Comments on this image please

[Star Gazer]

I took this image a couple of nights ago, and would welcome your comments. This is how I took the picture

7D with 10-22mm lens

Camera controlled by BackyardEOS

60 sec exposure

1600 iso

f4.5

I was trying to get a nice picture of the Milky Way but it doesn't really stand out, do you think light pollution is a big problem here? Do I need a filter? What about my exposure settings are they ok?

Anything else I could do to improve this?

I will crop the building out later.

Here's the image:

[swag72]

Looking at the HUGE (!!) image my first comment is that you've not got the focus right. The stars are bloated and not nice little points of light as they should be. The focus is possibly the main reason for you being able to see very little else in the image.

[malc-c]

When you open the image in a viewer the bloated star effect goes away and the image is very pleasing. There is a noticeable red tinge to the image so light pollution is a factor and a clip filter might reduce that.

You would probably get better results taking a dozen or so pictures all at the same settings and then stacking them, and then use an image processing application to remove the light pollution

[Psychobilly]

When shooting with wideangle lenses you might need to stop them down a bit more to help reduce the coma around the edges and especially in the corners but this will mean longer exposure times.. another thing to try is "optimising" the focus across the whole frmae ratehr than just centraly - ok you will have slighly less pinpoint stars at the center but they may well be a lot better at the edges of the frame...

Peter...

[Star Gazer]

Looking at the HUGE (!!) image my first comment is that you've not got the focus right. The stars are bloated and not nice little points of light as they should be. The focus is possibly the main reason for you being able to see very little else in the image.

Thanks Swag72. Yes I posted the same image into another thread asking about how do you focus at a focal length of 10 mm. I was using BackyardEOS to help me focus but it is impossible as the live view is effectively blank. Do you have any focusing tips for me with this short focal length lens?

[Star Gazer]

When you open the image in a viewer the bloated star effect goes away and the image is very pleasing. There is a noticeable red tinge to the image so light pollution is a factor and a clip filter might reduce that.

You would probably get better results taking a dozen or so pictures all at the same settings and then stacking them, and then use an image processing application to remove the light pollution

Thanks Malc-c. I did take 5 lights and 5 darks, but processing them in DSS the end result is quite unimpressive. I think I need some help with stacking or at least with DSS. If I let DSS do it's thing it only finds around 900 stars and the result is more or less a velvety black image with 900 stars on it. There's no milky, nebulosity I would expect from the Milky Way.

I tried DSS because it's free, but can you recommend stacking software?

[Star Gazer]

Thanks Psychobilly, as you might have seen from my other thread I am having problems focusing at all let alone optimising part of the view. Do you have any tips for me?

At the moment I just do this by trial and error which takes a lot of time and is very hit 'n miss. BackyardEOS is great with telephoto lens but no good with wide angle ones at least using the live view x5 window. That's not a criticism of BackyardEOS, as I recognise this would be a problem with any software.

[Psychobilly]

I use the Liveview remote autofocus option in EOS Utils this allows you to make adjustments to the focus whilst monitoring the image at x10 zoomed I keep moving the zoomed area between the corner and the center of the image...

IIRC Ivo has implemeted Remote Manual AF in APT as well as Fully auto AF based on FWHM measurements...I must admit I havent used APT in anger for nearly a year now though...

Peter...

[daz]

The only thing you can do is take an image, zoom in to a star, check and refocus, and then take another image...

Yes, it takes time, but I don't think there is another way...

I don't know if there are bahtinov masks available for that focal length, but that would be a way to speed things up...

Also, in future, could you post the image as an attachement - some members will not be able to see the image because it's on an image hosting site

[Psychobilly]

Crops also help so you don't have to scroll to find the Post Quick Reply box...

No one seems to bother with the max size advice these days

[swag72]

Have a look at this thread #17, Baz explains how he gets his focus on a short focal length. I've not tried it yet, but would be worth a go.

[Star Gazer]

Hi Psychobilly,

I think you just told me off . Quite right too.

Sorry this was my first picture post so I wasn't sure what would happen. I have resized the image to 50%, which helps a bit.

I'll try and be a better citizen in future.

BTW: thanks for all your interesting posts.

[Star Gazer]

These are my five lights an darks stacked in DSS and the squashed or is that stretched the histogram in PS

Look a bit yucky to me. May be I stretched the histogram too much. I guess it goes to prove you can't make a silk purse out of a sows ear.

Still it's all good experience....

[jgs001]

It does look like you need some form of LP filter... depends on the lens, is it an EF or EFS fit ? If it's EF then you can use a clip filter, if not... you're stuck.

The stack and edit has improved it, but I'd guess you lost some detail thanks to the LP and noise processing.

As you say though, it's all experience and that has to be good.

As for the coma in the corners, if you're using PS run it through the Lens Correction tool, that will help a lot.

[shaunster]

Pixinsight can remove your light pollution.

[Cloudwatcher]

Pixinsight can remove your light pollution.

Or you could really over do it in Photoshop......

[Star Gazer]

Pixinsight can remove your light pollution.

I'm using DSS because it's free, but I probably don't know how to get the best out of it. To me (I could be wrong here) it looks limited to quite a narrow workflow. Obviously its free so absolutely no complaints!!

I'm a Mac user so would like to use an OS X app rather than Windows, although I can run Windows apps running in VMware Fusion.

I am prepared to invest in a good stacking app, but which one? I've taken a brief look at Nebulosity and Registax, both of which look quite sophisticated and as a consequence have a steep learning curve. How does Pixinsight stack up here (pun intended) Would you recommend Pixinsight.

.. I think I need to do some reading and check out some tutorials...