Pixels, Bytes, and DPI – Oh My!

When it comes to sensors, size matters, but maybe not as much as people think - by Infomatique via Flickr

Understanding the difference between megapixels, megabytes and DPI is one of those subjects that makes people glaze over sometimes because it’s technical. But, if you’re angling to make money from photography or do it for a living, it’s important to understand what the terms mean and the difference it makes in your photos. So, while I realize a pictorial of hot models in skimpy clothing is how you’d rather be spending your time, I’m going to try to make this discussion as fun and interesting as humanly possible.


Probably the most ridiculously overused comparison in digital cameras today, and the camera manufacturers go along with it because it’s not worth the effort trying to explain why it’s not always a fair comparison. Comparing cameras by their megapixel rating is like my wife picking a new car because she likes the color. The number of megapixels has very little to do with the quality of the final image. Color, tone and sharpness will have far more sway over the quality of the final image, which is one of the reasons the highest rated cameras are all over the road when it comes to the megapixel rating of the sensor.

The difference in megapixels does effect the resolution of the final image, but even that is a geometric comparison and not a linear scale. The number of pixels increases by the square of the resolution. If you double the resolution of an image, you quadruple the number of pixels.

If you’re comparing a 5 megapixel camera, like your cell phone, with the 10 megapixel Sony TX300v, you now know that does not mean the 10 megapixel camera is twice as good. In fact, the difference in resolution is just 1.4 x in either dimension. Not so great now, is it?

sensor size chart
You have to nearly double the sensor size to see any significant increase in resolution - via Wikipedia

So when considering the difference between a 16 megapixel camera and a 19 megapixel camera, the difference is nearly insignificant. Other factors in camera and lens quality can erase such a small difference.

Where megapixels do matter is the image size, the more megapixels, the bigger the final image. That says nothing about the quality. A large blurry image through a bad lens is still a bad picture no matter how large it is.

If you’re just looking at your own pictures on a display device, it’s not an issue. If you’re hoping to sell stock photography, it becomes more important because many stock photo companies set minimum image sizes.

True resolution

Snapsort uses true resolution which is based on the physical size of a cameras sensor and not the manufactures advertised high megapixels, which can be misleading.


A megabyte is a measure of digital storage, the same as it’s applied to any digital storage. How large an image is is loosely related to the final image size, but every image file is a little different based on a large number of factors including the compression type (JPEG vs RAW).

NASA photo
In 1999 NASA had to take a composite image to get this 2,796 x 2,796 pixel image of Io. Roughly 8-megapixels, or about the same resolution as an iPhone 4s today - by NASA


Dots per inch is only relevant to a discussion of a printer or other display device. Outside of printers, you can pretty much forget about DPI. In the old days if you changed the picture DPI, your editing software would automatically resize the print output. These days if you tell Photoshop you want a 5×7 and change the DPI, you’ll still get a 5×7 print.

In photography it’s all about the resolution and resolution is measured in megapixels, but that isn’t necessarily significant unless the difference is very large.  There would be a noticeable difference between an 8-megapixel camera and a 12-megapixel camera, the difference between 12 and 16-megapixels would not be as significant, if it were even noticeable.

Taking Better Photos With Your Point and Shoot Camera

An award winning photo taken with a Olympus tough 6000 waterproof point and shoot camera, photo by Brenden Sherratt

Some of you might look at pictures taken with a DSLR with a bit of envy, imagining that the camera is somehow responsible for getting better photos.

Well, here’s one the dirty secrets that the High Council of Jedi Photographers will likely not like me telling you, but these days there is not a great deal of difference between many point and shoot cameras and high end DSLRs.

In fact, mirrorless cameras like the Sony Nex-5N, Pentax K-01 and Samsung NX-11 have the exact same sensor size as my Canon 7D (compare) and they’re a lot easier to carry around. Though they lack some of the other features like weather sealing and build quality, they all can take amazing photos. All you need are a few tips for getting the most out of your point and shoot camera.

