This post was last modified: 2020-06-07, 10:06 by wilko61.

Hello All,
This may not be the most appropriate place to share my finding so far but I suppose the following is a start.

I have just received my TimelapsePro and am keen to get out and shoot with it, for both Timelapse and Star Tails. But first I need to determine what is the minimal DarkTimes for my cameras. The tests carried out so far are not exhaustive and relate only to my 2x cameras, a Canon 5DmkII and Canon 5D SR. It is hoped that other forum readers will contribute to this discussion and share their Camera results. Also I haven't tried adjusting the Release Time and AF Time to attempt to squeeze (shorten) the Dark times. In the future these Parameters shall be adjusted in an attempt to further reduce the DarkTime.

As we know in Timelapse circles -> Interval = ExposureTime + DarkTime
ExposureTime is the time the shutter is open allowing light to the sensor.
DarkTime is the time between succesive ExposureTimes. DarkTime is used by the camera to write the digital data (image) to a memory 'card'.
Note: The absolute smallest DarkTimes possible while 'testing' didn't lead to any images being 'dropped' between successive shots/frames, but this might be different in the field. So test any values prior to using them in the field to be certain you won't have 'dropped' frames.

The following is my quest to determine the shortest DarkTime for my cameras, (by having the smallest DarkTime, the smallest gap is achieved for startrails, yes having a 5sec gap is probably insignificant in reality!). I carried out my tests in my study looking at a bookshelf where the light was stable, only adjusting aperture as required to keep the histogram levels the same during testing.

Unchanged Variables
---------------------------------
# 128GB CF simm, 160MB/sec
# No. exposures = 50
# ShutterSpeed = 2.5sec
# ReleaseTime = 200 & AF-Time=100
# Turned off any internal camera processing (LiveView Review, Chromatic Aberation correction, Noise reduction.... etc)

Changed Variables
----------------------------
# Interval (DarkTime shall change, as the ShutterSpd is kept constant)
# Tried High Speed continuous capture (in camera), but didn't seem to make a difference. Probably due to the release of the shutter signal and not being constantly on.
# Changed image quality on the Canon 5D SR, fom 50M down to 12M.

Canon 5DmkII :
---------------------
1. Interval = 5.0 (shutterSpd = 2.5sec & DarkTime = 2.5sec), 50/50 images captured => Successful
2. Interval = 4.5 (shutterSpd = 2.5sec & DarkTime = 2.0sec), 26/50 images captured => UNSuccessful
Note: I shall test Intervals between 5.0 - 4.5 sec to get the absolute min' DarkTimes.

Canon 5D SR :
-----------------------
1. Interval = 6.0 (shutterSpd = 2.5sec & DarkTime = 3.5sec), RAW size = 50M, 50/50 images captured => Successful
2. Interval = 5.0 (shutterSpd = 2.5sec & DarkTime = 2.5sec), RAW size = 50M, 26/50 images captured => UNSuccessful
Interval = 5.8 (shutterSpd = 2.5sec & DarkTime = 3.3sec), RAW size = 50M, 50/50 images captured => Successful
Interval = 5.8 (shutterSpd = 2.5sec & DarkTime = 3.3sec), RAW size = 50M, 100/100 images captured => Successful
3. Interval = 5.0 (shutterSpd = 2.5sec & DarkTime = 2.5sec), RAW size = 28M, 26/50 images captured => UNSuccessful
Interval = 6.0 (shutterSpd = 2.5sec & DarkTime = 3.5sec), RAW size = 28M, 50/50 images captured => Successful
Interval = 5.8 (shutterSpd = 2.5sec & DarkTime = 3.3sec), RAW size = 28M, 50/50 images captured => Successful
4. Interval = 5.0 (shutterSpd = 2.5sec & DarkTime = 2.5sec), RAW size = 12M, 26/50 images captured => UNSuccessful
Interval = 5.5 (shutterSpd = 2.5sec & DarkTime = 3.0sec), RAW size = 12M, 50/50 images captured => Successful

Summary for minimum DarkTimes
---------------------------------------------------
Canon 5DmkII DarkTime = 5.0sec. So add this value to the ShutterSpd to calculate the Interval.
Sorry the above statement is incorrect, it should have read :-
Canon 5DmkII DarkTime = 2.5sec. So add this value to the ShutterSpd to calculate the Interval.

