Camera megapixel ratings - are we being fooled

[Charlie99]

I am waiting for one of the companies to bring out a digital in a reasonable price range that maintains the proper aspect ratio. ..... They had the CMOS chip the same size as a 35mm negative, but they cost almost $5k or more for the body. I just hate having to decide what part of the picture I am going to crop to get a true 8 x 10 or 11 x 17.
I guess I just frame the picture I am taking to tight to allow for adjustment....

You also need to crop 35mm to get 8x10 or 11x17. Indeed, for an 8x10 you need to do more drastic cropping with a 35mm shot than with the standard digital format.

IIRC, 35mm frame is 24x36mm, ie 2 to 3 height to width rato. (0.67 to 1)
Most digital cameras are the same 3 to 4 ratio as a TV. (0.75 to 1)
The digital camera format is CLOSER to 8 x 10 aspect ratio (0.8 to 1) than is standard 35mm.

OTOH, 35mm and the common 4"x6" prints are nicely matched.

The smaller size of the sensor in most DSLRs does cause a problem of unwanted zoom or manification, but that's a separate issue.

 

[Puffer Fish]

That's an interpolated size. Software in the camera takes the 4MP image captured by the sensor and interpolates a 7.7MP image. It's really not a useful feature to have on a camera since most image editing software has that feature and it doesn't add any real detail.

However, your point is still well taken. Megapixelage isn't everything. The sensor type, the electronics that capture the image, the camera lens, and the camera software all have an impact on the final image quality. Not to mention the photographer.

DP Review does a good job of evaluating image quality. I also like their camera comparison option that lets you compare different camera's features.
Luke
P.S. This doesn't mean that I still don't want a D2X.

DPreview.com is a great site to get a better understanding of all the issues involved here.

In general, it is:

1. Lens quality.
2. Sensor size (bigger is better)
3. pixels
4. Image processing (but a lot of that can be fixed with software)

There is some amazing quality equipment out there right now, and a lot of junk. I believe a F10 fuji, for example, with 2,000 lines/inch resolution is around $299. Three years ago, the best commercial camera's would have had trouble with that.

I only switched from 35mm when it was possible to get better images with digital, and that is easily possible today. One just has to be very careful to not just read the hype.

More pixels is only useful, if all of the other aspects are of equal or better quality. Several big name equipment makes have already made that mistake.

I would suppose that this does not matter if you make small prints, but everything I do is 8 x 10 or larger.

Note: Beware the dpi debate, printing dpi is not monitor dpi, is not photo dpi. Different media has different rules.

 

[Gilligan]

Where did you hear of that image size for the C4000? Max is 2288 x 1712, in other words 4 megapixels (3917K, actually).

You are correct. I was looking at the enlarge size option under HQ or SHQ on the cameras menu which is 3200 X 2400.

 

[RiotNrrd]

I just hate having to decide what part of the picture I am going to crop to get a true 8 x 10 or 11 x 17.

Hey Rinkopr - sorry, but the problem is that print sizes <> film sizes. Digital cameras sample the same aspect ratio as a 35mm negative, which is 3:2. When you get a 4X6 print, you get the same aspect ratio, hence no loss. But almost all other print sizes involve some cropping.

I worked at a photo lab for a couple years and had to explain this to people all the time so they wouldn't get annoyed when their 8X10 came out cropped. We actually offered an 8X12 size for people who REALLY wanted the whole image... or we would print an 8X10 with larger margins on the long axis (like letterbox format on a TV). Otherwise, we had to get out a cropper, set the aspect ratio, and show them what cropping was availabe.

Some of your medium and large format cameras use a 4:5 aspect ratio, and therefore no cropping on 8X10s. But even then, you still ahve to crop on 5X7s, 11X14s, etc...

I have not idea why these arbitrary sizes were made standards.

RiotNrrd

 

[alcina]

Sometimes I think we all get too involved in the jargon.

More MP can be better, but you also need a good lens and a good sensor. Jamming more MP on the same sized or smaller sensor is a bad thing - which is why some newer cameras with more MP aren't actually as good as some older cameras with a different sensor.

I won't delve into dpi...it's just too scary Just remember that a professional printer, if the photo is valuable to you, can do a pretty darned good job from even a small file. A friend has a glossy 20" print on her wall from a 3.2MP camera from a cropped image.

I recently had an A4 sized (roughly 8x10) published in a national newspaper from a 3.2MP camera.

And not all digital cameras use 3:2 as standard. Pretty sure my Olympus 5050 was 4:3. The Canon 20D is 3:2. Neither makes much difference when you want to make different sized prints as all the "standard" print sizes always required some manipulation from 35mm! You just have to realize that when you print, you might not get the full frame. If possible I would change the file at home before you take it to the printer so you have control over what gets axed!

