Crop versus Full-Frame camera sensors


Some digital cameras have have a crop factor. Parts of the image captured by the viewfinder are cut-out from the final picture. A sensor that is 1.5-1.6 x smaller than a 35 mm negative (24 mm high x 36 mm wide). There are a lot of benefits when shooting with telephoto lenses on crop sensors.  Instead of just 200 mm, the lens’ focal length  can go as far as 300-320 mm. If you use these kinds of lenses , you’ll need to spend a great deal of money on them. 2008, was also the year in which the 35 mm diameter made a comeback. In this article, we will discuss the advantages and disadvantages of both options.

Full Frame VS Crop Cameras

Crop Factor

In digital cameras, the sensor has replaced the film as the light sensitive surface. Because the cost of the sensor has always been high, manufacturers have chosen to make the sensor smaller than the standard 35 mm. Depending on the camera brand or model, a camera sensor can sometimes be 1.3, 1.5-1.6 x smaller than the full-frame 35 mm.

As a result, only a limited part of the total image captured by the lens, projects onto the sensor. This is the crop factor. These cameras are crop sensor cameras. This has direct consequences to the focal length. The range of a 50 mm lens on a digital camera gives a picture of 75-80 mm converted to 35 mm. Users of crop sensor cameras can get the increased focal length,   their 200 mm lens can suddenly be a 320 mm lens. A permanent zoom.

This is especially useful if you are shooting sports events or wildlife. This is also the reason that some professional photographers don’t choose a camera for pros, but they buy brands or models for consumers/amateurs so they can take advantage of the crop sensors.

Another great advantage of this is that lens errors – primarily at the edges of the lens – are less likely to occur in a camera using a crop – sensor.

Use Smaller Lenses

Another great advantage is that it is possible to use smaller lenses. Many manufacturers released a separate series of lenses specifically created  for crop sensors. Compared to the bulkier full frame lenses, crop lenses have less parts, the glass parts  are lighter, more compact, and less expensive.

Crop lenses have a  protruding rear. Since the sensor is more compact, the rear of the lens still has enough room, even when the crop sensor’s mirror moves. However, when you use a crop lens on a full frame camera, it wouldn’t work. This is because when the mirror moves, it hits the protruding rear of the lens – (because the mirror is bigger, and bulkier), and thereby, may cause damage to the lens.

Editor’s note: I saw some videos on YouTube discussing these kinds of lenses, you can delete this paragraph if the author doesn’t want to include it. The paragraph is enclosed in parentheses.)

(Lenses developed for digital cameras, whether they have full-frame or crop sensors, usually have circular openings. The scene you are trying to capture via the lens , falls within the ‘image circle’. This image circle is then projected to the rectangular image sensor. (Think of a big circle with a smaller rectangle within.) Full-frame lenses create an image circle  bigger than the 35mm sensor, whatever falls within the rectangular frame of the sensor becomes the  final image, (which follows the shape of the sensor, resulting to a rectangular image).

Crop Lenses

But crop lenses are exclusively for crop sensors. If you use a crop lens on a full frame sensor,  the image circle created  is smaller than the surface of the rectangular sensor, thus, vignetting occurs, the area beyond the image  circle appears as dark edges .(Imagine a rectangle with a smaller circle within.)

The downside is that the extended focal length, also applies to the wide angle range. This increases the width of wide angle lenses by more than half. A wide angle lens is a lens that has a diameter of  35 mm, 24 mm, and ha shorter focal length. When applied to crop sensor cameras, this means you approximately add 16 mm at its  widest angle, 16 mm at its maximum is a very wide lens and ideal for you if you have been looking for a super wide angle, such as a 12-24 mm lens. In the beginning, these lenses were limited, and outrageously expensive. Today they are more readily available, and affordable.  If there is a disadvantage at all,  it is the wider area surrounding your subject within your image circle.

Full-Frame

Since digital cameras became available,  photography enthusiasts have always been interested in the 35 mm format. Because many photographers have worked  with, and still use the 35 mm, this format is still seen as a classic. Full-frame cameras  are for those who want better performance in dark conditions,  and  the low amount of image noise  (photos are clear, and not grainy photos) when using higher ISO values, make the full frame, a much sought after format.

