CMOS vs CCD Camera Sensors


A few days ago I watched a video of a photographer talking about CMOS versus CCD sensors*. Nearly all digital cameras nowadays have CMOS sensors, and the advantage of them apart from any other consideration is the speed with which the signal can be taken off the sensor and stored on the card.

The faster the signal can be taken off the sensor, the faster the camera can take photos one after another. It is not uncommon now for cameras to be able to take anywhere from ten to twenty frames a second.

And a photographer might want to take many photos in rapid succession for rapidly-changing events such as gymnastics, or wildlife in motion.

CMOS sensors can transfer information of the card in one batch. In comparison, CCD sensors are read line by line, so cameras cannot read photos from the sensor to the card at the same rate. If the information is still on the sensor, the photographer cannot take the next shot until the data has been transferred.

So why the interest in CCD sensors?

Well, the photographer in the video thought the photos from CCD sensors had a certain quality, a more film-like quality than photos from CMOS sensors.

I decided I wanted to find out for myself. I have Nikon lenses, so it made sense to buy a used Nikon camera with a CCD sensor.

In fact I used to have a Nikon D70, which has a CCD sensor. It was the second digital camera I owned.

So I turned to eBay. The camera was very cheap. After all it only has six mega-pixels. Smartphones have twice as many pixels (albeit smaller ones).

Here is a list of Nikon cameras with CCD sensors

D100
D200
D40
D40x
D50
D60
D70
D80
D3000

The photo at the top of this article is a sample shot from the D70. For the technical info – I shot at 1/125th of a second at f5.6 and ISO 200 with a 35mm f1.8 lens.

What do you think? Is the photo quality pleasing?

Tech Info

CMOS stands for ‘complementary metal-oxide semiconductor.’ A CMOS sensor converts the charge from a photosensitive pixel to a voltage at the pixel site. The signal is then converted by row and column to multiple on-chip, digital-to-analog converters that can transfer voltage read-outs at high speed, with low sensitivity, and high, fixed-pattern noise.

CCD stands for ‘charged coupled device’. A CCD sensor is a silicon chip that contains an array of photosensitive sites It is an analog device and its output is immediately converted to a digital signal by an analog-to-digital converter. The voltage is then read from each site to reconstruct an image.

The bottom line is that CCDs are slower to read out, consume more energy than CMOS sensors, and are more expensive to make – but they have higher capability to send a clean signal to the card.

Through the Rectangular Window

looking from M&S cafe onto the Market Square in Cambridge

This is the window through which I photographed the Market Square in yesterday’s post. Seeing the church now in the photo, I realise how very present it is the view.

Our eyes see things differently than a camera sees. To my eyes, when I sat at the able, the church was there in the scene but not so large or so dominating in the expanse of the view.

They say the camera never lies, but of course there is the ‘where’ of where one points the camera. News reporters tend to use wide-angle lenses to give the viewer a sense of immediacy.

There is another factor at play, as well. That is that the wide angle gives the viewer some confidence that the photographer has not purposely excluded something by careful framing that does not fit the narrative of the scene.

Market Square and Great St Mary’s Church, Cambridge

Market Square Cambridge

The Market Square in Cambridge photographed on a grey and dismal day through the closed window of a cafe that abuts the Square. That the window was closed is what accounts for the slightly less than clear photo. What word is appropriate – maybe ‘rough’ or gritty?

(Shot with a Fuji X-E3 with a 27mm f2.8 lens)

Great St Mary’s Church, or St Mary the Great is ‘great’ to distinguish it from Little St Mary’s, which is further out of the centre along Trumpington Street.

The church was built in the late 1400s, but the tower wasn’t completed until the beginning of the 1600s. For a fee, visitors can go up the tower of the church. I haven’t done it yet.

The construction of the church was paid for by two kings – Richard III and then Henry VII, because of course the Church (the idea of the Church) was hugely important in the divine right of kings to rule.

The other side of that equation was realised in the Peasants’ Revolt, when Wat Tyler and Joh Ball spread the heresy that questioned the right of kings to rule anything.

In the end, after promises of compromise, Tyler’s head was put on a pole. And the priest John Ball was hanged, drawn and quartered with King Richard II looking on.

The church is in the diocese of Ely. The city of Ely only has a population of about 20,000 compared to the 125,000 in Cambridge, but Ely has a cathedral, the seat of a Bishop – and that makes all the difference.

Not surprisingly, St Mary the Great is a Grade 1 listed building. That grade is the top of the tree and the most bound by rules that forbid changes to the structure or appearance of a building. There are 10,000 Grade 1 listed buildings in England and about 400,000 listed buildings of all grades (from 1 down to 3).

The church is also the university church for the University of Cambridge, and officers of the university must live within 20 miles and undergraduates must live within three miles of it. The officers are the Chancellor, the Vice-Chancellor, the Pro-Vice-Chancellors, the Registrary, and the Proctors.

As you can no doubt surmise, the colourful striped material is. the material used for the awnings of the market stalls. My guess is that the town councillors suggested colourful material to lend a festive air and hearken back to earlier times and the long history of the market.

There has been a market on the site since Saxon times – about twelve hundred years of continuous trading. There was a recent interruption when the Local Authority closed off the market during the COVID lockdown. I wonder whether it was the first ever interruption to trading? Were there were any similar precautions during the Black Death in the 1300s?

Back in 2017 I wrote about the Stourbridge Fair and the Leper Chapel. In days gone by the university ran the fair. The the Local Authority took over the most important function (taxing it) but the university kept the function of maintaining honest dealing and proper behaviour. By the late 1300s the fair was one of the largest in Europe, with traders coming from countries on mainland Europe to trade.

Here’s a photo of the provosts with the Lord Mayor of Cambridge, reading the rules of the fair. The two gentlemen on the right in the photo are provosts, who are masters of Colleges at Cambridge University.




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