“True Holy Grail” – 3-way auto ramping for time lapse transitions

After many months of research and development I’m more then happy that now I can present you the last step to the “True Holy Grail” of time-lapse photography, namely the technically perfect transition from day to night and night to day: a method for automatic, flicker-free 3-way ramping of exposure time, ISO and – this is new – the aperture.

Hamburg, Holy Grail shooting

To better understand what I’m talking about, it certainly makes sense, to watch my video about the “Holy Grail” approach before. There you will learn the best way until now to shoot such time lapse as 2-way ramping – namely by automatically adjusting shutter speed and ISO. In that article I also explain how to work with qDslrDashboard and the Auto-Holy-Grail feature and how to post process the sequences in LRTimelapse.

Check out that video and article here.

I had no aperture control implemented until now, because adjusting the aperture always introduced the danger that the notorious aperture flicker occurs. To understand why the method I am presenting to you today is so revolutionary, I first want to tell you briefly why this aperture flicker happens.

The reason for aperture flicker

Please check out the following video that I once created to advertise the Deflicker function in LRTimelapse. Here I made a time lapse of the diaphragm of a camera that takes a time lapse. But see for yourself:

Due to the fact that after each trigger of the shutter the camera sets the aperture back to “open” and then again to the chosen aperture, mechanical friction leads to the aperture not closing to the exact same diameter for each shot. For “normal” photography such differences do not matter at all – but when playing back the images as a time lapse, this causes an unpleasant flickering.

Of course LRTimelapse is also capable to ease such Flicker effects later in post – but it is always better to get the shooting right and flicker free and not have to deal with this later on the computer. Especially when using the holy grail approach – here the gradual adjustment of camera settings while recording already have to be compensated in post additional flicker effects only complicate the leveling and should therefore be avoided.

To already prevent flicker while shooting, there are several possibilities depending on the camera type and brand used.

With Nikon:

  • Shoot with the aperture wide open – where nothing have to be closed, no flicker can occur – in fact this is a good option to solve the problem
  • Use Nikon lenses with manual aperture ring, or other third party lenses without electronic aperture control, like Rokinon etc.

With Canon:

  • Use the Twisted-Lens Trick (deattach the electronics of the lens by slightly twisting the lens. This works but it also puts your lenses into the risk of dropping, I therefore do not recommend this method)
  • Adapt Nikon lenses to a Canon body with the Novoflex Adapter

You can see that the lapse community is quite creative, and even uses rather cumbersome approaches to solve this problem. One year ago I even bought a Canon 6D only for my time lapse work, just be able to adjust and lock the aperture mechanically with help of the Novoflex adapter.

Unfortunately, so far all of those “solutions” still have one thing in common – the aperture is fixed while shooting. In the simplest case (shooting with open aperture) it will be held wide open all the time, with the other methods you can close it, but you are not able to have it controlled anymore while shooting.

For shooting during the day that’s just fine – but for day-to-night and night to day transitions not so. I would like to briefly explain the issue.

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Challenges for the “Holy Grail” transitions

The visual appearance of a time lapse considerably benefits from the fact that you are working with longer exposure times. Rule of thumb is the so-called 180° rule: the exposure time should be about half as long as the chosen interval. With an interval of 5 seconds for example you would take 2 ½ seconds as a guide for the exposure time. During the day this would require a ND filter. When recording a transition from day to night however, using a filter is not such a good idea because you normally can’t remove the filter while shooting without shaking the camera. Furthermore, it is extremely difficult to make a visual approximation of the parts shot with and without filter in post, since nearly all filters introduce color shifts and cause vignetting.

So the use of a filter is not the best idea when shooting a transition. A flicker free stopping down with one of the above methods (Lens-Twist, manual lens or adapter) is ruled out as well, at least, if you really want to ramp until darkness. In that case you would just need the open aperture for the dark areas, or you would have to use significantly higher ISOs. Especially if you want to hold up to the stars or the Milky Way, you need to open the aperture for the darkest parts of your shooting.

