06-12-2018 04:59 PM
My shot above was from my front yard in Albuquerque, with a street light right across the street.
I believe you said you got total black, not washed out grey.
06-12-2018 05:00 PM
It would be helpful it you could post a link to your RAW file.
1. Manual settings... that's fine.
2. Focal length 24mm... fine.
3. 500 Rule ... maybe. That's for full-frame cameras. If you use an APS-C camera then divide 500 by the crop factor (1.6) or multiply the lens focal length by 1.6 before doing the math. For an APS-C camera it works out to 13 seconds.
4. ISO 2000 ... the best ISO depends on the camera model. You can always stretch in post-processing (which is basically what ISO gain does in the camera except it applies the stretch before writing the file.)
5. Aperture 2.8 ... fine (btw, was this "wide open" for that lens?
6. Focused on star... how did you do this? Can you provide some details on your method.
7. Steady tripod ... required... yep.
The image should not have been "black" and it made me wonder... did you have a lens cap on? Did you have a focus mask on the camera?
I usually tell people to crank up the ISO all the way just to get a shot (albeit with loads of noise) that you can use to confirm your compositional framing and focus are good... then dial the ISO back to a more sane value.
You should certainly have seen stars at ISO 2000 & f/2.8 (with any lens).
For example, here's a test shot using my 14mm f/2.8 at ISO 800 & f/4 and you can see lots of stars. (this is straight-out-of-the-camera other than the RAW to JPEG conversion and size reduction to be web-friendly).
That was 2.25 stops down in ISO and 1 stop down in f-stops but about 1/2 stop longer on exposure time. So this should be darker than what you got ... but you can see it's not "black". Your image *should* be brighter than mine. (this was a night trying capture Perseid meteors ... and shot from somewhat light-polluted skies). But the main point is that you can see the stars at this exposure.
And here's another (this is shot through an f/5.4 telescope) completely un-processed out of the camera shot. This is the Trifid Nebula. It's ISO 800, f/5.4 and it's a 4 minute shot. That's 2.25 stops slower on ISO, about 2 stops slower on f-stop (so that's 4.25 stops) but it's much longer. Still... if we multiple your 21 sec exposure time by 4.25 stops... it would be "as if" you could use my exposure settings but shoot for 420 seconds (and I only shot for 240 secs).
BTW, that was shot with my 60Da... which is a special edition of the 60D designed for astrophotography and is particularly sensitive to reds (hence the very nice sensitiivty to the red part of the nebula and the strong color cast on the stars). A processed version of this image would have a white balance correction... but this is straight out of the camera.
You should be seeing stars in your image. Clearly something is wrong.
Did you switch off the auto-focus on the lens? If the lens shifts focus... blurred stars will appear to more or less just vanish. This is, in part, why it would be good to post a link to the RAW file so we can inspect all the camera settings active at the time of the shot.
06-12-2018 05:06 PM
"Why? The APS-C sensor size affects neither the shuttrer speed of the camera nor the aperture of the lens."
It doesn't effect the exposure just the star trails the lens will produce.
06-12-2018 05:07 PM
"You should certainly have seen stars at ISO 2000 & f/2.8 (with any lens)."
My point. OP needs to check elsewhere for the problem.
06-12-2018 05:08 PM
Thank you for the great samples, questions and answers.
I am using the canon 5Ds with the 24-70 f/2.8 MK2. The lens was set at 24mm at f/2.8 (wide open). This is how I was focusing. I used live view mode to point to the star that I could see on the LCD. Zoom in 100% so that I can sharpen the focus. then use the 2 seconds timer to kick of the shooting, this was to avoid any camera shake. The only thing that was visible after the photo been taken is that star, and nothing else.
The photo was taken at approximately 10+PM.
06-12-2018 05:09 PM - edited 06-12-2018 05:14 PM
My first night in Zion National Park was a disaster. I tried to take photos of the night sky but to no success. Despited the fact that I thought I did everything right to get a decent photo of the stars, the photo came out BLACK!
