Maintaining exposure between stacks for time-lapse

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anoldsole
Posts: 24
Joined: Tue Feb 27, 2018 5:49 pm

Maintaining exposure between stacks for time-lapse

Post by anoldsole »

I decided I wasn't abusing my camera enough so I have been doing more macro time-lapse. As gratifying as it is punish my shutter with a 5000 shot stacking sequence, I am having trouble maintaining consistent exposure between frames, resulting in some flicker when I assemble the time-lapse. I know completely elimination of flicker can be hard, but I'm finding my results unacceptable.

I'm trying to puzzle out whether my issue stems from my lightning setup, or improper use of software.

Normally i'd just hop into Photoshop and correct the exposures, but it is too time consuming with this many shots. There are also some after effects plugins that work well, but there is still a bit of flicker they can't seem to get rid of. I'd rather take the shots properly than fix it digitally after the fact if possible.

I've tried both zerene and helicon, and get worse results in helicon for some reason. Turning on correcting brightness doesn't seem to help. Are there other parameters I should be adjusting that affect brightness?

I'm using continuous led lighting or flash. They are the only sources of light in the room. My big studio strobes should be capable of firing consistently without variations in illumination at the power levels i'm using. The LEDs are good quality. I've carefully tried to eliminate any factor that might be causing uneven light but it persists. Is it possible that variations in my electrical supply are causing small variations in light output between shots?

Anybody have experience or suggestions for reducing flicker when doing time-lapse?

rjlittlefield
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Re: Maintaining exposure between stacks for time-lapse

Post by rjlittlefield »

anoldsole wrote:Are there other parameters I should be adjusting that affect brightness?
In Zerene Stacker, if you turn off brightness correction, stack with DMap, and save without "Retain extended dynamic range", then no variations will be introduced by the software.

I cannot speak to any of the other possible sources.

--Rik

mawyatt
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Location: Clearwater, Florida

Post by mawyatt »

Hello,

I've seen this lighting variation before in long stacks and it would show up as bars in the chip images I stack, especially in wide metal runs. It can come from speedlights, strobes and even continuous lights (LED). With all sources they can vary as they get warmed up, so a good idea is to let the LEDs reach nominal temperature, with strobes and speedlights fire off 20~30 initial bursts can help.

Line voltage variation is also a potential source, many of the strobes & continuous LEDs don't have good internal voltage regulation, especially the cheaper ones. Sometimes I'll monitor the line voltage with a DVM. In my home when the AC kicks in, or the microwave is on the line voltage dips.

One possible solution for line voltage correction, abet not cheap, is a line voltage regulator.

I've found the Adorama Studio Strobe 300IIs (Godox SK300II) are pretty good about creating a uniform output, and are specified for such (2%). They are reasonably priced and come with built in RF receiver for their R2 system.

Anyway, these are some experiences I've suffered thru over the years, hopefully somewhat helpful.

Best,
Research is like a treasure hunt, you don't know where to look or what you'll find!
~Mike

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