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Old September 5th, 2009, 08:52 PM   #1
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Overexposed pictures with EX1

I have a problem with my EX1 in automatic mode. It tends to clearly overexpose my pictures. Even if I set the ND filter to 1 or 2 it tries desperately to set the aperture too high and images ate too bright.
In a still camera like Nikon we can easily set the aperture to -1 stop or more if we see that the automatism of the camera tends to overexpose. But I cant see this functon with the EX1.
Can someone help identifying this fonction ?
If it does not exist, I presume I can do it through a picture profile. If this is possible, which parameter should I change to adjust the f stop to a lower value ?
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Old September 5th, 2009, 11:28 PM   #2
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My advice.......

Stay away from any of the auto functions. It's pretty much a pro camera so use it like one and you will get far better results!
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Old September 6th, 2009, 05:58 AM   #3
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Originally Posted by Darren Ruddock View Post
My advice.......

Stay away from any of the auto functions. It's pretty much a pro camera so use it like one and you will get far better results!
With all due respect, this kind of advice is very popular and 'posh' among the 'pros' - but IMHO, the automatic functions are there to be used (though only where required, or unavoidable).

Francois - it can be set via the Camera menu -> TLCS -> Level.
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Old September 6th, 2009, 10:17 AM   #4
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And even among pro's, you can bet there are times to use it. Like when you are on a stabilizer and no one is pulling iris for you as you do indoor <-> outdoor shots, etc.
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Old September 6th, 2009, 10:35 AM   #5
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I agree with Perrone and Piotr,

Try nailing focus and iris while flying in a helicopter doing tight circles over bright objects on the water. You go from full backlit to looking for light in 20 seconds while a director is watching your shot in the front seat on a monitor saying can you pull out or closer. While you are going no ND to ND2, pulling focus and just trying to keep the shot close. Auto has its uses when the operator can not keep up with just two hands.

But as soon as you can go full manual it is always the way to go.
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Old September 6th, 2009, 11:34 AM   #6
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Hey Francois

The thing with auto Iris, is that it compensates for bright as well as dark areas in the frame, seeking to attain an overall pleasing/correct exposure.

so if there is alot of black or simply a larger amount of dark area in the frame, the auto is going to open the apperture for you, which might in turn burn the brighter areas out, while the dark areas are correctly exposed.

if there are more brighter areas in the frame, itīs going to shut the apperture down, perhaps at the cost of the darker areas of the frame being flat/black.

If you have a frame without any major brightness differences and your cam is still overexposing it, there is a problem with the sensitivity of the Auto setting

The chips on these cams are really great where contrast is concerned, so itīs strange that ALL? your stuff is overexposed...

maybe you could post a couple of frame grabs of different settings where you experienced overexposure.

I am all for shooting in full manual mode at all times, BUT..... the auto Iris is something everyone should know how to use, if you understand what the camera is "thinking", itīs a good tool to use for quick iris setting on the fly, BUT...... should be switched off and the exposure readjusted to your own manual setting according to whatīs in the frame, this also avoids "PUMPING"

so in your case,(and this is the emergancy fix) if you have a homogenous contrast in the frame in question, use the auto Iris....... if you donīt trust yourself to expose, ...........
then close the iris down a stop or half a stop (depending) and you should be ok

another thing to consider is what are you monitoring on?
it could just be your monitor????

also there is a tool called the histogram, which will tell you fairly quickly if the shot is correctly exposed or not(takes a bit of getting used to, but should help you alot)

to TLCS: the camera is a tool and you are the artist, donīt let it do all the thinking for you

compensating for the auto iris with a picture profile setting is gonna land you into more trouble than anything else, because the picture profiles react differently to different light situations

you might want to send your cam in and get it calibrated
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Old September 6th, 2009, 01:44 PM   #7
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Hey, I aint no pro! Just learnt the hard way!
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Old September 6th, 2009, 02:44 PM   #8
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If you have direct menu set to Part or All (in the others section of the menu). You can then use the thumbstick on the top of the handle to go to where iris is displayed and then push in to select then push up or down to add an offset to the auto iris of +1 to -1 stop.

I use auto iris. Not always, but it's a useful tool and in no way amateur, just another tool that helps in certain situations.
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Old September 6th, 2009, 03:36 PM   #9
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Quote:
Originally Posted by Francois Dormoy View Post
I presume I can do it through a picture profile.
Does the camera overexpose when using a picture profile? That may be one of the issues.

Alister Chapman has done some great screencasts about the various gamma modes which (and I am going all theoretical here) may push exposure too far up the curve or utilise brightness beyond 100%.

I am skidding around on two wheels here, so this may not be the case, but having watched Alister's screencasts, it made me think about how the camera would handle the exposure if in auto.
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Old September 6th, 2009, 06:07 PM   #10
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Originally Posted by Darren Ruddock View Post
My advice.......

Stay away from any of the auto functions. It's pretty much a pro camera so use it like one and you will get far better results!
Well, your advice is just theory. In practice, there are so many parameters than need to be changed when shooting (focusing, zooming, exposure, camera position etc.) that we cannot control all of them simultaneously. It is nice to have at least one of them in automatic mode. Say that you want to control manually the focusing. Can you really yourself control simultaneously the focus and the aperture, while ensuring the right framing ?
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Old September 6th, 2009, 06:25 PM   #11
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Originally Posted by Piotr Wozniacki View Post
Francois - it can be set via the Camera menu -> TLCS -> Level.
I checked my TLCS setting and it was set as "Backlight". Do you think this is the source of my problem? I put ti to Standard rather than Backlight.
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Old September 7th, 2009, 12:20 AM   #12
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Yes. Backlight opens the aperture to compensate for a bright background (subject in shadow).
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Old September 7th, 2009, 02:47 AM   #13
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Quote:
Originally Posted by Francois Dormoy View Post
I checked my TLCS setting and it was set as "Backlight". Do you think this is the source of my problem? I put ti to Standard rather than Backlight.
Yes, of course it should be at Standard. Backlight increases exposure to compensate for strong backlight (as the name implies:); you would only use temporarily (if ever at all)!

TLCS settings are sort of permanent (e.g. the Level is active all the time when Auto Iris is on). Therefore, you could alternatively use Alister's advice, and change it in the menu on a more shot-to-shot basis, with the joystick.

That said, I also would like to stress it that Auto Iris is a last-resort tool. But since it does happen to be used, one should learn how to use it correctly.
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Old September 7th, 2009, 02:57 AM   #14
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Francois
I reckon you might have figured it out, the backlight function pushes the darker areas in the frame up electonically, like the gain does to the entire shot....so you should have much better results with the Auto Iris now,

BUT..........do yourself a favour and learn to live without the Auto Iris, or use it DURING a shot only as a last resort.(pumping just looks amatuer and cheap)
itīs a good tool to check how the cam is sizing up the brightness of a scene, but wonīt always be perfect, so donīt let the cam do all the thinking

A good shooter can most definately pull focus, iris and hold a rad frame all at the same time, itīs all about practise, besides that, the good shooter will always try avoid major light changes in a shot.
Doing a 360° circle of a subject from a chopper is an absolute nightmare I know(as far as lighting is concerned), but hey weīre getting paid to produce those images
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Old September 7th, 2009, 03:14 AM   #15
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I don't consider auto iris a last resort tool. When I'm shooting aircraft against rapidly changing skies, pulling focus with one hand and controlling the zoom with the other, having the camera accurately control the iris is hardly a last resort. I find the EX auto Iris to be consistent and normally accurate.
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