It is currently Sat Jan 20, 2018 5:11 am




Post new topic Reply to topic  [ 106 posts ]  Go to page 1, 2, 3  Next
 Flicker 
Author Message
User avatar

Joined: Fri Jun 13, 2008 5:54 am
Posts: 611
Location: Oslo, Norway
Post Flicker
Let's start a flicker discussion here! I will try to summarize:
In manual mode sources of flicker are:
Aperture flicker: The iris does not close consistently at the same diameter. The effect is (probably) worse the larger the f stop is. For canon lenses, there is a nice workaround from Antz: http://timescapes.org/phpBB3/viewtopic.php?f=4&t=435

Exposure time flicker: The exposure time is not exactly the same for every shot. The shorter the exposure time, the larger the flicker.

Natural flicker: Artificial lights, clouds, ... change the amount of light entering the lense.

In AV/TV mode:
For DSLRs, the EV steps are 1/3, which is too large. Compact cameras have smaller EV steps.


Experts, tell me please where I am wrong and please correct :)


I actually have rather good experiences using a f-stop of f/8 and exposure time larger than 1/100s. When I use a very strong ND filter which allows exposure times up to several seconds during bright daylight, the flicker is completely gone.

_________________
Canon 400D, 50D, 5D Mk II. Canon L 16-35/f2.8, Sigma 10-20. Adobe Creative Suite 4.
website:
http://www.magictimelapse.ch/en


Wed Jun 24, 2009 7:20 am
Profile

Joined: Wed Jun 24, 2009 5:56 am
Posts: 12
Location: kendal
Post Re: Flicker
Nice one Michael,

been reading through some of the posts over the last few days on the site, and haven't been able to find a good description of the flicker problems everyone seems to talk about all the time. It's like it's assumed knowledge, but I don't have it! I'm completely new to all this (not even tried my first shot yet). Hopefully this thread might yield some answers for the newbies like me.

Couple of questions if you don't mind:

The workaround for the canon lenses sounds promising. I assume that to avoid it without the workaround you just have to shoot wide open?

Correct me if I'm wrong here though.... Like I said, I'm new and not sure I've got my head around it all. I take it from what you've just said that if using aperture priority to control the exposure there's a chance that the exposure levels might vary slightly due to changing shutter speeds while conditions change (1/3 of a stop jumps)? I'm surprised that there's such a noticable difference given how good most cameras are at metering these days, but I guess that if one area of a scene changes then you'll see a difference in the rest o the scene as the frame's averaged.... I take it this is why most people seem to shoot in manual? Which in turn is why sunsets and day to night shots are really difficult: once the exposure's fixed you can't change it at all while the shot runs or you get flicker?

Reading between the lines, are you saying that longer exposures in the region of second rather than hundredths of seconds will have a smaller error and reduce flicker? If so, low ISO, small aperture and some good ND filters sounds like the way forward (though I understand that you then compromise your timing)....

I've just invested in a 5D (not been delivered yet), but from what I understand it's got a rather cunning auto ISO feature. Would aperture priority and auto ISO combined give better than the 1/3 stop adjustments and do the trick to get smooth, flicker free images around sunset?

Do people find that using an ND grad filters around sunset helps any with the problem or is that just standard practice and the problem remains anyway?

Given the effort involved in these I'm keen to get my head around as much as I can before going out and giving it a go! Sure, the first few tries will probably still get binned, but you've got to give yourself as good a chance as you can!

Sorry about dumping loads of questions right at the get-go, I know it's a bit rude when I've contributed nothing to the group. I have had a good look around over the last few day's worth of lunch breaks and these questions are ones that I struggled to get my head around. I used the search feature to try and find a definitive explanation to the "Flicker Phenomenon" but it just said that it couldn't search for "flicker" or "aperture" because they were too commonly used!

Cheers,



Dougie

_________________
http://www.flickr.com/photos/oldnotbold ... 723145314/


Wed Jun 24, 2009 8:18 am
Profile
User avatar

Joined: Tue Jul 08, 2008 12:36 pm
Posts: 1787
Location: Antarctica/California/New Zealand
Post Re: Flicker
Dougie, you are right in pretty much all the assumptions you have made.

Alas there is basically no way around the 1/3 EV steps on an SLR in any of the auto modes.
Subtle variations in lighting will make the exposure toggle up an down in level, and introduce flicker even in fairly steady lighting.
Basically, if a scene has changing light to the extent you need to use auto-exposure to capture it, you will need a de-flicker application to smooth it out in Post.

In full manual, shooting wide open will also remove aperture flicker, but it limits your creative shooting, and will also reduce the shutter speed, which can introduce shutter flicker. You can use a strong ND filter to push the shutter speed out further though.

One of the big reasons I like to use the lens twist method on the canons is to reduce wear on the lenses.
No one has ever really addressed iris wear on lenses, and just how long they will last. When I am forking out thousands of dollars for the "L" series lenses, I am not too eager to rack up hundreds of thousands of aperture operations unnecessarily.

For shutter flicker, personally I have found it pays to keep the exposure longer than about 1/30th.

