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-   -   Tip For Manual Exposure (Kinda Obvious) (https://www.dvinfo.net/forum/canon-xl-gl-series-dv-camcorders/39128-tip-manual-exposure-kinda-obvious.html)

Richard Hunter February 9th, 2005 04:28 AM

Tip For Manual Exposure (Kinda Obvious)
 
Just thought I'd share a new finding that I hadn't seen mentioned before, but maybe that's because it's too obvious to everybody else?

I used to switch between Tv and Manual modes frequently. I would often start out using Tv mode, and then use Exposure Lock as necessary. However, if I needed to adjust the aperture for some reason, I would switch to manual, make sure that the settings hadn't changed, and then tweak the aperture and maybe the shutter speed again to get the final settings. It doesn't take long, but there's too many places I can screw up if not careful. I could stay in manual all the time, but I have more confidence if I use the Tv setting as a starting point and then adjust from there.

Anyway, I found out by accident that if Exposure Lock is selected, you can still control the aperture and shutter directly. This means that you can stay in Tv mode all the time, and effectively switch to manual just by pressing Exposure Lock. All the settings are displayed in the viewfinder so it's easy to keep track of what's going on.

Out of curiosity, does everyone else know this already? :)

Richard

Jimmy McKenzie February 9th, 2005 04:35 AM

new to me!
 
That's interesting that you have that kind of control. I have never used the tv setting. Just M.

On the very rare occasion that I need an immediate shot with no prep., I will use A ... but very limited.

Chris Hurd February 9th, 2005 08:00 AM

Thanks, Richard, I thought I was the only one.

This feature is held over from the old XL1 / XL1S days. It is an excellent tip.

Marty Hudzik February 9th, 2005 09:03 AM

I just discovered it myself last week and fell in love with it. It is an awesome tool and makes some shooting easier. Even in a scripted environment you can let it adjust the iris automatically and then lock it and tweak it to exactly what you want.

Another cool tip to go with this is to use the programmed AE modes. If you have always shot in Manual (like me) then you could never take advantage of this feature. When in TV mode the XL2 will open and close the iris to what it thinks is proper exposure. However sometimes it is not jiving with what you want. Turn the wheel up top to calibrate the auto exposure to either overexpose slightly (up to 2 stops in 1/4 increments)
or underexpose (down to 2 stops in 1/4 increments). This will essentially tell the camera to expose how ou want it instead of how it wants it. In general it works very well.

Add this to Richards tip and you've got a pretty potent tool that will help in a lot of situations and still give you complete manual control if you hit the expoure lock button.

Peace!

Richard Stiehm February 9th, 2005 09:41 AM

What does the TV mode do exactly??? I've never used it and I know I must have read about it in the manual but I don't remember. Does it set an automatic FStop and matching shutter speed???

Marty Hudzik February 9th, 2005 10:10 AM

TV Mode allows you to set the shutter and the CPU of the XL2 automatically find the correct Aperture (fstop) to properly expose the Picture. IF you hit exposure lock you can then overide this and control both manually. But it works well and you can let the CPU pick the best aperture it thinks and then lock it and tweak it to what you like.

TV is commonly known as shutter priority (you set shutter and CPU adjusts iris for proper exposure)

AV is commonly known as Aperture priority (you set aperture(fstop) and CPU adjusts shutter for proper exposure)


Have no idea why they use the acronym "AV" and "TV" for these but they do.

Richard Stiehm February 9th, 2005 10:18 AM

Thanks!! It makes sense now...

Marty Hudzik February 9th, 2005 10:26 AM

I'd like to add that this really helps overcome the funky decision Canon made with having the iris switch instead of wheel. If you are doing run and gun work and you go from a shot of a boat on a lake (bright sun and reflections) and quickly have to pan over to a subject off the shore in the shade of trees, the TV mode will do the iris adjustments fast. You could be at f11 filming the water and in an instant the camera will open up to f4 to properly expose the subject under the trees. It looks smoother than you could do by toggling that iris switch all the way through from f11 to f4 by hand. Then you can lock it and adjust in smaller increments to get the precision you need.

My biggest complaint about the iris switich is that in times where I nned to go from wide open to stopped way down it takes to long to keep clicking the switich. On the old wheel style you could at least spin the wheel very fast and it would go farther quicker.

FWIW.

As always anything that automatically adjusts for you is going to make mistakes sometimes so you can not completely rely on this. But for most run n gun and event video it does the job well.

Douglas Robbins February 10th, 2005 03:51 PM

Thanks Richard. Great tip. I did not know that!

Douglas

Greg Boston February 13th, 2005 08:00 AM

Marty,

I am not 100 percent sure, but I think in Tv and Av, the subscript 'v' may refer to speed. I know it's easy to think of a shutter in terms of speed, but remember that lenses are also speed rated by their 'max aperture'. So in terms of aperture and shutter, you are adjusting the 'speed of light' entering the lense. V is commonly used to mean 'velocity' in scientific terms.

Also used in aircraft operation manuals. Airplanes have various 'v-speeds' that the pilot must memorize. Like these examples...

Vso - wing stall speed in landing config.
Vsi - wing stall in the clean config.
Vfe - max flap extended speed
Vno - normal operation (green arc on airspeed ind.)
Vne - never exceed speed (start of red line on airspeed ind.)

Humor mode on: I'll never forget my flight instructor's memory aid for the first two items I listed. He said Vso means ***t out and Vsi means ***t in. Referring to flaps and landing gear.

Anyway, you get the idea.

-gb-

Richard Hunter February 13th, 2005 01:34 PM

<<<-- Originally posted by Greg Boston :

So in terms of aperture and shutter, you are adjusting the 'speed of light' entering the lense.
-->>>

Greg, surely you don't really mean that?

Richard

Greg Boston February 14th, 2005 01:00 AM

Well Richard, haven't you figured out how to adjust the speed of light yet? Hehe, ok you got me. It's clearly the 'volume' of light passing through the lense in a given amount of time which implies speed. But I know you have to have heard phrases such as "...the speed of this lense is f4.5 at 1000 lux." or similar phrases.

-gb-

Jon Bickford February 14th, 2005 02:53 AM

actually, the v in Tv, Av, etc stands for variable.

Tv stands for Time variable, Av stands for Aperture variable.

why Tv instead of SS for shutter speed I do not know.

Personally I pretty much always run the camera in Tv stuck at 1/48 then use the aforementioned technique with nd filters to get the aperture I want. that's how it feels the most like a film camera to me.
Also, i've been very impressed with results of gain adjustments, there is VERY little noticeable difference from -3 to +3 so i use that as a 3rd nd or to help me stop down a bit more for depth of field.

-jon

Tom Hardwick February 14th, 2005 05:04 AM

Here in the UK Canon have always said tv and av mean 'time value' and 'aperture value', but we're splitting hairs. What they really mean is shutter priority and aperture priority exposure control.


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