Read The Manual

read the manual
It's boring but you must read your camera manual

No amount of coaching will help you get the most out of your camera if you don’t understand how it operates and the features it provides. I’d be willing to bet a good 75 percent of camera functions never get used and half of the time because their owners had no idea their camera could even do that.

You’ll need to know how to set your camera to shutter and aperture priority modes, how to change the shutter speed and aperture manually, and how the exposure compensation features operate. If your camera has a built-in flash and how to change the flash compensation. All that knowledge is yours for a 30 minute date with the owner’s manual.

Shoot Everything

I recently calculated that National Geographic photographers are taking anywhere from 350 to 1,000 pictures a day, depending on the assignment. At a recent wedding, the prime photographer and I were taking around 200 photos per hour, each.

The more pictures you take, the better the odds of getting one that’s amazing. Some of my best photos were ones I remember wondering why I even bothered to take that shot. You just never know. Shoot everything, sort it all out in post.

Stop Taking Pictures of People Sitting On The Couch

people on couch
Taking pictures of people sitting on the couch is now banned - by Simon Law via Flickr

The photography world is flooded with pictures of people sitting on couches and, frankly, we’ve had enough. Get pictures of people doing something, anything. Get a picture of them playing a game, riding a bike, cooking, or engaging in some hobby that tells us a little about them as a person.

Besides, it’s a great excuse to get everyone off the couch and up doing something.

Your Camera Is Not a Rifle Sight

Stop treating your camera like a gun sight, putting your subject right in the middle. Take a look at this article on the Rule of Thirds and remember, it’s not the Helpful Hint of Thirds or the Recommendation of Thirds, it’s a rule. Get the subject over to one of the thirds.

This is why taking pictures of people doing things is so helpful. If you center the activity, frequently the person doing the activity will be off to one side of the photo. It’s a good way of training yourself to frame better.

Flash Off Inside, Flash On Outside

fill flash
Everything done right. Subject doing something, interesting angle, plus use of fill flash in daylight - by Aske Holst via Flickr

For all the amazing features of point and shoot cameras these days, the built-in flash is probably the worst light source in the history of photography. Turn it off whenever you possibly can. Get your subjects over by a window, or even better, outside to some open shade. Then turn the built-in flash on and make it fire.

While the internal flash is a terrible light source, it is quite a good fill light for outdoor portraits.

Digital Workflow – The Options

I've rarely been in a professional studio that didn't have a copy of Lightroom on hand

Much of your digital workflow is going to be dictated by the software tools you select to do your basic image manipulation and organizing. The tools you select will in part be determined by the type of computer you have and your budget.

Your digital workflow is really composed of two elements: Image organization and image manipulation.

Image Manipulation

Adobe Creative Suite

The gold standard for most commercial photographers is still Adobe Creative Suite, now at version 5.5 with 6 expected soon. The advantage to Adobe products is the fit, finish and integrated workflow. The downside is the price tag. The full version of Design Premium is just short of $2,000, more than many of you paid for your camera! Design Standard is still over $1,200. Recently, Adobe has started sticking it to their user base on upgrade pricing as well and limiting the older versions that qualify for upgrade pricing.

It’s my opinion that Adobe products are over-priced for what you get, but there are certainly compelling arguments to the contrary.


Gimp for Windows

GIMP has been around forever but lacks the sophistication and polish of Photoshop. The advantages of GIMP are the price tag and huge user base of support.

GIMP keeps getting better every year, so do check in it from time to time. You might be surprised.

Image Organization

Adobe Lightroom

Lightroom is the application you’ll find in most professional studios using Windows. You’ll find it in some Mac shops as well, but more Mac users are using Aperture.



Known to users of Linux for a long time, Digikam was recently packaged for Windows users as well. I use Digikam because it runs on both my Linux and Windows boxes and I like it.

