Jump to content

New To Imaging, help with camera settings


Recommended Posts

Hi, I'm new to this forum and the field of imaging and wondering about some advice on starting out, particularly exposure wise. Thankfully, I see that there's no such thing as a silly question!
I enjoy daytime photography and know how to use the 'exposure triangle' to get good photos at daytime; come to the stars, without my trusted flash, I'm at a loss (well, just haven't quite got there yet)!

I'm interested in starting imaging DSOs (nebulae, galaxies and clusters I guess!) As such, I have an astro-modded DSLR, a couple of filters (visible mainly, like the UHC and visual OIII), telescope and equatorial mount and guiding kit, but using it and nailing down the ideal camera settings still elude me.

I guess it's really the ISO - there's a couple of things I have seen on using the native ISO for the camera sensor which is preferred by some as it maximises the dynamic range of the sensor (this is usually ISO 100-400) but many use higher ISO (800-1600) as this reduces the exposure time required to get the sub, and therefore more subs can be obtained. The latter sounds like a better idea also if using stacking images and dithering in between (every few) frames as noise surely would get cancelled out by signal.

Can you share which you use and why?!
Also, what's an ideal exposure? Is there any 'starting point' for a DSO with magnitude 4 or 8?

eg, starting point is 30sec for Mag4, and 5min for Mag8, 10min for Mag10, with ISO1600 and f/7 scope.

I'd guess the aim is to avoid stars saturating, but that would imply use the max DR of the sensor, so back to first question! Or does one stack multiple exposures in DSS, or is it more deal with saturated stars in photoshop?! That's another topic!

Thank you in advance for any help!

Link to comment
Share on other sites

6 hours ago, Pete said:

Hi, I'm new to this forum and the field of imaging and wondering about some advice on starting out, particularly exposure wise. Thankfully, I see that there's no such thing as a silly question!
I enjoy daytime photography and know how to use the 'exposure triangle' to get good photos at daytime; come to the stars, without my trusted flash, I'm at a loss (well, just haven't quite got there yet)!

I'm interested in starting imaging DSOs (nebulae, galaxies and clusters I guess!) As such, I have an astro-modded DSLR, a couple of filters (visible mainly, like the UHC and visual OIII), telescope and equatorial mount and guiding kit, but using it and nailing down the ideal camera settings still elude me.

I guess it's really the ISO - there's a couple of things I have seen on using the native ISO for the camera sensor which is preferred by some as it maximises the dynamic range of the sensor (this is usually ISO 100-400) but many use higher ISO (800-1600) as this reduces the exposure time required to get the sub, and therefore more subs can be obtained. The latter sounds like a better idea also if using stacking images and dithering in between (every few) frames as noise surely would get cancelled out by signal.

Can you share which you use and why?!
Also, what's an ideal exposure? Is there any 'starting point' for a DSO with magnitude 4 or 8?

eg, starting point is 30sec for Mag4, and 5min for Mag8, 10min for Mag10, with ISO1600 and f/7 scope.

I'd guess the aim is to avoid stars saturating, but that would imply use the max DR of the sensor, so back to first question! Or does one stack multiple exposures in DSS, or is it more deal with saturated stars in photoshop?! That's another topic!

Thank you in advance for any help!

Maybe this can help you out with iso settings.

 

https://dslr-astrophotography.com/iso-values-canon-cameras/

 

I don't use a dslr myself, but there are a few settings you need to disable in a dslr. In camera long exposure noise reduction needs disabling, dark frames will remove any noise. Disable in camera sharpening. Enable mirror lockup to stop any vibrations. Only shoot in RAW mode it will give you more signal to work with.

Link to comment
Share on other sites

I am fairly new to astrophotography but I find that with my older 12 bit Canon EOS 1000D (modified) I have to use ISO 1600 otherwise the objects are just too faint.  I found the following very helpful.

 

https://www.astropix.com/html/astrophotography/settings.html

 

I am yet to master dark and flat frames so I tend to use dithering and also take BIAS frames.

 

I am not sure if there are any set rules on setting the exposure...I think it's best to experiment on the night by making sure the histogram is approximately 1/3 of the way from the left hand side.

Edited by PeterBolt
Link to comment
Share on other sites

For my aged Canon 550d ISO 800 is recommended as the sweet spot. I sometimes use 1600 if conditions are not good.  Lower ISOs don't really improve the noise performance much because you are warming up the camera and you will need a correspondingly longer exposure to register the same signal.

 

My recent image of M31

(which is a very bright DSO) was done with LP filter, ISO800 and 5 minute exposures with short focal length refractor. Because I wasn't sure, I had also taken 1 minute and 2 minute subs just in case the core was burnt out but it wasn't. So in summary, apart from point sources like stars you are  unlikely to clip signal.

 

In the past I have found that under 2 minutes was a waste of time for galaxies with too little signal compared to the noise. Having said that, if you are imaging a globular and don't want the core burnt out you may need to use 1-2 minute subs. It depends a lot on how fast your scope is of course. (Most of my imaging is done at F4.8).

 

The other limiting factors for exposure is often the light pollution and the quality of guiding. A light pollution filter will allow longer exposure. Use shorter exposures to combat egg shaped stars.

Edited by paul
  • Like 2
Link to comment
Share on other sites

Thank you for your detailed answer @paul - this is exactly what I've been looking for! I've an astro-modded 550D so had spied the same 800 ISO for use.

f/4.8 also is my scope.

I shall try with this now and hope my images improve.

Thanks to others for your input - the astropix website looks to contain lots of useful info so need to just get some reading done during these cloudy nights!

  • Like 1
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...