Fujifilm X-S1
Samsung ST93
Nikon Coolpix S4150
Kodak Easyshare M5370
Olympus SP-810UZ
Nikon Coolpix L120
Sony Cyber-shot DSC-HX9V
Sony NEX-7
Canon PowerShot S100
Canon PowerShot SX40 HS
Gary’s Parries 12/02/06
This week’s Gary’s Parries topics are:
1. CMOS Image Sensors Explained
2. How To Include Yourself In Your Own Photos
3. Fashion Model Seeks Fun-Loving Digital Camera With Long Zoom
Introducing Gary’s Parries. Everything you’ve always wanted to know about digital cameras but were afraid to ask. No question is too difficult, or too easy. As a Principal Software Engineer, and a former Assistant Professor of Computer Information Systems, as well as a recording studio owner/operator, and now, a digital camera enthusiast, GARY has more digital camera knowledge in his entire brain than most people would have in their little finger. And, in the unlikely event GARY does not know the answer to your question, he will answer it anyway, true to the spirit of the word “Parries”, a fencing term which, in this context, means “cleverly evasive answers”. So let your imaginations go wild. Email all of your nagging questions to: .(JavaScript must be enabled to view this email address), and then, En Garde!
The best question of the week will receive a small prize from the PhotographyBLOG goody bag, so send your questions now. If you would like your name, location, email address, and/or website included in the column with your question, please expressly give your permission in the email, along with the information you would like included. No private information will be included without your consent.
Here are this week’s questions and answers.
QUESTION 1:
What is the difference between a CMOS Image Sensor and a CCD?
[Warning: the following is a highly technical discussion. If you are uninterested in such discussions, please skip to Question 2 - Ed.]
ANSWER 1:
I can answer that question in one sentence.
A CMOS Image Sensor works differently than a CCD (Charge Coupled Device) which, as the name implies, processes the analog electrical charges that have accumulated at each photosite as a result of, and in proportion to, the light intensity at the photosite, such that all charges are shifted vertically, an entire row at a time, into a holding buffer where they are then shifted horizontally, one pixel at a time, into an output buffer where the pixel’s electrical charge is amplified, converted to a digital voltage, and then stored in digital memory in order to make room for the next pixel to receive such processing, processing which you would expect to be highly susceptible to errors, considering all the errors that would be introduced in an analogous situation of measuring a bucket’s water level by first transferring its water into and out of literally thousands of buckets in sequence, that situation being in complete contrast to CMOS Image Sensors, which employ the same circuit technology utilized in many tens of thousands of other CMOS circuit types already on the market, and not just in cameras, as is the case with CCDs, thereby making it economically feasible to integrate the additionally required circuitry at each photosite of the CMOS Image Sensor, for not only buffering and amplifying its electrical charge, thus enabling individual access to each photosite using a simple x-y addressing scheme, that is far less susceptible to errors than CCD charge transfers, but also for implementing hardware noise reduction circuitry which, unlike its software noise reduction counterpart, will not degrade image detail in the least, leaving one to conclude that, while there are many advantages to CMOS Image Sensors over CCDs, these advantages could all be lumped into one of the following two major categories: (1) advanced circuit technology, and (2) economies of scale.
QUESTION 2:
I prefer to vacation alone. It’s not that I am anti-social, it’s just that I do not like having to interact with other people in social situations. Even so, I do enjoy taking pictures of the many different sights I encounter in my travels, but the problem is, none of the pictures I take ever have me in them. I have tried shooting self-portraits at arm’s length with the desired sights in the background, but I often misjudge their framing, and end up with some part of me cut out of the picture. How can I avoid this problem? My camera does not have a fold-out LCD, or a wide-angle lens.
ANSWER 2:
Try practicing at home in front of and facing a mirror. Hold your camera at arm’s length and point it at yourself while observing the camera’s LCD in the mirror until you get the desired framing. Then lower your arm, and once again try positioning the camera for the desired framing. Check the LCD in the mirror to see if you were close. Repeat this process until you are able to return the camera to the desired position each and every time. Either that, or get a friend.
QUESTION 3:
Gary, are you really married? My name is Jennifer and I’m a 29 year old fashion model with an interest in digital photography. I would like to purchase a digital camera, one I can keep with me at all times, and use without a computer, just like you described for your “wife”. You seem to know quite a bit about digital cameras, and I was hoping you could turn me on to a good one.
[For more information on the above referenced camera, read the article “Take My Wife’s Digital Camera ... Please” - Ed.]
ANSWER 3:
Jennifer, yes, I’m married to my lovely wife (whose name escapes me at the moment). Still, I would be very happy to help you with your problem, but I will need to know a little more about you, and your intended use of the camera. Are you looking for a compact with a long zoom? If so, get in line behind my wife. That seems to be the one aspect of compact cameras most troubling to manufacturers. I am hoping something suitable will be introduced at the PMA show coming up at the end of this month, and I will keep you posted. But don’t hold your breath. As I like to say, “I’ll see it when I believe it.”
Column photo “The Photographer” by Brenda LaFleur of Brenda LaFleur Photography.
