# megapixels and sensor size



## mallard (Aug 8, 2008)

I was walking up the beach last weekend and was talking to a guy takin pics with a canon DSLR and he said that Pentax was crap because it had 14 megapixels on a small sensor (an APS size as opposed to a 35mm size). is there really that much of a difference? he said that more megapixels on a smaller sensor made for more noise.

then again, im used to people only favoring one product and saying everything else was bunk


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## KhronoS (Aug 8, 2008)

Well, he was right.  But hugely depends of the sensor. If it's the exact sensor and one has 10 MP and another has 14MP, well the 14MP will not take better photos, maybe just enlarge them a bit. The fact is that on a sensor with more MP, the extra pixels are crowded together, it's like you put in a car 8 people in stead of 5 people as it supposed to be. So yeah in this case this thing might generate some more noise.

I might be wrong though.

Anyway don;t worry about it, usually the difference is unnoticeable to the eye


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## Big Mike (Aug 8, 2008)

There are several factors that influence the amount of noise.

Yes, it's usually true that the less 'crowded' the sensor is, the less noise it will produce.  This is a big reason why digi-cams are so noisy...they cram 8, 10 even 12 MP onto a tiny little sensor.

However, you can look at a camera like the Canon 40D, which I think is 12MP....on the same size sensor as the digital Rebel or Rebel XT etc.  The 40D will give you less noise because it's newer technology and the camera's processor handles noise better, especially at high ISO.

It does sound like they guy was a gear snob...don't worry about it.  A good photographer can make great photos with either camera.


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## mallard (Aug 8, 2008)

thanks for the input. From what I read, the highest end Pentax, although it has the smaller sensor size, is a CMOS instead of a CCD (whatever those are) and its chips and software are supposed to be good.

he told me I could do better with a canon 5D which should be coming down in price.....but its still more (twice as much) than the pentax K20d


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## Big Mike (Aug 8, 2008)

CMOS and CCD are different types of sensors...CMOS does seem to be the preferred type for higher end cameras.

The 5D is a 'full frame' DSLR and has a large sensor (same as 35mm film)...which gives it an advantage over most other DSLR cameras.  It does have a fairly high price tag though.  

You should have told him that he could do better with a Canon 1Ds mark III ($8000)...or a Nikon D3....or a 60 mega pixel Hasselblad digital camera :roll:

There is always something better...but to some people, whatever they have, is always better than what you have...and they like to let you know about it.


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## mallard (Aug 8, 2008)

Big Mike said:


> CMOS and CCD are different types of sensors...CMOS does seem to be the preferred type for higher end cameras.
> 
> The 5D is a 'full frame' DSLR and has a large sensor (same as 35mm film)...which gives it an advantage over most other DSLR cameras.  It does have a fairly high price tag though.
> 
> ...



actually I can do better with a crown graphic and a real darkroom.....but if im limited to digital im trying to be as informed as i can. I can understand some people wanting to think that certain brands are better than others. I support CATIA software.....I think UG NX is just about as good....but i think Pro-E is crap. Then again, that is my field of expertise...cameras arent other than a fun avocation.


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## ksmattfish (Aug 8, 2008)

Some articles

http://www.cambridgeincolour.com/tutorials/digital-camera-sensor-size.htm
http://www.luminous-landscape.com/essays/sensor-design.shtml
http://www.outbackphoto.com/dp_essentials/dp_essentials_02/essay.html
http://www.clarkvision.com/imagedetail/does.pixel.size.matter/


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## mallard (Aug 9, 2008)

ksmattfish said:


> Some articles
> 
> http://www.cambridgeincolour.com/tutorials/digital-camera-sensor-size.htm
> http://www.luminous-landscape.com/essays/sensor-design.shtml
> ...



excellent links....thanks

another thing I forgot about was dust....it can be hell keeping dust off an 8X10 negative. Although compared to that, im sure it still can be an issue with the larger the sensor gets, the more chance you have to get dust on it


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## Garbz (Aug 10, 2008)

Well if dynamic range is what you're after I suggest you look at the Fuji cameras (I think), you know the ones built in the Nikon bodies. I believe they have a different sensor layout then the standard 4 pixel bayer GRGB, and include a greyscale luminance sensor too. Taken from the visual system of the human eye which has 3 rods (RGB) and a cone (grey scale luminance for low light) it apparently gives better dynamic range.

I'm talking from what I've heard here only, I've never actually used the thing.


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## fishacura (Aug 21, 2008)

Garbz said:


> Well if dynamic range is what you're after I suggest you look at the Fuji cameras (I think), you know the ones built in the Nikon bodies. I believe they have a different sensor layout then the standard 4 pixel bayer GRGB, and include a greyscale luminance sensor too. Taken from the visual system of the human eye which has 3 rods (RGB) and a cone (grey scale luminance for low light) it apparently gives better dynamic range.
> 
> I'm talking from what I've heard here only, I've never actually used the thing.