Canon 5Dm SR DarkTime = 5.8sec @ max' image resolution. This seemed the absolute min time, (I did perform a test against 100 frames and there were no dropped frames).
Sorry the above statement is incorrect, it should have read :-
Canon 5Dm SR DarkTime = 3.0sec @ max' image resolution. So add this value to the ShutterSpd to calculate the Interval.
This seemed the absolute min darktime, (I did perform a test against 100 frames and there were no dropped frames).

The next phase of testing would be to start with the found DarkTimes values and see if adjusting the ReleaseTime & AF-Time values to (and possibly other
parameters I find after reading the manual!) allow for the DarkTimes to be further reduced.

Any further comments and camera tests would be most welcome. Even just sharing the Interval and ShutterSpd values being used to capture a particular subject matter - Astro, waterfall, moving cars, moving people ... etc.

Cheers

Andrew

Hi Andrew,

on EOS R i'm able to achieve dark time of 1 sec, when shooting 50 images (Full RAW Res) with interval 3.5sec and shutter speed 2.5 sec. I had Release time 200ms and Autofocus time 100ms. I have SanDisk Extreme PRO with 170MB/sec. When i went to 150ms with Release time i was able to achieve 0.9sec dark time - 2.5 sec shutter speed, 3.4 sec interval.

Sorry for my delay in responding. Thank you for taking the time to add your results.

I have since carried out a few more tests, including a recently acquired 5DmkIV. I shall add the values below, please note that to achieve my values I disabled Live-View and disabled the screen displaying normal current camera settings between each shot on the LCD. This is achieved by cycling the "Info" options until the rear LCD display is blank.

Sorry for the way I've had to format the result to get a table like output.

Camera = 5DmkIV: ShutSpd(sec) = 1.6: f-stop = 8.0: ISO =100: Interval = 2.6: Gap(sec) = 1.0: 10 shots = yes: 30 shots = yes

Camera = 5DSR: ShutSpd(sec) = 1.3: f-stop = 5: ISO = 100: Interval = 2.8: Gap(sec) = 1.5: 10 shots = yes: 30 shots = yes
Camera = 5DSR: ShutSpd(sec) = 1.3: f-stop = 5: ISO = 100: Interval = 2.6: Gap(sec) = 1.3: 10 shots = yes: 30 shots = yes
Camera = 5DSR: ShutSpd(sec) = 1.3: f-stop = 5: ISO = 100: Interval = 2.4: Gap(sec) = 1.1: 10 shots = no: 30 shots = no
Camera = 5DSR: ShutSpd(sec) = 1.3: f-stop = 5: ISO = 100: Interval = 2.5: Gap(sec) = 1.2: 10 shots =no: 30 shots = no

Camera = 5DmkII: ShutSpd(sec) = 1.3: f-stop = 8: ISO = 100: Interval = 4.3: Gap(sec) = 2.0: 10 shots = yes: 30 shots = yes
Camera = 5DmkII: ShutSpd(sec) = 1.3: f-stop = 8: ISO = 100: Interval = 3.8: Gap(sec) = 1.5: 10 shots = yes: 30 shots = yes
Camera = 5DmkII: ShutSpd(sec) = 1.3: f-stop = 8: ISO = 100: Interval = 3.5: Gap(sec) = 1.3: 10 shots = yes: 30 shots = yes
Camera = 5DmkII: ShutSpd(sec) = 1.3: f-stop = 8: ISO = 100: Interval = 2.3: Gap(sec) = 1.0: 10 shots = yes: 30 shots = yes

So I have been able to get both the 5DmkIV & 5DmkII to have get the "dark gap" down to 1 sec. I didn't attempt to push the 5DmkIV shorter than 1 sec, as currently I don't require it (for interest may check it in the future). The 5DSR, I was only able to get the "dark gap" down to 1.3 sec, this is still pretty good when considering the amount of data being captured by the sensor (50.6 mp).

Cheers

Andrew