I miss my D200

Started Oct 27, 2011 | Discussions thread
Tony Beach
Senior MemberPosts: 5,025
Like?
Re: CCD, they myth that won't die
In reply to Cytokine, Dec 30, 2011

Cytokine wrote:

PHOTONICS SPECTRA © Laurin Publishing Co. Inc. CCD V CMOS Facts & Fiction

• Dynamic range, the ratio of a pixel’s saturation level to its signal threshold. It gives CCDs an advantage by about a factor of two in comparable circumstances. CCDs still enjoy significant noise advantages over CMOS imagers because of quieter sensor substrates (less on-chip circuitry), inherent tolerance to bus capacitance variations and common output amplifiers with transistor geometries that can be easily adapted for minimal noise. Externally coddling the image sensor through cooling, better optics, more resolution or adapted off-chip electronics cannot make CMOS sensors equivalent to CCDs in this regard. Author Dave Litwiller is Vice President,
Corporate Marketing at DALSA in Waterloo, Ontario, Canada.

Published in 2001, which is six years before the D300 and four years before the D200.

While CMOS is catching up and will and does provide very good sensors, your statements, (like your manners,) are highly suspect!!

"Ultimately, then, frame rate of a CCD sensor involves a tradeoff among pixel count, noise, and power considerations."

"When an application requires low-light operation, differences in CCD and CMOS technology impact image quality. At low light levels, where amplifier variations are more significant, CCD sensors have more uniform pixel response than CMOS sensors. The individual charge-to-voltage amplifiers at each CMOS pixel have gain and offset values that are difficult to match. Further, they are not adjustable. CCD sensors use the same amplifier for all the pixel data from a given output, so pixel variation is less.

Low light conditions mean that the resulting signals are close to the sensor’s noise floor. Because the individual amplifiers for CMOS pixels have low bandwidth, they have lower noise than the high bandwidth, common CCD amplifier. This allows the amplifier to offer higher gain before noise levels become intolerable, yielding a higher effective signal-to-noise (S/N) ratio for CMOS sensors. On the other hand, CCD sensors typically offer better fill areas, so the pixels are more sensitive and provide greater signal levels at low light. Further, CCD sensors can use a technique called electron multiplication, which imparts a small signal gain each time the pixel charge transfers to the next stage of the output shift register. While noise also increases with each transfer, it increases at a lower rate so the result of electron multiplication is an improvement in S/N ratio."

From: http://www.teledynedalsa.com/public/corp/applications_set_imager_choices.pdf   published in 2005.

It's a lot of technical stuff related mostly to the production costs of the competing technologies, but it can be summarized nicely in this passage:

"Today there is no clear line dividing the types of applications each can serve. CMOS designers have devoted intense effort to achieving high image quality, while CCD designers have lowered their power requirements and pixel sizes. As a result, you can find CCDs in low-cost low-power cellphone cameras and CMOS sensors in high-performance professional and industrial cameras, directly contradicting the early stereotypes.'

From: http://www.teledynedalsa.com/corp/markets/ccd_vs_cmos.aspx   published in 2011.

Regardless of the purely academic arguments, the fact is that the D200's CCD sensor is good at base ISO, just as the D300's CMOS sensor is good at base ISO. The argument that something was lost going from CCD to CMOS is absolutely unsubstantiated. Because there are no actual direct comparisons that can be made between existing cameras that use both technologies (no such camera exists), it all becomes hypothetical; on a practical level, the image quality from today's CMOS sensor DSLRs is as good as it gets given the current technology, and even if you could theoretically squeeze more image quality from a hypothetical CCD sensor, the costs and trade-offs would be an unacceptable compromise for most.

Reply   Reply with quote   Complain
Post (hide subjects)Posted by
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark post MMy threads
Color scheme? Blue / Yellow