MegaPixel Mystery

[brian_blattner]

<p>I have often read and heard that if you have an xx mega-pixel camera, then you can output a photo at xx size; however, I was in a home where there is a 20 x 30 inch family portrait above the fireplace that looks quite good. Later I find out that it was shot using a digital Rebel XT at 6MP.</p>

<p>So my question: is all of the talk about mega-pixels stressed way too much? And do we have to consider many other variables when really determining how many mega-pixels are required to acheive a specific size printed output? From my observation, one of these factors seems to be the distance the viewer will be from the posted work. When I looked closer at some of the pictures shot with lower mega-pixels, I could see they were not as sharp as I first thought. But when viewed from the normal distance expected, they looked quite good.</p>

<p>I shot a family portrait in my living room with a Rebel XTI, using the camera flash. The room has very poor lighting. The picture came out surprisingly good, so I cleaned it up a little using Photoshop, and output an 8-bit TIF file, that was sent to an agency to have a 18 x 24 portrait printed on canvas. The agency seemed to do a little touching up as well, and the end result is a very clean, sharp looking picture, at any distance. So I am wondering what your thoughts and experience are with this topic, as I would like to learn much more.</p>

<p>Thanks in advance for your comments.</p>

[ryan_k]

<p>yes, the megapixel wars are mostly hype, but they are not unwarranted.</p>

<p>Anything past 6 megapixels, given low ISO, and a well-resolving lens, can produce wonderful prints at large dimensions. <br>

Then there's the pixel density thing. Bayer and anti-aliasing filters, everything that can affect the sharpness and overall quality of a print. <br>

I've never thought about megapixels as a hinderence for prints. On the other hand, I have started shooting some medium format film for the big blow-ups. ; )</p>

[rjtully]

<p>I printed an 11x17 shot taken with a Kodak DC290 at about 3.2mp. The picture looked pretty good to me (at the time) but then again that is subjective. Someone else may have picked it apart for sure. All depends on what you really want and what kind of detail might be in the picture. Imagine any close-up of anything intricate done at 3.2mp. Imagine the same thing done at 15-21mp. Also figure resolution/150-300 dpi to get an idea of how big you can print. The higher the resolution, the bigger the print and the more detail available. So, you can get a pretty nice shot at lower resolution but, why? There are practical limits I suppose since our eyes may reach a point where we can't see any improvement but there is also a limit on the low end before we start losing detail and quality. Then again, someone may pick "this" apart! It all comes down to what "YOU" find to be enough resolution! (detail and quality)</p>

[mike_hitchen]

<p>Agreed all the way through. And software like Genuine Fractals makes all so much easier.</p>

 

[JAPster]

<p>Megapixels are just one technical spec, but other factors as well go into 'image quality'. This was brought home to me recently when I was playing around with an Olympus Camedia C-720 digi-cam, which is a 3 megapixel. One test shot came out suprisingly good when printed at 8.5x11 on an Epson Rx500 printer using nice glossy paper and 'Best Photo Quality'. Remember, the sensor is going to digitize the <em>optic image </em>formed by the lens and the photographer. So, in my mind, a good lens and good skills are just as important as the sensor megapixel rating. But also important are other issues like - how good is the lighting, how steady was the camera, how close are you to the subject so it fills the VF, was it focused correctly, etc, etc. Things like this impact that optic image which in turn gets digitized into an image file. If you dont get a good optic image, you wont get a good print no matter how many megapixels you got.</p>

[l_j_cappleman]

<p>I agree with Alan. A lot of other factors enter into image quality. With near perfect conditions almost any digital camera 5 megapixel and over wwith a decent lens can produce a great picture. Some of my favorite pictures were taken with a 10D but the lighting and the subject were very good. Unfortunately we don't always have perfect conditions and that is why high megapixel cameras and "L" lenses can be helpful in capturing a good image.</p>

[nathangardner]

