Annoying auto iris issue with the AF100

mainstreetprod

mainstreetprod

Veteran
I've only had my AF for 3 weeks and am enjoying it - but today I tried shooting a time lapse at sunset, as I've done hundreds of times on the HVX200. On the HVX, I learned to use auto iris when shooting at sunset to keep the image brightness stable. If you use a fixed aperture, as soon as the sun goes down you have a dark, unusable image.

I set the AF on auto iris and this is what I got :


As you can see, instead of bumping the exposure smoothly, the AF does it every few minutes with a jolt in brightness level. Unusable for stock footage. Looks like I'm going back to the HVX for these shots.
 
Nice shot.

Try a test using a fixed aperture for the brightest part of the sequence. Let the light do its thing .
 
What lens were you using? AFAIK, the stepped aperture response is more a consequence of the lens than the camera. But I'd agree with Shooter about the exposure.

- Greg
 
I've done alot of timelapse using my Nikon D200. With the AF lenses the aperture opens then stops down between exposures. It dosen't always stop down to the exact same aperture all the time. Makes the image flicker. I found a great plugin from Granite Bay that does a great job of fixing the flicker. Try there demo, it might work for you.

http://www.granitebaysoftware.com/Products/ProductGBD.aspx
 
banolan said:
I've done alot of timelapse using my Nikon D200. With the AF lenses the aperture opens then stops down between exposures. It dosen't always stop down to the exact same aperture all the time. Makes the image flicker. I found a great plugin from Granite Bay that does a great job of fixing the flicker. Try there demo, it might work for you.

http://www.granitebaysoftware.com/Products/ProductGBD.aspx
Click to expand...

Thanks for the tip, I'll give it a try- tried doing it by adjusting the brightness of the segments but tended to get a frame or two off at the junctions.I was using the 20mm pancake. I'll gie the 14-140 a try and see if it does the same thing.
 
This is a common and known complaint with the AF100 and auto iris. The camera changes exposure in click-stops, rather than gradually, like a still camera, not like a video camera should with stepless iris control.
Others have also complained about the fact that you can hear it clicking in the footage. Auto Iris is a wasted feature, as is facial follow focus, which requires auto iris to be on to work.

And it's not just with auto iris, even with manual iris control, it's not stepless with the native m4/3 lenses.

Could be a lens limitation, could be camera limitation, could be both. Maybe it could be addressed in firmware, maybe not. Panasonic told me they are aware of it, but they're silent on whether they're intending to do anything about it or not. There are also issues with zooming, clicks and flashing and going out of focus during the zoom.

You can get around the stepped auto exposure problem if you use a GH2 for this. Use aperture priority mode and auto gain (auto ISO). It works beautifully. The AF100 doesn't have auto gain. Pity.
 
D10S said:
I'd also advise NOT using auto iris. It's not necessary for this.
Click to expand...

It's necessary for the effect I want, which is stable exposure even after sunset. With the HVX on auto I can go on another half hour after sunset, with this camera on manual, at sunset, it's about over.
 
Surely thats the natural progression of light in a timelapse?

(It goes from day light to dark and thats what you are filming)

You calculate the exposure for the brightest part of the event and let it takes its course.

Auto exposure calculates everything to be an average tone ( based on a skin tone) . It will constantly correct to achieve that goal ( program).
 
Shooter said:
Surely thats the natural progression of light in a timelapse?

(It goes from day light to dark and thats what you are filming)

You calculate the exposure for the brightest part of the event and let it takes its course.

Auto exposure calculates everything to be an average tone ( based on a skin tone) . It will constantly correct to achieve that goal ( program).
Click to expand...

I've done timelapse for some of my projects and I agree with the OP, when you just leave one exposure when the sun is going down or coming up, it just doesn't work well. I tend to shoot these with my 7D and fix any flickering in post, but, I tried setting one exposure early on based on the brightest part of the scene and it really didn't look that great.

What I wanted was variable exposure time, not iris adjustment, on the 7D if I recall correctly (been a long time) which was shutter priority maybe?

I'll have to check out that tool so the next one I do I do not have to fix by hand.
 
Shooter said:
Surely thats the natural progression of light in a timelapse?

(It goes from day light to dark and thats what you are filming)

You calculate the exposure for the brightest part of the event and let it takes its course.

Auto exposure calculates everything to be an average tone ( based on a skin tone) . It will constantly correct to achieve that goal ( program).
Click to expand...

