How Important are the MegaPixels?

[teenat1701]

So I have been looking through the forums for this question and cannot seem to find it. Who important are MP when deciding on the camera to purchase? I am very new to Photography but my Goal and Dream is to be a professional Photographer someday and I have learned so much from this forum already. I am looking to get a good camera and was thinking of the Nikon D3100. I know there will be more equipment needed to make my dream a reality but for now the camera. My budget is $500 to $600. Any advice would be so appreciated. Thank you

[ravncat]

Megapixels are important for determining the largest size that you can print.
They're related to the resolution (detail) that you can capture in your image.
The more megapixels you have, the more "digital zoom" you can get away with - i.e. cropping into the image - but a proper lens is better.

Generally, if you aren't printing larger than 13x19 (largest size a desktop inkjet prints) you don't really "Need" more than 6 megapixels. (you can get away with less). As you get to higher and higher megapixels, you start to run into effects that make the gains worth less and less.

12 megapixels is enough for most things really. I'd say 16 megapixels on a crop sensor is pushing the edges of the "resolution gains sweet-spot". All things considered equal you can always downsample so more megapixels is not going to be a problem.

I'd put the minimum you want for pro work at 10-12 megapixels - for magazines, weddings and events. Fashion and commercial photoography, and you want to look at medium format with the 40-50 and higher megapixel range. (as rough guidelines)

though technically you can get away with nice 2 megapixel images for web and for magazines (though the editors won't agree).

Bottom line - if you're getting a modern camera that has more than 8 megapixels you're fine - more is better, but if it's a choice between a lower spec body with 16 megapixels and a higher spec body with 12 - the 12 may be the better choice (given similar sensor tech) Don't fret about it so much - and if you go with a high megapixel body (16 and up) Make sure you get good lenses that are sharp enough to really let the extra megapixels do their thing.

[ErikUngerPhotography]

I'd say that unless you are getting a medium or large format camera, there isn't a real worry for high MP count, though the next top of the line bodies from both Canon and Nikon may prove differently.

Right now, >20 seems to be a little overkill but not all that detrimental to the overall image quality. The rule of thumb is the more pixels you shove onto a sensor, they become less sensitive to light and there is more digital noise. (again, new bodies may prove that wrong)

So, you have to weigh what it is you want and what you are shooting. Shooting in good light, the higher MP count will be very beneficial. You wont really notice any noise at the low ISO's, and you will get a very high res and high detailed image. However, in poor lighting, the higher MP count will show more noise.

At the same time, noise reduction software just keeps getting better and so does the technology the big brands are putting in the top tier, and somewhat in the lower tier, bodies. The major upside to more pixels is the size you can print cleanly. More MP means larger, clean print, but you can still get nice, large prints from the somewhat lower MP (around 10) bodies.

[3bayjunkie]

There is nothing more important than megapixels!

[RichardTaylor]

Originally Posted by 3bayjunkie

There is nothing more important than megapixels!

I don't agree.
It appears that Canon & Nikon don't either as their latter high end P&S camera heve reduced pixel count to previous models in the same product line.

For me there are other considerations that take precedence.
(1) The photographer
Equipment wise....
(2) How good are the pixels (sensor size?) and in camera image processing software (noise reduction)?
(3) How good is the lens?

[sk66]

Depends on what you shoot. For action/sports/wildlife/landscapes/etc more MP is generally better. For low light shooting fewer MP is usually better. At it's simplest I would break it down like this...

MP advantages:
*larger image size
*better image resolution/detail

MP disadvantages:
*larger file size- fills card more quickly
*larger file size- increases camera processing time
*larger file size- fills buffer quickly slowing camera frame rate
*larger file size- post processing load/storage
*lower light sensitivity- not good for low light situations without supplemental lighting

But it's not that simple. You have to consider sensor size, processor capability, buffer sizes, storage medium/size/slots, etc etc as each camera will have a different ability to cope with the demands of the larger file sizes. And newer sensors are getting better at gathering light with smaller photo sites (more MP).

The D3100 is a very decent camera for the money..might want to compare with a Canon T2i.

[teenat1701]

Thank you all so much. Your knowledge and advice is so appreciated. I will look at the Cannon T2i and see if I like it too. I love this forum

[ravncat]

Originally Posted by 3bayjunkie

There is nothing more important than megapixels!

Originally Posted by sk66

MP disadvantages:
.

Also as you get higher into the MP realm on a fixed sensor size (or in otherwords as your pixel density gets higher )

Diffraction limitation is more of an issue and robs you of resolution gain
Shot noise is higher
Noise per pixel is higher. (Binning and downsampling can help)
Dynamic range is lower (due to smaller pixel well / size)
Lens flaws start to become much more apparent (Need sharper lenses)
Flaws in your hand holding technique become more obvious (can be fixed with technique, but really gets to the point where you have to be on a tripod or using faster shutterspeeds than the old 1/ (focal length x crop factor) rule.

(Though it is important to notice that this is for a given generation of technology - of course a current model at 12 megapixels will be better than an model at 6. But there are limitations and megapixel gains be less and less for more cost, as each generation shows up.)

[sk66]

Originally Posted by ravncat

Also as you get higher into the MP realm on a fixed sensor size (or in otherwords as your pixel density gets higher )

Diffraction limitation is more of an issue and robs you of resolution gain

It can, but we are talking about apertures above f/11....most lenses have their "sweet spot" well below f/11 (unless it's complete junk) so there really isn't a loss of sharpness due to MP's and diffraction limits in practical application with any current APS/FF models. (unless using small apertures to increase DOF for a particular situation...not usually the "best solution" IMO)

Originally Posted by ravncat

Shot noise is higher
Noise per pixel is higher. (Binning and downsampling can help)

Can be....but it's more "situational" than a "hard fact". Additionally, for a given print/display size the "extra noise" (if any) of the higher MP sensor will be negated because it is "finer".

Originally Posted by ravncat

Dynamic range is lower (due to smaller pixel well / size)

Again, it can be. But the DR of my D7000 is better than it was on my D3. Much of this has to do with "read noise" and processing more than pixel size.

Originally Posted by ravncat

Lens flaws start to become much more apparent (Need sharper lenses)

It would be more accurate to say you need lenses that are sharp at wider apertures....

Originally Posted by ravncat

Flaws in your hand holding technique become more obvious (can be fixed with technique, but really gets to the point where you have to be on a tripod or using faster shutterspeeds than the old 1/ (focal length x crop factor) rule.

This is true. The "rule" probably even needs modified for some current FF cameras operating above 20MP. Still, I think the "rule of thumb" is for those with "almost no technique" since most of us can hold well below 1/focal length...especially with IS.

Originally Posted by ravncat

(Though it is important to notice that this is for a given generation of technology - of course a current model at 12 megapixels will be better than an model at 6. But there are limitations and megapixel gains be less and less for more cost, as each generation shows up.)

Absolutely. And much of what you stated assumes you took the sensor sites/design and just shrunk them to get more onto a sensor. I don't think that can be done since every aspect of a sensor has to be redesigned for the photosite size/density change...(i.e. micro lenses, filtering, processing, etc)..Well, I guess it could be done; I just don't think it is.

It is actually pretty amazing at how well DSLR's are designed. When you look at "prosumer" and above designs almost every issue is addressed appropriately. (i.e APS sensors stop at around 16MP w/ a diffraction limit above f/8). I think it's safe to say that as the offerings "improve" these "issues" will continue to be considered and designed for appropriately....You just have to decide what you care more about, image resolution or light sensitivity. I don't think that will ever change (but I could be wrong)