what is AE shift?

[Adi Head]

what exactly is AE shift?
i checked the manual. it explains how to use this function, but doesn't explain what it is.

thanks

[Ralf Strandell]

Doesn't AE stand for Auto Exposure?

In autoexposure mode the camera chooses an exposure that it thinks is good. Using AE Shift you can tell it to add or reduce the brightness a bit.

[Jeff Donald]

No, adding or reducing brightness (exposure) is done with exposure compensation. Exposure compensation uses a button that looks like this, +/-

AE Shift preserves the exposure the camera selected, by locking the relationship between the aperture and shutter speeds. The user can shift the aperture or shutter speed to his desired setting, but the camera will automatically shift the other setting to preserve the exposure. For example if the camera says the exposure is 1/60 of a second @ F8, the user can shift the aperture to F4, and the camera will automatically shift the shutter speed two stops to 1/250. The two stop change in the aperture, allowing more light in, is compensated by a two stop change in the shutter speed reducing the time the light can hit the chip. The exposure (brightness) is preserved.

[Ralf Strandell]

Jeff, that sounds more like AE lock or something.

In my camera I can go to the custom presets and dial the AE Shift up or down and the brightness changes accordingly. Oh, it's a PDX10 - not PD170... But that shouldn't matter. Also, on the page 62 of the PDX manual I can read: Item: "AE Shift" Meaning: Brightness

It is of course possible that AE Shift has a different meaning on different kind of equipment. The PD170 beeing more sophisticated, could also have more complex controls... Haven't used any 170, really.

[Ralf Strandell]

I found this using Google:
AE Shift: http://www.urbanfox.tv/workbooks/son...50exposure.htm

[Jeff Donald]

Sorry for the confusion, I missed this was the Sony forum. Most manufactures use different terminology than Sony.

[Adi Head]

ralph, i read the link you posted.
i'm not 100% i got it. but from what i understand, the AE SHIFT can be used when exposure is set to auto and yet, while shooting this way, there is a need to brighten or darken the selected exposure).
this may explain why AE SHIFT is not accessible while exposure settings are set to manual (at least with my camera).

anyone know if i got it right?

[Ralf Strandell]

When you

- only set the shutter speed and let the camera choose an aperture

or

- only set the aperture and let the camera choose a shutter speed

or

- let the camera choose both the shutter speed and the aperture

then the resulting brightness of the image is chosen by the camera. Usually the camera makes good guesses...

Sometimes, however, you need to correct the cameras guess.

Some filters, like polarizing filters, might confuse the cameras light metering a bit.

You should apply AE-shift when you use some filter that requires exposure compensation. The Tiffen "Warm ProMist" requires 1/3 f-stops of compensation while the polarizer requires 2 f-stops. This compensation must be kept constant as long as the filter is on. Thus AE Shift.

Also, if you think that the camera usually makes too dark or too bright footage then you can adjust its automatics using AE Shift.

When you are using full manual control and set both the shutter speed and the aperture then there is no guess to be made by the camera that would need correction.

[Adi Head]

got it! thanks.

[Tom Hardwick]

Ralf - you've got it. Jeff, you've lost it ;-)

AE shift is just that: it shifts the automatic exposure either up or down.

Let's take an example. You film your black suited talent alongside a black car. The camera's exposure meter thinks "My, it's gone all dark" because it's only reacting to reflected light, and black items don't do that well. So it opens up the aperture to compensate and in so doing overexposes the face of the actor.

The AE shift allows you to keep the camera in the auto exp mode, yet "dial down" the exposure so that this facial overexposure doesn't occur and black cars look black and not grey.

Same with a snow scene. The camera's meter can think it's brighter than it really is, so AE shift can apply some of your experience and knowledge while still staying in the auto exposure mode.

tom.

[Steve McDonald]

I first encountered the equivalent of
AE Shift 16 years ago, in my first camcorder, the JVC GF-S1000U, an S-VHS model. Although it had every other manual function you could want, it didn't have a locking manual exposure control.
Instead, you could tweak the auto exposure's baseline up or down, in small increments. It worked very well, as long as you didn't need to lock the exposure setting.

Later, this feature appeared in the Canon L-1 and was called "Auto Exposure Level-control". You could leave it in auto, but by rotating the manual exposure wheel, the baseline was moved in 1/4-stop increments, as much as one full stop in either direction. I found this to be more useful in most settings, than the locking manual exposure. I have missed this feature in my last two camcorders, but I'm glad to have it back in my VX2100, regardless of what it's called.

That momentary "Push-auto" feature on the VX2100's manual focus is another great item I also frequently used on my L-1.

On my big ED-Beta's Fuginon lens, there's a similar momentary button to easily activate auto exposure when you're in manual control mode. This allows a quick reset to the auto exposure's choice of the best level, but keeps it in locked manual mode when you release the button.
Perhaps there's some way to achieve this same momentary exposure effect on the VX2100?

[Tom Hardwick]

There certainly is Steve. Once you've selected a shutter speed and then pushed the 'exposure' button ahead of the side-screen, this does two things. a) It locksd the shutter speed at the shown setting, and b) It locks the aperture at the automatically chosen setting. It may well say f5.6, but it could be anything from f6 to f5 or so, as only the nearest half stop is displayed.

Now you can film at this locked exposure setting, and if at any time you wonder what the camera would've chosen, simply push in the 'exposure' button and then push it a second time. This effectively reverts the camera to auto and the second push locks in this new reading.

This is a much, much better method than AE shift. Say your bride leaves the side of her dark suited man and walks in front of the white Rolls Royce to greet her dad in front of some dark trees. You simply cannot have this in AE shift as the diaphragm would be bouncingg around trying to sort out all the differing reflectivity levels. For this type of shot you must lock the aperture blades.

tom.

[Steve McDonald]

Thanks, Tom. As you are saying, auto exposure is still auto and regardless of how its baseline has been tweaked, it is liable to badly respond to a sudden change in background.

There would be times when AE Shift would be useful to me though. When I shoot short bits of footage of flowers, which are essentially still shots, but for the wind, I always have to lower the exposure from the auto setting, about 1/4 to 1/2 of a stop. Flowers are very reflective of sunlight. Just like with my old L-1, I set the AE Shift down 1/4 stop, put it on manual focus and hit the Push-focus button for brief moments, as I flit from flower to flower, like a busy Bumblebee.

Using AE in shots like this, doesn't risk any sudden changes that cause undesirable responses. If I have to get shots of 200 different rose bushes in a garden, this speeds up the task a lot. There's nothing the sweet old ladies like better than to see a collection of beautiful flower clips with Strauss waltzes playing in the background. There have been times when using this method very carefully, I've been able to shoot a long series of such shots without a glitch and copy it later with no editing.