According to my camera's focus assist, this is perfectly focused
According to my camera's focus assist, this is perfectly focused
Went out on a rare clear night to a wetlands near me to take some photos of the stars. As it was so dark, and the stars are so small, I had to rely on the focus peaking function of my camera to tell if the stars were in focus or not.
I've got home and started to process the photos, and I've found out that despite the camera telling me that they were in focus, they clearly weren't.
Hey ho, what's a wasted few hours in the freezing cold between friends...
TBH, that's significantly better than I would have expected for photos of the stars taken on a phone.
FYI stars (and anything over a few hundred feet actually) is at an infinite distance as far as your phone's optics are concerned. So it's not a matter of focusing, it's a matter of trying to resolve what are effectively pinpoints of light on a black background while in your hand, where the minutest movement will smear them across the sensor.
Photographing the stars is not trivial, even with a real camera and a tripod.
But op used the word camera 3 times and the word phone 0 times...
You're 100% right. Im going to look into a remedial reading course at the local elementary school.
Thanks, but this was with a real camera on a tripod 🙈🤣
I've done astrophotography with this camera a few times, and used to use my DSLR. I find this camera a bit more difficult to use because it's mirrorless, and the light from the screen gives me problems seeing the stars. I have astigmatism, so it takes me a while to go from bright to dark. Because of that, I use the focus guide to make sure that the stars are in focus. For some reason, this time it's showed them as being in focus, but they're clearly not.
I don't know what changed this time, but it's bloody annoying! >.<
Astronomers like using eye patches to minimize the risk of having both eyes getting bleached. I set my dslr to the lowest brightness and swapped it to a red-only color pallete for menus, but the image result can certainly still be blinding while I do some f/2.8 5s ISO 25600 framing shots. If you can't dim it enough and don't have a red menu option, maybe some tint film or even sunglasses could help. Maybe red plastic wrap for style points. Red doesn't bleach your eyes.
As for focus, even on my crop sensor dslr with a 11-16mm lens, I can use live preview and 10x screen zoom to find some bright stars to hone focus. For this picture, it doesn't get better than Sirius just to the left and down of this frame. Planets are good for the first attempt at focus if there's no lens markings or manual focus is still electronic, but any appreciable zoom makes them lose usefulness as they become disks instead of points.
Phones have come a long way but focus on those is still the most frustrating thing. The native app doesn't allow manual focus on my pixels but the pro mode apps don't have the 4 minute astro modes.
And yes, bleaching is the issue. Your pupils take a few seconds to dilate, but light will bleach the rhodopsin in your receptors. It takes more time to refill rhodopsin stores and dope your receptors again which is where the "dark adaptation takes 20 minutes" comes from.
I just came back from the grand canyon/arizona and that is a place you don't want to lose night vision. So much to see, even in winter with the thin side of the Milky way. Happy trails. Pack your red flashlight
These stars are millions of miles away, to your camera that essentially means infinity distant. Next time, switch to manual, and put focus on as far out as can go, then set exposure to a second or two. Trick there is really to get exposure long enough to get good light from the stars, without being so long that you get streaks from the spinning of the earth. Camera did okay though, you even got a bit of true color of the stars.
On a good number of newer automatic lenses going all the way out will take you past infinite. Best to zoom in on a bright target star, I usually use live view and zoom in on the display as well. Focus on that star and don't touch the focus the rest of the night.
Don't physically zoom the lens, that changes the focus
Shit, maybe I need a new camera
Next time, switch to manual, and put focus on as far out as can go
Unfortunately, that doesn't work with this lens. It's a Sony a6000 16 - 50mm kit lens, and in manual focus mode, roughly a quarter of the focus range is marked as infinity, and going all the way out goes 'past' the stars. They start off blurred, come in to focus, then get blurry again. I don't know what deep space objects Sony expect people to photograph with the kit lens, but apparently they're really far away 😝
Your camera’s focus most likely looks for hard contrast vertical lines in your picture then racks the focus through its range and looks for the sharpest transition between those contrast lines. In this picture you can see that all the vertical lines have very high and sharp contrast.
Looks great vs. what I’d expect. Hopefully you can fine-tune next time. Wonder if you can find a place to test your camera nearby at night so you’re ready for a special occasion.
Hope you enjoyed the stars, if so nothing much wasted!
I've used this camera for astrophotography quite a few times, and that's what makes this so annoying. I live at the edge of a dark skies site, so have been able to take photos from my back garden quite regularly. This was my first chance to get to the wetlands though, and get some different photos.
As you say though, the views were amazing, so that's definitely a bright side :)
Always good to verify in playback after a test shot for astrophotography!
You can flip it into MF and focus to infinity, do a test photo and it should be pretty dang close to perfect focus and you can tweak after.
Definitely!
I struggle to see the stars on the small screen on the camera though, especially in the cold and dark, which is why I used the focus guide. I don't think I'll be trusting it as much in the future though 🙈
This might make you laugh - in manual focus mode on this lens, almost a quarter of the focus range is marked as infinity! I haven't figured out what Sony thinks I need to focus on past the stars yet 🤣
Ah yeah my Panasonic mirrorless is kind of like that, it has a 'range' of infinity focus which is annoying!
Advantage of playback mode is you can zoom way in on a star and that makes it easier to see.
Assuming you have a modern digital camera, check if it has a Bluetooth phone app that lets you download images to local memory. I was able to zoom in and verify focus after my first shots, this was a major help when I tried stars.
It does have an app, but it only lets me take jpegs rather than raw. As I need to edit the photos afterwards, jpeg is no good for me.
I should have checked the focus after the first photo, but because the focus guide said that everything was ok, I didn't think to. I won't be making that mistake again :(
For images of objects that distant, you need to manually focus into infinity to get good results. Check of your camera app has a "pro" Mode where it lets you adjust that manually. Also, manually increasing the exposition rate helps to get starriers skies, but you need good pulse.
For images of objects that distant, you need to manually focus into infinity to get good results.
That's what I thought I had done. This camera, the Sony a6000, has a focus peaking mode, where it puts a coloured overlay on top of the object that's in focus. In a situation like mine, where it's difficult to tell with the eye, it tells you what the camera sees as in focus.
Last night it put the overlay on the stars, telling me that they were in focus. I've used it for astrophotography in the past, so I thought that it was correct. I don't know why it didn't work last night.
My camera is the a6400, and it has an option to manually set the focus, I believe that it's the PRO mode, where you can customise the exposure time with a number and the focus with the lens thingy.
You maybe did not set things correctly, but if that's the camera you have try tweaking the options so that you can set things like focus and exposure time manually. I mean, it's the sky, you don't need fast or dynamic focus or anything like that, all you need is a tripod and to point the camera up.
For sky photos I would set the focus as far as it lets you. Sadly, you will never be able to correctly focus stars because their focal point is just way too far, so manually setting is a far as the camera lets you should suffice.
Here's a guide to take sky photos with your camera model, but should work with any decent one: https://realisticwanderlust.com/2018/10/16/photographing-the-milky-way/
Could you have zoomed into the live view? I found that it helps a lot. But the camera would be to support it
Hey, it's Orien!
It is! 😁