What exactly does the exposure setting do? at DVinfo.net

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Old September 5th, 2010, 06:07 AM   #1
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What exactly does the exposure setting do?

Hi,

I've had my HV40 for a few months and love it but I'm still trying to a get a handle on the best aperture and exposure settings for different light situations. I shoot mostly outdoors so my 'problem' is nearly always too much light rather than not enough and especially the issue of sky white-out (which I hate). I understand the TV and AE settings etc and the way one can reduce the light with the exposure control. What baffles me is what this control is actually doing - my limited understanding is that exposure and aperture size are the same thing yet I can reduce the exposure and leave the aperture the same - how so? I have noticed if you take the exposure down to -9 or beyond the aperture setting does go up a bit in AE mode.

On a related topic does anyone have any thoughts about the optimum aperture value for sharpness etc - the scales seem different from other cameras I've used with 5.6 producing quite a fuzzy picture? I bought an ND filter the other day which will help I think.

Thanks.
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Old September 6th, 2010, 07:07 AM   #2
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Hi Geoffrey

I too have the same problem with my HV20. What I do to get control of exposure on the HV20 changes from time to time.
One thing I more or less allways use outdoors is a ND4 filter. By using it the aperture is more open than without it, which gives me more 'space' to adjust exposure. I seldom go below aperture 4.8 as smaller aperture starts to generate diffraction. I also use aperture priority mode and adjust the shutter speed. Faster shutter speed = less light => larger aperture. I avoid getting over 1/120 as faster shutter can result in strobing effects on moving objects.

I'm also using a XH-A1 where you have much better control of the exposure parameters. It's no doubt the HV models are more consumer oriented as they are very simple to use giving an accepted result, but I find it a real challange to master the picture from it.

As a matter of fact, the other week I started a thread about "Automatic ND filter on HV20/30/40" as I find it hard to get correct exposure on the HV.

Hope this helps!


Regards,

/Bo
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Old September 6th, 2010, 02:02 PM   #3
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Hi Bo,

Thanks for your thoughts (I did read your earlier thread too) - I've tried the Canon ND filter and it definitely helps though I can't use it (or anything else?) on the wide angle converter which is annoying. What puzzles me still is the function of the exposure joystick control - it's almost as if it is really a gain control as it doesn't apparently alter the aperture value. Maybe the best way is to not go above f4.8 then use the exposure control to reduce the light - does that avoid diffraction?

I'm puzzled When you say you use AE mode and adjust the shutter as I thought in that mode the shutter was automatic - it has gone as high 1/500 when I've used the AE mode (I checked this using the stills button trick), though as I mostly shoot fairly static scenes this isn't so much of a problem. Is there a way to fix the shutter in AE mode?

I also use an A1 which offers much more control - thanks for the advice re the aperture setting as on the A1 values higher than 4.8 produce perfectly acceptable results.

Geoff
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Old September 6th, 2010, 02:52 PM   #4
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Well, as a matter of fact you can adjust the shutter in Av mode. That's exactly what is happening when you adjust exposure. As the aperture is adjusted and locked to a value, the only way the exposure can be adjusted downwards is by increasing the shutter speed. Adjust it upwards an the camcorder decreases the shutter speed as far as it can, down to 1/25s, then i probably will start to add gain.
Using shutter priority, Tv, on the other hand will let you adjust and lock the shutter speed. The exposure control now affects the aperture. Faster shutter will open up the aperture, slower shutter will close it. When the aperture needs to open more than F1.8 the camcorder probably will add gain.

Watch out when the shutter speed goes down to 1/25 and also when the aperture opens to F1.8 as the camcorder then will start add gain which you can't se or can't control.

I don't know if you are aware that you can check the F-number and shutter speed of the camcorder. To do so you must have a Mini-SD card inserted in the camcorder. If you have that, by pressing the photo button on the camcorder half way down, to the first stop, you will see the exposure settings for F-number and shutter speed.

I hope my explanation is possible to understand.

Regards,

/Bo
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Old September 7th, 2010, 03:08 AM   #5
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Ha! The penny has finally dropped - thanks very much Bo, I now understand. It's funny, I've read the link you sent before but never twigged the most basic thing that the exposure setting controls aperture in TV mode and shutter in AE mode; strange also it doesn't simply state this in the manual. I've used the photo button to look at the values before so am now in a position to use my camera with decent knowledge of what it is actually set at and thus able to find the optimum aperture and shutter for various conditions. The basic problem of over-exposure outdoors doesn't go away but can be mitigated more easily.

Thanks again.

Geoff
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Old September 7th, 2010, 05:38 AM   #6
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Great to be able to help someone!

One last thing that I've noticed, and it's about the LCD. My LCD is too dark to rely on. I allways use zebras to get the exposure right but then the LCD get so dark so I expect to underexpose daker areas. Checking the recorded material at home on my PC monitor or on my TV it allways looks brighter.

What I've learnt from this is that even if I adjust the exposure down, the picture seldom underexposes.


Regards,

/Bo
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Old September 7th, 2010, 08:25 AM   #7
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Yeah I use the zebras too - on 100% (found 70% too sensitive). I suppose trying to calibrate the LCD screen would be good but not sure how one would do that with any accuracy - maybe another question for the forum!
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Old October 9th, 2010, 01:17 AM   #8
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I'm a novice hv30 user, and have been using two of them for weddings lately. I learned to use the tv setting, set the shutter speed to 60 , which is generally best for event video, and then adjust the exposure as needed. I agree, the lower the exposure the less grain, it seems like more of a gain control than iris controller. My footage from a wedding today was fantastic.
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Last edited by Jeff Harper; October 9th, 2010 at 02:24 AM.
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