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Esteemed Contributor
Posts: 3,805
Registered: ‎06-11-2013

Re: Strange light streaks with long exposure EOS 80D

In a long exposure the mirror swings up, the shutter opens, the camera waits the appropriate amount of time (based on how many seconds of exposure you want), the shutter closes and the mirror swings down.

 

It is possible to enable a mirror lock-up mode that requires a double press of the shutter to take a shot.  In that mode the first time you press the shutter, the reflex mirror swings up... and that's it.  The second time you press the shutter (the mirror is already up) the shutter opens and the camera takes the shot.   At the end of the shot the shutter closes AND the mirror swings back down.   But the point of the mode is to reduce any possible vibration caused by the mirror-slap as it swings up.

 

Vibrations tend to settle down (unless something is keeping them going).  So on a very long exposure I'd expect to see some signs of vibration... which calm down a few seconds later and disappear.

 

When we do astrophotography we go to great lengths to deal with vibration issues (otherwise you get stars that are elongated instead of pin-point).

 

Tim Campbell
5D III, 5D IV, 60Da
Honored Contributor
Posts: 7,966
Registered: ‎08-13-2015

Re: Strange light streaks with long exposure EOS 80D


@Andydreadsbmx wrote:

I know both of you are probably going to say "well there is your issue" but do you think it could have been because I was shooting a timelapse and the shutter opening and closing along with being on a tripod created this issue?

Here is the full shot just for reference.

LA light issue-1.JPG


Oh, the original shot is that big.  I wonder if what you're seeing is the limit of the sensor's resolution.

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"I don't rent software. I use Photoshop CS6, ACR 9.8 and Lightroom 6.8 ."
Occasional Contributor
Posts: 10
Registered: ‎05-21-2017

Re: Strange light streaks with long exposure EOS 80D

I have used mirror lock up but in the case of the time lapse the time between frames was just long enough for the camera to process the image and start the next and I didn't think it would work correctly without having some time to do so.

Is there a way in camera to do a time-lapse and have the mirror flap up and stay open the whole time and close at the end??
Occasional Contributor
Posts: 10
Registered: ‎05-21-2017

Re: Strange light streaks with long exposure EOS 80D

I am seeing this now and before I was shooting with the original EOS 7D and never saw things like that.

I mean how would that happen if it is a limit to the sensor??
Highlighted
Occasional Contributor
Posts: 10
Registered: ‎05-21-2017

Re: Strange light streaks with long exposure EOS 80D

[ Edited ]

I think it does have to do with the mirror flap because in another shot pulled from the time lapse you can see the wiggle that calms down mid shot to more of a straight line.

See example of a small cropped piece of the traffic in this shot.

 

I guess I got confused because I feel like the shot itself would have been much more fuzzy and out of focus.

Screen Shot 2017-05-21 at 7.33.53 PM.png

Honored Contributor
Posts: 7,966
Registered: ‎08-13-2015

Re: Strange light streaks with long exposure EOS 80D


@Andydreadsbmx wrote:

I know both of you are probably going to say "well there is your issue" but do you think it could have been because I was shooting a timelapse and the shutter opening and closing along with being on a tripod created this issue?

Here is the full shot just for reference.

LA light issue-1.JPG


"ISO 100, 50mm Plastic fantastic on manual focus mode, F5.6, 2 second exposure in Manual mode on the camera."

I thought you said that it was a 2 second exposure.  How long of a time lapse, 2 seconds?  What was the shutter interval?  

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"I don't rent software. I use Photoshop CS6, ACR 9.8 and Lightroom 6.8 ."
Occasional Contributor
Posts: 10
Registered: ‎05-21-2017

Re: Strange light streaks with long exposure EOS 80D

It was a time lapse with each shot being 2 seconds with an interval of 4 seconds so it had 2 seconds to process before the next shot.

Esteemed Contributor
Posts: 3,805
Registered: ‎06-11-2013

Re: Strange light streaks with long exposure EOS 80D


@Andydreadsbmx wrote:

I think it does have to do with the mirror flap because in another shot pulled from the time lapse you can see the wiggle that calms down mid shot to more of a straight line.

See example of a small cropped piece of the traffic in this shot.

 

I guess I got confused because I feel like the shot itself would have been much more fuzzy and out of focus.

Screen Shot 2017-05-21 at 7.33.53 PM.png


Yeah - I think you're right.  The headlight shots really do show it well in this section.  We know the cars are traveling toward the camera and your an see the vibration is the worst when the shutter opens... and then calms down by the time the shutter closes.

 

If you are physically pressing the shutter with your finger (you touch the camera) then you can induce some vibration.  Otherwise it would likely be mirror slap.

 

Here's a video that shows how to enable the mode:  https://youtu.be/EqXI5l96Gp8

 

Just don't forget to disable it when you finish the time exposures or the next time you use the camera you'll be wondering why the camera doesn't take a shot when you press the shutter button.

 

 

 

Tim Campbell
5D III, 5D IV, 60Da
Occasional Contributor
Posts: 10
Registered: ‎05-21-2017

Re: Strange light streaks with long exposure EOS 80D

The mirror lock up is great but when shooting a timelapse I cannot use mirror lock up.

Timelapse is disabled when mirror lock up is enabled.  Maybe if I attach an intervalometer to the camera I could by pass that and have the mirror lock up work.


Esteemed Contributor
Posts: 3,278
Registered: ‎02-17-2016

Re: Strange light streaks with long exposure EOS 80D

Could you just be seeing a stair-step due to the square pixels? It isn't as noticable on the vertical shots.

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