_________________
Anthony Powell
"Antarctica: A Year On Ice" Feature Film
Vimeo Youtube Photos
Twitter Instagram Google+
Facebook Facebook Movie Page


Wed Jun 24, 2009 12:26 pm
Profile
User avatar

Joined: Tue Apr 29, 2008 2:48 pm
Posts: 1144
Post Re: Flicker
Antz wrote:
One of the big reasons I like to use the lens twist method on the canons is to reduce wear on the lenses.
No one has ever really addressed iris wear on lenses, and just how long they will last. When I am forking out thousands of dollars for the "L" series lenses, I am not too eager to rack up hundreds of thousands of aperture operations unnecessarily.


Actually I have heard of this happening the iris began to disintegrate inside the lens, not a pretty sight..

timt

_________________
Please check out how to embed a Vimeo link.
Tim T


Wed Jun 24, 2009 3:32 pm
Profile
Post Re: Flicker
Antz wrote:
No one has ever really addressed iris wear on lenses, and just how long they will last.


Interesting perspective.


Wed Jun 24, 2009 6:22 pm

Joined: Wed Jun 24, 2009 5:56 am
Posts: 12
Location: kendal
Post Re: Flicker
Cheers Antz,

guess it's wide open or "the Canon Twist" for me then....

Thinking about giving it a go this weekend, if I've got the time.


Dougie

_________________
http://www.flickr.com/photos/oldnotbold ... 723145314/


Thu Jun 25, 2009 2:37 am
Profile

Joined: Tue Nov 11, 2008 8:43 am
Posts: 100
Post Re: Flicker
One thing that I noticed, and this appears in the Canon Manual, is that you MUST tap the eyefinder with the little black ribbon, as see in this photo:

Image

In my tests, there is less flickering.

_________________
-------
http://www.timelapses.es
http://www.transfercinedigital.com
-------


Thu Jun 25, 2009 3:37 am
Profile
User avatar

Joined: Wed Jul 09, 2008 11:54 pm
Posts: 888
Location: Aars, Denmark
Post Re: Flicker
The list reflects well what the first thing is people see when they enter this forum - Aperture flicker. In my opinion, aperture flicker is a minor problem that has been blown out of proportions, getting way more attention than it deserves. That is not to say that it isn't a real problem for some, but that it's something most of us don't have to worry about. Aperture flicker is only a problem if:
1) You shoot full manual with the lens stopped down AND
2) You find it too elaborate/difficult to apply a decent deflicker filter in post processing
The thing is, aperture flicker is *generally* mild, much less than the exposure stepping resulting from using AV/TV/P. I've done some short tests to compare aperture flicker and exposure stepping, and the results are like this (M on left, AV on right):



I can see a hint of flicker in this full manual shot. In the other tests I saw nothing at all. But, some lenses are bound to be worse than others, and those who use full manual and stopped down regularly (I don't) may well run into cases with one or more frames that are significantly off. However, cases that a good deflicker filter won't cure are rare. If you have any such footage and you're willing to share it, please PM me.

"Good deflickers": For Windows users, VirtualDub + Graft or MSU deflicker are excellent free tools that will do the job. If you use After Effects, GBDeflicker is a not too expensive option. I suspect that effective deflicker tools are harder/more expensive to come by for Mac, but virtual PC + VirtualDub is still an option that can be had for cheap or even free (you can export as image sequence or uncompressed and import in your favorite editor for further processing).

Michael wrote:
For DSLRs, the EV steps are 1/3, which is too large. Compact cameras have smaller EV steps.

1) On automatic settings at least some DSLRs use smaller steps than are available in the menus. Exif shows that Canon DSLRs use 1/8 ev steps. For other brands I'm not sure. My Nikon D700 doesn't write correct/accurate values to exif, making it hard to tell.
2) I'm not sure all compact cameras have smaller EV steps. The Canon compacts I've dealt with do (S2, S3, SX100, SX110, ~1/32 EV in both aperture and shutter speed), but I think Ricohs have coarser steps - milapse?

DougieC wrote:
I'm surprised that there's such a noticable difference given how good most cameras are at metering these days

The cameras are indeed perfectly capable - the problem lies in the firmware. DSLRs are aimed at still photographers, and they don't need anything better than 1/8 or even 1/3 EV steps (so I doubt auto ISO is better, but I haven't actually tried it). All it would take to cure the problem is for manufacturers to make a simple tweak in the firmware, decreasing the step size for shutter speeds (for aperture it would require stepless aperture lenses which we may start seeing now thanks to the introduction of video). Then AV and P modes would be *almost* as good in terms of flicker as manual, and the day/night transition problem (dubbed by some as the "holy grail" of timelapse) would be a thing of the past. I say almost because if the subject changes too much from frame to frame, so will the metering and you can end up with visible exposure variations that you wouldn't get with full manual. Well, it is a matter of time before manufacturers will do it. I've sent this suggestion (along with implementation of internal intervalometer) to both Canon and Nikon. If more of you do the same, maybe they will bump it on their priority list.

