Settings for Brighter Image Capture


#1

I’ve recently moved from BYEOS to SGPro acquisition software so I’m still learning about SGPro and what it can do. But over the last few nights I’ve noticed SGPros raw images that are captured have been darker (less sky objects) then what I captured through BYEOS. So I’m assuming I don’t have the SGPro settings correct.
Here’s my test results;

  1. I captured 10 images of the double cluster and stacked them with DSS using BYEOS then SGPro.
  2. I brought each of the stacked images into PS-CC and converted them to JPG files (see attached).
  3. From these unaltered stacked images you can see the difference. Using PS I can brighten the SGPro image and bring out more stars but I draw out many more stars using the BYEOS stacked image.

I notice the same difference (in lack of brightness) in real-time when capturing each of the images on the BYEOS vs SGPro displays.

What am I overlooking in my setup?


#2

If you “right click” on your image, you can choose the auto stretch that’s suitable for your raw images.
If you want to make this a permanent setting, simply open the Tools menu on the top bar, click Options at the bottom of the pull down menu and select your Auto Stretch Level preference.

Steve


#3

Hi Steve,
Thanks for your reply. But doesn’t the Auto Stretch Level preference just affect the image that is displayed on the SGP Main Screen? Would it have an effect on the raw image that is saved as well?
Thanks again, Bob


#4

Hi Bob,

No it doesn’t affect the raw image as they are still in their Linear state.

Steve


#5

The problem isn’t a screen display adjustment in SGPro but some camera setting in SGPro that is reducing the amount of image dynamic range that is effecting my saved images. The images above are from the raw files in BYEOS and SGPro.

Any help someone else can give would be appreciated.
Thanks, Bob


#6

Hi Bob

If I’ve understood what you have posted, you have taken the linear stack and simply saved it as a jpeg without any processing other than calibration, alignment and integration - is that correct?

If so, to help you understand, SGP does not stretch the Raw files and as Steve states they are in a linear state. If you use a processing programme like Pixinsight you will need to stretch the Raw stack output from DSS using the Histogram Transformation tool or Curves to ‘reveal’ the image.

Barry


#7

Hi Barry, Thanks for your response. Yes I took the linear stack and saved it as a jpeg without any further processing. But I did that to both sets of files from BYEOS and SGPro.

So my question is why does the BYEOS raw images appear to have more data then the SGPro? When I take both stacked images into PS and stretch them there’s more data from the BYEOS capture application.


#8

I do not think you can compare jpg files. How RAW images compare?

As far as I know SGP does not have the option of saving as jpg so probably whichever program you use to convert to jpg may be introducing modifications to the histogram.

Does BYEOS saves images as jpg files? If it does, Does it introduce changes in the image histogram?


#9

RWS,
Neither BYEOS nor SGP saves their captured files in jpeg format. After noticing the difference in the raw files I loaded them into Photoshop to save them in jpeg format so I could attach them onto my original question above. I appears that the raw files are different. The SGP raw files don’t have as much stars as the BYEOS files given the same ISO and Exposure times.
Is there something in SGP that would cause this to occur?
Thanks, Bob


#10

OK, after some exploring I noticed by comparing the metadata for my raw files (from BYEOS and SGP) that the BYEOS metadata had an exposure time of 300sec which is what I requested in the BYEOS application. Meanwhile the SGP raw file metadata had a 2 sec exposure even though I had specified a 300 sec exposure time in the sequence window. The crazy thing is that SGP did take the full 300 sec to take the image although it only took a 2 sec exposure.
Now I’m really confused!
Bob


#11

An off-the-cuff thought, did you have the camera set on Bulb when you used it with SGP?

Mike


#12

A second one, also of-the-cuff: Do you use mirror lock-up? Is the setting in the camera identical to the setting in SGP?

Kind regards,
Horia


#13

Mike, Yes I have the Canon set on Bulb setting. Thanks.


#14

Horia,

Not so off-the-cuff. Not sure if I have my mirror locked up but I do have it set to a 2 sec settling time in SGP. 2 Secs is the exposure time of all my images. I’ll run some tests today to see if this may be the problem.

Thanks for your input, Bob


#15

I finally discovered the problem. My Canon camera mirror lockup was not enabled which caused SGP to use my mirror settling time of 2 sec as the exposure time instead. In all fairness the SGP users manual mentions to make sure the mirror is in the lockup enabled when a mirror settling time is specified, but it shouldn’t result in the settling time being used as the exposure time.

Does this sound like a software bug to be reported?
Bob


#16

Horia,

Thanks for your tip. Actually I started looking on my own and noticed the 2 sec Mirror settling time as being suspicious but needed some time to verify it as the culprit.
Thanks,
Bob


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