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Old Feb 15, 2006, 3:49 AM   #21
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Look, you've got some slight differences between the way the two cameras are metering the scene, as well as how they are setting the color.

Change WB to the same for both (try incandescent versus auto), and use a +EV setting only if you want it brighter (and you may need to do that with one to make them look closer).

These are two different camera models. You'll have slight differences between cameras in how they interpret a scene, just like you'll have slight differences in how different film renders a scene, even if it's the same speed.

You can then post process if you want to make further changes. Many editors can help you correct exposure, color, contrast, etc.


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Old Feb 15, 2006, 5:14 AM   #22
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Im sorry.
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Old Feb 15, 2006, 5:22 AM   #23
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Sorry for what? I'm just pointing out that you'll see slightly different behavior from different cameras, especially since you have little control over the way images are being processed with these models.

You can change things like White Balance and Exposure Compensation to get the photos close to what you're probably looking for. Then, use an editor to further tweak color, contrast, brightness, etc., as needed for best results.

Better lighting would probably go a long ways, too (and don't forget to try changing the WB to match the lighting, as Auto WB usually doesn't work well in artificial lighting with most cameras).

Given the white background, it's not unusual that you'd need to set a +EV value with exposure compensation to brighten iimages (lots of white tends to fool metering, underexposing scenes, and it doesn't look like your cameras have spot metering available).




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Old Feb 15, 2006, 10:11 PM   #24
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Your either using a fully automatic camera or have no idea how to use it. Just like an automatic transmision in your car, if you feel like using a different gear while going down the highway your out of luck, you have no control.

The way the picture is exposed is ISO X Aperture X Shutter, so the camera picks the three settings it thinks are best and thats that. If you use +1 exposure compensation the camera will pick its arbitrary numbers then step one value higher. The way each camera makes these decisions is totally out of your control (read the manual, maybe not).

This is pointless though, as if your going to use it in automatic mode then thats how they should be compared. Forget the exposure compensation, its based on dynamicly changing numbers. The camera meters may be miscalibrated in some way, in which case its possible to think EC would level the playing field. The ISO differences are not important, because the other two settings will be changed to compensate for that already.
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Old Feb 16, 2006, 3:49 AM   #25
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Well im toataly confused now. I must have bad eyes because these 2 pictures look to have the same exposure to me yet the EV is lower, alot lower.

http://i5.photobucket.com/albums/y19...lyconfused.jpg
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Old Feb 16, 2006, 7:47 AM   #26
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The exposure looks the same because it is the same. The shutter speed and aperature are identical for each picture. EV compensation has no effect in manual mode in most cameras as metering is off and the photographer is assumed to be dialing in the necessary shutter speed and aperature to achieve proper exposure. Most of the examples you have provided have had at least one camera in manual exposure mode, which would explain the lack of "effect" you are seeing from using EV compensation, since the camera disables this function in manual mode.
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Old Feb 16, 2006, 8:45 AM   #27
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BowerR64 wrote:
Quote:
Well im toataly confused now. I must have bad eyes because these 2 pictures look to have the same exposure to me yet the EV is lower, alot lower.

http://i5.photobucket.com/albums/y19...lyconfused.jpg
Repeat after me, "THE EXPOSURE COMPENSATION IS MEANINGLESS".

Ok, do it again.

NOW, look at the exposure parameters. ISO 200, f/5.6, 1/2 second. THE SAME for each picture. If thats what we started with, THEN added +1 exposure compensation, the shutter speed would change to 1 second (or aperture to f/8, or iso to 400, remember the equation ISO x Aperture x Shutter). +1 Exposure compensation is like rolling the dice and adding one to the number you get, with that number being your exposure. IT IS NOT A FIXED RELATIONSHIP TO THE EXPOSURE. In that regard, its meaningless. Furthermore, since the camera is not choosing the settings (no rolling of the dice), exposure compensation is disabled.
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Old Feb 16, 2006, 12:48 PM   #28
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You guys are screwing with me now right?

http://i5.photobucket.com/albums/y19...a/evmanual.jpg

It says in manual mode i have control over the EV what does EV mean then?

it says i can also chose the white balance. only in manual modes. I was in manual modes and havnt used the flash in any of these images.

http://i5.photobucket.com/albums/y19...amera/EVWB.jpg
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Old Feb 16, 2006, 1:26 PM   #29
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Here is the deal, ive been using this MX1200 for years and ive learned how this EV works on this camera. To me the way i see it is the EV is like a filter or a shade. +1.5 is like no shade -2.1 is like a heavy dark filter. As i increase or decrease the values it adds the filter to the finished image. I know it is actualy controling the shutter speed but the results are like a filter kinda.

