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09-19-2020, 12:27 PM - 3 Likes   #16
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OK so a couple of nuggets I've trial & error'd myself into understanding -

1) The wider you shoot, the less effective your astrotracer is going to be. Even with perfect calibration, extended exposure times are going to have pronounced star trails in the edges and corners still. The wider you're shooting, the worse it's going to be. It's one of those ugly things about taking the real-life vision dome that we see, and projecting it to a flat image plane.

On APS-C, I've found 14mm to be the widest where it's still kind of effective. By 16mm, the effectiveness is greatly increased.

Plus, the wider you shoot, the less you're emphasizing the more spectacular bits of the Milky Way. In fact, shooting extremely wide is sacrificing details in the juicy galactic core only to show off wider parts of the less interesting outer features... which also invites tons of uninteresting open space.

2) Light pollution filters *do* make a pronounced difference in how the sky looks. I keep an RA54 filter in front of my lens even shooting in the darkest skies. I wish I had some direct side-by-side A/B test shots to show.

3) Light painting! This is just a creative suggestion. Looking at some of the trial photos, if you're wondering why your foreground looks sort of flat, shapeless, and undefined, I'd say it's because you're shining the light directly behind the camera. While that's indeed illuminating your subject, it's also casting no shadows at all from your lens's frame of reference. That means it erases so much potential for you to add depth context and texture into your foreground elements.

Next time try walking away from your camera and shining the light directionally off-plane to where your camera is pointing. You can really craft the light to show off details in the foreground.

Example of all 3:



This is a 24mm field of view on the K-1 (probably could have shot this identically with the Samyang 16mm on my KP). 24mm equivalent is great for dialing in the interesting parts of the galactic core, while still leaving plenty of room to organize foreground elements. In North America, sometimes the Milky Way is presented perfectly vertically... for those weeks I'll shoot at 20mm instead. In the early and late parts of the season, where the Milky Way is flatter to the horizon, you can do great with a 35mm equivalent FOV too.

The RA54 filter cleaned up the blues in the sky without having to resort to an artificailly-low White Balance value, while simultaneously dialing back some of the orange at the horizon. It makes a ton of difference for color clarity in the sky.

Lastly, this is a 2-light setup to make shadow shapes with the ruins in the foreground, but the lights were also positioned to to reveal the textures in the lit brick faces. So many people shoot this spot, and use a headlamp behind the camera, and their foreground just looks like illuminated shapes of bricks, without any real context to what those bricks are.

09-19-2020, 01:03 PM   #17
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QuoteOriginally posted by reh321 Quote
So, which focal length prime would you get??

The 'problem' with prime lenses is that each - by definition - comes in only one focal length. Has your use of the Sigma lens allowed you to concentrate on just one length??
I was originally interested in the 10 but now I like the 14mm. But looking wider has me playing around with my Tamron 17-50 again. I haven't used it in a while. When I had my K20D I always used it. But I sold that body with that lense on a rainy day years ago. My new copy has been trouble. Then I noticed the front element was loose, so I took the trim ring off and was able to tighten the element and it seems to be better now. Might give it a go in the next clear night. The skies pretty blue today. It's been hazy last few days from the west coast wild fires
09-19-2020, 01:17 PM   #18
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@disasterfilm- Wow! Beautiful shot! And some great advice. I have often wondered about going too wide with astro shots. Just in using wide angle for terrestrial scenes it becomes obvious that the wider you go the smaller are more distant objects in the frame compared to the foreground objects. So it makes sense that exercising moderation here in this endeavor will also result in a more natural outcome.
09-19-2020, 01:34 PM - 1 Like   #19
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Last time I had good clear skies was in Hilton Head. K3 50mm F2 8s ISO3200. I think it was an Pentax FA F2 lens. I have the 1.4 now.



