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Old Jan 28, 2004, 2:25 PM   #1
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Default What about CCD and lenses?

I'm just about to buy a new camera, I'd like to know about the CCD: some cameras has 1/1.8, others 2/3, my old one has 1/2.7. What is the best? I know what CCD is, but dont know what this number means.

And the lens? I have a 35-105mm, its the Canon Powershot A70. Some cameras have lens of 35-140, 35-280. What is the best and what does this means? Which one should I get?

Thanks for any answers.

Roberto
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Canon Powershot A70
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Old Jan 28, 2004, 2:53 PM   #2
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(more experienced users, correct me if I am wrong)
The number 1/2.7", for example, means the phyiscal size of the CCD (I believe it is diagonal length). So it is really tiny. The smaller the CCD is, the more noise your images are likely to have.

The 35-105mm number means how far the lense can zoom in. Back before digital cameras came around the film had a size of 35mm, a lense with no zoom would said to be a 35mm lense because it produces pictures at 35mm. However, if it was, for example, 35-70, and you took the picture at 70mm, it would optically enlarge the picture so that if you wanted the same amount of stuff in the picture, you would need 70mm film. But on 35mm film it would appear to be closer, or zoomed in.

Basicly the numbers mean how much it can zoom. To find the total zoom you divide the highest number (lets use the first example, 105) and divide by the lowest (35) and you get 3. That means that it can zoom in 3x times. Your second one (35-140mm) would mean a 4x, and the last one (35-280mm) would be a 8x.

Since the CCD of most digital cameras are really tiny, much smaller than 35 mm, these number are just equivalent to the standard film size of 35mm. The Panasonic DMC-FZ10 has a 12x zoom, it really is 6mm-72mm (at 6mm is at its widest angle), but it's 35mm equivalent is 35mm-420mm

I hope all I said is correct, and I am sure someone else could explain it better.
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Old Jan 28, 2004, 3:13 PM   #3
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When comparing CCD's, you have to look at both the size and density of the sensor (which controls how large the individual photosites for each pixel can be).

Many of the newer 3MP subcompacts are using a much smaller 1/2.7" (.37") sensor, compared to the 1/2" 3MP sensors used in older model cameras (Nikon 990, 995; Olympus C-3030z, etc.).

The "newer generation" of subcompact cameras using this 1/2.7" CCD typically have more random noise in low light, due to their very tiny 2.7 µm pixel pitch (size of the individual photosites for each pixel).

This compares to 3.4 µm in the 5MP 2/3" Sony CCD used in the Sony DSC-F717, Nikon Coolpix 5700, and other larger 5MP models.

For comparison purposes, the pixel pitch in the 5MP 1/1.8" (.556") CCD used in many of the compact 5MP models is 2.8 µm (still larger than in many of the newer 3MP models, and neither of these are exactly "low noise champs").

BTW, the pixel pitch of the 2/3" 8 Megapixel CCD in the new Sony DSC-F828 is also 2.7 µm (same as in many of the new 3MP models). This is one of the reasons you're hearing complaints about noise in this new model at higher ISO speeds.

Even though they increased the number of Megapixels in this 2/3"
CCD to 8 Megapixels (compared to the same size 5MP 2/3" CCD), it's going to have higher noise, since the photosites for each individual pixel are smaller (to fit more of them in the same area).

A better compromise in a smaller camera model may be the 4MP 1/1.8" CCD (not the 4MP 1/2.5" CCD used in some newer models). The 4MP 1/1.8" CCD seems to have a better noise profile than either the 3MP 1/2.7" CCD, or the 5MP 1/1.8" CCD.

I like to think of noise from a CCD, in the same way I think of a Sound Amplifier turned up without any input. You get lots of hum and hiss with the sound amplifer.

With a Digital Camera, the photosites for the individual pixels work in a similiar way. When not enough light reaches the sensors, at higher ISO speeds (which is "turning up the volume" from the sensor), you get image noise (versus sound noise).

In order to make up for the small size of the photosites (which can't gather as much light), the manufacturers must amplify the signal from them to get the equivalent sensitivity of a larger sensor. This increases noise in low light and underexposed areas of the image.