Digikam puts professional level image organization and basic corrections in your hands for free. What I can’t live without in Digikam is the automated batch processing.

Hasselblad Phocus

I don’t like Phocus as well as Lightroom or Digikam but I want to give Hasselblad credit for coming up with a very polished application that’s available for the trouble of a free registration. Originally developed to work only with Hasselblad raw images, they have opened it up to other users and image formats.

After some initial issues with DirectX, I found Phocus to be a very nice application for cropping, straightening and color corrections. I’d highly recommend giving it a try.

The $8.99 Flash Snoot, Lunch Included

One of my friends at Pixel-Mesh took a few household tools and the leftover pizza box from his lunch and fashioned it into a homemade flash snoot that yielded surprisingly good results.  A snoot restricts the light and allows you to direct it at a specific location, helping you to eliminate “light spill”

The Tools

Razor knife, builders square, and dark duct tape (it's not a hack without duct tape)

A razor knife, builders square and a roll of dark colored duct tape (you knew duct tape was going to make an appearance somewhere).






Using The Top of The Box

Any flat piece of cardboard will do, but will they also be a pizza scented air freshener?

Cut the outline of the snoot shape and cover the cardboard with a layer of duct tape.





Fold Into the Proper Shape

Tape flat first

Fold into the proper shape and tape it into position.





Then tape into shape








Attach to The Flash

The homemade snoot attached to the flash

If you sized it right it will fit on the flash without taping it.





The Results

With the flash attached to a Canon 5D MKII the results are not bad, not bad at all.

Lighting Portraits With Candlelight

lighting by candlelight
Valentine's Day is a good opportunity to experiment with lighting by candlelight - by Chantel Beam Photography via Flickr

Valentine’s Day presents an opportunity to experiment with a really old-fashioned light source; it’s one of those days a lot of people choose candlelight.

There’s something visceral about fire in the human psyche and candles provide a single, pure pinpoint of fire that is both warm and intimate at the same time. You know you’re a real photo geek when a romantic candlelight dinner inspires you to break out the camera and tripod!

One of the really amazing things about new digital DSLRs is their low light performance. Just a few years ago trying to light exclusively by candlelight meant risking a house fire. Today even APS-C sensors like the Nikon D7000 or Canon 7D (compare) can yield decent results in low light and full frame cameras like the Canon 5D MK II and Nikon D700 (compare) can shoot in extremely low light.

Don’t Worry About Noise

This is one time you can forget about the ISO. Most digital cameras start showing low light artifacts anywhere over ISO 800. But candlelight portraits are one instance when the noise can actually add to a photo, so don’t be afraid to experiment with higher ISOs. If the pictures are too noisy you can always add more candles.

candlelight 4
Low light noise can actually add to a candlelight photo - by Miss Baker

Use a Tripod

Trotting out a tripod for some candid shots may not be the most romantic gesture, but it’s still better than hand-holding at slow shutter speeds. Even a gelled fill flash will spoil the effect, so there’s no real option here.

I wouldn’t go any lower than 1/15 of a second with a human subject as it’s hard for anyone to hold that still.

Use Reflectors

A white tablecloth actually works quite well as a natural reflector. A mirror will give you sharper shadows and strong directional lighting. Your standard photographic reflector clamped to a light stand will also come in handy to fill in the deeper shadows.

You can use aluminum foil over a piece of cardboard if you want a more irregular effect. If there’s a whiff of breeze, a flickering candle with an aluminum foil reflector can look like a campfire.

candle 3
Candles can function equally well as foreground or background lighting - by Walt Stoneburner via Flickr


There are two ways you can go with candlelight photos: You can expose for the subject and overexpose the candle flame or you can expose for the candle flames and deliberately under-light the subject.

Try it both ways and try different combinations. You can sometimes use LED or incandescent bulbs as background light if you need more depth.

Do remember that a couple pictures of a special occasion is one thing, but a good photographer also knows when it’s time to hang up the camera and enjoy the moment.