I think with the price of the 4MP and even some 5MP right now you just can't go too wrong. www.dpreview.com and www.steves-digicams.com are two excellent resources - you can get as much techno informaiton as you are comfortable with or just get the basics.

Whatever you get - have fun and get out there and use it!!

 

[Don Burke]

I have been playing with the resolution settings on my D-70 and have found that I can rarely hold the camera steady enough to tell the difference between 3008x2000 and 2240x1488 anyway.

The number of pixels is important, but not all important.

If you want more real world resolution, try a tripod before buying a new camera.

 

[markfm]

If anyone is interested, I can check at work tomorrow -- I recently had to dredge up some background material on digital imaging, which leads you to the "magic" pixel count for a given imager size.

Essentially, a good quality lens has a certain innate resolving ability, expressible as xx microns at the imager plane. You then want a Nyquist-type solution -- multiple pixels span that smallest resolvable size, so that you're getting a faithful digital representation.

At the end of the day, it turns out that 10 megapixels is that magic number for one of the common imager sizes -- you've got enough digital samples so that you're resolving as well as a good quality lens can do if you had stayed in the analog domain. At that point you are "as good" as analog film. That's why a handful of years back, the first really pricey 10 megapixel jobs from Nikon and Canon were called "film quality" -- enough samples so that you weren't limited by the CCD.

 

[Scubatooth]

Ok, jumping in here with limited knowledge of the digital cameras and how they work. Since I am looking for a camera (the 3 and 4 megapixels are really cheap right now!)
I think you have it there. From what I understand the default DPI is 72. 72 DPI is web graphic quality images. Simple print images are about 300 DPI, and good print quality starts at 600 DPI. Simply put the more pixels in a given area, the sharper and better the image.
So, while megapixels are nice, the higher resolutions are whats most important. Correct?

Jenny

just wondering where you got that information from. reason that i ask in getting photo prints done 600 dpi files are way over kill in that most photo printers native printing DPI is around 300-315 DPI(this would be for fuji frontiers) and then for the higher end printers that do much larger prints (lightjet 2000 and 4000) on need between 200-400 DPI for prints.

The only true way to get higher resolution prints would be to be working from large format negatives (4"x5" or larger) using optical enlargers to make very good high rez images.

FWIW

Tooth

 

[Puffer Fish]

Jenny

just wondering where you got that information from. reason that i ask in getting photo prints done 600 dpi files are way over kill in that most photo printers native printing DPI is around 300-315 DPI(this would be for fuji frontiers) and then for the higher end printers that do much larger prints (lightjet 2000 and 4000) on need between 200-400 DPI for prints.

The only true way to get higher resolution prints would be to be working from large format negatives (4"x5" or larger) using optical enlargers to make very good high rez images.

FWIW

Tooth

In the digital world, there are several other ways to get higher resolution. The most common is to combine photos - there are several really good software's that do this really well.

The dpi becomes very difficult to manage when you shift from a computer monitor to printing. In printing, the first issues is the number of colors/heads. If you use a good 7 color system, 700 dpi = 100 dpi on a computer screen. That is because it takes 7 dots to make one real dot. For that reason, dpi changes with the method of presentation.

I shoot in 12 meg files and poster size images look very similar to 2 1/4 / 2 3/4 film images. Stick three of those together and they make a 4 x5 image look bad (although perspective is so much better with a 4x5, that I would much rather have that)

Markfm - 10 meg is for the best 35mmm, with the best lense and the best processing. 6 meg is equal to "average" 35mm. This difference is actually very small when one compares % difference. The digital "problem" is that they have gone, for the most part, with smaller sensors than 35mm, so they tend to be restricted by the lense quality more than standard film. Look at the Panasonic top of the line camera on DPREVIEW, as an example of what can happen when done correctly. The Leica lense, with image stabilization, has better resolution than any 35mm camera currently made.

 

[Scuba_Jenny]

Jenny

just wondering where you got that information from. reason that i ask in getting photo prints done 600 dpi files are way over kill in that most photo printers native printing DPI is around 300-315 DPI(this would be for fuji frontiers) and then for the higher end printers that do much larger prints (lightjet 2000 and 4000) on need between 200-400 DPI for prints.

The only true way to get higher resolution prints would be to be working from large format negatives (4"x5" or larger) using optical enlargers to make very good high rez images.

FWIW

Tooth

I'm a graphic designer and now in hindsight realized when I said printing, I should of specified that I was referring to commerical print jobs, not photo printing.