Photography for Beginners Part 24: Buying a Camera – Sensor Sizes

Each post in this series builds on information discussed in previous posts. See the Photography for Beginners page on the menu for links to all the posts.

Part 23: Buying a Camera – Types of Cameras


In the previous post we discussed that camera type and sensor size are interrelated, and that you need to decide what you want in both categories before you can move on to thinking about specific camera features.

In that post we covered the different types of cameras. In this post we cover sensor sizes.

If you need help with photography jargon you can open the glossary in another browser tab for quick reference.


Sensor Size

The rule of thumb is a that larger sensors produce better photos than smaller sensors. However, the differences when compared to the next smaller or next larger sensor size are incremental, not dramatic.

There is an easily detectable difference between photos from a 1″ sensor and a full frame sensor. But the differences between an APS-C sensor and FF are small, and often undetectable without making large prints or pixel peeping. (Pixel peeping is when you zoom in on an image to 100% or more to look for flaws.)

Because significant advancements have been made in sensor technology there is also some overlap. The quality gaps between some sensors have narrowed so much that in some cases the top cameras with a smaller sensor make images as good as the lowest cameras with the next larger size sensor.

What this means is that, despite its vital importance to IQ, sensor size isn’t necessarily your ultimate deciding factor on which type of camera to get. Camera specs are often less important in the real world than marketing materials want you to believe.

If you are on the fence in choosing between two sensor sizes, think about how much sensor size will or won’t affect the types of photos you take and what you do with them. If you need high resolution for making large prints or great low light performance the sensor is more important than if you do a lot of general photography and mostly share photos online.

You can use other aspects of the cameras offered in each sensor size to push you in one direction or the other.

This graphic shows the relative sizes of the most common sensors and their crop factors. (Not shown actual size.)



This has been the most used sensor size in P&S cameras. It’s tiny. Cameras with this sensor size take very nice photos in good conditions, but that’s about it. Noise can be a problem even at medium ISO numbers. These cameras are mostly intended for family and travel snapshots.

I strongly recommend that you avoid cameras with this sensor size, especially since a really good one costs almost as much (more in some instances) than a camera with a much better sensor. You can still learn a lot about photography when using one, but you’ll hit a limit with what you can accomplish pretty quickly.

If it’s all you can afford, get a model that has buttons and dials to easily access advanced features. Also pay close attention to the lenses. Most aren’t fast, but there are a few models with f2.8 lenses or better. This helps to somewhat compensate for ISO limitations of the tiny sensor.

When looking at P&S product listings online, if the sensor size isn’t mentioned in the marketing details it’s probably a 1/2.3″ because it’s not a bragging point. You can look up the specs to be sure.


The 1″ sensors are also used in P&S cameras and are still pretty small, but they’re a definite improvement over 1/2.3″. Four years ago this sensor size was a new thing, only available in two bridge models, and the cameras were very expensive for a P&S.

Now Canon, Leica, Panasonic, and Sony all make 1″ models in both compact and bridge styles. A few models are available in the $500-700 price range, though some are more than $1000.

If you’ve decided that you want the convenience of a P&S with a fixed superzoom lens then I recommend getting a bridge camera with a 1″ sensor.

My older camera is the Panasonic FZ1000. I can’t think of any features my more expensive APS-C mirrorless has that the Panny doesn’t. The Panny does actually have a few features the ILC doesn’t have. It takes great photos under the right conditions.

The reasons I switched were I wanted higher ISO without significant noise and a better lens. (The lens is soft at wider apertures even though it’s a better than average P&S lens.) Though to match the focal lengths of the bridge zoom I had to buy more than one lens for the new camera. They are very good lenses, but bye-bye precious dollars.

I went into those details not to promote or knock that specific camera, but to give an idea of the trade-offs from personal experience. If I had been content with the limits of the lens and lack of ability to use high ISO I’d still be using the 1″ Panasonic because I dislike having to change lenses. I kept it as a backup do still use it to make timelapse videos.

Micro Four Thirds

You will often see this sensor size referred to as micro 4/3, m43, or MFT.

Cameras with this sensor size are all mirrorless and most are ILCs. M43 cameras are a more mature system than APS-C mirrorless, and because of this the cameras are very feature rich. These are excellent general purpose cameras.

Micro 4/3 is the smallest of the bigger sensors. It’s a compromise size between the small P&S sensors and the large sensors, but it’s a compromise that a lot of photographers genuinely prefer rather than settle for.

