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Old Jul 14, 2004, 5:08 AM   #1
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Hi people.

I have just bought a new minolta dimage Z2 camera. (it is not even 24 hours yet) I have used a simple aim and shoot hp 620 so far. But I have quite practical knowledge about the photograpy. I have also used a conventional Minolta XE-5 SLR machine.

My problem is that: Even though I didn't have the time to test it completely the pictures I have taken sofarwith my Z2are dissappointment. There is just too much noise in thepictures, esspeciallyin the dim light conditions without flash.I used mostly the auto mode but also the manual mode and some others but the there was no satisfying enhancement. I changed the iso speed, tried different aperture sizes, and different shutter speeds but couldn't get the desired results except for a few shots. Maybe I guess I haven't get acquinted with my new camera yet and this could be an important point but I also doubt about a serious CCD defect. I think so bacause I have read the steve's review and took a look at the sample photos and in comparison with my results they are nearly perfect.

I really appreciate your opinions and suggestions about the issue. Cause I am beginning to feel regret for my final choice between the minolta dimage Z2 and Casio QV-5700 I am on a travel right now and I post messages in cafes and because of this I am not able to upload the shots I've taken but I will do so as soon as I get the chance. Thanks for your help.
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Old Jul 14, 2004, 6:20 AM   #2
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hello I have a Z2 too. The Z2 begins to show high noise levels at 200 ISO, so whenever possibile take your shots at 50 or 100 ISO. At 200 ISO images apper blurry and noisy.

To be sure you are shooting at the correct settings just use program 'P' and avoid using the Auto ISO mode but choose 50 or 100 ISO.

At first I was quite disappointed with my pictures too but I soon discovered that the first thing to do to be happy is to stay away from AUTO mode and use P mode instead.

Home this helps, probably you can post one of yout ISO 50 shots so we can give you a more precise opinion.

Bye, Iacopo
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Old Jul 14, 2004, 6:27 AM   #3
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It would be good to know the parameters of the good shots to eliminate ISO problems. Anyway, try putting the camera to a tripod or just to a table, engage the self timer, set the ISO to 50 or 100 and make some pictures in dim light (keep the exposure under 1 second to avoid noise reduction mechanism to turn on). If they are noisy, then something is probably wrong with your camera.

The camera goes up to ISO 200 in Auto mode, which can be quite noisy.

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Old Jul 14, 2004, 9:46 AM   #4
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It's the sensor size.

The trend in consumer digital cameras is to go with smaller and smaller CCD sensors. Because the sensorsare so small, the image circles can be smaller, too. This allows manufacturers to build cameras that are very compact, with very long focal length lenses.

For example: the lens on the Z2 has an actual focal length of only 6.3mm - 63mm. However, because the sensor is so small, you get a "35mm Equivalent" Focal range of 38-380mm.

If you look at other non-DSLR cameras, you'll see the same thing. For example: the Casio QV-5700 is using a 5 Megapixel 1/1.8" CCD. To get a 35mm equivalent focal range of 34-102mm, it' using a lens with an actual focal range of only 7mm-21mm.

Now, in fairness to the Casio, it's lens is about twice as bright as the Z2's. So, you could shoot at lower ISO speeds (for example, ISO 100 versus ISO 200), and still get shutter speeds just as fast for the same lighting conditions. However, you're not going to get the focal range (or the speed) of the Z2.

Back to my original point (it's the sensor size)...

Basically, the noise you see has to do with size of the photosites for each pixel.When you're trying to pack 4 or 5 Megapixels into a very tiny CCD, the size of the photosites for each pixel is very tiny. Because of their tiny size, they are not able to gather as much light. As a result, more amplification of the CCD Signal is needed, to get the same equivalent ISO Sensitivity you'd have from a Physically larger sensor (all else being equal).

There are pros and cons to any digital camera model. For one thing, you wouldn't even find a lens with the focal range of the Z2 in a 35mm camera (or a larger Digital SLR). The lenses would need to be HUGE, and extremely heavy (not to mention VERY EXPENSIVE).

So, these types of camera serve a niche.

However, they are not perfect for all conditions. The vast majority of non-DSLR models are not really suitable for "existing light" shooting without a flash.

When you see sample photos in the reviews, guess what? They are either taken using Flash, or are taken in very good light. Noise is minimal in good light. In poor light (where you have shadow areas in a photo), at higher ISO Speeds, you get high noise from the photosites in the CCD (sort of like an amplifier turned up with no input -- only with a CCD, it's image noise, versus sound noise).