_________________
Nikon D3s, D600, Canon 5D II, S3, SX100.
Feature film Beneath the Aurora on Vimeo.


Thu Jun 25, 2009 4:59 am
Profile
Site Admin
User avatar

Joined: Thu Mar 27, 2008 2:15 pm
Posts: 1695
Post Re: Flicker
actpower wrote:
One thing that I noticed, and this appears in the Canon Manual, is that you MUST tap the eyefinder with the little black ribbon, as see in this photo:

Image

In my tests, there is less flickering.


I assume that if you are shooting in Live View mode, you don't have to worry about covering the eyepiece?


Thu Jun 25, 2009 5:36 am
Profile

Joined: Tue Nov 11, 2008 8:43 am
Posts: 100
Post Re: Flicker
Good Question...I don´t know. My 450D have LiveView, but don´t use it for Timelapse. Check the manual about this...you are using the "Betty" isn´t?

_________________
-------
http://www.timelapses.es
http://www.transfercinedigital.com
-------


Thu Jun 25, 2009 5:47 am
Profile

Joined: Wed Jun 24, 2009 5:56 am
Posts: 12
Location: kendal
Post Re: Flicker
flyvholm: good work lad, cheers! Nice comparison too.

Does that mean that when you see flicker on the automatic exposure settings on the likes of a canon you're actually seeing differences of just 1/8 of a stop?

Timescapes: when shooting long exposures for stills you should always cover the eyepiece. Stray light from behind the camera can get in through the viewfinder and prism and interfere with the shot. If it has an effect on long exposures I can't see why it wouldn't have an effect on using live-view (the camera's in the same state during the exposure in both cases - mirror up). I don't normally cover it until doing long exposures at night though, and would never have thought to do it for something as short as 1/30th of a second, but then I've never tried timelapse and never had to get a series of perfectly exposed shots!





Dougie

Edited to fix typos.

_________________
http://www.flickr.com/photos/oldnotbold ... 723145314/


Thu Jun 25, 2009 6:14 am
Profile

Joined: Thu Jun 25, 2009 7:19 am
Posts: 1
Post Re: Flicker
Hi All,

I do minimize flicker as much as possible, but I know I could make things much better if I were able to run everything through a de-flicker filter. I do everything on my Mac and I am not going to buy a windows machine just to do this. Nor am I going to lay down hundreds of dollars for a plugin. It absolutely blows my mind that no one has made a freeware de-flicker program or plugin for Macs. If anyone knows of anything that can help, aside from the obvious, please let me know. I have tried the tool mentioned at my disposal - Color Stabilizer in AE, but the results were pretty bad, even for correcting a slight flicker, and with my tweaking the parameters endlessly.

Any suggestions?


Thu Jun 25, 2009 7:27 am
Profile
User avatar

Joined: Wed Jul 09, 2008 11:54 pm
Posts: 888
Location: Aars, Denmark
Post Re: Flicker
timescapes wrote:
I assume that if you are shooting in Live View mode, you don't have to worry about covering the eyepiece?

If you are shooting full manual it shouldn't matter (with respect to flicker) as the exposure should be independent of metering. However, I think the metering sensor is still exposed to stray light from the viewfinder during live view, so for automatic settings it is still a good idea to cover the viewfinder to be on the safe side.

Regarding aperture flicker, I guess I should be more cautious with my statements. I've said it's a rare case that can't be cured with a deflicker in post, but if the problem is particularly bad for some specific cameras/lenses (it *should* be a matter of the lens only - if the camera is involved, it isn't really what we understand by aperture flicker), then it may not be a rare case for owners of those cameras/lenses.

DougieC wrote:
Does that mean that when you see flicker on the automatic exposure settings on the likes of a canon you're actually seeing differences of just 1/8 of a stop?

Yes. The flicker you see in the video above are from 1/8 EV steps (you can verify this from the exposure times printed on top).

fowlshot wrote:
Any suggestions?

You could try some virtual PC software (some of which is free) and run VirtualDub plus Graft or MSU deflicker (also free) to deflicker your image sequence and then import the deflickered sequence to AE. I know I suggested this earlier in this thread too, but just in case you missed it. It's an option.

_________________
Nikon D3s, D600, Canon 5D II, S3, SX100.
Feature film Beneath the Aurora on Vimeo.


Thu Jun 25, 2009 8:28 am
Profile
User avatar

Joined: Thu Jul 10, 2008 8:10 am
Posts: 84
Post Re: Flicker
flyvholm wrote:
...run VirtualDub plus Graft...


This is my weapon of choice. The combo does a nice job and both are free. Here are the links for VirtualDub and Donald Graft's Deflicker filter. I wrote a short tutorial on the bottom of this thread.

_________________
'
Chris Raezer Photography


Tue Jun 30, 2009 10:24 am
Profile
User avatar

Joined: Wed Nov 11, 2009 10:29 am
Posts: 1
Location: Philadelphia
Post Re: Flicker
As a newbie, this is the subject I am hoping to address first. I am excited that this forum exists, and wish I had found it earlier. I am also a Mac user, and have tested all of the deflicker solutions out there and have been disappointed. Is anyone successfully running Virtual PC with Virtual Dub to address these issues? flyvholm?
Thanks!