MFT is a 2x crop (reduction) from full frame. The crop size is considered an advantage by many because it means you have greater depth of field with large apertures (good for things like landscape and macro photography), and the field of view of a 50mm m43 lens is equivalent to a 100mm FF lens. Because of this you get a lot of reach with a small and light lens. However, the crop factor also means that it’s more difficult to achieve good shallow depth of field when it’s wanted.

You get much better IQ and low light performance than with the small sensor cameras. But when compared to larger sensors m43 doesn’t perform as well when it comes to dynamic range and low light.

The biggest advantage of m43 cameras is that they are small and light for an ILC, making them especially well-suited to hiking, street and travel photography, and for anyone who physically can’t or doesn’t want to carry heavy gear. A kit with one body and 2-4 lenses can fit in a surprisingly small bag.

The other main advantage is that all brands use the same lens mount. This means that once you have your body you can buy lenses from any of the m43 brands and several third-party brands with no adapters needed.

These are good cameras for people who want good IQ and a variety of lens options in a smaller package, and for those who prize getting a lot of highly advanced features for a relatively reasonable price.

Olympus and Panasonic are the top two brands. There are several good brands for lenses. Panasonic m43 cameras are especially valued for their video capabilities.

Don’t expect to save much, or even any, money over what you’d spend on an APS-C camera. The advantage is in the size, lenses, and features, not price.

Prices start at around $500 and go up to over $1000.


APS-C sensors are available in compact fixed lens mirrorless cameras, mirrorless ILCs, and DSLRs. Most APS-C sensors are a 1.5x crop from full frame, but Canon makes theirs as a 1.6x crop, which is slightly smaller. Nikon calls theirs DX sensors.

Full frame sensors have been considered the size all serious photographers should aspire to. For some types of photography that’s still true, but APS-C sensors have come far enough that there is little difference in the output of a high-end APS-C camera and a low-end FF camera.

An APS-C sensor can handle almost anything you ask it to do.

APS-C cameras are slightly to a lot smaller than FF bodies, and the lenses are also smaller and lighter, especially the primes and short zooms. The long zooms are still pretty hefty.

Fujifilm and Sony are the top two brands for APS-C mirrorless cameras. For DSLRs Canon and Nikon are the top two.

The biggest advantage of APS-C over FF is price. If you don’t have a specific photography need that requires full frame, you’re better off buying an APS-C body and spending the difference on glass.

Prices start at about $500 and go up to well over $1000.

Full Frame

Full frame sensors are the largest that are in common use. They are available in compact fixed lens mirrorless cameras, mirrorless ILCs, and DSLRs.

Full frame sensors have the best dynamic range, the best high ISO performance, and some have much greater resolution. If you get into specialized photography that requires a top-notch camera you’ll probably be looking at FF cameras. For the average hobbyist FF can be overkill.

The only drawbacks are size, weight, and price. Size and weight are especially an issue if you use long lenses. FF cameras simply aren’t as much fun to lug around and are more frequently left at home than all other types because of this.

Sony is the top brand for mirrorless full frame cameras. Canon and Nikon dominate the field for DSLRs, though Pentax and Sony are also in the mix.

There are a few exceptions, especially there’s a good sale, but in general prices start at around $2000 and go up to over $6000.

Medium Format

This post wouldn’t be complete without mentioning medium format sensors, but they are very much a high-end niche product. It’s a sensor size even larger than FF. These high resolution sensors are most useful for commercial, landscape, and macro photography when making very large prints.

Only hobbyists with very deep pockets would consider one. The body alone for the only “cheap” medium format camera (Fujifilm) is around $6000. Add on lenses and you’re shelling out a few thousand more. The prices for all other bodies start at about $10,000.


Aspect Ratio

The commonly used sensor sizes come in two different aspect ratios. Aspect ratio is the proportional relationship of the width to the height of the sensor and resulting images.

Full frame and APS-C sensors have a 3:2 aspect ratio. This is the same aspect ratio of 35mm film. The images are quite a bit wider compared to height, so a more elongated rectangle.

Micro 4/3, 1″, and 1/2.3″ sensors all have a 4:3 aspect ratio. (That’s where the m43 format gets its name from.) The width compared to height is shorter than with 3:2. So even though 4:3 still produces a rectangular image, it’s a bit closer to a square than 3:2.

The native aspect ratio doesn’t matter to most people when buying a camera. But if you do a lot of printing in the old standard sizes consider this:

The 3:2 ratio is the same as standard 4×6 prints, no cropping needed. If you have a 4:3 sensor you’ll need to crop slightly. But 4:3 has an advantage for 5×7 and 8×10 prints. Less of a 4:3 image needs to be cropped than with 3:2.

