In the past film cameras were commonly designed to be hand held and were optimized for taking pictures of people (Kodak's main busness) and landscapes. When digital cameras came out they typically imitated the prior art film cameras. Web cams are digital cameras that can be used to take either still or moving pictures and are designed for connection directly to a computer and typically are for head shots like in a video conference.
I use anumber of different cameras. Here they are and my comments about them:
HP 6200 Flat Bed scanner
This is connected to my computer by USB and is plugged into the AC mains for electricity.
Pluses
- Very convenient to use. This is a very big plus. Place an object on the scanner and you can have a very high quality image in about a minute. Because of this it's my most used imaging device.
- Good exposure control. You can set the lower and upper exposure limits based on a histogram of intensity values and also set the gamma by looking at the image on the computer monitor.
- What amounts to unlimited resolution. A single image may result in a file size of over 10 Mega Bytes that is in the computer at the end of a scan. But once on the hard disk it's easy to work with.
Minuses
- Software nightmare. The software often does not work. Windows software should NEVER NEVER use the base 640 k RAM space at boot time. When an application does this it drastically reduces system resources. This is especially bad when you may not even use the application yet it's eating up your resources degrading the performance of the computer. The 6200 software forces a number of programs to load at boot time and not only do these waste your very limited resources but they often fail crashing the computer. The HP 6200 software and the Kodak DC 290 software can NOT be on the same computer or it will crash!
- Only images of the flat side on an object can easily be made. You can not make a 3/4 view, only views where gravity causes the object to be stable.
- Limited depth of focus. The flat bed scanner will focus to maybe an inch but for an object that's a few inches tall the focus will be very poor at the higher elevations.
- Poor lighting as the object gets taller. At a few inches the object is in the dark. External back or side lighting helps a lot but takes a lot of time to get right.
- The glass gets scratched and the scratches are in sharp focus.
- The plastic parts inside out gasses crud that makes a white coating on the inside of the glass. More near the end where the lamp spends most of it's time. This requires periodic disassembly and cleaning.
Kodak DC 290 Digital Camera
Pluses
- Can take 3/4 or other views that the HP 6200 flat bed scanner can not do.
- If the flash setting (auto, fill, off) is correct and the lighting is good for the subject the quality of the image can be fantastic. This typically requires using a 6+ Mega Byte file size.
- Optional close up lens atachment and the ability to see on the LCD the image (the viewfinder is of no value when doing closeups) what the lens sees allows tight framing.
- Even when using the normal lens the viewfinder is wrong for close work. The LCD viewer allows better framing of the shot, but it's hard to tell exactly where the edges are becasue of the gray bands at the top and bottom of the LCD.
- Has "Over ride" control of exposure. This is very important as it allows difficult subjects to be properly exposed.
- Has manual focus, again allows getting good focus on difficult subjects.
A camera that is all automatic will produce poor images of some subjects and that can not be improved.
Minuses
- Exposure is automatically controlled and often is very wrong. For example using outside North light to photograph a black or dark colored subject where the background is lighter causes the exposure ot be set for an "average" of all that's in the scene making the subject turn black. A very large number of on line photos and eBay subjects have this problem The image looks just like a black rectangle and the subject can barley be seen at all. Some of this can be corrected by working with the image brightness after the fact, but the result is no where as good as proper exposure to start with. This is a huge shortcoming of the DC 290 and most all other digital cameras. This statement is incorrect, I just did not know how to use the exposure override!
- Focus is automatically set and often wrong when working with small objects. The DC 290 uses a reflected light system that an be fooled when the camera is angled. For example with a tripod beside a table with the camera looking down at 45 degrees the focusing system is seeing a point that's maybe a foot behind the subject. This is easy to spot by just looking at what part of the image is in sharp focus. This statement is incorrect, I just did not know how to use the exposure override!
- The built in flash memory card can only hold 2 exposures when the file size is 6 MB. I fixed this be getting a new 256 MB memory card that holds many more images.
- Can not hand hold. The DC 290 appears to be designed for taking pictures by holding it in your hands, just like any other camera, BUT when taking photos of eBay sized objects this results in blurry photos. Good mechanical support is needed for quality images. A solid tripod, not a cheap flimsy one, solves this problem, but a tripod takes up a lot of space.
- The built in jpeg settings are no where as good as what can be done using computer applications. If you compare a jpeg image direct from the camera to a jpeg image of about the same file size made in the computer starting from a 6 MB tif file from the camera (they both came from the same CCD chip in the camera) the jpeg from the computer can look much better.
22 Aug 203- The DC-290 does support "override" control of exposure by means of locking the exposure to the prior exposure and also can be computer controlled for zoom. So far my laptop has locked up when trying to use the remote software, but the exposure can be locked using the manual menu items.
Nikon N90
This is a 35 mm film camera. It has 4 "brains":
This camera is fantastic at getting good exposure automatically in almost all lighting conditions. I comes the closest to a point and shoot camera as I have ever seen. A lens swap takes seconds and when the computerized lenses are used they automatically tell the camera and flash their settings.
- one dedicated to exposure in the camera body
- one handling all the I/O in the camera body
- one in the lens
- one in the external flash
This is the most flexible camera I have ever used. Kodak will scan the negatives and supply digital images in different file sizes for an extra charge. The problems are the expense of buying and processing film and the time delay between taking a photo and getting the digital file. The latter is the biggest problem. With a digital camera I can set up the tripod, make an exposure, and leave the subject and tripod alone, then have a look at the digital image on the computer a few minutes later. If there's some problem I can re-expose and check in another few minutes. It might take 3 or 4 tries to get a good image and an hour's time. But this could not be done with film, you would just make the best of whatever you got back.