So, you're better off keeping the camera set to lower ISO speeds. Then, use flash if indoor or "existing light" photos are needed (to keep shutter speeds fast enough to prevent motion blur).

Sorry, but this is the "nature of the beast". Some "Consumer Grade" CCD Sensors are a little better (because they have larger photosites for each pixel). An example would be the 4 Megapixel 1/1.8" CCD (larger than the 4 Megapixel 1/2.5" CCD used in the Z2). Unfortunately, none of the "Super Zoom" models use the larger sensor (because the camera size/weight would need to increase too much). But, you may be dissapointed by this sensor, too (it's still dwarfed by the size of the sensors used in Digital SLR models).

So,to do significantly better, you'll need to buy a Digital SLR. The two lowest priced models right now are the Canon Digital Rebel (EOS-300D) and the Nikon D70. These sell for around $899.00 and $999.00 respectfully (body only, no lens).

Because these cameras have dramatically larger sensors, they can shoot at higher ISO speeds with much lower noise. However, you'll still want a "bright" lens (or rather, lenses) to go with them (and these can be VERY expensive -- especially if you need longer focal lengths).


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Old Jul 14, 2004, 9:58 AM   #5
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BTW, if you absolutely must shoot at higher ISO Speeds, there are products to reduce noise.

Two of the best noise reduction products are Neat Image and Noise Ninja. They are available from these links:

http://www.neatimage.com

http://www.picturecode.com

There's a free product called "Noiseware" that I've been impressed with, too (although it does not give you a lot of user control, and strips the EXIF header from the images). I've seen some 100% crops from ISO 400photos (from a DiMAGE A1) comparing Neat Image and Noiseware, and was quite surprised at how well it works:

http://www.imagenomic.com/


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Old Jul 17, 2004, 6:52 AM   #6
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Hi there,

Thanks for all your help, especially to JimC for his huge explanation about the issue. Since I sent this message I have had enough time to test the machine in manual mode and I also took some night shots using a tripod iso speed set to 100. Theyare nice and the noise level is not annoying for night taken photos. Now I am happy with Dimage Z2. Thanks for all your advices again. Even though I overcame the problem I shall consider them also.. :-)
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Old Jul 17, 2004, 12:11 PM   #7
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***raVen*** wrote:
Quote:
Since I sent this message I have had enough time to test the machine in manual mode and I also took some night shots using a tripod iso speed set to 100. Theyare nice and the noise level is not annoying for night taken photos. Now I am happy with Dimage Z2. .. :-)
Yes, it is always preferrable to take your photos at the lowest ISO speed you can, in order to reduce noise. So, if you can use a tripod to get around motion blur from slow shutter speeds, then you've got most of the battle won.

The problem comes in when you can't use a tripod or flash, or if your subject is moving (since a tripod won't help for subject movement - only camera shake). Then, you have often have no choice but to use higher ISO speeds to prevent blur, in lower light conditions. In those cases, try the noise reduction tools I mentioned above.

One other thing that you may want to know about your night photos.Most recent manufacturer digital camerasemploy a dark frame subtraction noise reduction techniqueon longer exposures.

With a long exposure photo,you'll usuallyget a lot of "hot pixels" (bright colored dots in the image). The number of hot pixels will increase as your exposure time increases, or your ISO speed increases. So, your camera is actually taking two exposures when you use slower shutter speeds. One exposure is taken of your subject. Then, immediately after this image, your camera also takes another image with the shutter closed, using the same settings (exposure time, etc.).

Because the two exposures are being taken at approximately the same time, using the same settings, the "hot pixels" will usually appear in both images in the same places. This lets the camera "subtract out" the hot pixels. Because the camera knows where the hot pixels are in the "dark frame", it simply finds the pixels at the same coordinates in the image of your subject, then replaces them with values (brightness and color) derived from neighboring pixels (that way, it's hard to see where this process worked, versus it trying to "fill in the holes" with another color -- which would be more obvious).

For older model cameras (without a dark frame noise reduction system), you had to accomplish this manually, by taking a photowith the lens covered, using the same exposure as theyour actual image containing your subject. Then, you could use software to accomplish the "dark frame subtraction", on your PC.

I don't know when your Z2 engages this type of noise reduction (it may be in your manual). In many modern digicams, it automatically kicks in on exposuresof around 1/2 second or longer (this time will vary, depending on the model). This is one reason you'll see your long exposure night photos, taking much longer to process (because the camera is actually taking two photos, in order to perform the dark frame subtraction process).


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