All About Sensor Sizes

[Jason Dunn]

<div class='os_post_top_link'><a href='http://www.kenrockwell.com/tech/dx.htm' target='_blank'>http://www.kenrockwell.com/tech/dx.htm</a><br /><br /></div><i>"Digital SLRs take advantage of using sensors about 16 x 24 mm, close to the original standard 35mm (movie) film standard of 18 x 24 mm introduced over 100 years ago and still in daily use for multi-million dollar Hollywood movies and TV. When minature still cameras were designed to use 35mm movie film in the 1920s they were called "double frame" and shot a double wide frame of 36 x 24 mm. This remains the size of today's 35mm film (still) cameras which are fast becoming obsolete. Some old timers think there is a need for a double-sized CCD sensor to mimic the old 35mm film (24 x 36 mm) for digital cameras. I have no idea why they would think this, except that before short zoom lenses like Nikon's 12 - 24 mm and Canon's 10 - 22 mm were introduced it was hard to get ultra wide shots on digital SLRs. There would be a minor potential improvement in noise with the bigger sensor, but not particularly important when comparing the two versions of these big sensors."</i><br /><br />An interesting article about sensor sizes in cameras. It clarified a few things for me, and is worth the read. He definitely has an opinion about the lack of a need for full-frame sensors though, so don't expect an un-biased view.

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Does he disprove...

* Fullframe sensors are better for most existing optics.
* Bigger pixels are better.
* Bigger glass is better.

If he does, then I missed it.

Malte

[Jason Dunn]

Fullframe sensors are better for most existing optics.

I think that if someone has a significant investment in lenses that require a full-frame sensor, then full-frame is the way to go. But if you have no investment in lenses, you can get a 1.5x or 1.6x sensor camera AND an expensive lens for the same price as a full-frame sensor camera. That's where I'm leaning right now - I get way more value for my money.


* Bigger pixels are better.
* Bigger glass is better.

I don't really follow you here. Can you elaborate?

[Lee Yuan Sheng]

* Fullframe sensors are better for most existing optics.
* Bigger pixels are better.
* Bigger glass is better.


1. Untrue if you take the point of view for the main reason for needing full-frame; compatibility with focal lengths below 80mm. Legendary lenses like the Nikkor 17-35/2.8 don't look particularly impressive.
2. True.
3. No relationship to sensor sizes.

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1. Lee: Are you saying that a lens made for 35mm looks less impressive on a fullframe sensor than it does on a smaller sensor? Or do you consider the difference negligible?

2. The writer actually links to a page that explains benefits of bigger pixels, http://web.canon.jp/Imaging/cmos/technology-e/size.html , but he seems to think that bigger sensor must mean more pixels, not bigger pixels.

3. Lee: Well yes and no. The more light you can let into the camera, the better, no? Seems a shame to let a big portion of that light end up outside of the smaller sensor. It's a stretch, I know.

[Lee Yuan Sheng]

1. Lee: Are you saying that a lens made for 35mm looks less impressive on a fullframe sensor than it does on a smaller sensor? Or do you consider the difference negligible?

2. The writer actually links to a page that explains benefits of bigger pixels, http://web.canon.jp/Imaging/cmos/technology-e/size.html , but he seems to think that bigger sensor must mean more pixels, not bigger pixels.

3. Lee: Well yes and no. The more light you can let into the camera, the better, no? Seems a shame to let a big portion of that light end up outside of the smaller sensor. It's a stretch, I know.

1. Yes, by the simple fact the smaller sensor crops the outer region of the image circle formed by the lens. Lenses typically get worse the further you deviate from the centre.

If you compare lense designed for smaller sensors to 35mm lenses, they might still have an advantage, as sensors require light to strike at close to perpendicular angles as possible, and a smaller sensor helps with that.

2. That's because most companies do that with bigger sensors. The megapixel race has resulted in companies piling as many of them as possible into a sensor.

3. That's what Jason meant when he only wanted full-frame for the concept, as opposed to the practical application of it.

Finally, Ken Rockwell is a bit of a nut. He can talk plenty of sense, but at times he can be factually way off. Be careful when you read his site.