Help needed DSLR settings for Milkyway

[daveangie0110]

Hi All

Help needed please !! Newbie !!

Sorry if this sounds stupid.

After dusting off my Star Adventurer I attempted my first Milkyway shot from my back garden in Portsmouth which has quite bad light pollution, I am using a Canon 600D with a Sigma 50mm F1.4 lens, I set up the Star Adventurer with good polar alignment then I set the lens to its widest aperture and set the ISO to 800 set the exposure to 5 minutes all via BYEOS, after it took the first image it was completely washed out, what is the best thing to do lower the aperture or lower the ISO ?

Thanks for your help.

[Yamez]

5 minutes in a light polluted area is far too much. start off small say around 10-15 seconds then go from there to 30 seconds. ISO is fine and your other settings sound good as well.

[kendg]

Probably a bit of both.

Try 2 min at 800 f1.4 first. Then go from there depending on if it's washed out or dark.

 

[Starwiz]

The only stupid questions are the ones that aren't asked 

I'm no expert and relatively new to imaging myself, but I would try using a light pollution filter and reducing exposure time.

There's no real advantage to reducing the aperture other than to increase depth of field, but that's not needed for astro imaging if you're correctly focused.  

John

[Alien 13]

As above, an ISO of 800 on modern Canon`s is close to unity gain so thats fine you could stop the lens down a little but as said reduce the exposure time.

BTW I have had data that is almost completely white and still managed to pull a good image out of it.

Alan

[Jonk]

I used 15 seconds at iso 1600, Canon 6D, 24mm 1.4 fixed tripod.

The effects of light pollution can be reduced in processing and stacking multiple subs will remove most if not all of the noise.

Here's a recent test from my garden in Portsmouth. It can be done!

 

 

[daveangie0110]

9 hours ago, Jonk said:

I used 15 seconds at iso 1600, Canon 6D, 24mm 1.4 fixed tripod.

The effects of light pollution can be reduced in processing and stacking multiple subs will remove most if not all of the noise.

Here's a recent test from my garden in Portsmouth. It can be done!

 

 

Hi Jonk, there is no image on your reply.

I have also got a CLS filter for my Canon, is it worth using that as well as i have read that it can make the final image blueish.

[Jonk]

If you click on Milky Way from my garden it will open a thread with the image I'm referring to.

Basically, you need to have a fast lens (f2.8 or better, you have 50mm 1.4 so fast, but not very wide) to be confident of capturing enough light from the skies within a short period of time.

The shorter the better, to minimise star trailing (assuming fixed tripod). If you up the ISO, and shorten the time, you will increase noise, but stacking multiple images will average out the noise per pixel (median stack in Photoshop).

If you're using a tracking mount, then you will get a blurred foreground, assuming you have a foreground in your shot (trees, fences, house etc.).

You will certainly have a washed out orange sky when you first look at the image, but assuming you're shooting raw files, not jpgs, this is straight forwards to remove.

Are you using Lightroom, Photoshop, GIMP...? These all do much the same in processing terms. I find Lightroom the easiest for single files, before stacking in Photoshop.

To answer your specific question, the CLS filter will certainly reduce the orange, but it will also reduce the light captured, so you need to increase the exposure to counteract. Not a problem on a tracking mount.

This will make the captured frames blue yes, but a white balance setting against the blue sky, will make things look more natural, then colour and saturation tweaks will bring out some colour detail.

My advice would be to do the following:

Set the camera to widest aperture (1.4 on your 50mm) and ISO 800 or even 1600 on the 600D.

If you're using a tracking mount, take an image for say 30 seconds. Make sure your histogram of the raw image is not touching the right hand side (you'll blow out the highlights), but the peak is 2/3rds to the right.

If the histogram looks good, the try the other way around, lower the iso and increase the exposure to say 45 seconds. Decide which you prefer in a single sub.

Take 10 or so shots, one after the other.

Then ideally in Photoshop if you have it, load each image as a layer, then auto align the layers, masking the foreground (plenty online about this) with median blend mode, to drastically reduce the noise.

You should see aligned stars, blurred foreground.

Set a custom white balance, using a blank piece of blue sky which will make things look more natural.

Tweak the colour saturation, sharpness etc. this is practice, slightly overdoing it will make the stars etc look too unnatural.

If you want a nice foreground, you can take a couple of fixed shots of the foreground from exactly the same location (ie don't move the mount), then aling the foreground shots by masking the background blurred stars.

Then you can layer the stacked stars image, and the stacked foreground image to composite the 2.

It's a lot to take it, I'm still learning but I know what to do, it's just doing it and doing it a lot to practice.

I find video tutorials online, then on one screen have the tutorial, and copy move for move on the other screen. Repeat a few times, and it should become second nature.

Good luck.