<p>MPs are not everything. Sensor size affects the ability to print large more than MPs. Think of stretching the original sensor to the desired print size. If you start with a sensor the size of a 35mm piece of film it won't have to "stretch" as much as a sensor the size of a dime, thus retaining more of the original image quality. Also, photographic factors, such as shutter speed and a steady camera on a tripod can help maintain IQ to large sizes.</p>

[matt_needham]

<p>It's a typical advertising/sale strategy. Get the buyers focused on a single number. Then the salesperson can say "See this camera is better because it goes to 11. These other cameras only go to 10." It's quick and easy, and seems to make sense. </p>

<p>I used to shoot with medium format and 4x5 film. It's easy to find folks claiming that medium format film is equal to 40mp or 70mp or a gazillion megapixels. Yet when I started hanging large prints (20"+) from my EOS 5D (a mere 12.8mp) next to prints from my Hasselblad 500c/m and Pentax 67II it was obvious to me that they appeared sharper and more detailed. At that point I gave up on the math. Now I make test prints, and just decide with my eyeballs if they look good enough.</p>

<p>Trust your eyes. They do a much better job of assessing image quality than using mathematical formula. Again and again I see posts like "What lens/camera/film/Photoshop action should I use to get sharpness like in this photo?" When I go and look at the photo 9 times out of 10 it's the lighting that's creating the effect. </p>

[KenPapai]

<blockquote>

<p><em>Anything past 6 megapixels, given low ISO, and a well-resolving lens, can produce wonderful prints at large dimensions. </em></p>

</blockquote>

<p>However, you'll be stuck with old DSLR tech (hi noise at ISO 400) if you buy that argument. No such thing as too many low-noise pixels.</p>

<p>It's *all* about equipment and technique (getting the photo itself and its attendant post processing) in printing above 150 sqr. inches.</p>

[KenPapai]

<p>...and with medium care and OK technique 19x13 inches from my old 10D (6MP) are very, very nice looking. I can easily see a 20D/30D printing nicely at 24x16 inches with their lowly 8MP's.</p>

[ljwest]

<p>I agree that there is a lot of hype, but some truth to it. If you want your print to look like a "real" photograph made with film, etc., then sticking closer to the recommended spec is probably a good idea.</p>

<p>One of my favorite photos was taken in 2001 on holiday in Sweden, with a 2MP Olympus C-2040Z (decent f/1.8 lens...). Supposedly, it's far too small to print at 8x10, but I've printed some myself, and had other services print it, and it looks fine at "normal" viewing distances. I'm sure if you took a loupe to it, an expert could see the problems, but I enjoy it just the same.</p>

[marco_palladino1]

<p>I'm am having similar thoughts in thsese days since preparing 10 MP files from my "old" 40D for an exihibition at 20x30 inches by using photoshop's smoother enlargement and a little sharpen mask after that...I see very good detail on the monitor (about 90 PPI) what should mean good resolution at the distance of view of the print (240 DPI but you don't look images that big from so very close such as when pixel-counting on a monitor.<br>

At the moment I use a 1dmk2 which is evel less (8 MP) but never regreat the change...as many said the quality of the image comes from many things, not least the right tecnique, but even only camera-wise what makes me love this camera is a very precise and fast AF which translates into better pictures for sure. Not only when occasionally used for sport or moving objects (of course) but also only 'couse you have AF assist points arond the central one to help the focussing, that makes the diffrence for me.<br>

Now my mind keeps on thinking that probably an eos 5dmk2 would be a better choise since I often make large prints but there is something that doesn't convince me. The MP myth...is a really a myth?...as the good Ken keeps on repating from long time :-) ...see: <a href="http://www.kenrockwell.com/tech/mpmyth.htm">http://www.kenrockwell.com/tech/mpmyth.htm</a> or simply google "megapixel myth".<br>

At the moment I need a second body and could afford an eos 5dmk2 but am not really sure it would be a +1500$ worth upgrade to a second 1d2 or mybe and old 5d...what do you people think? Apart from LV, video, better LCD, ecc. mean pure resolution only, do you think that would make the difference? I really cant' say...any input on this from people printing very large, from both native resolutions (10 vs 20) , would be very appreciated...:-)</p>