Full Frame VS Crop Sensor VS Micro Four Thirds: Camera Sensors Explained

Full Frame VS Crop Sensor VS Micro Four Thirds: Camera Sensors Explained

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1 - Full Frame VS Crop Sensor VS Micro Four Thirds: Camera Sensors Explained

‘DSLR Camera, Full-Frame, Crop Sensor’- Just 3 terms which are prevalent in virtually every discussion involving photography. The two terms in use to classify sensor sizes of a DSLR camera are ‘Full-Frame’ and ‘Crop-Sensor.’ A Full-Frame camera contains a sensor size equivalent to a 35mm film format whereas a Crop-Sensor camera has a sensor size smaller than a full-frame sensor or a 35mm film format.

Micro-Four-Thirds (4/3) is a relatively new format (and term). First introduced around 2008, this sensor is slightly smaller and compact in nature. However, owing to a variety of factors, this format is now considered almost equal to, if not better than, the Crop Sensor format.

Apart from the physical size difference, there are several other points of difference between a full-frame sensor, a crop-sensor, and a micro-four-thirds sensor. Let’s take a look at a comparison between them under the following characteristics, to get an accurate understanding of their differences.

Crop Factor

As mentioned above, a full-frame camera has a 35mm sensor based on the old film-format concept. Whereas, a crop-sensor (also called APS-C) has a crop factor of 1.5x (Nikon) or 1.6x (Canon). Micro-Four-Thirds are even smaller sensors having a crop factor of 2x.

This crop factor also directly affects our field of view. Simply put, an APS-C sensor would show us a cropped (tighter) view of the same frame as compared to a full-frame sensor, and a Micro-Four-Thirds sensor would show an even tighter (more cropped) output of the same frame.

2 - Full Frame VS Crop Sensor VS Micro Four Thirds: Camera Sensors Explained

LEFT: Photo clicked using a Full-Frame camera. CENTER: Photo clicked using a Crop-Sensor camera. RIGHT: Photo clicked using a Micro-Four-Thirds camera.

Focal Length

The focal length obtained by different sensors is also directly associated with crop-factor. The focal length measurement of any given lens is based on the standard 35mm film format. Whenever we use any crop-sensor camera, its sensor crops out the edges of the frame, which effectively increases the focal length. However, this is not the case with any full-frame sensor, as there is no cropping involved with a full-frame field of view.

For example, in the Nikon eco-system, a crop-sensor camera such as the D5600 has a ‘multiplier factor’ of 1.5x. Thus, if I mount a 35mm f/1.8 lens on my Nikon D5600, it would multiply the focal length by 1.5x, thus effectively giving me a focal length output of around 52.5mm. If you mount the same lens on a full-frame Nikon body such as the D850, it gives an output of 35mm.

Similarly, if you mount a 35mm lens on a Micro-Four-Thirds sensor, which has a crop factor of 2x, it effectively doubles the focal length obtained to around 70mm.

3 - Full Frame VS Crop Sensor VS Micro Four Thirds: Camera Sensors Explained

LEFT: Photo clicked at 35mm on a Full-Frame camera. CENTER: Photo clicked at 35mm on a Crop-Sensor camera. RIGHT: Photo clicked at 35mm on a Micro-Four-Thirds camera.

Depth of Field

Similar to focal length, the aperture or f-stop measurement of a lens is based on the full-frame 35mm format. Similar to focal length, a ‘multiplier effect’ gets applied to the f-stop when using crop-sensors. As we know, the f-stop or aperture is the singular most important factor that affects the Depth of Field.

Thus, a Micro-Four-Thirds camera gives us less (shallow) Depth of Field at similar focal lengths when compared with a full-frame camera. For example, an image shot at f/1.8 on a Micro-Four-Thirds camera would give an output similar to an image shot at f/3.6 on a full-frame camera, and f/2.7 on a crop sensor camera. This is assuming that the effective focal length, and other shooting conditions, are the same.

Low Light Performance

Generally, full-frame cameras provide not only better low light & high ISO performance, but a better dynamic range. These factors combined eventually produces a much better image output than any crop-sensor camera can achieve.

Full-frame cameras are capable of capturing the most light and will almost always out-perform an APS-C or Micro-Four-Thirds camera body under low-light conditions. Micro-Four-Thirds sensors don’t perform well under low-light conditions where the ISO needs to be cranked up to say, above 2000.

For these reasons, despite full-frame camera kits being expensive, bulky and heavy to carry around, they are still industry-standard and the preferred cameras for virtually all professional photography work.

Conclusion

Thus, while full-frame DSLR’s remaining the industry standard even today, we cannot ignore the undeniable advantages of the Micro-Four-Thirds cameras. Micro-Four-Third cameras, such as the Olympus EP-5 & the Panasonic GH5, are affordable and easy to carry around. Thus, enabling a much larger group of people (who are hobbyists and enthusiasts but not professionals) to have access to DSLR-like shooting conditions at a fraction of the price.