I like to shoot a long timelapse starting before sunset and continuing afterwards. Even with auto exposure (which works flawlessly on the HVX) the scene eventually darkens when there is just not enough light for the camera's capabilities, so it looks natural. If one exposure were used, it would have to start out way too bright to be properly exposed around sunset, then immediately darken to unusable. With good auto exposure I can continue shooting the best part, right after the sun drops, with the changing sky colors. Like this shot:

http://www.revostock.com/Stock-Video-Footage/34596/Dusky-sky.htm
 
Shooter said:
Surely thats the natural progression of light in a timelapse?

(It goes from day light to dark and thats what you are filming)

You calculate the exposure for the brightest part of the event and let it takes its course.

Auto exposure calculates everything to be an average tone ( based on a skin tone) . It will constantly correct to achieve that goal ( program).
Click to expand...

But that doesn't solve his dilemma because his goal is not to capture the natural progression from day light to dark. He's saying he WANTS it to constantly correct to achieve a relatively average tone, so that he can continue capturing light imagery well after the sun has set. Otherwise it just goes to dark and it's over before he wants it to be. The problem is that there is no way to make the AF100 do that in a smooth progression. As he said he's going to have to go back to using his other camera.
 
Rick Burnett said:
I've done timelapse for some of my projects and I agree with the OP, when you just leave one exposure when the sun is going down or coming up, it just doesn't work well. I tend to shoot these with my 7D and fix any flickering in post, but, I tried setting one exposure early on based on the brightest part of the scene and it really didn't look that great.

What I wanted was variable exposure time, not iris adjustment, on the 7D if I recall correctly (been a long time) which was shutter priority maybe?

I'll have to check out that tool so the next one I do I do not have to fix by hand.
Click to expand...


It would be aperture priority.

The Canon 7D and 60D don't have aperture priority in movie mode - only "auto" or "manual". In "auto" everything is auto - aperture, shutter speed, and ISO. In "manual", aperture and shutter speed are manual, and ISO is can be either manual or auto.

The Panasonic GH2 offers M - manual, A - aperture priority, S - shutter priority, and P - auto aperture and shutter, and in addition to that allows either a manually set ISO or Auto ISO.

The AF100 offers only manual, or auto iris which is equivalent to shutter priority.

All of these cameras change iris in "stops" so the light actually changes. Changes in shutter speed and/or ISO don't seem to flicker the way the change in iris does. Automatic changes in shutter speed or ISO are more subtle.
 
No, it doesn't. It is unfortunate that the still-photography lens division in no way caterings to the video camera division.

[edit - or do I have that wrong; it's the camera.]
 
Either it's the camera, because it does it with both Lumix lenses (which should "talk" as well as any lens to the body, in theory)
or...
It's the lenses, and the Lumixes just don't change smoothly- pancake or X.

Theories?

And I agree for this type of sunset TL, auto iris is the way to go- I've done it this way for over 25 years.
Other option is to change shots (CU, MS, WS) setting iris for each- but for a long continuous shot, auto is the way to go.
 
Gugulino said:
I own the new Lumix X Lens 45-175 and I am very happy with it. It shows no visible stops anymore.

Did you already see this thread: http://www.dvxuser.com/V6/showthrea...and-Manfrotto-521P-remote-work-great-together!

There I share my experience with this lens. I will do also a sunset timelapse with the new X lens. I am curious, if auto-iris works better on this lens for slow light changes like a sunset.
Click to expand...

And the latest vid you posted in that thread shows that the visible stops ARE still there when light changes and according to what you said, also in manual iris. Big disappointment, the frustration continues. The X zoom lenses are not stepless after all.
 
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Turbodog said:
It would be aperture priority.

The Canon 7D and 60D don't have aperture priority in movie mode - only "auto" or "manual". In "auto" everything is auto - aperture, shutter speed, and ISO. In "manual", aperture and shutter speed are manual, and ISO is can be either manual or auto.

The Panasonic GH2 offers M - manual, A - aperture priority, S - shutter priority, and P - auto aperture and shutter, and in addition to that allows either a manually set ISO or Auto ISO.

The AF100 offers only manual, or auto iris which is equivalent to shutter priority.

All of these cameras change iris in "stops" so the light actually changes. Changes in shutter speed and/or ISO don't seem to flicker the way the change in iris does. Automatic changes in shutter speed or ISO are more subtle.
Click to expand...

Why would you shoot in movie mode for a timelapse on a 7D or 60D? I always just use an intervalometer and just do photos that I convert to a video. With movie mode, you are limited by the record length and you can't take advantage of the full resolution of the sensor. No thanks.
 
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