09-19-2020, 01:34 PM   #20
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A light pollution filter? I never knew that such things existed and now I want one. I am a little apprehensive about it will cost in 82mm size for said Sigma UWA zoom, though. Thanks for the tip!
09-19-2020, 01:42 PM   #21
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QuoteOriginally posted by titrisol Quote
You are right, LED have introduced another variable to the mix

I did some reading and there are a few "wide range" filters that also take care of LED pollution

Sich as the optolong L-pro or the SkyTech LPro

They supposedly block a wide range of frequencies, nlducing the bluis/green from LEDs







Articel here: 10 Light Pollution Filters for Astrophotography in the City
Thanks for the info. Always nice to have.

09-19-2020, 03:43 PM   #22
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QuoteOriginally posted by disasterfilm Quote
OK so a couple of nuggets I've trial & error'd myself into understanding -

1) The wider you shoot, the less effective your astrotracer is going to be. Even with perfect calibration, extended exposure times are going to have pronounced star trails in the edges and corners still. The wider you're shooting, the worse it's going to be. It's one of those ugly things about taking the real-life vision dome that we see, and projecting it to a flat image plane.

On APS-C, I've found 14mm to be the widest where it's still kind of effective. By 16mm, the effectiveness is greatly increased.

Plus, the wider you shoot, the less you're emphasizing the more spectacular bits of the Milky Way. In fact, shooting extremely wide is sacrificing details in the juicy galactic core only to show off wider parts of the less interesting outer features... which also invites tons of uninteresting open space.

2) Light pollution filters *do* make a pronounced difference in how the sky looks. I keep an RA54 filter in front of my lens even shooting in the darkest skies. I wish I had some direct side-by-side A/B test shots to show.

3) Light painting! This is just a creative suggestion. Looking at some of the trial photos, if you're wondering why your foreground looks sort of flat, shapeless, and undefined, I'd say it's because you're shining the light directly behind the camera. While that's indeed illuminating your subject, it's also casting no shadows at all from your lens's frame of reference. That means it erases so much potential for you to add depth context and texture into your foreground elements.

Next time try walking away from your camera and shining the light directionally off-plane to where your camera is pointing. You can really craft the light to show off details in the foreground.

Example of all 3:



This is a 24mm field of view on the K-1 (probably could have shot this identically with the Samyang 16mm on my KP). 24mm equivalent is great for dialing in the interesting parts of the galactic core, while still leaving plenty of room to organize foreground elements. In North America, sometimes the Milky Way is presented perfectly vertically... for those weeks I'll shoot at 20mm instead. In the early and late parts of the season, where the Milky Way is flatter to the horizon, you can do great with a 35mm equivalent FOV too.

The RA54 filter cleaned up the blues in the sky without having to resort to an artificailly-low White Balance value, while simultaneously dialing back some of the orange at the horizon. It makes a ton of difference for color clarity in the sky.

Lastly, this is a 2-light setup to make shadow shapes with the ruins in the foreground, but the lights were also positioned to to reveal the textures in the lit brick faces. So many people shoot this spot, and use a headlamp behind the camera, and their foreground just looks like illuminated shapes of bricks, without any real context to what those bricks are.
Great tips.
The astrotracer has a harder time because it's the projection of a 3D spehere to a two dimensional surface. The wider the lens, the less similar those surfaces are. Kind of like how a regular polygon with less sides, less of a circle makes.
What 24mm lens do you use?
Have you had experience with the Sam/Rok 1.8/20?



09-19-2020, 07:20 PM   #23
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QuoteOriginally posted by torashi Quote
Great tips.
What 24mm lens do you use?
Have you had experience with the Sam/Rok 1.8/20?
The Rokinon 24mm. It partners with my Sigma ART 35 for early-season shooting, and the Rokinon 20mm when the MW is more vertical.
They're all absolutely fantastic lenses. They partner with the K-1 and especially the astrotracer very, very well.

Also in my stable is the Roki 10mm f/2.8 and 16mm f/2 for crop cameras. I frequently shoot timelapses with crop cameras alongside the giant K-1 images, and star trails with a 3rd camera and the 10mm.

The Irix 15mm has replaced my Roki 14mm f/2.8, which will roll up for sale as soon as I get off my butt and take product photos. And they're all also supplemented by a Tamron SP 14mm f/2.8 too, which I've surprisingly never shot in an astro setting.

