Anti flicker test

[Ben Egbert]

This boring TL was a test to see if I could eliminate flicker. It was shot in full manual at 1/10 second shutter, f13 and ISO100l. I had to use a polarizer to get exposure, my nd grad is broken. I think I see some polarizer artifacts in the clouds but I don't see any flicker.

This would be very hard to implement during golden hour unless I allowed the TL to get very dark.

I could add auto iso which would probably also be flicker free, but would have brightness jumps when the ISO changes

CC welcome.

 

[JimFox]

I am at the beach right now, so it will be hard for me to tell. Did it eliminate the flicker for you?

 

[Ben Egbert]

I think it did, Like I say, there are some color artifacts in the clouds which I think is from the polarizer. I a, going to try another one this evening at sunset using manual shutter and exposure but auto iso. I will be at f14 and 1/10 second again, but let iso fix exposure. No polarizer as it will be dark enough to ignore that.

 

[AlanLichty]

I don't see any flicker. I do notice that when viewing at full screen there is a dust spot just below center left

 

[Ben Egbert]

Right, and you are sure it's not on your screen?

 

[AlanLichty]

Right, and you are sure it's not on your screen?

I checked carefully this time using a white application window over the location on my screen where the spot appeared. It is not visible in the small version - only at full screen.

 

[Ben Egbert]

Now I need to check my sensor, this is a problem with f13. Spot removal for 700 images is not fun.

 

[JimFox]

So Ben, one benefit of photographing say at f5.6 instead of our normal f11 or f13 is dust bunnies won't be as obvious. I have been cleaning my sensors almost everytime I change a lens now because of doing these timelapses. Before I didn't care if there was a spot or two because it wasn't a big deal to just remove them in photoshop later. But now, whether it's being in a movie mode, or like I just shot 3000 images for a timelapse at the beach today, that's just too many to have to deal with a spot.

 

[JimFox]

On your video Ben, I don't see any flicker.

 

[Jameel Hyder]

I have a feeling that auto ISO will result in flicker when during a sequence it changes the ISO from one value to another. One way is to verify at what point the flicker occurs and then check the sequence at which point the ISO changes.

 

[JimFox]

I have a feeling that auto ISO will result in flicker when during a sequence it changes the ISO from one value to another. One way is to verify at what point the flicker occurs and then check the sequence at which point the ISO changes.

I would agree with Jameel, unless you are using a camera that has an Anti-flicker option that might be the only way to get Auto-Iso not to cause flicker.

 

[Ben Egbert]

So Ben, one benefit of photographing say at f5.6 instead of our normal f11 or f13 is dust bunnies won't be as obvious. I have been cleaning my sensors almost everytime I change a lens now because of doing these timelapses. Before I didn't care if there was a spot or two because it wasn't a big deal to just remove them in photoshop later. But now, whether it's being in a movie mode, or like I just shot 3000 images for a timelapse at the beach today, that's just too many to have to deal with a spot.

The issue with using f5.6 is I can't get the exposure I need when set to 1/10 second. Slow shutter speed is one of the cures for filcker. They recommend using an ND grad which I currently don't have.


I do have anti flicker but not exposure smoothing. I never clean my sensor ever since I broke the one in my 1DSmk3 for $2100.

 

[Ben Egbert]

I have a feeling that auto ISO will result in flicker when during a sequence it changes the ISO from one value to another. One way is to verify at what point the flicker occurs and then check the sequence at which point the ISO changes.

I did one last night with auto iso and the shutter and aperture fixed. I got the focus on the clouds by mistake but there was no flicker. There is a slight one time exposure change when the iso changes, but it's nothing like flicker that goes back and forth. I suppose it could if clouds or something passed in front of the target. Maybe a very broad exposure target would help.

The alternative is to set a fixed exposure for the entire run. This is fairly easy for light to dark, but will end up very dark. Not se easy from dark to light (sunrise)

 

[JimFox]

Ben, since we can use ACR to process these... I am just thinking out loud now... The Shadow Recovery adjustment. Wouldn't it pull up the exposure essentially in the darker frames at the end while not affecting the ones in front as much? So when you Batch process, or you do a Video edit in the Camera Raw Filter, maybe the Shadow Recovery could help even out the exposure a bit then?

 

[Ben Egbert]

I already use shadow recovery, and in fact I do a lot of PP in ACR, lens correction, exposure, haze, clarity, contrast saturation, etc. They all work. You can do it to any image in the stack so long as all are selected. It's a good idea to check what it does to the last image if you do corrections on the front. I have not tired it, but you can probably use a gradient mask. NR and sharpening also work. You can also load jpgs or tiff files this way.

 

[Ben Egbert]

Ok, another run today at 1/200 second has flicker. So I need to find a good way to slow down the shutter.

And another later at 1/10 second, no flicker. I do need more than a grey sky to really test this. the last one was over changing light and started at ISO125 ending at ISO2000. I did not see any exposure changes, but a lot of noise at the end,