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Auto Holy Grail won't increase shutterspeed over 0.3s

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#1 kayooo
Hi together

I have a little problem with the Auto Holy Grail.

I tried it 3 times at an similar place with a similar situation, you can see my first result here:
http://youtu.be/hpPXNnE46FM

I started with 1/4000, f3.5 and ISO100. The Auto Holy Grail was set to max ISO1600 and max shutterspeed of 2 seconds.

My external Timer is a cheap copy from china, but he makes his job. (set on 5 seconds)

Now the problem: the shutterspeed is encreasing to 0.3 seconds (the first time to 1/5) but stops at that value. Neiter increasing the ISO.

Here you can see that the dslrdashboard is working very well at the beginning, but gets problems when its too dark i think??? :

   

You can see at the end the picture is getting darker and darker because the shutterspeed isnt correcting correctly. At my first try (in the youtubevideo) i had to cut the last 4 or 5 seconds of the finished movie because it was even darker than the analysis of the picture i posted before. Even in the video i posted i had to increase the luminance in lightroom more than 2.5 points at the end to get the end of the video as bright as it is....

Just now i had an idea: could it be that at the beginning dslrdashboard takes the average luminance of the whole picture (very bright at the upper half, very dark at the lower half). After the sun went down, the whole image has more or less an equal luminance, but mabye both situations have the same average luminance?

If its that problem how can i solve it, in the other case: any other ideas? Smile

Thank you and Greez Kayooo

PS: I work with an Canon EOS 600d, Sigma 18-250mm and use the dslr dashboard on a notebook with windows.
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#2 Gunther
You should observe the floating avg and reference values when shooting.
When Floating Avg goes below reference, the adjustment takes place.
I assume that your intervalometer somehow locks the camera for too long, for example triggering the autofocus signal, this would then block qDDB from accessing the camera for too long and then prevent it from doing adjustments after a certain shutter time.
Try using the internal intervalometer of qDDB and try if that helps. Use the latest version of qDDB.
Or use the Pixel timer, that's known for working flawlessly: http://amzn.to/1Hbbeah
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#3 imagency.eu
Hello,

I'm new to this but I noticed some -coincidental?- similarities to a problem I had:
what I see is you are on Canon and the slowest speed threshold you cannot pass is 1/30s.

I had the same 1/30s problem whenever and wherever I used Live view. I discussed it with Zoltan here:
http://dslrdashboard.info/phpBB3/viewtop...=457#p1974
And solved it by:

Going into the menu of the camera (before connecting to qDD) to 'Live view/Movie funct. set.' selecting 'LV funct. setting' choosing 'Stills only' in stead of 'Stills+movie' and finally 'Exposure simulation'.
This solved it for me. Apparently Movie LV limits your slowest shutter speed.

I am on Canon 5DII and III but I suspect it wouldn't be very different on your 600d.

good luck
Stef for www.imagency.eu

Canon 5D II & III - Samsung Galaxy 3 (SM-T210) on Android 4.4.2 - TP Link MR3040 v2
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#4 omnibook2100
Hello Gunther,

Thank you for your reply in your auto holy grail video in the comments section on Vimeo. Just to remind you my question (on the vimeo video comments) and your answer, so we can avoid covering them again. :Smile

Questions:

First of all thanks for the video. It works fine with the Nikon D7k. I do have two questions though. 1. When I set it to auto holy grail (sunset) it starts with e.g. F4 1/1000 ISO:100 and it gets stuck at F:4 S:1/320, ISO: 100. I have set it not to change the aperture so that's fine, but I've also told it that it can go up to 30'' (seconds) and ISO:3200 as I want to make a true day to night hyperlapse. Why is it stopping at S:1/320 and ISO:100? My guess is that I'm missing something, though I have read the manual twice... Sad. My other question is: As I am using a slider and the slider takes care of the movement (Shoot-Move-Shoot) and also the triggering of the shutter, how can I set qDDB settings to only change the exposure whenever a jpeg lands on the tab? I thought that it is compulsory to also start the interval for the auto holy grail to work...

Answer: 

Normally you trigger the shutter of the camera with an external intervalometer or controller. Set the controller to only briefly trigger the shutter (af-time and exposure time on the controller as short as possible). The real exposure time should be set on the camera and will be controlled by qDDB. Normally it should not stop ramping inbetween. But make sure to always have the longest shutter time set in qDDB 2-3 seconds lower then the interval set on the controller!
Set the Camera to RAW+JPG and the jpg size to the smallest possible.
Please come to my forum for further questions! forum.lrtimelapse.com
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[url=http://forum.lrtimelapse.com]Well, I am doing all of the above things you propose. I will make another test tomorrow and see if by just clicking the auto holy grail button (without clicking the intervalometer of qDDB) if the app will make the necessary changes in exposure. The reason I am writing in this thread is because as the other members have mentioned qDDB does not change the shutter speed or ISO after a certain value. Is there anything I can do to fix this? As I am interested in doing a day to night timelapse, so I cannot have qDDB stopping at 1/320s and ISO:100, when I have set it to go up to 30'' and ISO:3200, which is enough to see e.g. the milkyway.

Any ideas will be really really helpful.

Thanks.

Nikitas
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#5 Gunther
Hi Nikitas,
again, on all of my workshops where I see different camera configurations etc. I've never experienced that qDDB has a bug there.
If something goes wrong it's mostly a problem with the individual setup or understanding.
Again: if you set the longest shutter time to 30" (to cover the milky way) you have to be aware, that your interval has to be longer then 30 seconds (from the beginning) since the interval has to accomodate the longest shutter time, otherwise it will work at the beginning but not when you reach longer exposures.
More tips:
- set the screen of the tablet to stay on all the time, especially on iOS devices!
- Don't use Live View!
- Set the camera to RAW+JPG whith the smallest JPG Size/Quality

I'd recommend to do some tests with simple setups and trials (balcony) and get it going, before doing a "real" shot.
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#6 omnibook2100
Well in the slider settings the duration from move-shoot-move is 50'', which well covers the maximum 30'' shutter speed on qDDB. I am also not using live view and the camera is set to RAW + Jpeg (the smallest size, so it can be easier to transfer to the tab for qDDB to make its calculations in order to change the exposure). By the way I am using an android tablet (Lenovo brand if that plays any role, which I really doubt it).

Trust me, the only thing I have been doing the past few sunsets is go to my roof and make tests... Big Grin

Anyway, I have been reading other peoples' similar problems and I will try 1-2 ideas they followed and maybe I'll be able to fix the problem that the shutter speed gets stuck at 1/320 and ISO does not move from 100, though it should be going SH: 30'' and ISO: 3200.

In the meantime, if any idea comes to your mind of how to fix it please let me know.

Thanks.
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#7 Gunther
Iso will only start ramping, after exposure time is equal to “longest shutter“.
Not related to your problem, but an interval of 50“ is way too long. Try making intervals of 20 secs, if you want to shoot till the milky way, longest shutter then is 16.
Make sure that the motion controller does not “hold“ AF or shutter. For example the emotimo does this if you configure a static time. So set any static time and af time it to the shortest possible.

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