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Regarding Contax N digital and Leica digital back

> Does it mean that in fact the 5Mpix camera has only ca 1.25 M "full > color" pixels???

Well, no...not really. The luminance information is still pretty intact, which is more important than the chrominance information, which is reduced. Typically, and this is very image/algorithm dependant, it's about a %20 degredation in image "fidelity" because of the Bayer pattern.

Regards,

Austin
 
> I'm sure that the lens makes a difference even with 2 or 3 MP cameras

With a P&S camera, how do you know it's the lense, as you can't replace the lense to test out other lenses?

Of course the lense CAN make a difference, but only to a certain point. For the P&S cameras, their sensors are actually very fine pitch (close spacing of smaller sensing elements) because of the type of sensor they are (Interline), so they are actually more sensitive to lenses than the D-SLRs are...but their image quality is far below that of most any D-SLR. Remember, these little digi P&S cameras use a VERY small sensor...but again, you really can't compare images from any P&S digi to a decent D-SLR...except may be the TVS digital ;-)

Only recently, have the better lenses mattered on the D-SLRs, as evidenced by the D-30 and D-60 test reports.

Regards,

Austin
 
> Well, no...not really. The luminance information is still pretty > intact, which is more important than the chrominance information, > which is reduced. Typically, and this is very image/algorithm > dependant, it's about a %20 degredation in image "fidelity" because of > the Bayer pattern.

Now I understand! Thanks a lot:)

Krzysztof
 
Okay okay, good old Austin, I, am the mysterious IT friend Sheu talked about.

Very interesting, other than Contax Mailing list, now you are trying to grow some believers here, hum? Miss the fun time how I teased you about anti-aliasing filter on Contax Mailing list? You still haven't learned, have you?

Anyway, let's say that I have done quite a few chips for Sony and Sanyo. I have dealt with Foveon and have a very close relationships with National Semi which has done a few projects with Foveon. Is this clear enough?

Big part of digicams is all about chips and image processing. Chips are not really your territory and you do not have to pretend that you know a lot.

Anyway, the A/D stage is not as simple as what you have imagined. A cheapie 10 cents A/D can produce a result totally different from a $10K one. Clear enough? Ever wonder why ND is so much cheaper than a Phase One digiback?

The Norman Koren's website is a good beginning for people who are interested in getting to know digital photography technology; However, the stuff he talks about is still very simple and superficial. Most infos are correct but still, minor mistakes here and there. For instance, the discuss about a sensor's pixel size and its performance issue is not 100% correct.

It can take me hours just to explain the difference between CCD and CMOS. Too bad that I do not have the time to do this now.

-finney
 
Hi Finney,

As an interested observer of this forum in general and this discussion in particular, I would like to urge you in the two ways following:

1. Please avoid entering into a flame war on this board, it is a place which has been refreshingly free of this up until now and I suspect most of the regulars here would not like that to change. I appreciate that some of the comments made towards you by Austin were not exactly respectful, but in the end if you have solid understanding of the issues then that will shine though and the matter will be closed in your favour.

2. Please share the specifics of what you *do* know, as regards the various technical aspects that you have alluded to in your postings and the message of yours that Sheu posted at the start of this thread.

On the second point, I'd particularly like to know more about the transformations or processing that take place in the ADC. Your point about the quality difference between different A/D designs is clearly valid, but I would have thought the only relevant design parameters are linearity and noise floor (obviously there are other parameters such as s&le-and-hold time but hopefully we can assume that the system designers have chosen components that give sufficient margin in this area). If there are digital processing steps that are applied to the converted data before it's saved as a RAW image, then that changes the rules of the game completely. Are you suggesting this is what happens in the Canon designs and others?

Thanks in advance,

-= mike =-
 
Hi everybody,

since the interest in digital cameras and the whole pro and cons incl. technology are attracting more and more interest among Contax users, we will have in autumn some kind of interview/ Q&A with some people from Carl Zeiss at Contaxinfo.com.

We can not yet disclose the exact date, but it will be definitely after August, because of vacation time. There will be different issues discussed and we will also offer all Contaxinfo.com members the possibility to send us their burning questions, which can be then answered by employees of Carl Zeiss.