This is why you have dramatically less noise at higher ISO speeds in a DSLR (because the sensors are dramatically larger, with larger photosites for each pixel).

The problem is that the larger the sensor, the greater the actual focal length of the lens design must be, in order to get the same "equivalent" focal range in a 35mm camera.

So, you must have a larger and heavier lens using a larger sensor.

The current trend seems to be smaller and smaller cameras, with smaller and denser sensors. This is also why you're seeing so many new "super zoom" models coming out (using tiny sensors, allowing more compact lens designs to get the focal range). But, nothing is without it's price. That's why most of these new models are not "low noise champs".

Also, most consumers equate more megapixels with higher quality. This is not necessarily true. When you get CCD's that are too dense, noise can be a big problem (especially at higher ISO speeds). Noise destroys detail.

As far as focal lengths, a good way to see how the focal length (equivalent, not actual) impacts what you see, is this neat application at Canon. Use the arrow keys at the bottom of the page to see what to expect with different focal lengths:

http://www.usa.canon.com/eflenses/le...gth/index.html
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Old Jan 28, 2004, 7:27 PM   #4
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8) Thanks Jim, you answered a question I culd never get an answer to. Gerald M
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Old Jan 28, 2004, 7:54 PM   #5
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Quote:
Back before digital cameras came around the film had a size of 35mm, a lense with no zoom would said to be a 35mm lense because it produces pictures at 35mm.
50mm is considered a “normal” lens in 35mm photography and a 35mm lens is considered a wide angle. A 57mm lens is a true normal lens with no telephoto or wide angle characteristics. That is the diagonal measurement of the 35mm film.

However you figure it a 35-105 zoom goes from a slight wide angle to about a 2X telephoto.
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Old Jan 28, 2004, 11:42 PM   #6
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Thanks a lot for the help guys!

So, should I get the camera with the largest CCD right? Not considering DSLRs, Nikon 5700 and Sony F717 has 2/3, so I will get less noise than other cameras. Btw, my Canon has a lot of noise at ISO 400, for example. But works very fine and very low noise at ISO 50. Nikon does not have ISO 50, it goes from ISO 100 to 800. I guess Sony works the same way. Using this Nikon or Sony, I'll get less noise at ISO 400 comparing with my Canon A70, that's what I understood, correct me if I am wrong.
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Old Jan 29, 2004, 2:24 AM   #7
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Default why did you think about Canon powershot G5?

Canon powershot G5 get lowest noise in all the cameras which have same price.
if you don't mind opital zoom times ,i suggest you choose it.
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Old Jan 29, 2004, 12:22 PM   #8
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Quote:
Originally Posted by Robest
So, should I get the camera with the largest CCD right? Not considering DSLRs, Nikon 5700 and Sony F717 has 2/3, so I will get less noise than other cameras. Btw, my Canon has a lot of noise at ISO 400, for example. But works very fine and very low noise at ISO 50. Nikon does not have ISO 50, it goes from ISO 100 to 800. I guess Sony works the same way. Using this Nikon or Sony, I'll get less noise at ISO 400 comparing with my Canon A70, that's what I understood, correct me if I am wrong.
Yes, this is true. Your Canon A70 has a very small pixel pitch (size of the photosites for each individual pixel). However, you must also take into consideration how the manufacturer processes the images. Some do better than others (in keeping noise under control, via noise reduction algorithms).

BTW, there is also a difference in how the ISO speed is rated between models. It should not be different, but it is. For example: Canon's ISO 50 in most models, is really closer to some other models ISO 100. Again, this should be consistent between models, but unfortunately, there is some variation.

Bear in mind that if the lens cannot gather enough light, then you must increase ISO speed to compensate (in order to keep shutter speeds fast enough to prevent blur).

For example: F2.0 is twice as bright as F2.8; 4 times as bright as F4.0; 8 times as bright as F5.6, etc. So, you must look at the lens rating (rated at both wide angle and full zoom). A compact camera may have a lens rating of F2.8/F4.9. So, dramatically less light can reach the sensor using zoom.

