DPI

Stands for Dots Per Inch and goes back to the printing and publishing world. This is where the absolute of "… and you gotta have 300 DPI to make a decent print" fallacy comes from. (Beside the fact that when referring to digital images you should be using PPI!)

In our digital photography world, DPI is a term used to refer to film and print scanners, and inkjet printer, resolution. In scanners, it’s how many dots (actually pixels) are rendered in the final image file per inch of original. 35mm film scanned at 2000 DPI gives you a 2000×3000 pixel file. A 4×6 print scanned at 600 DPI results in a 2400×3600 pixel image.

In inkjet printers DPI is the number of dots of ink laid down per inch of printing paper. You may see different numbers for the horizontal and vertical numbers. Don’t worry. I’ve read a few articles that claim the human eye can’t distinguish difference in anything past 2000 DPI.

PPI

Used to refer to digital files going to print as 4×6s or 8×10s, Pixels Per Inch is no more than a reference number. It tells you how many pixels of your image are being used per inch of print. Again, simple math.

How many do you need? What’s the perfect PPI? Only you can decide. It’s rather subjective. Most people will try to keep between 200 and 300 PPI. In larger sized prints (16×20 and bigger) you can easily get away with 150 PPI and they look fine.

Ever see a billboard up close? They get printed at 10-20 PPI, but we view them from such a distance that it looks great.

Now here is something to wrap your head around. Imagine a 6 mp image at 2000×3000 pixels is printing to a 10×15. That’s 200 PPI. Your inkjet printer prints at 2400 DPI. That means each pixel is represented with 12 dots of ink. Is that enough fine detail for your liking?

Make some test prints for yourself and find your "level of tolerance" for your camera. You may find 150-200 PPI perfectly acceptable. My D70 has produced nice 16×20 prints and that’s my level. Everyone has a different perception and you need only find yours instead of accepting someone else’s.

Just do me one favor. Use the terms DPI and PPI properly. Thanks!

Some sailors I knew were suffering from the “One foot longer” syndrome. They were always looking for another boat that was just a bit bigger than what they had.

Digital camera users suffer from a similar affliction: “One more megapixel.” The assumption is that the newest Whizbang camera must be better than what they have. It must take better pictures. Of course, the camera manufacturers are more than happy to feed the need. This year we’ve seen Casio’s 12MP Point and Shoot camera and Canon just broke the 20MP barrier for DSLRs. WOW!!

Will these new high MP cameras take better pictures? Nope! More MP just buys you bigger prints. Plain and simple. The new cameras may have a slightly more sophisticated Autofocus or shoot at a higher frame rate, but any picture still comes down to shutter speed and aperture.

Learning about exposure, lighting, composition, and other photographic techniques will get you better pictures.

Spend some of your time and money on educating yourself before you consider the next Wonder Camera. Reading this blog and the articles on TeachMeToShoot.com are a good place to start. Join a camera club. Buy a DVD tutorial on lighting or Photoshop. Take a photo workshop from Mentorseries or Rocky Mountain School of Photography.

Feed your brain!

First and foremost, read the Manual. Read it four times if that’s what it takes. Have the camera in front of you as you go through the book. Be sure you know (at least) how to Reset to factory defaults, change the ISO, use the exposure modes and Scene modes, switch from AF to MF, and be able to force the flash On or Off. Know where Macro mode is and Exposure Compensation.

Second, don’t muck around with all the settings in the Menu unless you know exactly what they do. My friend set the camera to shoot TIFF files (presuming better quality images) and didn’t understand why a 2 gig card would only hold 100 images instead of 400. RTFM. And, if you change some settings for a particular shot be sure to change them back!!

Lastly, use the camera enough that you’ll use and remember different buttons and settings. Experience is a great teacher. Besides, a palm to the forehead during that “Ahah” moment is better than a 2×4 to the back of the head!

** NOTE to techno-geek, digital photography expert buddies: To reduce your stress while helping a friend, go download a copy of the Manual for THEIR camera. It’ll make things so much easier for you.

How much is too much?? I can certainly see the benefit of 12MP or more in a DSLR, but P&S cameras have such small sensors. Packing 12 million receptors on a roughly 1/2 inch sensor seems ridiculous to me. Since most P&S users are making mostly 4×6 and 5×7 prints, a 5MP camera is more than enough.

When I was selling cameras at Ritz and Wolf I never jumped to the highest MP, most expensive camera. I talked to my customers, assessed their needs and found them the right mix of features and performance. Bigger isn’t always better.

We silly Americans are always searching for bigger, better, faster, longer, stronger products. And digital camera manufacturers are more than willing to feed your desires. I think you should buy based on Need and not Want!   [end of rant]