This will be probably a recurring event on a unregular basis. Subjects can be for ex&le insights in digital photography, the N-lenses and the MF-lenses, recent changes in lens design and their influence on digital photography etc.

But we will announce this all via our newsletter as soon as we can present more facts and the time frame for the first event.

Dirk
 
Hi Finney,

> Very interesting, other than Contax Mailing list, now you are trying > to grow some believers here, hum? Miss the fun time how I teased you > about anti-aliasing filter on Contax Mailing list? You still haven't > learned, have you?

I have no idea what you're talking about, but I know I have encountered you on the Contax list before, but I don't remember what the issue was, nor am I particularly interested in YOUR interpretation of what transpired. Stick to the here and now.

> Anyway, let's say that I have done quite a few chips for Sony and > Sanyo. I have dealt with Foveon and have a very close relationships > with National Semi which has done a few projects with Foveon. Is this > clear enough?

Clear enough for what? I'm not clear what you are trying to claim here. Though it may to some who don't understand the field well enough to understand the significance, or insignificance, of what you said...it certainly doesn't mean anything to me that signifies that you know what you're talking about with respect to the subject at hand (or really any subject for that matter). I've designed over 100 ASICs, and been designing digital imaging devices (amongst many other things) for over 25 years... I am a professional engineer. I'm either on, or have been on, corporate staff, or consult for some major players in the EDA, computer and imaging industry.

What you say (actually write) is what I base my opinion on...not your purported qualifications, which, no offense meant, as I said, don't mean you know what you're talking about with respect to digital imaging.

> Big part of digicams is all about chips and image processing. Chips > are not really your territory and you do not have to pretend that you > know a lot.

I don't have to pretent anything, as I've said, I HAVE designed over 100 ASICs, so chips ARE my territory and I DO know a lot in the area of digital imaging and ASIC design. We own our own Synopsys, VCS and Synplify seats (actually, we were seeded by these companies because of our dominant position in the ASIC/FPGA design indusrty). I currently own a company that does ASIC/FPGA and board level development.

> Anyway, the A/D stage is not as simple as what you have imagined. A > cheapie 10 cents A/D can produce a result totally different from a > $10K one. Clear enough?

Being that I've designed quite a few A/Ds, and have used just about any of them in the market place from the 10 cent ones to some of the most expensive ones (mostly for audio applications in that case), yes, I know quite a bit about A/Ds, AND...what they do is convert voltage/current to a number, period, end of sentence. NO processing is done. What is different between A/Ds is how accurate and repeatable and fast they are. All that is needed is for the characteristics of the A/D to be matched to the characteristics of the CCD. Having a better A/D than the CCD does you NO good.

> Ever wonder why ND is so much cheaper than a > Phase One digiback?

More limited market, smaller sensor, no follow on income from lenses...to name a few reasons.

> However, > the stuff he talks about is still very simple and superficial.

You can call it what you want, but it IS correct information, and is clearly to the point of the conversation. Clouding it with anything more technical does not serve any purpose here, that is unless you specifically want to obfuscate the issue.

> Most > infos are correct but still, minor mistakes here and there.

Like what, specifically?

> For > instance, the discuss about a sensor's pixel size and its performance > issue is not 100% correct.

Specifically what? Be specific here, Finney...you want to come across as being some expert on something, and if you're going to criticize someone, do so with facts...be specific. Also, please don't try to diffuse the issue with tangenting. Stick to a specific statement you believe is incorrect/inaccurate and say why, and show some substantiation. Just saying something is wrong doesn't really mean anything.

Just keep in mind I AM a professional engineer, who has over 25 years of experience designing this stuff. And, I don't need someone attacking my credibility based on some unsubstantiated background. You've said you've designed "quite a few" chips, but never said if they were in any products, or what they actually do...and "quite a few" chips is what seniors in college have designed, so I don't hold much credence in that without knowing more. I DO know that some of your statements are not in agreement with my actual design experience, and that of many of the other professionals in the industry that I work with...what's the explanation for that? Are we all doing it wrong for the past 25 years? Somehow I doubt that.

If you want to see some of what I've designed, then simply go to my web site...www.darkroom.com. I am currently designing the rendering/LAN (Infiniband) board for a 1024 node super computer visualization system. Like I said, digital imaging IS one of my areas of expertise, as is ASIC/FPGA design.

Austin
 
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