It's usually a hike in to where I'm going, so I make an effort to minimize weight (haha carrying 3 cameras, 3 tripods, 3-5 lenses, and 2 light stands), so I get lazy and don't bring 2 similar lenses to compare them. I just stick with what I know will work well.
09-20-2020, 12:51 PM   #24
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QuoteOriginally posted by disasterfilm Quote
The Rokinon 24mm. It partners with my Sigma ART 35 for early-season shooting, and the Rokinon 20mm when the MW is more vertical.
They're all absolutely fantastic lenses. They partner with the K-1 and especially the astrotracer very, very well.

Also in my stable is the Roki 10mm f/2.8 and 16mm f/2 for crop cameras. I frequently shoot timelapses with crop cameras alongside the giant K-1 images, and star trails with a 3rd camera and the 10mm.

The Irix 15mm has replaced my Roki 14mm f/2.8, which will roll up for sale as soon as I get off my butt and take product photos. And they're all also supplemented by a Tamron SP 14mm f/2.8 too, which I've surprisingly never shot in an astro setting.

It's usually a hike in to where I'm going, so I make an effort to minimize weight (haha carrying 3 cameras, 3 tripods, 3-5 lenses, and 2 light stands), so I get lazy and don't bring 2 similar lenses to compare them. I just stick with what I know will work well.
Yeah, I get it. Too much to carry. What are the best apertures on all of those lenses? Can they do the job wide open?

09-21-2020, 01:36 PM - 1 Like   #25
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QuoteOriginally posted by Wasp Quote
I am a little apprehensive about it will cost in 82mm size for said Sigma UWA zoom, though. Thanks for the tip!
At $120 for the Hoya red Intensifier it isn't too bad and for a quality filter is probably on the cheap side. The NiSi Natural Night filter in theory would be better but I don't think one of those is available in 82mm size but if they are that would be spendy. I compared them at one point and I think the 49mm NiSi was substantially more than the Hoya 77mm one.I believe you can get the NiSi ones for 100mm and 150mm square filter holders so that may be a cheaper option.
09-23-2020, 05:59 AM   #26
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I learnt about these filters after trying to take pictures of the Comet a few weeks back.
I also found this "sensor-side" filters which in theory can be used for any lens


I have not tried them, but seem like a legit alternative to having several sizes
11-14-2020, 06:04 PM   #27
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Sorry, was out a bit. Me and the gps thingy aren't getting along. I played around other day up at camp. No moon but only about 9pm. So not the darkest of skies. Just my Tamron 17-50 f2.8, iso 3200, 30s



11-15-2020, 06:12 AM - 1 Like   #28
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Did you use live view with max magnification to determine infinity focus?

There's always the Pentax DA* 11-18/2.8 for astro photography. The focus lock is priceless and the corners ain't too shabby

11mm F:2.8



11-15-2020, 06:38 AM   #29
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QuoteOriginally posted by Pål Jensen Quote
Did you use live view with max magnification to determine infinity focus?

There's always the Pentax DA* 11-18/2.8 for astro photography. The focus lock is priceless and the corners ain't too shabby

11mm F:2.8


I tried but just too dark to see. It was also poorly planned, I used the roof of my suv as a tripod so seeing through view finder was tough. Lots of click n' pray. It does drive me a bit bonkers though that "infinity focus" doesn't focus on stars. On my 17-50, the stars were more in focus at the begining of the infinity focus area, about 5mm from full turn
11-15-2020, 07:36 AM   #30
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QuoteOriginally posted by no694terry Quote
I tried but just too dark to see. It was also poorly planned, I used the roof of my suv as a tripod so seeing through view finder was tough. Lots of click n' pray. It does drive me a bit bonkers though that "infinity focus" doesn't focus on stars. On my 17-50, the stars were more in focus at the begining of the infinity focus area, about 5mm from full turn
Try the brightest star if there aren't any artificial light sources far away, like city lights. Engage live view and max magnification. Turn the focus ring until the star is as small as it gets on the screen. It should work......
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