12 replies to this topic

[wlibby]

hello folks, I am looking for advice on how to do exposure setting for timelapse nightscape photography from twilight to dark, and if manual setting a must or auto exposure is possible. 

 

my setup is DSLR & mirrorless camera with wide field and 180 degree fisheye lenses, I want to do timelapse photography to record the scene from twilight till dark when the stars appear, I want the timelapse movie have a smooth transition of brightness, showing the landscape from daytime till dark and stars appear. I know after the sky is completely dark it's better manually set the exposure, while during twilight auto exposure works well, however when is the transition needed from auto to manual, or if there is better handling method? 

 

or I should monitor the histogram of each photo, when it's too close to the left, I should switch to manual setting, and keep increasing the exposure till the sky is fully dark?

 

I have programmable shutter cable, and I have DSLR / mirrorless camera control software through computer, or I can use ASIAIR mini to control it. 

 

thanks in advance for all advices. 

[EGregerson]

I'll bet there are books on it. 

[michael8554]

Is it just sky, or is there landscape in the images ?

 

Try auto exposure if it gives you a decent exposure of the stars when dark.

[wlibby]

yes I am searching for that also, and not sure if there is simple and straight forward method here... 

 

I'll bet there are books on it. 

[wlibby]

thank you, I want to have timelapse starting at sky at twilight with landscape, and ends with starfield with landscape when dark, or vice versa

 

Is it just sky, or is there landscape in the images ?

 

Try auto exposure if it gives you a decent exposure of the stars when dark.

[timaras]

I use https://dslrdashboard.info, it's very flexible. On how to do it, I recommend this book and the corresponding software for processing https://lrtimelapse.com/ebook/.

[wlibby]

oh, that's great, let me look into this, thank you very much!

 

I use https://dslrdashboard.info, it's very flexible. On how to do it, I recommend this book and the corresponding software for processing https://lrtimelapse.com/ebook/.

[cuba]

1. qDslrDashboard should work

2. Another option is to use Aperture priority. Usually you can achieve good results with it. Sometimes when you need really really smooth transition you would need to adjust parameters 3-4 times during rapid light change(not necessary). 

3. LrTimelapse has good tutorials

4. I personally use Timelapse+ VIEW device with my custom fork of firmware and able to achieve day-night-day timelapses. Unfortunately you won't buy this unit anymore, only second hand. However I find it the most advanced approach

[timelapser]

Definitely use a fixed aperture setting (aperture priority if using autoexposure).  Changing the aperture during a timelapse will mean a change in vignetting (and possibly sharpness) which could be obvious in the final video.  The change in vignetting could be corrected but it could be a pain to deal with well.  And the shutter speed range of most cameras (1/8000s to 30s or more with bulb) is enough to shoot full sun to fully dark.

 

And exposing to the right is usually the best way to go to keep signal-to-noise high, unless there are saturated areas (sun or moon at night) and then you have to decide how much clipping you want.

 

I use custom hardware and software for my day-night lapses so I can't help you with the commercial stuff.

[erictheastrojunkie]

Definitely do not use aperture priority mode, it will make your life absolute hell trying to correct changes in brightness/exposure over the duration of the "holy grail" portion of the timelapse (this is called "flickering" and IMO it ruins timelapses). qDSLRDashboard is probably the easiest way to accomplish the auto-transitioning of exposures and aperture for the holy grail timelapses, you can tell it to ramp aperture first and then exposure next that way you isolate different settings and optimize the quality. You want fast exposures during the day to freeze motion, this gives timelapse better smoothness when there is more light and you can run at a faster framerate, it makes motion in things like water or clouds, breezes blowing trees/flowers/bushes, etc to be clearer and cleaner during the timelapse. Then during the transition to astro dark you can ramp your exposure because lighting of the foreground will dissipate, you won't care as much about freezing those elements with fast exposures because you simply can't see them. I've done quite a few timelapses and holy grail ones, especially sunset to into the night, I've done a few sunset to sunrise ones as well. This one is probably my favorite, back with Comet Neowise, we had a great sunset this night over the lake and then Neowise came into view with a good reflection in the calm waters. We also had good airglow with some thinner clouds that highlighted stars in the Big Dipper, I utilized my slider rail with no rotation of the camera:

 

https://youtu.be/d1j...?feature=shared

 

I liked the result from this Bryce Canyon day to night transition because you could see the earth shadow race across the sky during twilight, golden hour at Bryce is incredible for Holy Grail timelapses:

 

https://youtu.be/2Y-...?feature=shared

 

I've got quite a few timelapses on our youtube channel:
https://www.youtube....raphy796/videos

 

LRTimelapse is a must, it's the easiest and most complete timelapse software for this, you'll also need Adobe Lightroom as it's kind of a two-in-one editing suite that utilizes functions in both to smooth out the frames. Some tips I have would be:

Do not touch the camera once it's started, do as good of planning as you absolutely can in terms of framing and orientation prior to starting, then once the exposures are going you absolutely do not touch the camera at all until you are ready to end it. A dummy battery with a big battery brick is 100% necessary, especially if you do twilight to twilight sequences and temps are cold. Slider rails and rotators are fun, but exceptionally difficult to get running correctly and take tons of practice to understand how the camera is going to move and cover views over a sequence. Like I said above, ramp order should be ISO-> Aperture -> Exposure for a Holy Grail sequence, I preferred to keep my ISO the same at the invariance point for whatever camera I was using to keep it a bit more simply, so I always ramped aperture and then exposure. 

 

[timelapser]

Definitely do not use aperture priority mode, it will make your life absolute hell trying to correct changes in brightness/exposure over the duration of the "holy grail" portion of the timelapse (this is called "flickering" and IMO it ruins timelapses).

At risk of getting off the OP's topic, can you expand on the problems you've had with aperture priority?  I've always shot at fixed aperture, and haven't had any trouble smoothing day-night lapses.  One possibility is sticky blades: with each shot, the blades close and reopen, so if they stick a bit they may not close completely to the aperture you set.  Then the shots will jump around in brightness from frame to frame.

 

I prefer to fix my aperture where I want it for the night - at a sweet spot maximizing aperture and minimizing aberations.  Usually that's fine for the daytime part too, unless you want high depth-of-field.

[erictheastrojunkie]

At risk of getting off the OP's topic, can you expand on the problems you've had with aperture priority?  I've always shot at fixed aperture, and haven't had any trouble smoothing day-night lapses.  One possibility is sticky blades: with each shot, the blades close and reopen, so if they stick a bit they may not close completely to the aperture you set.  Then the shots will jump around in brightness from frame to frame.

 

I prefer to fix my aperture where I want it for the night - at a sweet spot maximizing aperture and minimizing aberations.  Usually that's fine for the daytime part too, unless you want high depth-of-field.

Sticky blades could be a/the problem, the inaccuracy of blade movement and subtle changes in sky brightness from frame to frame (perhaps a cloud moves overhead, or someone walks by with a headlamp on, or a car drives by, or there's a lightning flash, etc) can result in the metering causing a different aperture setting for a single (or multiple) frames within the sequence. Then when you load and preview the sequence you'll see the brightness values listed in LRTimelapse and see the occasional outlier within the sequence reflecting that odd aperture setting. A lot of times that outlier can be smoothed and corrected for within the software, but depending on the general brightness of the scene at the time you might get clipped highlights or shadows that can't be recovered and then you'll either have to delete the frame or just deal with that quick change in brightness. I try my best to avoid deleting frames within a sequence to prevent the clip from noticeably jumping. 

 

Some lenses are manual only so you can't adjust the aperture automatically anyways, like I said when I start imaging I prefer to have the qDSLRDashboard app start with a smaller aperture (like f3.5-f4) and then open it up first, then ramp exposure up to whatever value is the longest given the calculated maximum shutter time for the focal length/pixel size (I prefer the NPF rule over the other rule of 500/200/whatever calculators). If I'm shooting from very bright daylight (before golden hour, real daytime) into dark then I'll start with a low ISO and ramp that, then aperture, then exposure, but I didn't do too many of those. If the lens is manual aperture only (Rokinon, for example) then I just set it to the widest aperture and ramp ISO first and then exposure. 

 

The most annoying sequence I've had to edit was a winter timelapse at Bryce Canyon, setup above Thors Hammer, where tons of people (including at least one workshop) were happening. The amount of headlamps and flashlights, laser pointers, foreground lighting and other stuff that was happening, made the sequence constantly changing in brightness. I used it as an example for "nightscape etiquette" in terms of how people should manage their light usage and how it can be extremely detrimental to others who are out shooting in popular locations. 

[timelapser]

A lot of times that outlier can be smoothed and corrected for within the software, but depending on the general brightness of the scene at the time you might get clipped highlights or shadows that can't be recovered and then you'll either have to delete the frame or just deal with that quick change in brightness.

Yeah clipped highlights can be tricky to deal with, and pushing to equalize the frames is the best way.  It's critical to never pull saturated pixels, and that can take some planning.  Unrecoverable frames can be recreated from averages of before and after frames as a last resort.

 

For these reasons if you're starting out, I'd recommend not shooting into the sun or nighttime moon.

 

Sticky blades can cause problems regardless of whether you're at fixed aperture or not.  As can non-uniform shutter speeds at the fastest (1/8000s).  Varying the aperture during the lapse can give you noticably varying depth-of-field and lens aberrations, as well as the varying vignetting that I mentioned before.