Wed Nov 11, 2009 11:21 am
Profile
User avatar

Joined: Wed Jul 09, 2008 11:54 pm
Posts: 888
Location: Aars, Denmark
Post Re: Flicker
I am not using Mac myself, but as far as I recall others have posted that they've used this method successfully.

I'd say the Graft filter is surprisingly good; the best I've tried. I also use GBDeflicker in After Effects, and it happens frequently that GBDeflicker can't eliminate the flicker or produces horrible artifacts, and the Graft filter fixes it. It depends on the footage though. The Graft filter does have a tendency to produce ghosting which some cloud scenes are particularly vulnerable to.

_________________
Nikon D3s, D600, Canon 5D II, S3, SX100.
Feature film Beneath the Aurora on Vimeo.


Fri Nov 13, 2009 5:21 am
Profile
User avatar

Joined: Tue Jun 30, 2009 6:14 am
Posts: 61
Post Re: Flicker
I can't believe I haven't tried these deflicker filters. In the past I was always directed to try Lightroom's "Match Total Exposure" feature but haven't found a way to fit it in my workflow (so I try to avoid flicker situations).

Currently I'm going through a flicker (sunrise/sunset) nightmare situation and will definitely try these deflicker filters.

Could someone please tell me how this compares to the Lightroom "Match Totla Exposure" feature? I'd like to compare the two and run tests but perhaps someone else could offer their experience.


Sat Nov 14, 2009 9:49 pm
Profile

Joined: Fri Nov 13, 2009 4:33 am
Posts: 12
Post Re: Flicker
I have just started using a DSLR (Pentax K200D) and am experimenting with night timelapse. Using my own intervalometer, I set the interval to be 1 shot per minute with a 25 second exposure. This allows time (around 35 seconds) for the noise reduction feature to take a ~25 second shot with the aperture closed, then substract the noise recorded in the second shot from the first shot.

The problem I have is that the photos vary alternately in brightness. One bright, one darker, one bright, one darker....

If I make the interval larger, the pictures become fairly consistant.

Is this flicker or some other problem?

Thank you.


Tue Nov 17, 2009 4:57 am
Profile
User avatar

Joined: Wed Jul 09, 2008 11:54 pm
Posts: 888
Location: Aars, Denmark
Post Re: Flicker
marshallarts wrote:
Could someone please tell me how this compares to the Lightroom "Match Total Exposure" feature?

I haven't heard it mentioned, but it sounds like a function that would work for adjusting individual frames whereas I'm not sure whether you could use it for batch processing a sequence as deflicker filters do. In any case I doubt anybody here can tell you how they compare.

beavercreek wrote:
Is this flicker or some other problem?

Sure sounds like flicker, but not sure what the source is. I'd assume you're using full manual settings and maximum aperture. What if you don't use the noise reduction feature? You could take just one 25 sec dark frame at the end of your session and subtract that from all your images in post if hot pixels are significant. That way you could cut your interval in half which might well be worth the effort.

_________________
Nikon D3s, D600, Canon 5D II, S3, SX100.
Feature film Beneath the Aurora on Vimeo.


Tue Nov 17, 2009 11:59 am
Profile
User avatar

Joined: Tue Jun 30, 2009 6:14 am
Posts: 61
Post Re: Flicker
Flyvholm,
Well I've investigated, tested, and learned further about the Lightroom match total exposure technique. This is certainly not the way to go as I've misinterpreted the name of the feature and it's use is for something different. It looks as EXIF data and sums exposure level based on f/stop, shutter speed, and ISO for a selected image, and then changes the EV in other photos to match that preferred exposure level based on the changes you've made in f/stop, ISO, and shutter speed (for instance if you wanted to change DoF). This assumes the light levels haven't changed and so corrects inconsistencies shot to shot as you change perimeters.

So I went ahead and downloaded VirtualDub on my Mac running Windows 7 through Parallels. Now I've realized VirtualDub doesn't open .mov files.... Is there a preferred method for converting to PC friendly video files? My QuickTime can export to AVI (not sure if that was a plugin I have or comes with it), but does this preserve the best image quality? I exported a lossless animation from AE thinking VirtualDub would accept that but it still won't. Any suggestions?

Also, side question, when exporting, what happens to the dynamic range we've tried so hard to preserve by shooting RAW? I import my sequences either RAW or 16-bit Tiff. What have you learned about this? Is it better in AE to work with RAW or Tiff, and am I correct to use 16-bit Tiff to preserve dynamic range? And when I export is the dynamic range crushed anyhow?

EDIT-- I just saw another thread discussing VirtualDub workflow. You explain about using VirtualDub to build the actual image sequence. Because I'm coming from Mac and am used to AE I figured I'd use VirtualDub just as a deflickerer. Should I just build the time lapse in VirtualDub to correct flicker instead of importing a video? But then how do I do my other stuff in AE?--stabilize, pans...??


Sat Nov 21, 2009 10:16 am
Profile

Joined: Wed Nov 11, 2009 8:08 pm
Posts: 8
Post Re: Flicker
A few questions regarding flicker, as I'm just starting out here and I'm trying to make each sequence better than the last.