Logitech Pro 4000 Web Cam
Pluses
- Very light and small. If a lot of the features that are on the DC 290 that are not needed for this application were removed, such as:
- Batteries
- memory card
- viewfinder
- focusing system
- handles
- top LCD display
- rear LCD display
- all buttons and controls
It would be considerably smaller and lighter. This is important to allow the use of a desk lamp, 2 arm support. This type of support can not carry a camera the weight of the DC 290 but can easily hold something the weight of the Pro 4000.
- Can take still or video with sound. Some ideas can easily be conveyed with a video that are very difficult to convey with still images.
Minuses
- Difficult to focus.
- The stock support doesn't allow getting the camera where it's needed. A small tripod or maybe tripod thread to door clip would be a better support. Need to look into how to mount it on a desk lamp.
- Very limited exposure control. It has a strong automatic exposure control that's hard to overcome. When a desk lamp is used for illumination the automatic control still fights you. It seems to work best with very even illumination, like a studio with North light.
- limited resolution. TV type not camera type.
Nikon D300s
This camera more than meets the idea but at a much higher price.
With the advent of eBay there is a need for a camera optimized for taking pictures of objects being sold.
Object Size
The vase majority of items sold on eBay can be shipped from someone's home using the USPS, UPS or Fedex. This means a product, camera subject, that can easily fit on a table top.
Lighting
In order to get a good image even lighting is needed. This might be provided by a number of lamps or by a reflector like an umbrella. The camera should have good low light sensitivity to minimize the need for lighting power. The camera should have built-in strobe lighting with provision for external slave strobes either connected by wire or triggered by the main camera flash.
Included with the camera would be at least 2 strobe lights with an option for more. The first two would be mounted on the desk lamp support.
Photographing objects for auction - This Kodak web page is aimed at using their low priced cameras for takng eBay photos. You can see the poor quality that you get using this type of camera. You can do much better than these examples if you have a digital camera that supports "Override" control of focus and/or exposure.
Interchangeable Lens
The standard lens should be a C or CS mount zoom lens with the zoom and focus controlled by the computer. A user could remove the stock lens and attach any C or CS mount lens desired. Greatly adding to the flexibility. Maybe the stock camera would come with a manually controlled lens and the computer controlled lens would be an option.
Macro Lens
The lens needs to be able to focus on a dime that's filling the field of view.
Still or Video
It would be an added feature if the camera could be used like a web cam with sound. In this mode the image size and data format needs to be selectable. This camera would have a huge advantage over conventional web cams due to the computer control of exposure, white balance, etc.
Resolution
The final image will not need extreme resolution, but since some image processing may need to be done, such as erasing backgrounds, image rotation, etc. the starting image size should be adjustable up to something in the 10 MB file size area. The output file should be in the users choice of a number of common image formats such as tiff, jpeg, bmp, etc.
Support
In order to get sharp well focused images the camera needs to be supported. Rather than use a conventional tripod, it would be much more convenient if the camera was on a support very similar to a 2 arm desk lamp. This is a very convenient support and allows positioning the camera easily. For larger objects the table lamp mount could be attached to a ladder or other suitable object. For outdoor use a laptop computer and optional battery power supply would be needed.
Note that the old Polaroid 4x5 copy camera with a light on either side is close to this concept, but there was not enough flexibility in positioning the camera.
Convenience
When a flat bed scanner is permanently connected to a computer it's much more convenient ot use than a digital camera that requires connection for every upload of image files. This new camera should be designed to be used when connected to a computer and has no need for battery power.
Computer Control
Conventional cameras have built-in exposure control designed for taking portraits or landscape shots. This type of exposure control does not do a good job on objects of the size we're talking about here since a black subject on a white background will fool the camera's exposure controls. This camera should have computer control of all the settings while providing an automatic starting point. This is similar to the exposure control of a flat bed scanner where you can set the threshold, highlight and gamma based on a histogram of intensity or press the "AUTO" button.
The histogram and three exposure sliders (shadow level, high light level and gamma) on the HP 6200 might be replaced with 9 sliders, one for Red, Green and Blue.Zoom control from the computer as well as cropping should be easy to do.
Note that the HP 8200 flat bed scanner uses a newer type of software, not the ScanJet software, and although the 8200 software has a histogram display, it is NOT useable since it's physical screen position is not aligned with the shadow and highlight controls and there are NO cursors, very poor human interface. It's so bad that I returned the 8200 scanner.
The strobe lamp output should be under computer control and would also have standardized modes. Flat lighting would be one mode, and a number of shadow modes for subjects where you want some shadow to make the surface texture more visible than would be the case with flat lighting.
This is what's called a tethered camera. Tethered cameras are now used in studios where the CCD chip in the camera is generating a hugh file for a single image and by having the camera directly connected to the computer the file download problem is greatly reduced. But in this case the tethering is to allow removing all the manual controls from the camera thus reducing it's price and to allow seeing the image on a computer screen so the exposure and cropping can be adjusted to get it right the first time. This will eliminate those black rectangles often seen on eBay and on web pages.
Blue Screen
It would be great to have a Blue (or whatever color) background subtraction feature. By making the table top and background a certain color (that can be selected on the computer screen just by clicking on the desired background color) that color can be subtracted leaving either a white background or the subject can be overlaid over some other specified image.
Open Standardized Interface
The camera interface should follow an existing standard and be available for users and/or third parties to support with their own software.
Price
Under $ 500 for the camera, software, camera to computer USB cable, instruction book and documentation on CD-ROM. Free software updates and bug fixes from internet download.
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