VFR and Interval Recording question/issue/observation?

M

MichaelA

Well-known member
Hi all!

I’ve been playing with both VFR and Interval recording, and came across something I’m trying to get my head around because I stumbled onto something a bit unexpected so I’m looking for either validation or perhaps an explanation so I can better understand this. Now, I’VE READ THE MANUALS and Barry’s book, so I based my experiments on this.
The setup is simple. I took the camera to work early to shoot some test time-lapse TYPE shots using both modes. Taken at night from the parking lot of my office. Wanted to see if I could get some cool streaking of the car lights as they went past.

Here’s the breakdown and a link to the test footage if the embedded player isn't: https://vimeo.com/196959604:

Scenario 1:
Camera set to record on a 30fps timeline; UHD 2160; 100M; Dual record to 1080. Set interval record to 1 second; shutter manual to .5 sec; iris manually to open; 500 iso.
Set camera to run about 8 minutes.
What I got:
On playback I got 8 minutes of footage! One frame of “stuff” followed by about 15 frames duplicated, then the next real frame of “stuff” followed by 15 duplicated. But it did come out in UHD 2160. To get the effect I was after, I sped it up in post x15 and added a slight delay.

Scenario 2:
Rotated camera 180 degrees to get traffic from a different angle (to keep me from getting confused with scenes/settings when I got home); reset to 1080; used VFR @ 2FPS; manual shutter @ ½ sec; manual iris at 4.5; high sense at 2000 iso. A bit noisier.
Camera recorded for a bit over 9 minutes.
What I got:
footage runs about 19 seconds, as expected in a “time lapse” type scenario, and was in 1080. Each frame a different shot. Pretty much as one would expect. Had a bit more noise, but this was a test!

Question!
Scenario 2 ran as expected. Each frame being a separate exposure. But scenario 1 I am puzzled by. Is the camera, by being told to take a picture every second with a ½ sec exposure, doing as its told then going back and “adding” about 15 frames of the same stuff to fill in the timeline? It would seem so rather than taking each exposure sequentially without the “filler” frames. I didn’t think on interval record it would do this! I was expecting about 17-18 seconds of playback footage rather than a very “choppy” 8 minutes essentially playing back in “real time”. Am I tripping over a circumstance of using such a long shutter and would not encounter this if I was shooting in daylight with anything faster 1/30 sec? Seems like when I used interval to do some cloud movements during daylight I didn’t encounter this. I’m coming from a DSLR mindset with this, whereby a long exposure on a time-lapse would still “count” as 1 frame, but the DVX is doing something a bit different under interval record than was expected. Now, it’s not really a problem, just trying to understand a bit better what’s in play here as I wasn’t expecting the camera to do what it did! But that’s why I play around with a lot of tests…

 
Your understanding of what scenario 1 was supposed to do, is correct. Your actual results? All I can say is you must have done it wrong -- you must not have had interval recording actually enabled.

Try your test again. Make sure that when you hit record, a red "I-REC" gets printed on the display where you'd normally see REC.

I just did your test, and when it says I-REC during recording, I can verify for you that you do get exactly the results you're expecting -- a few seconds of footage.

What you're describing (duplicated frames) would happen if you were recording in normal recording mode, not interval mode. That's exactly what would happen -- the camera needs to hold on the current frame to accumulate the 1/2 second of exposure, so it writes out duplicate frames until the new frame is ready.

So, again -- try your test again, and make sure it's saying I-REC. You should find that it works exactly as you expect it should.
 
Thanks Barry!
Even though I took notes, I don't recall if I really saw the "I-Rec" come on, but what you describe makes sense!
What I gleaned from my notes is that I turned the camera off after getting it set up in my office (to do the interval record), then turned it on once I got outside and rigged up. It seems it didn't "remember" the interval setting and reverted back to "normal"! My Canon's that I got used too would "hold" the last settings so I got in a habit of "pre-setting them up" for time lapses and stuff. No can do with the DVX! My defense is it was early, and I didn't have my coffee yet!
Just re-ran the scenario on my desk with the camera aimed at a clock so I could watch the sweep second hand, and confirmed I got the "I-REC" icon when recording.
Presto. It worked!
I also confirmed the interval recording "cleared" when the power was cycled.
So the lesson I just learned is that "pre-setting" as I had gotten used to doing on other gear AINT GONNA WORK IF YOU TURN THE DVX OFF!
Again, thanks so much!
:dankk2: :dankk2: :dankk2: :dankk2:
 
Glad to help. Yes, there are a few settings that re-set when you power off, like interval recording and variable frame rate, etc. But glad to hear the issue is resolved!
 
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