Before I discovered these forums, I was working mostly off advice from Timothy Allen's blog at http://timothyallen.blogs.bbcearth.com/ ... otography/. He reccomends using manual focus lenses with a preset aperture and jamming the open/close lever for the diaphram. I haven't really investigated how this would work mechanically, but it sounds dodgy.

Has anyone tried it? Does use of a manual lens improve the flicker situation in any way?

Also, can anyone recommend a tutorial on using VirtualDub + Graft? And where can you download this software?

I've made two videos so far, and both have some degree of flicker. As you'll see, I tackled the holy grail right out of the gate before I really knew what I was doing, and the results are less than ideal.

Beach scenes:
http://www.youtube.com/watch?v=mIqm3rL5KOs
Dusk in Philly:
http://www.vimeo.com/7526394


Sun Nov 22, 2009 8:46 am
Profile
User avatar

Joined: Tue Jun 30, 2009 6:14 am
Posts: 61
Post Re: Flicker
Hallpass,

Your first question about 'jamming the lens' is already discussed in detail in this very thread. Any reservations you have about the method are surely felt by all of us but it's arguably the best way to handle this problem.

About VirtualDub, this was discussed in this very thread too. It doesn't seem you bothered to even read the whole discussion. In addition there's an entire other thread in the DSLR section dedicated to VirtualDub in step by step detail. If that doesn't help a quick google search will answer your problems... you'll see VirtualDub is free and available online, as is MSUDeflicker (I don't use Graft).

I'd read through this thread in it's entirety, it's barely over a single page, and do some searches.


Sun Nov 22, 2009 9:14 pm
Profile
User avatar

Joined: Wed Jul 09, 2008 11:54 pm
Posts: 888
Location: Aars, Denmark
Post Re: Flicker
marshallarts wrote:
Is there a preferred method for converting to PC friendly video files? My QuickTime can export to AVI (not sure if that was a plugin I have or comes with it), but does this preserve the best image quality? I exported a lossless animation from AE thinking VirtualDub would accept that but it still won't. Any suggestions?

Also, side question, when exporting, what happens to the dynamic range we've tried so hard to preserve by shooting RAW? I import my sequences either RAW or 16-bit Tiff. What have you learned about this? Is it better in AE to work with RAW or Tiff, and am I correct to use 16-bit Tiff to preserve dynamic range? And when I export is the dynamic range crushed anyhow?

EDIT-- I just saw another thread discussing VirtualDub workflow. You explain about using VirtualDub to build the actual image sequence. Because I'm coming from Mac and am used to AE I figured I'd use VirtualDub just as a deflickerer. Should I just build the time lapse in VirtualDub to correct flicker instead of importing a video? But then how do I do my other stuff in AE?--stabilize, pans...??

I'm afraid it's limited how much I can help you here as I have no experience with Mac/Quicktime and I rarely shoot RAW. When I do shoot RAW I tweak the photos as desired and save them as JPGs that I import in VirtualDub. This does reduce the dynamic range, but since it is done after the RAW processing I've already taken advantage of the extra dynamic range in the RAW footage (e.g. to adjust shadows/highlights) to the extent needed. However, if you want to avoid any JPG compression I believe you should be able to open the RAW footage in AE and export as uncompressed AVI which VirtualDub should accept. You can then export from VirtualDub as uncompressed AVI (deflickered) that you can import back into AE. This way you won't compress your footage until your final export of the video. However, you'll spend some processing time and hard drive space on that uncompressed footage. I did a quick test to verify that this workflow works between AE and VirtualDub within Windows. The editing you want to do in AE could be done either before or after deflickering with VirtualDub (superposing text/graphics should be done after).

Hallpass wrote:
Also, can anyone recommend a tutorial on using VirtualDub + Graft? And where can you download this software?

Just in case you didn't find it already, the other thread with a rough VirtualDub guide (and links for downloads) mentioned by marshallarts is here.

_________________
Nikon D3s, D600, Canon 5D II, S3, SX100.
Feature film Beneath the Aurora on Vimeo.


Mon Nov 23, 2009 12:50 am
Profile

Joined: Wed Nov 11, 2009 8:08 pm
Posts: 8
Post Re: Flicker
marshallarts wrote:
Hallpass,

Your first question about 'jamming the lens' is already discussed in detail in this very thread. Any reservations you have about the method are surely felt by all of us but it's arguably the best way to handle this problem.


Actually Marshall, if you'd followed my link, you'd see the tutorial I was asking about recommends:

Quote:
There are a couple of things you can do to combat time lapse flicker. Firstly, use an old, fully manual lens on your digital body – one of those lenses where the aperture control ring is on the barrel of the lens. On the lens mount, you need to jam something (a small piece of plastic is good) into the gap on either side of the small lever that controls the aperture size in order to fix it at one position. This way, the aperture is stuck at the f-stop you designate and cannot open and close as normal when the camera shoots a frame, thus eliminating any potential fluctuations.


The jamming discussion in the thread above appears to discuss the method of disabling the aperture actuation on Canon lenses by blanking off the contacts or twisting the lens out of position.

I was wondering whether anyone has had any experience using old glass to do time lapses and whether the technique described above actually works.

Fly, thanks for the link.