Fujifilm X-S1 Review
Samsung ST93 Review
Nikon Coolpix S4150 Review
Kodak Easyshare M5370 Review
Olympus SP-810UZ Review
Canon PowerShot S100
Fujifilm FinePix X10
Canon PowerShot SX40 HS
Nikon Coolpix AW100
Sony NEX-7
#1 phule
[[ but the problem is, none of the pictures I take ever have me in them. ]]
You could have answered the question with one word: tripod.
6:26 pm - Sunday, February 12, 2006
#2 Gary's Parries
Thank you, Phule, but I do not see how practicing in front of a tripod
would have helped.
Another reason why I did not mention the "t" word is because I have
an obsessive compulsive fear of them. They have an odd number of
legs and you can never get the legs to be all the same length. I hope
you understand.
8:41 pm - Sunday, February 12, 2006
#3 Jon Read
Hmm. Can I say "riddled with innaccuracies?"
For answer 1, you seem to have swallowed Canon's marketing manual, neglecting to mention any of the advantages CCD sensors have. I do agree that the current generation of Canon 's large CMOS sensors are leading the field in terms of high-ISO noise, but witness the absolutely awful CMOS sensors used in the really low-cost digicams and camera phones. They're both CMOS.
10:47 pm - Sunday, February 12, 2006
#4 Nicholas
Hey Gary,
This sounds like a real nice gig.
Should be alot of fun.
Since I bought my first camera, I always wondered just how many photographers, during a typical year, get arrested for shooting somebody. No one seems to talk about it. I have had no problem. Have I just been lucky? Have you been arrested yet?
Regards, Nicholas
Regards, Nicholas
11:22 pm - Sunday, February 12, 2006
#5 Barry
For question 2, how about asking someone nearby to oblige? Tourist spots are full of people who would only be too happy especially if you return the favour. Photographers have love/hate relationship with tripods. The best result will be with a tripod and the camera self timer. For a compact with a long zoom, I used and still use from time to time the olympus C765UZ and keep it in my coat pocket. Autofocus in low light is the weakness of this camera.
1:20 am - Monday, February 13, 2006
#6 GARY POGODA
Jon, I may have "chewed" on the Canon manual, but I did not swallow.
What you say makes sense. CMOS Image Sensors are actually lower
in image quality than traditional CCDs, that is until you add the on-chip
support circuitry to enhance them, which is not feasible with CCDs due
to its higher fabrication costs of such circuitry compared to CMOS.
Nicholas, I have never been arrested, but I came close one time in my
b&w film days. Fortunately, I had forgotten to load the camera that day.
Barry, the C-765 UZ is a great camera, but the C-770 UZ has a remote
control, which would be ideal for tripod use. Unfortunately, the submitter
of question 2 has neither. He has a Sony DSC-N1 which he keeps in his
shirt pocket, so a tripod is out of the question. Apparently, so is asking a
nearby tourist to oblige, although I don't see why. You just make sure to
have them show you a photo ID with their name and address before you
hand over the camera and then you wipe it down thoroughly with a damp
cloth when they return it. What's the big deal?
11:55 am - Monday, February 13, 2006
#7 Jason
I'll pass. That smarmy one-sentence bull wasn't even funny, and something I couldn't have found by a google search. Why Mark is giving a soapbox for a know-it-all to grandstand is beyond me.
2:14 pm - Monday, February 13, 2006
#8 GARY POGODA
Sorry to hear of your passing, but I thank you for your comment.
3:01 pm - Monday, February 13, 2006
#9 phule
[[ They have an odd number of
legs and you can never get the legs to be all the same length. I hope
you understand. ]]
I understand that you don't know how to use a tripod, yes.
[[ Sony DSC-N1 which he keeps in his
shirt pocket, so a tripod is out of the question. ]]
No it is not. There is a tripod mount right on the bottom of the camera. There are plenty of small, lightweight, digicam-specific tripods for just such applications.
4:10 pm - Monday, February 13, 2006
#10 GARY POGODA
I know of no tripod that will fit in a shirt pocket. You must be thinking
of an iPod.
4:49 pm - Monday, February 13, 2006
#11 Jon Read
Gary,
Thank you for your reply. I think you've started something dangerous here; if you try and answer complex questions in short paragraphs, there will always be people complaining of inaccuracies or omissions!
Regarding CMOS vs CCD, it's also worth noting that the extra circuitry on CMOS sensors takes up space, space that is otherwise used for the photosites themselves. This may not be an issue in large sensors with good microlenses, but you have to ask why there are very few (if any?) quality compact digicams that use CMOS sensors. No room for the extra circuits? Here CCD is the tech of choice.
Regards,
Jon
6:25 pm - Monday, February 13, 2006
#12 GARY POGODA
Excellent point Jon. There's definitely a tradeoff between using a chip's
real-estate for auxiliary circuitry vs. photosensors. However, I have no
doubt this problem will soon be resolved. CMOS LSI has been around
since the 70s and it's amazing what these designers can do. Multilayer
integrated circuits, where the photosensors would occupy the top layer
and the auxiliary circuitry would occupy a separate layer, is just one of
the many possibilities.
7:04 pm - Monday, February 13, 2006