 

[John Baker]

I would just add that stopping the lens down can improve the quality of the image quite significantly, I appreciate that you are normally trying to shoot wide open to get as much light in as possible, but where conditions allow, stopping down can also get the lens into its sweet spot and in particular reduce chromatic aberration.  Not sure which Siggy 50 you are using, but the attached MTF chart shows the difference between f1.4 and f2.8 - the MTF charts are from   http://www.imaging-resource.com/lenses/sigma/50mm-f1.4-dg-hsm-a/review/

 

 

 

 

[Jonk]

Yes, this is true if tracking.

With fixed, I find that stopping down to decrease the CA and increase sharpness requires higher ISO and / or longer exposure, neither of which are desirable without further post processing.

Accurate focusing is also key to good results.

It's all about the best combination for the equipment / conditions and everyone will find their own sweet spot.

Practice and practice some more!

[daveangie0110]

1 hour ago, Jonk said:

If you click on Milky Way from my garden it will open a thread with the image I'm referring to.

Basically, you need to have a fast lens (f2.8 or better, you have 50mm 1.4 so fast, but not very wide) to be confident of capturing enough light from the skies within a short period of time.

The shorter the better, to minimise star trailing (assuming fixed tripod). If you up the ISO, and shorten the time, you will increase noise, but stacking multiple images will average out the noise per pixel (median stack in Photoshop).

If you're using a tracking mount, then you will get a blurred foreground, assuming you have a foreground in your shot (trees, fences, house etc.).

You will certainly have a washed out orange sky when you first look at the image, but assuming you're shooting raw files, not jpgs, this is straight forwards to remove.

Are you using Lightroom, Photoshop, GIMP...? These all do much the same in processing terms. I find Lightroom the easiest for single files, before stacking in Photoshop.

To answer your specific question, the CLS filter will certainly reduce the orange, but it will also reduce the light captured, so you need to increase the exposure to counteract. Not a problem on a tracking mount.

This will make the captured frames blue yes, but a white balance setting against the blue sky, will make things look more natural, then colour and saturation tweaks will bring out some colour detail.

My advice would be to do the following:

Set the camera to widest aperture (1.4 on your 50mm) and ISO 800 or even 1600 on the 600D.

If you're using a tracking mount, take an image for say 30 seconds. Make sure your histogram of the raw image is not touching the right hand side (you'll blow out the highlights), but the peak is 2/3rds to the right.

If the histogram looks good, the try the other way around, lower the iso and increase the exposure to say 45 seconds. Decide which you prefer in a single sub.

Take 10 or so shots, one after the other.

Then ideally in Photoshop if you have it, load each image as a layer, then auto align the layers, masking the foreground (plenty online about this) with median blend mode, to drastically reduce the noise.

You should see aligned stars, blurred foreground.

Set a custom white balance, using a blank piece of blue sky which will make things look more natural.

Tweak the colour saturation, sharpness etc. this is practice, slightly overdoing it will make the stars etc look too unnatural.

If you want a nice foreground, you can take a couple of fixed shots of the foreground from exactly the same location (ie don't move the mount), then aling the foreground shots by masking the background blurred stars.

Then you can layer the stacked stars image, and the stacked foreground image to composite the 2.

It's a lot to take it, I'm still learning but I know what to do, it's just doing it and doing it a lot to practice.

I find video tutorials online, then on one screen have the tutorial, and copy move for move on the other screen. Repeat a few times, and it should become second nature.

Good luck.

 

Thanks Jonk,

This is very helpful, i also have a 10-20mm F1.4 lens, but where i have a small garden if i was to use the 10-20mm i will get both neighbors houses in the image.

I will be using my Star Adventurer so i can track the sky, also i will be using BYEOS, what would the maximum exposure time would you recommend ?  

I have Photoshop and Lightroom but i also have deep sky stacker.

[Jonk]

10-20mm F1.4?! This is probably an f4 lens? (1:4-5.6?) F4 when at 10mm.

If you have a 50mm 1.4, then this is probably better (lower FOV so less chance of houses in the shot, but less of the sky). Try both!

If you're on a tracking mount, then expose for as long as you can without the raw file's histogram touching the right hand side. This will get as much detail from the sky to extract from the light pollution later.

It's hard to know which exposure time to use.

Try 30 seconds, then 45, the 60 etc until you're happy you haven't clipped the highlights on the histogram.

Then try closing the aperture (F2, then 2.8 etc.) whilst increasing the exposure.

It's different for every setup / conditions.

The main thing is understanding what you're doing and why each time you change.

Then when you hit the sweet spot for your camera / lens / conditions, have a go at editing 1 image to look the best you can, then apply the same to the rest of the images.

After this, stack in the program of your choice with median (average) stacking. This will certainly help with the noise.

lonelyspeck.com is a great resource for this type of thing, which is where I've learnt from.

Jon

[daveangie0110]

Hi All

Here is my first attempt at imaging using just my DSLR with a 50mm lens on my Star Adventurer, this is the star Deneb in the constellation of Cygnus.

Thanks for the people who gave me advice especially Jonk, on camera settings which helped me get this image.