StarTools

I consulted the unofficial user guide about Auto Dev. and it left me with a question, How much of the image do I highlight as if I'm cropping, I normally click on the upper left hand corner and drag down and to the right until the entire image is highlighted. Then I move my slider (ROI) over to 50%, and keep. Am I doing this right? What is the reason for the click and drag method? And why do I need to move the slider over to 50%, vs leaving it at 15%. I did not get a lot of useful info from the guide in this area. I'm sorry for the wrong info. I did not mean to put Binning, sorry....Glenn

MadMaxwellSmart wrote:I consulted the unofficial user guide about Auto Dev. and it left me with a question, How much of the image do I highlight as if I'm cropping, I normally click on the upper left hand corner and drag down and to the right until the entire image is highlighted. Then I move my slider (ROI) over to 50%, and keep. Am I doing this right? What is the reason for the click and drag method? And why do I need to move the slider over to 50%, vs leaving it at 15%. I did not get a lot of useful info from the guide in this area. I'm sorry for the wrong info. I did not mean to put Binning, sorry....Glenn

Hi Glenn,

The optional 'Region of Interest' area that you can select is exactly that; the region that you think is the most interesting. AutoDev will then do its best to optimize the global stretch for that area, giving much less attention to the area outside the ROI (how much is 'much less' is governed by the 'Outside ROI Influence').

It's very useful for objects that aren't screen filling, for example a galaxy. With an ROI over the galaxy (or cross section of the galaxy), you can help AutoDev optimize the global stretch for those areas that really count (the galaxy) and much less for the areas that aren't very interesting (for example a noisy background).

admin wrote:

MadMaxwellSmart wrote:I consulted the unofficial user guide about Auto Dev. and it left me with a question, How much of the image do I highlight as if I'm cropping, I normally click on the upper left hand corner and drag down and to the right until the entire image is highlighted. Then I move my slider (ROI) over to 50%, and keep. Am I doing this right? What is the reason for the click and drag method? And why do I need to move the slider over to 50%, vs leaving it at 15%. I did not get a lot of useful info from the guide in this area. I'm sorry for the wrong info. I did not mean to put Binning, sorry....Glenn

Hi Glenn,

The optional 'Region of Interest' area that you can select is exactly that; the region that you think is the most interesting. AutoDev will then do its best to optimize the global stretch for that area, giving much less attention to the area outside the ROI (how much is 'much less' is governed by the 'Outside ROI Influence').

It's very useful for objects that aren't screen filling, for example a galaxy. With an ROI over the galaxy (or cross section of the galaxy), you can help AutoDev optimize the global stretch for those areas that really count (the galaxy) and much less for the areas that aren't very interesting (for example a noisy background).

Ivo, thanks for that info. I will do it a little different next time...Thanks Glenn

Ivo - I have a bit of love-hate relationship with Autodev. Sometimes it works great, but other times -- especially in dense star fields -- it blows out the background, even with serious ROI and "Ignore Fine Detail" control. Often I get a more ascetically appealing result with just a straight Gamma stretch in the 2.1-2.5 range, or by playing with the Digital Development %. However, scientifically, I do appreciate that Autodev can potentially get the most of out my dynamic range!

What I've been trying recently is to do an Autodev, with a fairly tight ROI and IFD of 3-5 pixels, and then accepting the result even if I think it looks overexposed. I then fire up Develop, and 'tune' the image by pulling back the Gamma until I'm happy with the background. Does this strike you as a reasonable balance to adopt, to get most of the value of Autodev but at the same time bring 'blow out' under control?

At the end of the day, it's about what you feel looks good of course.
AutoDev will try to ignore stars and bring out the background. If there's not much other detail to go by (e.g. a busy star field in a wide field), results may indeed not be very nice and Autodev may not be the answer.