Ultimately, factors such as your budget, use and other criteria define whether you choose either Full-Frame, Crop-Sensor, or Micro-Four-Thirds cameras.

Read more info on sensors here.

Read more from our Cameras & Equipment category

Kunal Malhotra is a photography enthusiast whose passion for photography started 6 years back during his college days. Kunal is also a photography blogger, based out of Delhi, India. He loves sharing his knowledge about photography with fellow aspiring photographers by writing regular posts on his blog. Some of his favorite genres of photography are product, street, fitness, and architecture.

  • Spoonie

    The sensor size doesn’t “effectively” change the focal length of the lense. A 50mm lens is always a 50mm lens, the angle of view is the only thing that is affected by sensor size. Applying the crop factor to the focal length is just a term of reference against full frame cameras to enable comparison of angle of view. I think it’s a really important distinction.

  • sdreamer

    This applies to the f-stop as well from what I understand. Just a reference to the full frame, but in the end it still captures the same amount of light, but at a narrower angle, therefore it will just be as fast.

  • Spoonie

    The aperture or f-stop measurement of a lens is also NOT based on the full-frame 35mm format.

    The f-number is the ratio of the lens focal length to the diameter of the aperture and has nothing to do with sensor size.

    If I take a photo with a 50mm lens on a medium format, 35mm, and APS camera without changing my distance to the subject with the same aperture, the exposure and depth of field will be the same.

    Yes, if I move to account for the change in angle of view my depth of field will change as my distance to the subject has changed, but that’s a secondary effect.

    The fstop allows for comparison of exposure. It’s not designed as a comparison of depth of field. You need to be aware that moving will have the secondary effect of changing depth of field.

    This is the short of stuff I would expect to see in a Tony Northrup video, not DPS

  • KC

    Nicely done. All cameras are “full frame to their specs”. A Panasonic MFT is a full frame MFT camera.
    That’s so wonderfully confusing. I guess calling a “Full Frame” camera “35mm-like” would be confusing.

    Yes, focal length is what it is. 25mm is 25mm. That it’s equivalent to a 50mm on a 35mm doesn’t mean a lot if you’ve never shot 35mm. Since few cameras come with zoom and not a “normal lens” it’s just something confusing.

    The whole “f/stop equivalence” thing is interesting nonsense. An aperture is a mechanical device. Focal length is a physical measurement. A DOF scale or app is more useful if you need that precise info. That’s math. Since few cameras/lenses have distance scales you’d need a tape measure, too.

  • Karsten Seiferlin

    It’s been a while that I read so much nonsense in one post. This inaccurate text confuses beginners, repeats nonsense, and leaves non-beginners puzzled. But let me be more specific.

    1. Crop sensor is not a synonym for APS-C, but for any sensor that is smaller than FF.

    2. Sensors don’t collect light. Lenses and only lenses do. How much light is cast at a single pixel depends on the pixel size, the physical diameter of the lens’s aperture and the diameter of the image circle (this is BTW a disadvantage of larger sensors: the image circle is bigger, thus the intensity is lower for lenses with the same physical aperture diameter (not f-stop)).

    3. DoF depends on two quantities only: the physical diameter of the aperture (not f-stop) and the distance to the subject (the closer I am, the shallower is the DoF, take a look at the DoF scale on classical lenses). With a FF sensor I need to get closer to a subject to get the same field of view. This is the only reason for the shallower DoF of a FF sensor compared to a crop sensor (unless I use a lens with a larger front element).

    4. Lenses are not aware of the medium behind them. Whether it’s a sheet of paper, an FF sensor or a crop sensor: the image at the focal plane looks the same. A smaller sheet of paper or a smaller sensor cuts out a smaller part of that virtual image, and produces an image with a narrower field of view. In order to get the same FoV with two camers with different sensor sizes and the same lens attached, the larger sensor camera must be brought closer to the subject. Or needs a larger focal length.

    5. Comparing a 23 mm lens on an APS-C sensor with a 35 mm lens on a FF camera (both producing the same field of view from a given distance), the 35 mm lens needs a larger front element in order to provide the same f-stop. This makes the lens expensive and heavy, but provides a more shallow DoF compared to the APS-C camera’s lens (see above). The bigger front element also gathers more light, but this light needs to be spread across a larger image circle in order to illuminate the larger sensor.

    6. Dynamic range and noise do not depend on sensor size but rather pixel size, or even more specific on signal (i.e. light) to noise ratio. The more light a pixel gets, the better. But remember the larger image circle of large sensors, which reduce light intensity per pixel when considering lenses with the same front element diameter (and fully open).

    7. DSLR or not: neither the prism nor the mirror influence the image. They are both out of the way during the exposure. A DSLR and a mirrorless might share the same sensor, the same processor, and even (adpated) the same lens. The result will be the same.

