Readout Noise


#1

Hi all,

I just joined the forum bc I am looking for an answer to a question I have. I have been having SGPro since Sept of this year and have figured out how to create a sequence and get the program to activate ‘almost’ all my equipment, mostly through T&E, without throwing any errors. The one issue I still have and am not sure about the answer is what value to enter for Readout Noise for my camera. I shoot with a Canon T1i and can’t seem to get the program to engage the sensor all the way when it goes to start shooting.

The couple times I have created a sequence and let the program run through it, it seems like everything is going to work except once it engages the camera and takes an exposure, you can hardly see anything in the image that is revealed.
The only reason I can think of that this is happening is bc the readout noise is not set under the camera tab. Can someone help me out with this issue?


#2

The image from your T1i simply needs to be stretched. SGP simply displays
the raw, unstretched image unless you tell it to display a stretched
version. You can right click on the image and tell SGP to “auto stretch”
(low, medium or high). And if you have the histogram module open you can
set SGP to automatically stretch every image as it is downloaded. Note
that the stretch is just for display purposes and does not actually change
the raw image. Also, this has nothing to do with the read noise.


#3

Thanks for the reply JoelShort!

Do I need to enter a value for read noise? Can you tell me how to find this information if I do? Can the camera manufacture tell me this? I think this is all I need to know to get SGPro working

Also I have stretch an individual Raw image in SGP to see if I could see anything and it looked like something was there but it was very faint and hardly reconizeable. I also shoot with a CLS filter and in my other program I use to do this, an individual RAW image has a blue film over it from that filter. In SGPro this is not happening. Idk if SGPro filters out the blue from the image before it writes it to the program or if something is not set right in the settings.

Thanks for the help!


#4

It looks like the read noise changes with what ISO you have the camera set at. Take a look at this thread, which gives you some idea of the read noise of the T1i.

You don’t really have to enter the read noise. All it is used for is to determine the “ideal exposure time” calculation that SGP displays in the camera stats. I’ve never found the “ideal exposure time” to be very accurate or realistic. The read noise parameter has nothing to do with displaying the image.

Can you post a raw image file so I can take a look at what you’re seeing?

SGP displays images in monochrome so you won’ see any color.


#5

Here is a raw image I took the other night of the horsehead nebula

Horsehead Nebula image


www.mainsequencesoftware.com