 


I don't notice "sensor size" as a spec on many of the sites when looking for new cameras. Is it called something else?


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## ksmattfish (Aug 21, 2008)

mallard said:


> another thing I forgot about was dust....it can be hell keeping dust off an 8X10 negative. Although compared to that, im sure it still can be an issue with the larger the sensor gets, the more chance you have to get dust on it



Dust can be a problem, but with a digital sensor you only have to fix the file once, and if you screw up you just start over.  Compared to retouching a neg of any size, or spotting every print it's a breeze.


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## ksmattfish (Aug 21, 2008)

fishacura said:


> I don't notice "sensor size" as a spec on many of the sites when looking for new cameras. Is it called something else?



It might be called "format".  At dpreview.com it's usually just specified under "sensor".

http://www.dpreview.com/learn/?/Glossary/Camera_System/sensor_sizes_01.htm


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## dklod (Aug 21, 2008)

I read that matching the lens and the sensor size was an important factor. This right off the Pentax website.

The image circle in DA-series lenses is designed to perfectly match the 23.5mm x 15.7mm size of the CCD used in PENTAX digital SLRs to optimize camera performance (now a cmos sensor in the latest model).

Is this true or is it just advertising spin?? If its the case, how do Canon make their lenses work on a 5D 35.8x23.9 and just as good on a XSi which is only 22.2x14.8?? Maybe Im not fully understanding something here.


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## fishacura (Aug 22, 2008)

ksmattfish said:


> It might be called "format". At dpreview.com it's usually just specified under "sensor".
> 
> http://www.dpreview.com/learn/?/Glossary/Camera_System/sensor_sizes_01.htm


 

Found it...Now the $1,000,000 issue.  So I have a Canon today that is 4 megapixels with a 1/1.8 sensor.  The ones on the market now are 8 megapixels with a 1/2.5 sensor.  It would then seem as if there is no way these could take as good a picture since they are cramming double the megapixels into a much smaller sensor.  But then my current camera is 5 years old so how can something newer take a poorer picture.  I am missing something right?


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## photo28 (Aug 25, 2008)

So is the Canon Rebel Xt (8MP) sensor "crowded"?  Would the 6MP Nikon D40 produce better pictures?


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## Garbz (Aug 26, 2008)

Will it? I don't know. The Nikon D200's is even more crowded but produces better pictures. The sensor pixels size is a small part of a much larger system full of noise sources to be refined at every angle. The number of photons that can be caught is just a small part.


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## pez (Aug 26, 2008)

This link shows what cameras use which sensor size. 
A full frame sensor sure is a great thing, but I see some practical disadvantages: cameras that have these magic sensors are (so far) almost prohibitively expensive unless you just have a lot to spend on hardware and glass or you're planing to use it for your livelihood, and both the bodies and the glass are larger and heavier than APSC stuff. You can forget about being the least bit stealthy- or comfortable- while lugging your high-tech Nikon D3 anvil and your jumbo backpack full of glass around.


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## skieur (Aug 26, 2008)

fishacura said:


> Found it...Now the $1,000,000 issue. So I have a Canon today that is 4 megapixels with a 1/1.8 sensor. The ones on the market now are 8 megapixels with a 1/2.5 sensor. It would then seem as if there is no way these could take as good a picture since they are cramming double the megapixels into a much smaller sensor. But then my current camera is 5 years old so how can something newer take a poorer picture. I am missing something right?


 
You are assuming cramming because you are also assuming that everything else is the same.  Layering the megapixels, adjusting their size and shape and using small lenses on the chip etc. means that there is no "cramming".  As a matter of fact, they have an approach for developing a gigapixel camera chip.

skieur


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## djacobox372 (Aug 28, 2008)

Garbz said:


> Well if dynamic range is what you're after I suggest you look at the Fuji cameras (I think), you know the ones built in the Nikon bodies. I believe they have a different sensor layout then the standard 4 pixel bayer GRGB, and include a greyscale luminance sensor too. Taken from the visual system of the human eye which has 3 rods (RGB) and a cone (grey scale luminance for low light) it apparently gives better dynamic range.
> 
> I'm talking from what I've heard here only, I've never actually used the thing.



Truthfully, if you want dynamic range--use film.  Digital is years away from coming close to film in that regard.


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## prodigy2k7 (Aug 28, 2008)

Its also the processor, a better processor will probably have better noise reduction. Also some people say shooting in raw you have less noise...

Lower end Canons have a smaller sensor even though the lenses are made for full sized 35mm sensors. This is where "crop factor" comes in. You are not seeing the full image that the lens sees. Unless you are on a 35mm sized sensor


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