To stack or not to stack?

[Kim_Captures]

I've just recently gotten serious about astro photography and feel like I've nailed down my settings. I've taken some single-exposure shots I'm very happy with that needed only minimal work in LR (white balance and dehazing). I'm curious though, what are the advantages (or disadvantages) of stacking exposures? I understand if you're trying to get a distant galaxy or something really faint in the sky, but I seem to see a lot of stacked shots online that aren't that.

I'm not knocking this technique at all -- I genuinely want to learn if this is something I should be doing!

 

[Mark Winter]

Hi Kim,
I only have experience shooting the Milky Way, and co-taught a workshop this past weekend. I am a pretty big fan of exposure stacking. I have an A7R4, which has a lot of pixels which normally isn't the best for high ISO shooting. With that said, I have been quite impressed with the noise. Normally I shoot at ISO 6400, so there definitely is noise in the image. So, I normally shoot multiple images, possibly up to 20 with all the same settings. I then shoot maybe 10 dark frames with the lens cap on. Doing this reduces the noise, enhances the stars, and gets rid of hot pixels. I am a PC user, so I use a free program called Sequator, which stacks the photos for me and redcues the noise levels. The is MAC software available as well. I would recommend trying this approach as you will see an improvement in the quality of your images. I hope that this helps.

 

[Kim_Captures]

That's great info, thanks @Mark Winter
I'll definitely give this a shot next time I am out doing astro shots. I've only been going up to about 1600 iso with my A7Rii and didn't get a lot of noise, but I'm curious to compare. I loved the longer exposure times, but found that anything more than 25 seconds would give me star movement.

 

[Martin Harrison]

I'm going to a Dark Sky site in a couple of weeks and, if the weather is decent, I'm hoping to do some astro photography. I've done some of the Milky Way before, but as you say, limited it to around 20 seconds to avoid the star trails. I've been reading up on Star Trackers that fit between your tripod and camera and allow for exposures up to 5 minutes! There is a range by a company called iOptron called SkyGuider that get good reviews. It will be interesting to see how they compare to stacking multiple exposures. If I get one I'll let you know how I get on.

 

[Kim_Captures]

That sounds like a fun tool! Can't wait to hear the report. Best of luck on the weather!

 

[Mark Winter]

I know of a few folks that have one of these and they love it. I would like to see the results. I stack images when shooting to reduce noise and would like to compare.

 

[Sdhiker]

I love using stacking on my astro photography images. I've tried stacking, tracking, light painting, and single shot. They all have a place in your repertoire depending on the situation. If you are in a situation where there is a lot of trees or foliage in your image around the horizon it may be better to do lighting painting and single image, but it can be done with stacking as well, just a lot more work. I like to enter my images in the San Diego Fair competition every year and I sell some as large prints so I also want to make sure its going to look good without a ton of noise, but its not always necessary, I printed a 3 by 4 foot Astro image on metal using only one exposure and light painting and I really liked how the final image came out. The more I learn the more I look back and previous images I may have taken and wish I would have been able to use the knowledge I have now back then . Definitely take that 24mm f/1.4 your sporting out in the field and do some astro with it, I absolutely love using that lens for Astrophotography. As someone else said here if you are using a PC use Sequator and if you are using a Mac use Starry Landscape stacker, they are both pretty easy to use once you play around with them for a while.

 

[JC Photography]

Stacking your images greatly reduces the noise. It will make your good image even better especially if you are planning on printing. I stack sometimes but mostly use a star tracker because you can get so much more detail in the milky way. Here is an image I shot using my a6100, sigma 30mm, and iOptron Skytracker Pro.

 

[Killzen]

look up 'Sequator' as in software...you can use it with 'blank' shots to computer noise reduction (Youtube videos)