Kase Filters AstroBlast Review

June 08, 2021  •  1 Comment

If you've been doing Milky Way photography for a while now, you might be getting a bit bored with the same old results.  I know I was getting tired of the same small, sharp stars in all of my Milky Way photos.  There are some great astrophotographers out there that create really dreamy looking nightscape images.  There are two different ways to create these types of photos - Photoshop or filters.  Photoshop is pretty fast and easy.  There are also a few plugins you can buy that handle all the hard work for you.  But some people like to get the results in-camera, with minimal edits.  This is where the Kase AstroBlast filter comes in.

Since I couldn't use the AstroBlast filter with my 14-24mm lens, I had to create this large vertical panorama with a 24-70mm lens.  It turned out great, but was a lot of work!  I prefer to keep things easy, usually with just two exposures (one tracked sky, one foreground)


Like most other filters, the AstroBlast is a 100mm square filter.  This brings up the first problem I have, I cannot use it with my Nikon 14-24mm lens.  That's the main one I use for nightscapes, so I was a bit disappointed.  Therefore, in order to test the filter I used my Tamron 24-70mm lens, which is a bit tight for nightscape compositions.

One recommendation I would have for Kase is to create circular versions of the AstroBlast filter.  I know many photographers don't have 100mm filter holders, and would prefer to stay as portable as possible.  If the AstroBlast filter was included along with Kase's brilliant magnetic filter system, I think a lot of people would prefer that.  Then again, the 100mm square filters can be easily used with all lenses that have a filter thread.   

Before we go any further, I should mention that I do my nightscapes a bit differently.  First, I find an interesting foreground to photograph.  After I get my composition lined up, I take a 4 or 5 minute long photo with Long Exposure Noise Reduction On.  This gives me a very clean, detailed foreground with minimal noise.  After my image is complete, I double check the position of the stars in the background.  Then I find a nearby flat, open area to setup my SkyGuider Pro.  This is a star tracker which allows me to shoot 5+ minute exposures with sharp stars!  After I take my tracked sky exposure, I've got everything I need!  I can easily blend the two exposures in Photoshop for a very high-quality final image.

There are some alternative methods if you hate the idea of taking 2 exposures.  You could take 20 images, one after the other, then use some software like Sequator or Starry Landscape Stacker to stack all 20 images.  This should give you a clean image as well, although it may not be perfect, especially if you have a lot of trees or bushes along the horizon.  Finally, you could keep things very simple and take a single 15 - 30 second exposure and be done.

The reason I bring up these different shooting methods is because they will change how the Astroblast filter works for you.  In my case, I only use the AstroBlast filter when I'm taking my 4 minute exposures with the star tracker.  Over the course of 4 minutes, the AstroBlast filter has a very strong effect on the stars. 

The AstroBlast filter is too intense when shooting 4 minute exposures on a star tracker


As you can see in the image above, I think the effect is way too strong when using a star tracker.  To make matters worse, any chromatic aberration from your lens will show up magnified.  In my case, the stars have a blue halo that becomes much more obvious with the filter.  There are a couple different ways to fix this problem.

First, you could take two photos - one with the filter, and one without.  This will give you a star glow image and a normal image.  Then, you can take both photos into Photoshop and create a layer mask for the AstroBlast image.  Invert the layer mask so it's completely black.  Finally, use a white paintbrush on your black layer mask to paint in only the stars you want to glow.  You can easily target the brightest or most important stars, while leaving the rest of the stars small and normal looking.  This technique might sound a bit confusing, but it's very easy.  You might want to check out my Astro Post Processing Course to learn more about photo editing.

For those that don't want to mess around in Photoshop, there's an alternate method you can try.  Rather than leave the filter on for all 4 minutes, you could leave it on for the first 60 seconds, then carefully remove the filter.  That would give you 3 minutes with no filter.  The comparison below shows the difference.


No Filter

If I keep the filter attached for 1/4 of the exposure the result is much more natural!

I think the new technique worked much better, and gives a more pleasing result.  Only the very brightest stars have a soft glow now.  Of course, this method isn't perfect.  I had to very gently slide the AstroBlast filter out from my Lee Filters 100mm Holder, without blocking any incoming light with my hand.  I managed to do an okay job, but I wouldn't necessarily want to do this for every photo.  I can imagine most people would not be able to pull this off very well either...  If Kase made a magnetic circular version of the AstroBlast filter, that might be more easy to remove without shaking the camera/lens.  But you'd still need to practice that technique quite a bit to not mess up the photo.

Looking back at the photo, I could have probably left the filter on for another minute.  I think that would have given a more noticeable glow, without over-doing it.  If you have the AstroBlast filter, or plan to buy it, give that a try!  (Leave the filter on for only half the exposure)


No Filter

Here we see the same problem again.  Taking 4 minute exposures with the filter on the entire time is just too much.  Leaving the filter on for only 1/2 the exposure should provide a much more pleasing result


Final Thoughts

The Kase AstroBlast filter is a unique way to change the mood of your astrophotography images.  Depending on your shooting style and lens selection, this filter may be a great new tool!  However, I can't necessarily recommend it for the average astrophotographer.  The first major problem I have is the price - $200.  There's a great Photoshop plugin that will allow you to have full control over star glow and star spikes, for just under $40.  The other issue is that you'll need to have a 100mm filter holder.  If you don't have one already, that will essentially double the price of the AstroBlast filter (a filter holder + adapter ring will cost between $100 - $200 in most cases).  As I mentioned earlier, I mainly use a Nikon 14-24mm lens for astrophotography, and it needs 150mm filters.  Therefore, I can't even use the AstroBlast with my favorite lens!  If you're the type that hates using Photoshop, and you've already got a 100mm filter holder, and your main astro lens can utilize 100mm filters, then the AstroBlast might be a good investment!  For the rest of us though, I think you'd be better off buying something like StarSpikesPro 4 and creating a star glow in Photoshop.


Great and useful review/tips as usual! Thanks Peter. You mentioned you created the final pano shot with your 24-70mm. Did you also have to stitch separate sky images using the same lens? If so, that is a lot of work - but so worth it in the end. :)
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