imaging).  And the Imaging Mode, with it's Imaging Plan control of Longer Exposures and RAW Output is intended for DSO Imaging.

As you gain experience in AP Imaging - and in using BYE - you'll become familiar with the Uses of each Mode.


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even If i use raw, the resolution is the same , why is it? I would like a much larger resolution at 5X zoom.


If i use imaging mode, I cant see Live view and also 5X zoom ?


5X zoom is a function of live view.  This is why it is only available in a mode where live view is possible.  


You seem to confuse image size with image resolution.  They are not the same.


What you care about is a 1:1 pixel resolution.  Meaning 1 pixel on the sensor = 1 pixel on the image.  Anything else and you lose quality, full stop!  And you do not want that.


In imaging mode you get 1:1 pixel resolution when you use RAW or Large JPG.  Always use RAW and never look back.


In planetary you get 1:1 pixel resolution when you use live view.  Always use 5X zoom and never look back.



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