    8. The term “Full frame” has a connotation that anything else is incomplete or inferiour. When Oskar Barnack invented cameras with this format, they were called “Kleinbild”, which means “small image”. FF is one out of many sensor sizes, and not a gold standard. Neither is FF the largest sensor on the market. There are good arguments for a FF sensor camera, and good arguments against.

    9. The fact that – on average – FF cameras are “better” is to a big extent due to things that haven’t much to do with sensor size. Because FF sensors are expensive per se, an FF camera will be kind of expensive anyway, targetted at enthusiasts and pros. This leaves room for a better overall technology: best sensor technology, best processor, and lenses with a large front element. In other words: the smaller the sensor, the cheaper it is, and the cheaper the overall product is. This has an impact on the overall camera design – not because of sensor size but because of marketing constraints.

  • ColYoung

    This has to be one of the worst articles posted on DPS. Confusing and just plain wrong. Karsten Seiferlin explains why in great detail below.

  • Jack

    No, the front element does NOT have to be larger, as the f-stop is the ratio of the focal length of the lens divided by the smallest diameter of the lens. So for a 50mm lens with a 25mm min dia, the f-stop is 2.0. It does not matter what camera it is on or what size the sensor! However, you are absolutely right that this article is awful!

  • Dan Burke

    Micro Four Thirds refers to the camera system, not the sensor, and is relatively new only insofar as digital compact system cameras are to the market but the 4/3rds sensor is the same as used in dslr 4/3 systems. Unless you’re talking about specific cameras can 4/3rds simply be referred to as…… well…..4/3rds!!!

  • dabhand

    The constant discussion around ‘equivalence’ is about as helpful or meaningful as would be discussions relating to the levels of optical atmospheric diffraction in various locations around the world. As a ‘School’, DPS should not be perpetuating this pointless and confusing issue and concentrate on helping make the best of the gear a person has, whether FF, APS-C, m43rds, phone.

    I use Panasonic m43rds bodies with a range of lenses and shoot primarily land and sea scapes. When I look to take an image I use my knowledge of those lenses to determine which one to use, it is a matter of complete indifference to me as to which lens would be needed by any other system.

  • PDL

    A truly bad article. But let’s digress for a minute.
    Take a 135 format film camera and mount a 50mm lens on it. Focus on a square “thing” such that the “thing” is projected on the film to be 10mm high.

    Now, take the SAME LENS and the same spot with a cropped sensor camera and what do you get? The “thing” is 10mm ON THE SENSOR. What has changed is the field of view, but the focal length of the lens is built into the optics. Just like exposure, the shutter speed, aperture and ISO do not really change when measured AT THE SENSOR.

    The parameters of exposure are measured at THE SENSOR. Crop-factor is a indicator of field-of-view as compared to 135 format film. (For those of you who never used film, 135 was the common number used by film manufactures to designate 35mm film – other terms were 110, 120 137, 620 etc. Look it up)

  • KC

    Wow. The response to this writeup is a bit harsh. We may be looking at this as experienced photographers. I am, but I can see the “why are cameras different?” topic being utterly baffling to someone entering the field.

    There are many different camera “formats”. In the end, they’re cameras. Some with bigger sensors, some with smaller. Somewhere along the line a whole lot of rubbish marketing terminology was created to make them “different”. Even better, then they had to be compared to 35mm film cameras because they might be familiar.

    (In my opinion) the whole “crop factor” and “cropped sensor” nonsense started with photographers who had 35mm SLR’s and wanted to use their existing old lenses on their same brand digital SLRs. Since the sensor was smaller it captured a cropped section of what a 35mm frame would capture. They needed a “factor” so they could comprehend how a lens behaved on different camera types/formats. A 50mm is still 50mm, F/8 is F/8, no matter what camera it’s on.

    It’s nice knowing the difference between cameras – if you own different cameras, or plan too. If you’re just getting started, buy what feels good in your hand, and what you can afford. It’s not a life-long purchase.Odds are it will come with kit lenses and you will learn what works for you. There’s always the next camera. Always.

    Your camera is your tool. That’s all it is. There’s few bad cameras out there.

  • Spoonie

    The “crop factor” nonsense didn’t start with 35mm camera owners using their lenses on APS cameras. Long before 35mm there was medium and large format. The idea that any of this is new is what is nonsense.

  • KC

    Possibly. I go back to sheet and roll film and I never thought in terms of “crop factor” because the option to switch cameras wasn’t a typical option.

    If a project called for 8X10 film, that was the camera. No point in thinking 4X5, 6X7, 6X6 or 35mm. 8X10, 4X5 and 6X7 visually are about the same ratio. 35mm and 6X6 are the odd formats.

    A second point is there was very little lens interchangeability, even among 35mm cameras. There was little point to it.

    I can go deep into this, but it’s a fairly dull topic. But I can honestly say I never thought: “oh, I need the equivalent of a 50mm on a 35mm on that 8X10 camera.” That’s around 320mm, give or take.

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