If you look at these images, this camera is working like it has been for years. The first image was to bright at +1.5 so i backed it down to +0.6 and the color starts to change as the brightness is taken out because the shutter speed is faster.



Now my question was originaly was how i could calculate what the camera is doing based on the steps of the EV or exposure compensation. +0.6 = 1/3 sec shutter speed changing the brightness of the image. +1.5 = 1/2 sec shutter speed.



Now, what i think maybe happening with the 2 images on the A120 when i was at +1.5 and the image was not changed when i backed the ev down to +0.6 is the brightness is past the threshold of the ev. It is so bright it cant correct it because the ISO is 200. +0.6 + 0.9 +1.2 +1.5 will all be over the threshold that the camera can correct because the sensor is so sensative being at ISO 200 wich is more sensative then the 160 ISO MX1200. i think im not sure. Ill need to try each ev setting and see what happens but i think thats the case.

I know the compensation changes the image because ive been using this camera for years and i know it works. The 2 cameras are different because one has ISO 160 and one has ISO 200. So there is a slight difference here but no where else.

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Old Feb 16, 2006, 1:28 PM   #30
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You're making this harder than it needs to be.

Don't worry about the specifics (aperture, shutter speed). You can't directly control them with your cameras. They don't have a true manual exposure mode (where you can manually set both the aperture and shutter speed).

Decide how you want the image to look (brigther or darker than the camera's autoexposure would normally expose it).

That's when you use those settings (when you're not satifisifed with the brightness of the image via the camera's autoexposure algorithms).

Then, use the White Balance settings so that the camera is aware of the color temperature of the lighting (otherwise, you can get color casts in artificial lighting). I see a color cast in some of the images you've posted. Incadescent (Tungsten) probably works best for the lighting you're shooting in.

See my very first post in this thread for what you are setting with + or -EV values with your cameras (Exposure Compensation).


I'll repeat it:

Quote:
What you're asking about is Exposure Compensation. As others have already mentioned, you're just altering the exposure from what the camera's autoexposure would normally use.

A +EV value gives you a brighter exposure. The camera uses a slower shutter speed and/or larger aperture to get a brighter exposure, compared to what the camera's autoexposure algorithms would have selected.

A -EV value gives you a darker exposure. The camera uses a faster shutter speed and/or smaller aperture to get a darker exposure, compared to what the camera's autoexposure algorithms would have selected.

Unless there are metering differences between models, you should see identical exposure (brightness of the image), regardless of the ISO speed used. Ditto for changes to Exposure Compensation. The same settings (+ or - EV setting for Exposure Compensation), should have the same impact on exposure.

Correct Exposure comes down to the amount of light, the ISO speed, and the aperture. A variety of combinations will produce identical exposure. You only need to use Exposure Compensation if you want a brighter or darker image compared to what the camera's autoexposure would normally give you in the same conditions.

An example of when you may want to use a +EV setting is for a backlit subject, where the subject would normally be much darker than the rest of the image. Since the camera has a limited dynamic range, it doesn't know that you want the dark subject exposed properly (as the expense of the rest of the image). If you brighten the exposure for one part, the rest may be overexposed.

If your subject is much brighter than the rest of the image, you may want to use a -EV setting for Exposure Compensation so that your subject is not overexposed (making the rest of the image darker, too).

The camera has a limited range of bright to dark that it can capture. So, it makes choices so that most of the image is correctly exposed, depending on your metering mode. Sometimes that may not be what you want. That's where exposure compensation comes in.

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