Incidentally, the search function on this forum leaves a lot to be desired.


Thu Nov 26, 2009 8:31 am
Profile
Post Re: Flicker
Hallpass wrote:
Actually Marshall, if you'd followed my link, you'd see the tutorial I was asking about recommends:


Actually hallpass if you want to get technical about it there are many ways to disable body to lens aperture control depending on the camera model
Image


Hallpass wrote:
I was wondering whether anyone has had any experience using old glass to do time lapses and whether the technique described above actually works.


Yep it actually works but be aware that the method in which bodies communicate with lenses varies quite a bit and many hold the aperture open even with rings. AND be aware that it's not a panacea. Flicker has many sources , one of which is the physical shifting light conditions in the field.

hallpass wrote:
Incidentally, the search function on this forum leaves a lot to be desired.


This information has not always been easy to find... the phpBB search has always had it's flaws but at least it's here. Not 2 years ago you'd be hard pressed to find a smalll fraction of information & experience we've shared here.


Thu Nov 26, 2009 9:34 am
User avatar

Joined: Tue Jun 30, 2009 6:14 am
Posts: 61
Post Re: Flicker
flyvholm wrote:
I believe you should be able to open the RAW footage in AE and export as uncompressed AVI which VirtualDub should accept. You can then export from VirtualDub as uncompressed AVI (deflickered) that you can import back into AE.


Well..... What frustrates me to no end is how incredibly tedious each and every step the digital world has become. That nothing works the way it's needed to is making me cry blood.

It appears a Mac can open the uncompressed video file produced by VirtualDub and use it in AE or Quicktime or whatever.. But I have not been able to export any video file on the Mac side that VirtualDub works with. Whenever I apply the deflicker filter and press "OK" the program crashes. Details say "An out-of-bounds memory access (access violation) occurred in module 'VirtualDub'... ...reading address 00000000."

Has anyone encountered this?! I'm beginning to freak out as my deadline is tomorrow....


Fri Nov 27, 2009 4:31 pm
Profile
User avatar

Joined: Wed Jul 09, 2008 11:54 pm
Posts: 888
Location: Aars, Denmark
Post Re: Flicker
That sure looks like a bug. My first try for an immediate solution would be to try a different version - e.g. if you don't have 1.9.7 (latest stable), try that. If you already have 1.9.7, install a previous version. If that doesn't help it's time to visit the VirtualDub forums. Here's one post that may or may not be relevant:

http://forums.virtualdub.org/index.php? ... b163d41283

If you can't find anything to fix the problem I suggest you post your error report in the VirtualDub forums to see if it can be helped/fixed. The only time I've posted an error there it got fixed right away, and it appears that the developer is still on the mark. Even if you can't make it by your current deadline it might prove useful to have it fixed for future use.

_________________
Nikon D3s, D600, Canon 5D II, S3, SX100.
Feature film Beneath the Aurora on Vimeo.


Fri Nov 27, 2009 6:04 pm
Profile
User avatar

Joined: Tue Aug 26, 2008 3:30 am
Posts: 824
Location: Sydney, Australia
Post Re: Flicker
Quote:
There are a couple of things you can do to combat time lapse flicker. Firstly, use an old, fully manual lens on your digital body – one of those lenses where the aperture control ring is on the barrel of the lens. On the lens mount, you need to jam something (a small piece of plastic is good) into the gap on either side of the small lever that controls the aperture size in order to fix it at one position. This way, the aperture is stuck at the f-stop you designate and cannot open and close as normal when the camera shoots a frame, thus eliminating any potential fluctuations.


The jamming discussion in the thread above appears to discuss the method of disabling the aperture actuation on Canon lenses by blanking off the contacts or twisting the lens out of position.

I was wondering whether anyone has had any experience using old glass to do time lapses and whether the technique described above actually works.

matt b : I have a set of early Canon FD lenses (fantastic optics) that I use on the 5D2.

I use the rigid top part of a foam coffee cup cut to size and blackened with a suitable pen. The curved shape of the coffee cup rim fits the contours of the aperture control slot and jams it for manual use. As suggested a firmer piece of plastic can work but don't forget to blacken it to prevent internal flare.


Fri Nov 27, 2009 11:21 pm
Profile
User avatar

Joined: Tue Nov 17, 2009 10:00 am
Posts: 5
Location: Los Angeles, CA
Post Re: Flicker
I did some sunset-at-the-beach shots the other day. I had my 5D set to manual, 17-40L lens set to f/4 (wide open) and the shutter speed was around 1/3200th.

There is drastic flicker, and if I read this thread correctly, that's due to my shutter speed? Is an ND filter the only answer for daylight shots in order to reduce flicker originating from shutter speed irregularity?

I use Lightroom 2 and AE CS3 for all my post processing, which consists only of cropping, renaming, and exporting as a Quicktime file.

_________________
Brad Garner Photography
Hollywood, California
http://www.bradgarnerphoto.com


Mon Nov 30, 2009 11:55 am
Profile
User avatar

Joined: Wed Jan 14, 2009 8:34 pm
Posts: 626
Post Re: Flicker
bgarnerphoto wrote:
I did some sunset-at-the-beach shots the other day. I had my 5D set to manual, 17-40L lens set to f/4 (wide open) and the shutter speed was around 1/3200th.