So until now, shooting such sequences all the way with an open aperture have mostly been the technique choice. But: if you have strong movement in the foreground, such as water, the open aperture would need you to use short exposure times during daytime, which would lead to a choppy appearance then. The smoothing would only happen after being dark enough and thus the shutter times long enough.

I happen to be a perfectionist with such things. And although many would say that you can maybe neglect this because it’s only affecting certain types of shootings, it was always a point that didn’t make me completely happy.

When even my wife then commented on some sequences that I shot in Thailand close to the shore and asked “why does the water’s looks so choppy?” – And I could only reply, “that has technical reasons – wait until it gets darker” – this further bothered me and made me once again think hard about the problem.

Please have a look at the following video. The first sequence from Thailand I recorded with the “old” 2-way method – i.e. with open aperture and by automatically ramping shutter speed and ISO via qDslrDashboard. Note the part where the water is getting choppy towards the end. In the second video I have used the new 3-way “True Holy Grail” technology: A automatic ramping of all 3 parameters – ISO, shutter speed and aperture. As a result, the water stays nice and soft all the time.

The solution

Until now the only other solution that I knew for flicker-free changing of the aperture while recording a time lapse, requires a lens with manual aperture ring or appropriate adapter and a motor that controls it. The effort to establish a solution like this is significant, especially as it also requires a software-based synchronization – in other words, a software must be able to control the motor for the aperture as well and synchronize everything.

You would have to motorize the aperture with something like this

You would have to motorize the aperture with something like this

I know some professional time lapse photographers who use such a solution, but mainly because they have to.I myself am always a friend of uncomplicated, straight forward solutions, considering that the stuff has to be a) paid, b) carried and c) operated.So for me it had to be simpler and more straight forward.

One day, when playing around with my D750, I noticed that when triggered in Live View mode she does not close the aperture between.This finally was an approach to my problem.Especially since I quickly found out that this is also the case for D800, D810, D4 and D4s – i.e. for all “major” Nikons that a lot of time-lapse photographers use.

Prior of practically benefiting of this knowledge, unfortunately there were still some challenges that had to be solved.

  1. I didn’t want the camera display to be active during the shooting due to the Live View
  2. The solution should work via internal WiFi of the D750, via USB and of course via the TP-Link router in conjunction with the D810, D800, D4 and D4s.
  3. qDslrDashboard should be able to automatically adjust the aperture additionally to the shutter time and ISO as a third parameter during the “Auto-Holy-Grail” and automatically control it according to my rules.
  4. The solution should also work if a slider or motorized head would be used.

Thanks to Zoltan, the developer of qDslrDashboard the implementation of the topics 1 to 3 happened rather quickly, since he immediately agreed to incorporate the corresponding functions into the LRTimelapse page in qDslrDashboard.

Point 4, however, gave me a lot of headaches.The Nikons kept refusing to accept any trigger from an external intervalometer when they were simultaneously connected to the tablet (whether via USB or WiFi) and in Live View mode.When working with the camera on a tripod that is not a problem, in that case you can use the internal interval timer of qDslrDashboard.However, if you use a slider, you would usually want the controller to trigger the camera to get a proper synchronization between camera movement and shutter release.

Update: At least with the D750 (that’s what I tested) the above applies only, if the Liveview is being switched on from the app (for example from qDDB). If you turn on the Liveview manually on the camera instead, then the camera can be triggered externally, if it is connected via the internal WiFi. This means you do not have to use the slave-mode-solution below. For this just activate the LiveView after you switched to the LRT screen of qDslrDashboard. Please note that the screen will be on all the time then.

The hot shoe adapter for the Nikon D750

The hot shoe adapter for the Nikon D750

So close before the finish line, I did not want to give up.I was at a point where I would even accept an additional hardware solution to finally solve this issue.In my desperation I called Matthias Uhlig from Kids of All Ages – if one is familiar with such tinkering, it’s him.And in fact, he could turn the last piece of the puzzle. “Why are you not doing it the other way around,” he asked me.”Put the motion controller into slave mode, and trigger it via the flash sync terminal of the camera.”Then you can use the internal timer of qDslrDashboard to trigger the camera”.

