# Why do some cameras crop in 4K mode?

> Some cameras crop the image in 4K because they cannot read the full sensor fast enough to deliver 4K video. Instead of reading all pixels and downscaling…

URL: https://camerashop.com.eg/why-do-some-cameras-crop-in-4k-mode/
Language: en

## Some cameras crop the image in 4K because they **cannot read the full sensor fast enough** to deliver 4K video. Instead of reading all pixels and downscaling, they read only a smaller central portion — effectively turning your full frame camera into an APS-C or even MFT camera during video recording.

## **Why full sensor readout is difficult**

A 4K frame contains 8.3 million pixels. At 30fps, the camera must process 249 million pixels per second. At 60fps, that doubles to 498 million.

A 24MP sensor has 24 million pixels per frame. Reading all 24 million and downscaling to 8.3 million (oversampling) produces the best quality — but requires enormous processing power and generates significant heat.

Many cameras lack the processing power or thermal headroom to oversample, so they take a shortcut: read only 8.3 million pixels from the center of the sensor. This is the crop.

## **How crop affects your shooting**

**Field of view narrows:** A 24mm wide-angle lens behaves like a 36mm (with 1.5x crop) or even 48mm (with 2x crop). Your wide-angle shots become standard shots.

**Depth of field deepens:** The effective crop factor gives you deeper depth of field — harder to achieve that shallow cinematic blur.

**Lens planning changes:** You need wider lenses to compensate. An ultra-wide 16mm becomes essential if your camera crops in 4K.

**Quality varies:** Cropped 4K from line-skipping is lower quality than oversampled 4K from full readout.

## **Full-readout 4K cameras at Camera Shop Egypt**

## **Cameras that avoid the crop**

Premium cameras with powerful processors and stacked sensors can read the full sensor and oversample to 4K — no crop.

**Canon EOS R5 / R6 II:** Full-width readout in most 4K modes. Slight crop only in 4K 60fps.

**Sony A7 IV / A7C II:** Full-width 4K 30fps. Crop in 4K 60fps.

**Sony FX30 / FX3:** Full sensor readout with oversampling in 4K — designed for video.

Always check your camera’s specific recording modes — crop behavior can vary between 4K 24fps, 4K 60fps, and 4K 120fps.

## 

Before buying a camera for video, check the crop factor in every recording mode you plan to use. A camera that shoots beautiful full-frame 4K at 24fps might crop to APS-C at 60fps and Super35 at 120fps.

## Gear that does this

Available in Egypt and suited to what this guide covers.

- [Sony a7 IV Mirrorless Camera](https://camerashop.com.eg/product/sony-a7-iv-mirrorless-camera/) - 95000 EGP, in stock, SKU 1567
- [Canon EOS R3 Mirrorless Camera](https://camerashop.com.eg/product/canon-eos-r3-mirrorless-camera/) - 325000 EGP, in stock, SKU 1574
- [Canon EOS R7 Mirrorless Camera](https://camerashop.com.eg/product/canon-eos-r7-mirrorless-camera-with-18-150mm-lens/) - 65000 EGP, in stock, SKU 1623