Below are the settings:
1. Manual settings.
2. Focal length was 24mm
3. Applied the 500 rule, i.e. 500/24 = roughly my shutter speed (21 seconds).
4. ISO 2000
5. Aperture 2.8
6. Manual focused on the distant star.
7. Steady tripod.
There was no wind, or cloud of any kind. Granted there was no milkway to been seen, that said, I was expecting to have at least captured all the stars when looking with my naked eyes.
Please let me know what I am doing wrong? I am heading over to Bryce Canyon tomorrow morningm hopefully, I'll figured out what I am doing wrong by then.
Never trust your lying eyes in such a situation. Not only is the dynamic range of the human eye much greater than that of any camera, the eye's sensor has extra pixels that kick in specifically for night vision. This forum has one or two members who are experts in astrophotography. See if they offer advice, and take it if they do. EDIT: Tim Campbell is one of them. I see that he responded while I was typing.
Unless they've completely remodeled Bryce Canyon since the last time i was there (1970?), it's not a particularly suitable venue for nighttime photography.
06-12-2018 08:26 PM
You live-view focus method is pretty popular... I manually dial the lens to “infinity” and point the camera at any bright star. That wont be accurate focus, but it’ll be close enough that you should see something when you go to live-view. Then I crank the ISO to max (Canon has “exposure simulation” in live-view so if you crank the ISO to max and crank the shutter to 30 secs it’ll give you a brighter (more amplified) view of the sky and that helps with the focus. Go to the 10x (max magnification) in live view and *carefully* adjust until I can get the star to the smallest pin-point possible (don’t use a planet to focus ... they don’t actually become pinpoint like stars so it’s harder to tell when you’ve nailed focus.)
”Lonely Speck” makes a focusing mask called the “SharpStar”. It attaches just like a slide-in filter (such as. Lee Filter, or Formatt Hitech, or Coken, etc.) but it’s got groves cut into it to make the stars throw diffraction spikes (you’ll see three distinct spikes lines). When all three converge at the same center point, you’ve nailed focus (it’s very accurate for stars.)
One you’ve nailed focus
1. Don’t forget to set the lens to manual focus mode
2. Return the ISO to something sane.
3. Return the shutter speed to something sane (if using an intervalometer then switch to Bulb mode.)
Is there any possibility you left the AF/MF switch on the lens in AF mode ... and the camera attempted to re-focus after you manually focused?
I have taken “black” astrophotos before ... only to realize I lost focus. Since stars are pretty dim, instead of getting bright bokeh balls... they just wash out and you can end up seeing nothing.
Otherwise I’d re-check the exposure data to make sure the settings actually were what you intended.
Also... be aware of the “long exposure noise reduction” option in your camera. That option (if enabled) causes the camera to take a dark frame and it uses the noise build-up from the dark frame to subtract from the light frame. Photographers who are caught off-guard sometime think their camera locked up or is failing to write to the card. E.g. if you took a 20 second exposure, it would do 20 secs with the shutter open, then 20 seconds with the shutter closed, subtract the “dark” frame from the “light” frame and then write the file (so it takes 40 seconds to get a 20s exposure).
06-12-2018 08:48 PM
I am using the Canon 5Ds.
I am begining to wonder if I have to do a whole lot of post processing to get anything decent?
Will try again tonight. Last night in Zion before heading over to Bryce.
Stay tune for uodate, thanks
Post processing helps, but if you are in a dark sky situation you should be able to capture a lot.
Taken 15 miles from Times Square, and the camera was pointed towards Times Square. Any other direction would have put street lights in the frame. I was ready to toss this photo, and decided to play with it. I didn’t reallly see how much it captured until I turned out the room lights.
06-13-2018 02:17 AM
Just realized I took these at 70mm instead of 24. That said, below are the series of photos taken at different ISO. Clearly ISO 100 has the least stars captured but the photo is relatively clean. I would say even at 1600 it is still reasonable, minus the fact that I can't really focus at night without my reading glasses LOL!
06-13-2018 08:29 AM
"Just realized I took these at 70mm instead of 24."
24 vs 70, doesn't matter. It is the exposure that matters. The 70mil will have more streaks, star trails, then the 24mm would have.