Pre-made picture frames bought in stores still usually only fit the irrational and outmoded sizes of 5×7 and 8×10. (I say irrational because those print sizes didn’t fit standard film formats without cropping either.)

So if this will affect you a great deal it should be factored into your decision process. (The best way to avoid such print size problems is to shoot a bit wide so you don’t lose an important part of the image when cropping to print.)

Most digital print labs have thankfully caught up with the times and when making larger prints they offer sizes to fit both aspect ratios. You need to look at an online conversion chart to see which print sizes have the same aspect ratio as your sensor so you know what to order. With canvas, board, glass, and metal options available you can skip the store-bought frames.

Most cameras provide an option to change the aspect ratio of the images you take. It depends on the model but, in addition to the above two native sizes, 1:1 (square), 5:4 (8×10 print size), and 16:9 (video format size) are sometimes offered.

Choosing any aspect ratio that is different from native means the camera is automatically doing a crop. So you’re losing pixels and resolution. But that’s no different from doing the crop yourself in an image editor after the fact. The benefit of doing it in-camera is that you can make sure you’ve framed your composition correctly.



Since we’re already discussing sensors let’s go ahead and cover megapixels here also.

You see the word “resolution” a lot in reference to sensors and megapixels. The basic meaning is how much detail is captured in an image. A sensor with more megapixels can capture more detail and is called a higher resolution sensor.

But what is all too often left out is that the sensor is only half of the story. The lens is the other half.

The pixels (more properly called photosites) on the sensor capture the light coming in through the lens aperture. More pixels can capture finer detail. But the glass of the lens is what directs the light to the pixels. How soft or sharp the lens is plays a large role in resolution and how well the pixels are able to do their job.

This means that buying a sharper lens can often do more to improve IQ than buying a camera with more megapixels. If you already have a sharp lens, then buying a camera with a higher resolution sensor can be an improvement.

Related to this, the more megapixels a camera has the sharper a lens needs to be to get proper resolution. It’s not uncommon to get worse IQ from a high megapixel camera using a soft lens than a medium megapixel camera using a sharp lens.

If you want a camera with a very high resolution FF sensor you should limit yourself to using pro quality lenses. If you use a kit lens or other consumer grade lenses you’ve wasted a lot of money on that high-end sensor.

Camera companies have done a great job of over hyping the importance of megapixels and many consumers have bought into it. Camera makers want to sell their latest offerings and most of the market is existing photographers, not new people taking up the hobby, so they try to entice you with more megapixels.

In the early days 6MP was vastly better than 2MP so more megapixels was a legitimate selling point. But these days it’s mostly just marketing because the differences between 16MP and 20MP are negligible. The lens used makes more of a difference.

More pixels isn’t even always better. The size of the pixels (photosites) and pixel density also play big roles. The larger the pixels are the better they are at capturing light. The more space there is between the pixels (less density) the better they are at capturing light.

A 1/2.3″ sensor with 16MP has teensy pixels crammed tightly together. The sensor technically has great resolution, but it’s less light efficient than a 8MP sensor of the same size. On a m43 sensor those 16MPs can be bigger and more spread out, so you get better performance from the same resolution. This is why some FF sensors are available with very high pixel counts not seen in any of the smaller sensors.

Another potential negative is that the more pixels there are the more easily the sensor picks up and records slight camera shake. Camera shake is responsible for more soft photos than anything else. A high resolution sensor makes you more reliant on using a tripod to get sharp images.

More megapixels are beneficial in two ways:

When enlarging an image, the larger you make it the more resolution you need to retain detail and keep it looking good. This is mostly important in commercial photography or when selling very large prints.

When you crop a photo you are eliminating pixels and reducing resolution. So if you do a lot of significant cropping it helps to have more resolution to start with, especially for making prints. This probably affects wildlife photographers more than anyone else.

All of the above detailed info was provided to support the point that I really want to make about megapixels:

Any camera you decide to buy will have more than enough megapixels.

The average hobbyist shares photos online, in email, and with 4×6 prints. The images are viewed at a size small enough that the megapixel count is mostly irrelevant. Even if you plan to make a few nice prints as gifts or to display on your living room wall, you’ll have enough megapixels.

The cameras that you’ll probably be looking at most likely have between 16 and 24MP. Lots of professional photographers sell prints made with sensors of the same resolution. (A few years ago they were selling prints from 8 and 12MP sensors.)

When deciding between different camera models there are usually other things that are more important than whether one has more megapixels than the other.


What Should You Get?

