Al Beatty Loc: Boise, Idaho

Hi Group,

I bought my wife a Nikon D7000 (refurbished) for Christmas and she loves it. Over the last couple of days I've been showing her how to set it up and during that process she asked about "picture quality" (Large, Medim or Small). Her question (I couldn't answer) was, When you change the quality setting to "Medium or Small" does the camera use every other pixel on the sensor or does it use a smaller surface area of the sensor? When I asked Google I didn't find the answer to that particular question. Do any of you know? Take care & ...

jimmya Loc: Phoenix

Interesting question I wish I had the answer. I would think, I don't know, that each smaller size would limit the portion of the sensor used. Imagine the sensor getting smaller and smaller... that's what I would think at least.

MT Shooter Loc: Montana

The entire sensor is used in all shots. The L, M or S you are talking about refers to the amount of compression used on the saved JPG image and does not affect the saved RAW if shooting them.

CaptainC Loc: Colorado, south of Denver

Image quality setting controls the amount of compression applied to the JPG.

Image size is different and I don't know how that is applied, but would guess it is a firmware setting that does in-camera what we can do in an image processor.

These are the kind of questions for which my answer would be, "It doesn't matter." It just does what it does.

mdorn Loc: Portland, OR

Compression is the answer to your quesiton as others have stated, but what about aspect ratios? My camera can be configured to a few different aspect ratios (4:3, 3:2, 16:9). I suspect the camera firmware also crops these JPG images. Since I print mainly 8x10s, is it better for me to set my camera to 4:3 or crop it myself in post when I don't use raw?

Edit: After reading this, I noticed it was a pretty silly question as well. Nevermind. Where is my coffee cup? :-)

Wahawk Loc: NE IA

The aspect ratios just have the camera cropping the picture in camera and doesn't use the extra pixels.

I prefer taking full size images and then I am able to make my minor adjustments in cropping in post before I print. This also helps me analyze later and maybe do several different crops, all from one shot.

dirtpusher Loc: tulsa oklahoma

CMOS sensor: Includes solid-state circuitry at each and every photosite, and can manipulate the data for each pixel right in the sensor. The CMOS sensor can respond to lighting conditions in ways that a CCD can’t. Every photosite can be accessed individually.

CCD sensor: Captures photons as electrical charges in each photosite (a light-sensitive area that represents a pixel). After exposure, the charges are swept off the chip to an amplifier located in one corner of the sensor. External circuitry converts the analog signal to digital form and handles storing it on your memory card.

jimmya Loc: Phoenix

Thanks folks, now I know the answer as well.

mwsilvers Loc: Central New Jersey

I agree with you that knowing how it works will probably not provide any tangible benefit. However, it is intellectual curiosity which usually drives people to ask such questions which to my mind is entirely appropriate.

BigDaddy Loc: Pittsburgh, PA

I would think regardless of the Large, Small setting all the surface area of the sensor is used.

Changing size (Large, small) changes the pixel density per square inch. Pixel density is is the number of pixels divided by the area of the sensor. You can't change the area of your sensor, but you can tell the camera to use less pixels, so a large setting has more pixel density than a small setting. This also means you get a larger FILE size but you can print a larger picture with a higher pixel density.

In short, I don't think either of your guesses happens. The entire surface area of the sensor is used, but spread over more, or less pixels.

This is how I *think* it works. I'm not an expert but found the question quite interesting, making me think more than I would like.

As far as compression goes, Large Small has nothing to do with compression, compression also uses the entire sensor, but converts very similar colors (Numbers) into the same number before encoding. When it decompresses, it has the same amount of data it always had, just a wee bit different, depending on compression level. This is controlled in the camera by Fine, Normal and Basic settings as opposed to Large, Medium and Small settings, depending on camera nomenclature.

amehta Loc: Boston

The D7000 has two different settings:
* L/M/S, which changes the resolution of the image (4928x3264, 3696x2448, 2464x1632)
* JPEG fine/normal/basic, which changes the compression level of the JPEG, leaving the RAW unchanged.

I am pretty sure the L/M/S is done by "averaging" groups of pixels, not using a smaller set of them ("sampling" ), and definitely not using a smaller area of the sensor. When Nikon does that, it calls it a "crop mode", like the 1.3x crop mode in the D7100 or the DX crop mode in the full frame cameras.

CaptainC Loc: Colorado, south of Denver

Oh, I do not think it inappropriate, just "so what?"

Back when I sold cameras, I could tell an engineer within a few minutes. They had a natural curiosity of how these things worked. To tell them to aim and push the button was not enough, BUT the knowledge they wanted to acquire did zero to help them take photos. I do understand people wanting to know arcane (however useless) information.

amehta Loc: Boston

I think it does matter:

* Changing the jpeg compression (fine, normal, basic) keeps the full pixel count of the sensor, which can affect your choices with cropping and printing.

* Chainging the image size (large, medium, small) changes the pixel count, but uses the full area of the sensor. This means that the field of view of any lens is unchanged.

* Changing the crop factor, if an option (4:3, 16:9, DX, 1.3x, ...) changes the portion of the sensor which is being used. This also changes the field of view of the lens, except for 16:9, since that still uses the full length of the sensor.

CaptainC Loc: Colorado, south of Denver

1- Compression does not change the pixel count- only how much the image is compressed. You have ALL the pixels, but a high compression degrades the image.

2- I agree. If you are using a high-megapixel camera, this is good to know as a way to save memory space for images not needing great size. But how it gets there is not necessary information. It just is.

3- Correct. But that is pretty obvious and not pertinent to the OP's question.

amehta Loc: Boston

The OP thought the answer to different sizes was #3, so I included it to explain how that is something real, but not the answer to the question. And since they misunderstood what it was, it apparently wasn't obvious to them.

And, with #2, the OP didn't realize that "it just is". Nobody is answering how it gets done, but it is useful to know what is done. Specifically, that the whole area of the sensor is still used.