There is drastic flicker, and if I read this thread correctly, that's due to my shutter speed? Is an ND filter the only answer for daylight shots in order to reduce flicker originating from shutter speed irregularity?

I use Lightroom 2 and AE CS3 for all my post processing, which consists only of cropping, renaming, and exporting as a Quicktime file.


Brad I actually did a test last night that is somewhat related. My conclusion was that a 3% inconsistency in exposure time (read: shutter speed) yielded flicker that I would regard as unacceptable. 1/3200 is so much faster than the camera's xsync speed that the shutter curtains are traveling across the sensor together with only a narrow slit between them - under these extreme conditions I don't believe the shutters are synchronized with 3% accuracy. That would require very fine engineering. I guess the best solutions are to stop down lens (remembering to lock aperture) and ND filters...

_________________
Little Bramper website and on Timescapes
Link to Time-lapse FAQ


Mon Nov 30, 2009 12:55 pm
Profile
User avatar

Joined: Tue Nov 17, 2009 10:00 am
Posts: 5
Location: Los Angeles, CA
Post Re: Flicker
astronomerroyal wrote:
bgarnerphoto wrote:
I did some sunset-at-the-beach shots the other day. I had my 5D set to manual, 17-40L lens set to f/4 (wide open) and the shutter speed was around 1/3200th.

There is drastic flicker, and if I read this thread correctly, that's due to my shutter speed? Is an ND filter the only answer for daylight shots in order to reduce flicker originating from shutter speed irregularity?

I use Lightroom 2 and AE CS3 for all my post processing, which consists only of cropping, renaming, and exporting as a Quicktime file.


Brad I actually did a test last night that is somewhat related. My conclusion was that a 3% inconsistency in exposure time (read: shutter speed) yielded flicker that I would regard as unacceptable. 1/3200 is so much faster than the camera's xsync speed that the shutter curtains are traveling across the sensor together with only a narrow slit between them - under these extreme conditions I don't believe the shutters are synchronized with 3% accuracy. That would require very fine engineering. I guess the best solutions are to stop down lens (remembering to lock aperture) and ND filters...

Thanks. Glad to know the problem and that there is a solution.

In case anyone is curious to see, here's the sample video. I didnt doublecheck my ISO, though, so it's at 3200 from a previous shot...but even in shots with the ISO correctly set, I can see flicker at these shutter speeds. Also, I was incorrect above, my shutter speed was actually 1/8000th, the maximum the 5D can do.

_________________
Brad Garner Photography
Hollywood, California
http://www.bradgarnerphoto.com


Mon Nov 30, 2009 1:27 pm
Profile
User avatar

Joined: Mon Apr 21, 2008 4:35 pm
Posts: 78
Location: Asheville, NC
Post Re: Flicker
It's easy to see how you get flicker using anything other than the lenses largest are smallest aperture in this example:


Nikon D3 shutter and aperture @ 5,000 frames per second: (lens is set to ƒ/16)


_________________
blackvisual.com


Mon Dec 07, 2009 6:10 am
Profile
User avatar

Joined: Tue Apr 28, 2009 7:48 pm
Posts: 144
Location: Vista, California
Post Re: Flicker
After seeing the yotube video of shutter, mirror and aperture in slow motion, I'm amazed these camras survive what we put them through! I sometimes run one of the time filters in AE and that gets rid of flicker by blending frames together. You may get an unwanted look to your clip though.

Dan


Mon Dec 07, 2009 9:33 am
Profile
User avatar

Joined: Tue Aug 26, 2008 3:30 am
Posts: 824
Location: Sydney, Australia
Post Re: Flicker
Dan Eckert wrote:
. You may get an unwanted look to your clip though.


When you guys use the various deflicker software fixes, do you notice a trade off in image quality?

The mirror bounce in that clip is amazing, I'm also impressed at the duty cycle at those speeds.

I have been fortunate that in several recent shoots, I have been using a manual Nikon 55mmm Macro lens (set @ f32) with a Cinevate EOS convertor and exposure times of around 1/8sec. - No flicker :D


Mon Dec 07, 2009 2:59 pm
Profile
User avatar

Joined: Fri Jun 13, 2008 5:54 am
Posts: 611
Location: Oslo, Norway
Post Re: Flicker
Hi William, welcome!
william wrote:
Reading between the lines, are you saying that longer exposures in the region of second rather than hundredths of seconds will have a smaller error and reduce flicker? If so, low ISO, small aperture and some good ND filters sounds like the way forward (though I understand that you then compromise your timing)....

Yep, that's a good summary how to prevent flicker. Exposure > 1/100s, low ISO, f < 8.0 and ND filters, that's the way I usually go!