This was just genius! I’d use the internal timer of qDslrDashboard that has lately proved to be very reliable.This triggers the camera and the camera triggers the motion controller.For this, I’d not need any additional hardware, not even an extra cable hanging around. And as a little icing on the cake I could even use the interval-ramping of qDslrDashboards timer, which allows to have longer intervals during the night, if needed. And all of this would even work for motion controlled shots. For me this felt better then Christmas. 🙂

The normal release cable to the camera would not be needed anymore, instead I’d use the sync cable.Only the D750 would need a additional hot shoe adapter, because it does not have a sync port.Matthias kindly shipped everything I needed the next day and I was able to test the new solution.What can I say: Hooray – it worked! 🙂

Matthias kindly agreed to backorder some of those cables and adapters just in case you need them and put them on stock in his shop. You can get them here.

Matthias ships from Europe, if you are located in the US it might be better to order at amazon.com: Hot shoe adapter, Sync Cable.

TLDR;Summary so far

With the Nikon cameras D750, D810, D800, D4 and D4s you can now shoot automated transitions from day to night and vice versa. When using the Auto-Holy-Grail function of qDslrDashboard on Android or iOS smartphone or tablet, a real 3 -way control (exposure time, ISO, aperture) can be realized without any aperture flicker occurring. We use the fact that in Live View, these cameras do not open and close the aperture after each shot. This is the “True Holy Grail” of time lapse photography. The method also works in conjunction with a motion control system such as a slider or motor head, provided it supports a “slave” mode. qDslrDashboard will then trigger the camera and the camera will trigger the motion controller. The common controllers NMX, MX3 and EMotimo have that feature in any case.

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Here’s how it works

The Holy Grail approach, that I have explained here and also described in my EBook is still the basis for this technique. If you already shoot with that technique, everything will look very common to you.

Please make sure that you have installed the latest version of qDslrDashboard from here.You’ll need at least version V0.2.6 of qDslrDashboard.For iOS users, from the publication of this article on, it might take a few more days until Apple has released the update.

Please do not use the old DslrDashboard version from the Play Store (without q) anymore!

On the tripod

When the camera is mounted on a tripod, just set up as always, but omit the shutter release cable. The shutter will be triggered by qDslrDashboard now. This means as well no more stress with faulty triggers that block autofocus etc…

With motion control

If you use a slider or pan/tilt head with a motion controller, then just put it in slave mode (for the NMX this for example works by clicking the blue button three times).Now connect the flash sync port of the camera or, in case of the D750 the hot shoe adapter, with the sync input on the controller.

On the tablet / smartphone

Connect the camera via USB or Wi-Fi to qDslrDashboard, open qDslrDashboard and switch to the LRTimelapse page.

Under “Settings” you will find a settings page that you should now open.

Screenshot_2015-02-16-12-54-14

Here you can now activate the “Use Aperture ramping” checkbox. This will adds + and – buttons for the aperture to the LRTimelapse page in qDslrDashboard. Via the Lv button you can switch the camera to LiveView mode now.

After closing the dialog you will come back to the LRT page in qDslrDashboard.

Screenshot_2015-02-16-12-54-58

Here you can now set up the shooting as usually. Decide whether you are shooting a sunrise or sunset and set the boundaries within which the Auto Holy Grail should ramp shutter speed, ISO, and now as well the aperture.This is done via the settings Slowest Shutter Speed, Max / Min ISO and Wide / Small Aperture.In the following I’ll explain, how I set it up.

How I set it up

When starting I set up the camera so that I have a well-exposed image (histogram!). I try to have the longest possible time considering the 180° rule, the lowest possible ISO and an appropriate aperture.Depending on how dark it already/still is, the settings may vary.