This has led Canon to develop their first reasonably priced full-frame camera that came out in 2005, the EOS 5 d. A camera that was, (and still is) enormously appreciated for its unprecedented performance regarding image quality. It took a  long time before other manufacturers responded to match this move,  until  at the end of 2007,  the first full frame Nikon camera was released in the form of the D3.

In 2008, more Nikon full-frame cameras followed. Sony also introduced this year , a camera that has a sensor with a 35 mm diameter. Especially in the Nikon camp, this earned an enormous amount of positive responses, partly due to the camera’s excellent image quality in dark conditions. That was achieved by Nikon’s choice, less mega pixels on the sensor to cram, were corrected by  Sony with the alpha 900 and Canon with the 5 d mark II to choose the larger surface for more.

Full-Frame Cameras

The reason why there hasn’t been any full-frame cameras released recently, has to do with the cost of the sensors. A 35 mm sensor is much more expensive to make than a smaller sensor. Their exorbitant prices discourage amateur photographers from making full frame cameras as their first choice, thus limiting its target market. This could mean that the price of the sensors won’t drop for a long time.

Full Frame VS Crop CameraA full-frame camera also sets higher demands in manufacturing. The larger sensor needs a heavier mechanism for the mirror that swings sideways, when taking each picture. The advantage of this, is that full-frame cameras have a bigger viewfinder. The downside of this, is that the whole camera is bulkier than a crop factor camera, and is also heavier. Batteries with higher capacity are needed, since a larger sensor requires more power consumption.  All these components, would, of course, add to the total cost, making them quite

Cleaning full-frame cameras also require more time, and effort. Since the sensor is larger, there is a greater risk for dust to get into the sensor.

Depth of field

The greatest advantage of the 35 mm sensor compared to the crop-sensor is the depth of field that can be achieved. For example, if we look at a lens with a maximum aperture of f/2.8 attached to a 35 mm camera, it means that on a crop-camera, at least a lens with a maximum aperture-opening of f/1.9 (F2.8 divided by the 1.5 x crop factor). We have a maximum aperture of f/2 on a 35 mm camera, then we have on the crop camera an f/1.3 aperture opening. We’re talking about huge, expensive lenses that many hobbyists, but also professionals use. With a full -frame  camera, you can achieve depth of field  that can hardly be achieved by crop frame cameras.

Image quality

The image quality is better on full-frame, provided that the extra sensor size is not used to disproportionately add more mega pixels on the sensor. The sensor size strongly determines the image quality. The more megapixels that are compressed on this small surface, the greater the chance of image noise. Some manufacturers (particularly Nikon) choose to limit the amount of megapixels in favor of image quality. This reduces the light sensitivity and, with it, the dynamic range.

However, the sensor is not the only thing that determines the image quality.  The quality of the lens on full-frame cameras, plays a very large role. When using a full-frame camera, you have the advantage that the entire lens surface is used, but this also means that the sensitivity to lens errors increases. The lenses’ edges need to be considered as well.These  may cause dark edges (vignetting), decreasing sharpness, etc. A switch to a full-frame camera is a big jump, it often means you have to invest on new lenses. If you have the Canon EF-S or Nikon Dx, you can use lenses specifically developed for crop factor cameras.

Photography And Your Budget

The best choice is mainly determined by the subjects  you like to  photograph, and your budget. A full-frame camera is still a hefty investment, especially if you factor in the cost of higher quality lenses, and that if you need  to buy your lenses, telephoto lenses may  have the same range as  lenses  with a normal focal length when used  with a crop factor camera. The amount of detail in the photos, and the performance under non-optimal conditions, are better with a full-frame camera. Hopefully, more, and more manufacturers would sell full-frame cameras, so the prices  will go lower, and more reachable. But we’ve also seen features of crop factor sensors continuously improving. Usually the choice ultimately comes down to personal preference.

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