Go Back   Steve's Digicams Forums > Digicam Help > Newbie Help

Reply
 
Thread Tools Search this Thread
Old Mar 8, 2005, 7:20 PM   #1
Member
 
Join Date: Feb 2003
Posts: 70
Default

I have a Casio QV-R40 currently. I'm very unimpressed with the quality of the pictures, especially indoors where the lighting is lower. Just forget about night shots because they will most certainly suck.

I want to be more informed when I make a replacement purchase so this leads to my question. What do all of the numbers mean?

1/1.8 CCD - what does this mean?

How does ISO work in a digital camera? In film, the higher the faster. How does the film know the shutter speed of a camera? Or does something on the film tell the camera what to use?

The numbers on the lens. 2.8-5.7 or whatever they may be for a particular camera. What do these numbers represent and what should you look for?



Any help, or pointers to anywhere on the web that will explain them would be appreciated.



Thanks!!
mckeand13 is offline   Reply With Quote
Sponsored Links
Old Mar 8, 2005, 8:50 PM   #2
Senior Member
 
pianoplayer88key's Avatar
 
Join Date: Jan 2004
Posts: 405
Default

mckeand13 wrote:
Quote:
I have a Casio QV-R40 currently. I'm very unimpressed with the quality of the pictures, especially indoors where the lighting is lower. Just forget about night shots because they will most certainly oops.

I want to be more informed when I make a replacement purchase so this leads to my question. What do all of the numbers mean?

1/1.8 CCD - what does this mean?
A 1/1.8" CCD is the size of the sensor, although actually they are lying - if you figure the actual dimensions of the sensor, that size is 7.176mm by 5.319mm. Diagonally, that would be about 8.932mm. 1/1.8" is .556", or 14.111mm.
Generally, the fewer pixels are on the same size sensor, or the larger the sensor with the same number of pixels, the lower the image noise is. Typically, most current compact cameras have a 1/3.2" (4.536x3.416mm) sensor, 1/2.7" (5.351x4.039mm), 1/2.5" (5.76x4.29mm), or 1/1.8" (7.176x5.319mm) sensors. Prosumers usually have the 1/1.8" size as well as 2/3" (8.8x6.6mm) for the 8 megapixel cameras. dSLRs usually have something like 18x13.5 for the Olympus E-Volt, and 22.5x15mm (approximately) for some cameras, about 27x21mm or so for others, with the EOS-1Ds Mark II having a 36x24mm sensor.

Quote:
How does ISO work in a digital camera? In film, the higher the faster. How does the film know the shutter speed of a camera? Or does something on the film tell the camera what to use?
It's the same way in a digital camera. Higher ISO speeds will allow you to use faster shutter speeds in the same light with the same aperture. However, assuming the same camera, that comes at the expense of image grain, or noise. Small compact cameras, high megapixel prosumer cameras, and ultra zoom cameras (those with fixed lenses) are usually much noisier than digital SLR cameras. For example, an 8-megapixel prosumer camera like the Canon Pro1, Minolta A2, Sony F828, or Nikon 8800, will be quite noisy at ISO 400. However, a dSLR like the Nikon D70, Canon 20D, etc, will be quite usable at ISO 400 - about like the 8 megapixel cameras at ISO 50 or 100. I would even venture to say that ISO 1600 on those dSLRs would be better than ISO 400 on the 8 megapixel prosumer cameras. This is because the SLR cameras use a MUCH larger sensor than the 8 megapixel prosumers.

Quote:
The numbers on the lens. 2.8-5.7 or whatever they may be for a particular camera. What do these numbers represent and what should you look for?
That number is the aperture range of the camera for the zoom. For example at full wide angle you can set the lens to F/2.8 to let in a fair amount of light, but at telephoto it only opens up to F/5.7 which is about 2 full stops slower. If you could get a 1/60" shutter speed at wide angle, you would only be able to get a 1/15" shutter speed at full zoom on that camera.
The lower the number on that camera, the better it is - the more light it can let in. For example, the Canon G6 has a lens that is F/2.0 to F/3.0. My Canon S1 IS has a lens that is F/2.8 to F/3.1. The Panasonic FZ20 has a lens that is F/2.8 throughout the zoom range. Lenses that have a constant aperture throughout the zoom range are more expensive but are quite nice to have.