1. Sunset

2. Sunrise

Framing parameters in qDslrDashboard
Slowest Shutter Speed approximately two seconds less than the interval – during the “dark time”, the camera has to submit the JPG preview to the tablet and the tablet has to be able to control the camera.So, this “dark time” between slowest shutter and interval should not be too short! irrelevant
Max ISO the highest ISO up to which the camera will be pushed. 3200 is a good value, but you can of course go higher, if needed. irrelevant
Min ISO irrelevant the lowest ISO, to which the camera will be set.I mostly use ISO 50 (or 32 with the D810) here.
Wide Aperture the widest aperture until which the camera should open up. irrelevant
Small Aperture irrelevant the smallest aperture that the camera should use during the ramping.
Procedure
1. qDDB will increase the exposure time until the value of Slowest shutter is reached qDDB will reduce the ISO until Min-ISO is reached.
2. Then the aperture will be gradually opened up until the value of Wide-Aperture is reached. Thereafter, the aperture will gradually get closed until the value of Small Aperture is reached.
3. Finally, the ISO is increased up to the maximum of Max ISO. Finally, the exposure time will be shortened.

This may sound more complicated than it is. Practically, you simply provide the initial camera settings that get you get a nice, long exposure time and leave the rest for qDslrDashboard. It will then do all the magic according to the specifications that I thought through and Zoltan implemented.

Just check the histogram from time to time while shooting. If the previews are getting too bright, simply decrease the reference value by clicking on “-” next to “Set Reference now”. If the previews are getting too dark, just increase the reference accordingly. This manual override is incredibly valuable, since it allows to follow the actual luminance of the situation. In the city the luminance profile for example is completely different than anywhere in nature without artificial light.

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Conclusion

This is indeed the “true” holy grail for everyone: a flicker-free, fully automatic control of shutter speed, ISO and aperture with manual override – and all of this, without having to use expensive and complicated equipment. However this requires a camera that allows for interval shooting without opening and closing the aperture in between shots. Currently this works with the LiveView trick for the “big” Nikons only – but it might even be the reason to get one of those cameras, if you are really into time lapse shooting.

Unfortunately it does not not work with Canon, at least not with my 6D. Maybe the guys from Magic Lantern could do something to help here, so far I did not have the time to deal with this. You might try it with your camera by yourself. Just run a time lapse shot and look from the front into the lens while qDslrDashboard triggers the camera. Then you’ll see how the aperture behaves. Should you find a way to trigger your camera without opening and closing the iris inbetween shots, please let me know in the comments!

With the presented technique you can achieve rather long exposures during the whole shooting of a day to night and night to day. This, plus the use of the function “LRT plus motion blur” in LRTimelapse leads to extremely smooth and very nice, technically perfect time lapse clips.

The technique of equalizing the exposure steps caused by the camera adjustments using LRTimelapse, and all further processing and rendering of the video is explained in detail here.

As a basis, I would recommend that you get my EBook – this sets the foundation in understanding of all that I have explained here.

By the way: of course you can ramp all three parameters by hand as well, if you do not want to use qDslrDashboard. However, the Live View stays bright then while shooting. But let’s be honest – who wants to still fiddle on the camera manually while recording if you can have qDslrDashboard and “Auto Holy Grail”… 🙂

Personally, I am incredibly happy with this solution, for me it represents a large milestone on the way to the perfect time lapse. I would like to see this solution implemented for other cameras as well, but this it really depends on the camera manufacturers!

If you are shooting time lapse professionally, and don’t own one of the cameras mentioned above, I’d really recommend you to get a D750. With the presented technique, the built-in Wi-Fi, the fantastic sensor and the swivel screen, it is currently the perfect time-lapse camera. And also happen to be one of the best photo cameras as well… 🙂

But please do not get discouraged if you do not have one of the supported cameras: to this day I recorded almost all of my time lapse without this new “True-Holy-Grail” technique. That’s works too! 😉 In that case you just work with the established 2-way ramping in qDslrDashboard and either use an open aperture or make sure the aperture stays put via one of the methods described above.

Happy time lapsing!

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