This is a decision only you and your wallet can make. The camera needs to fit your lifestyle, personality, and what you want to do with your photography. (If you need tips on what works fine and what is best for different types of photography scroll to the end.)

Here are the primary factors:

*  Size and weight.
*  Changing lenses – yes or no.
*  Lens quality.
*  Desired focal length(s).
*  Resolution.
*  Dynamic range.
*  Low light performance.
*  What you do with your images.
*  Price.

Make a list of the above things that are important to you for the camera you plan to carry around. For each item on your list write down which type(s) of camera and which sensor size(s) best meet your needs for that category.

Hopefully a pattern emerges and the answer will be fairly obvious, or you’ll at least have it narrowed down to two different camera type and sensor combos. If your list is all over the place, you have to decide where you are most willing to compromise before you can move on.

Now listen to your gut.

If your head is telling you one thing for logical and practical reasons, but you can’t shake off an underlying feeling that you’d be happier with something else, don’t dismiss that feeling. Practical factors are definitely important, but your gut instinct may be telling you what would make photography the most enjoyable for you at this point in time.


Camera Buying Guides

There are camera buying guides posted all over online. Some are great and some are worthless. Don’t pay any attention to sites that just regurgitate marketing info and specs because they exist only to make money from your clicks. Look for sites that give performance details and opinions based on hands-on experience with the cameras.

In the upcoming posts we’ll be discussing camera features and how to narrow your choices down to 2-3 specific camera models. In the meantime, if you want to get a general idea of what’s available out there in your price range and preferred camera type(s) you might want to take a look at the buying guides at DP Review.

The DP Review buying guides don’t list every model available in every category. They list their top one or two choices, and then a few alternates. But even if the right camera for you is lurking somewhere else and not on these specific lists, it’s a good way to get an initial overview.


Types of Photography

Action and Sports

Excellent autofocus tracking and high frame rates. Indoors, a constant aperture zoom and great high ISO performance.

Full frame (DSLR or mirrorless) designed for action are best. (Very expensive.) Lower performing FF and top performing APS-C or m43 okay, but fewer in focus shots and maybe noise issues. Superzoom P&S can work outdoors with inconsistent results.


Full frame is ideal, either DSLR or mirrorless. APS-C is pretty good, m43 is so-so. Fast, sharp wide-angle lens with minimal coma and chromatic aberration, no matter the sensor size.

For telephoto and deep space work sharp lens and star tracker for the tripod required.

For solar any camera with a long lens and a solar filter. Any camera with a long lens for the moon, the sharper the lens the better.

Events and Ceremonies

Reliability, 2 memory card slots, low light performance, and variety of high quality fast lenses. Pros mostly use Canon and Nikon full frame DSLRs, Sony FF mirorless getting more popular. APS-C okay with high-end camera. M43 works but might run into noise issues indoors. Mirrorless best for silent shooting.

Point and shoots for casual photography but not pro-level results.


Any camera for posting online and 4×6 prints. The larger the sensor the better for improved resolution and dynamic range, especially for making large prints. Sharp lenses in both wide-angle and telephoto. Size and weight crucial for hiking. Weather sealing for misty waterfalls, snow, rain, or dusty conditions.


Any camera. Point and shoots usually have built-in macro capability. With ILCs a close-up diopter or macro capable lens required (not cheap, but they’re also for non-macro shots). Larger sensors better for resolution. M43 good for greater depth of field. Sharp lenses with little chromatic aberration best.


Any camera for cityscapes and moonscapes on a tripod, but the larger the sensor the better. Wide-angle or telephoto, fast lens preferable but not required.

Aurora borealis at least m43. APS-C and FF are best. Sharp, wide-angle fast lens with minimal coma.

Handheld at night (you need lots of ambient light) good stabilization, fast lens, good high ISO performance.


FF best because of shallow depth of field. APS-C okay, m43 a bit lacking but doable. Fast lenses of long standard or short telephoto focal length.


Any camera. For great IQ and being more discreet m43 and APS-C are best, either ILC with a small zoom or prime, or a compact fixed lens camera.


Similar to street, but if you want telephoto capability you need either a P&S with a zoom or an ILC.

For shooting inside landmarks and museums m43 or APS-C and an ultra wide fast lens.


Good selection of quality long lenses. For birds in flight excellent autofocus tracking and high frame rates.

Lenses on superzoom point and shoots have the reach but not the quality.

Top of the line Canon and Nikon full frame DSLRs and Sony full frame mirrorless are best (very expensive). Lower tier FF, and high-end APS-C and m43 okay.



Part 25: Camera Features


Comments or questions always welcome!

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s