_________________
Canon 400D, 50D, 5D Mk II. Canon L 16-35/f2.8, Sigma 10-20. Adobe Creative Suite 4.
website:
http://www.magictimelapse.ch/en


Thu Dec 10, 2009 3:44 am
Profile
User avatar

Joined: Mon Nov 30, 2009 6:50 am
Posts: 329
Location: France
Post Re: Flicker
Michael wrote:
Hi William, welcome!
william wrote:
Reading between the lines, are you saying that longer exposures in the region of second rather than hundredths of seconds will have a smaller error and reduce flicker? If so, low ISO, small aperture and some good ND filters sounds like the way forward (though I understand that you then compromise your timing)....

Yep, that's a good summary how to prevent flicker. Exposure > 1/100s, low ISO, f < 8.0 and ND filters, that's the way I usually go!


what an interesting thread ;)
i've only uses manual settings yet but ill test the Aperture one for sunset.

Ok so you all recomand less than 1/50 sec to reduce flicker.

What about nights shoots ?
Nô sûre using F9 is great if i want not to go over the. 30sec exposure Time ;)
what is a good iso ?
My D3 isnt really noisy but not sûre that the using long exposure doenst Heat the sensor !!

_________________
Timelapses.fr http://www.Timelapses.fr
Pro http://www.bziegler.com
Blog http://blog.bziegler.com

Nikon D800 - Canon 5DMkIII- scalped 10.5 - 15mm sigma - 14/24 - 17/35 - 24/70 - 70/200 - 28/300 105 macro - 50 f1.4 - 85 f1.4- 24 f1.4


Thu Dec 10, 2009 3:20 pm
Profile
User avatar

Joined: Tue Apr 29, 2008 2:48 pm
Posts: 1144
Post Re: Flicker
Sputnik wrote:
It's easy to see how you get flicker using anything other than the lenses largest are smallest aperture in this example:
Nikon D3 shutter and aperture @ 5,000 frames per second: (lens is set to ƒ/16)


wow that is easy to see how the aperture is flexing and how impossible it is to get the exactly same setting frame after frame. thanks for posting it

_________________
Please check out how to embed a Vimeo link.
Tim T


Thu Dec 10, 2009 10:35 pm
Profile
User avatar

Joined: Thu Jan 22, 2009 3:05 pm
Posts: 109
Location: Cleveland, Ohio
Post Re: Flicker
Quote:
william wrote:
Reading between the lines, are you saying that longer exposures in the region of second rather than hundredths of seconds will have a smaller error and reduce flicker? If so, low ISO, small aperture and some good ND filters sounds like the way forward (though I understand that you then compromise your timing)....

Yep, that's a good summary how to prevent flicker. Exposure > 1/100s, low ISO, f < 8.0 and ND filters, that's the way I usually go!


That's pretty close to my approach as well. My process is:

Start with LOWEST ISO and f 7. (any f>8 and your lens/sensor better be spotless)
Choose interval between shots
divide that interval time by two to get the exposure time (creates smooth motion)
If these settings are under-exposed: Bump ISO up and or f down.
If these settings are over-exposed: Add ND filters.

I always disengage the lens first to get rid of aperture flicker, and set manual white balance.

It is interesting to note how good results can be in full AUTO mode:
http://timescapes.org/phpBB3/viewtopic.php?f=7&t=1614
I imagine it helps to have the 5D2 and a lens that is probably worthy of it?

Alex Boxerbaum (kirby)
www.36viewsofabridge.com
http://www.peristalticmayhem.com


Tue Jan 12, 2010 9:34 am
Profile

Joined: Wed Jan 13, 2010 6:51 am
Posts: 1
Post Re: Flicker
I have a crazy work around 'flicker'. Although from now on, I'll probably set manual. But in these past few instances experimenting with the 5DMII, I set Aperture Priority and let the shutter do the work. From sunset, through to night. And I got lots of flicker. I shot a small curve JPEG, on the Canon 5DMII. Anyway. I opened QuickTime Pro and ran an Image Sequence on them, converting them to a 25fps movie. I then took this sequence into to FCP7. I dropped a piece of HD video on the timelime, to set the Sequence settings; then dropped the movie on the time line, and sized up the 4:3 to 16:19. I then exported the sequence, using Modify Speed, at 500%. I then brought it back in, and decreased the speed to 25%; The end result; noticeably reduced flicker. Its nowhere near perfect but it will get you out of trouble:
http://platinumhd.smugmug.com/Tourism/5 ... 8120_nfJjP
To TimeScapes.Org, I can only say WOW. Thanks for all your inspiration.


Wed Jan 13, 2010 7:24 am
Profile

Joined: Thu Jan 28, 2010 12:24 am
Posts: 8
Post Re: Flicker
Quote:
That's pretty close to my approach as well. My process is:

Start with LOWEST ISO and f 7. (any f>8 and your lens/sensor better be spotless)
Choose interval between shots
divide that interval time by two to get the exposure time (creates smooth motion)
If these settings are under-exposed: Bump ISO up and or f down.
If these settings are over-exposed: Add ND filters.





Hmm, may have to try this. thanks


Thu Jan 28, 2010 12:26 am
Profile
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 106 posts ]  Go to page 1, 2, 3  Next


Who is online

Users browsing this forum: No registered users and 3 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
cron
Powered by phpBB © phpBB Group.
Designed by Vjacheslav Trushkin for Free Forums/DivisionCore. pozycjonowanie