A camera like the Sony DSC-F717 has a lens rating of F2.0/F2.4. So, more than twice as much light can reach the sensor at wide angle compared to many compact models, and more than 4 times as light can be gathered at full zoom. This means that it can use a lower ISO speed (with lower noise), compared to most compact models in many lighting conditions to get the same shutter speeds.

Also, bear in mind that even though some models have higher ISO speeds available (the models you mentioned having ISO 800), the photos may not be useable due to excessive noise. A digital SLR is a much better choice, if existing light photos without a flash are needed.

To get the biggest jump in performance (lower noise at higher ISO speed), you must skip the consumer (non DSLR models) entirely, and go with a Digital SLR. For example: the Canon EOS-300D/Digital Rebel, Canon EOS-10D, Nikon D100, etc. These cameras use dramatically larger sensors, with much larger areas for each pixel.

Their performance is vastly superior in low light compared to non DSLR cameras. As a result, these cameras are usually considered the minimum necessary for indoor sports. Even then, you must use a faster (able to gather more light) lens to go with them.
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Old Jan 29, 2004, 12:30 PM   #9
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Default Re: why did you think about Canon powershot G5?

Quote:
Originally Posted by livingsoul3
Canon powershot G5 get lowest noise in all the cameras which have same price.
if you don't mind opital zoom times ,i suggest you choose it.
The Canon Powershot G5 uses the 5 Megapixel 1/1.8" CCD. This CCD is not a good low light performer at higher ISO speeds. In fact, some reviewers mentioned it's higher than average noise.

In fact, in noise tests I've seen, it tests higher than it's competitors using the exact same 5MP 1/1.8" CCD (Nikon 5400, Sony V1) from ISO 100 upwards.

The model that preceded it (Canon Powershot G3) had a larger area for each pixel (4MP 1/1.8" CCD), and had lower noise at higher ISO speeds.

The best thing about the G5, is that it does have a brighter lens (F2.0/F3.0). So, in low light, you may be able to use a lower ISO speed, to get the same shutter speeds as it's competitors. This helps to compensate for the G5's higher than average noise levels, when compared to other models using this 5MP 1/1.8" CCD.

BTW, when I say "higher than average", this doesn't mean it's a lot worse. Usually, when these noise graphs are taken, the difference is not that signficant for cameras using the same CCD.

For example: one cameras ISO 100, may be higher than another models ISO 100; but still much lower than the other models ISO 200.

Also, the G5's ISO 50 is closer to some other model's ISO 100. However, the review I'm thinking of took this into consideration when comparing noise from similiar models (G5 noise was still higher from ISO 100 upward, even when adjusted for true sensitivity).
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Old Jan 30, 2004, 1:02 AM   #10
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Thanks JimC for the great explanation. I'm about to buy a new camera, and I'm finally getting to some conclusions. I need to buy a camera that:

- has EFV, cause it's awful to take pictures looking at the optical viewfinder or LCD when it's a very sunny day.
- take better landscapes photos than my Canon Powershot A70! I took some pictures here at Rio de Janeiro where I live and didn't like the quality that much.

Well, what I am looking here is the best non-DSLR digital camera, cause I dont have that money to buy the Digital Rebel, for example. Comparing the cameras, I got to this conclusion:

- between G3 and G5, I go with G3. Has the same CCD and 4MP, should have less noise than G5. But, oh well, they dont have the damn EFV, that is a problem.
- Nikon 5700 seems to be a great camera, with a great optical zoom and CCD. Same here to Sony F717, although its zoom is only 5x.
- I checked Fuji cameras also, S602 and S7000. Same idea of the powershot ones here, they have the same CCD but S602 is 3MP. Seems to be a great value.
- btw, forget about Minolta cameras, I can't find any here in Brazil.

Sorry if I wrote something wrong, but I'm new here. What do you guys think? Good idea to change my Powershot A70 to a Fuji S602 or Sony F717? Will I get much more quality in the pictures? Thanks for any advice,

Roberto
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Canon Powershot A70, wanna buy it? :P
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