Quote:
Any help, or pointers to anywhere on the web that will explain them would be appreciated.



Thanks!!
pianoplayer88key is offline   Reply With Quote
Old Mar 9, 2005, 8:43 AM   #3
Senior Member
 
IanWgglswrth's Avatar
 
Join Date: Dec 2004
Posts: 410
Default

Hi,

Just as a bit of backup this link is good for seeing the CCD size comparison between prosumer cams and DSLR's

The CCD on DSLR's is soooo much bigger very suprising!

http://www.dpreview.com/learn/?/Glos...r_Sizes_01.htm

Cheers

Ian
IanWgglswrth is offline   Reply With Quote
Old Mar 9, 2005, 2:16 PM   #4
Senior Member
 
Monza76's Avatar
 
Join Date: Jul 2004
Posts: 3,960
Default

QUOTE:How does ISO work in a digital camera? In film, the higher the faster. How does the film know the shutter speed of a camera? Or does something on the film tell the camera what to use?

Older film cameras had an ISO scale which had to be set for your film. Newer 35mm cameras have DX coding on the film cartridge which automatically tells the camera what its ISO is.



Ira

Monza76 is offline   Reply With Quote
Old Mar 9, 2005, 6:35 PM   #5
Member
 
Join Date: Feb 2003
Posts: 70
Default

I guess that goes to show you that you still can't beat film huh?



Thanks for the info so far.
mckeand13 is offline   Reply With Quote
Old Mar 11, 2005, 10:25 AM   #6
Senior Member
 
Join Date: Nov 2004
Posts: 376
Default

mckeand13 wrote:
Quote:
I guess that goes to show you that you still can't beat film huh?



Thanks for the info so far.

?? What do you mean "you can't beat film"? Yes, film has its advantages (especially when talking about enlargements), but if by that you're talking about the camera "automatically" detecting ISO speed, I think you might be missing the point.

ISO is the measure of how sensitive your recording medium (whether it be the film or sensor)is. Thus, ISO 1600 film is SUPER sensitive to light -- meaning you can take properly exposed pictures with faster shutter speeds in lower light. But, such film is going to have a lot of natural "film grain" because it's so sensitive. In a digital camera, the sensor can be adjusted to be more or less sensitive to light. But you have the same problem in digital -- the more sensitive the sensor (i.e. the higher ISO) the more digital noise that is present in the picture.

Note that film speed is NOT THE SAME AS SHUTTER SPEED. Your original question was "How does the film know the shutter speed of a camera? Or does something on the film tell the camera what to use?"

The answer is The film does not "know" the shutter speed of the camera. Modern cameras on an auto exposure (both film and digital) use a light metering system, take into account the ISO, available light, and any user preferences (like a user-set shutter speed in shutter priority [Tv Mode] or a user-set aperature in aperature priority [Av Mode]) then calculate what it thinks is the appropriate exposure. Regardless of whether you're using a film camera or a digital camera, the CAMERA, taking into account these settings, will make these choices, not the "film" (unless of course you have the camera set on manual controls, then the photographer chooses the aperature and shutter speed and, on digital cameras, the ISO)


The comment above about DX cameras merely meant that when you loaded a certain ISO speed film, the camera automatically recognizes it (instead of you having to set that on the camera manually). You still had to choose the ISO because you bought film of a certain speed. The camera just recognizes that choice. On a digital camera, you make the same choice, but you don't have to wait to use up an entire roll of film to change ISO speed -- you can do it one picture at a time!


perdendosi is offline   Reply With Quote
0
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -5. The time now is 1:59 PM.




SEO by vBSEO 3.6.0 RC 2