Originally Posted by
Kev-Cali
I am in the process of digitizing files onto the computer.
Blueprints and larger files do not fit in the scanner so I would like to create a setup where I could take high quality photos of the larger documents and convert them to .pdf (for example). The picture would need to be taken from directly on top of the drawing.
I need to be able to see all the details, so I need a really high quality and professional image.
Do you know what equipment and materials I would need to be able to do this (eg: camera megapixels, lighting? reflectors? tripod?).
All details would be much appreciated as I am trying to purchase all the equipment tomorrow.
Thanks and cheers.
In order to know what type of camera you need, I need to know details of your scanner and scanned files. How big are your scanned files - in pixels (heightxwidth, e.g. 3300x2250) If you are scanning 8.5x11 pages at 300 dpi (3300x2250) you have 7.4 megapixels and most modern digital cameras (6-8 megapixels) will give you about the same resolution on an 8.5x11 file. If you are scanning at 600 dpi, then to get equivalent quality you would need a higher resolution camera, around 16 megapixels for an 8.5x11 file. Obviously, if you need this same resolution for a very large document, it will require many megapixels - much more than consumer-grade cameras provide! Your files will also be huge, consume a lot of disk space, and be slow to open and display on the computer. But, it is very likely you do not need that much resolution in the scan or digital image if you merely need to read the blueprint clearly.
In order to determine the setup needs, I also need to know how big the blueprints are. This determines if you can easily setup a tripod to shoot straight down, or if you need a slanted table to position the blueprint and then angle the camera down to match the slant of the table. Shooting straight down can also be complicated for setting up the camera (how do you look through the viewfinder to determine that everything is in focus and in the frame) so using an angled shooting table is usually easier.
Your tripod choice will be dependent on the shooting table or vertical shooting decision, and the weight of the camera. Depending on the camera's weight you may also need a tripod head as only cheap/lightweight tripods come with built-in heads.
You need 2 lights and light stands. Depending on the size of the blueprints you may wish to umbrellas or softboxes, rather than reflectors to help produce uniform light across the width of your blueprints. The critical thing is understanding the "angle of incidence" so that you position the lights correctly to avoid glare reflecting off the document and into the camera. I suggest you get the book Light, Science and Magic and read Chapter 4 "Surface Appearance" and understand the "family of angles" so you can determine how to properly place the lights.
You don't need strobes, hot-lights will suffice. However, there can be issues with hot lights creating, well, heat, which can make your studio uncomfortable, or even cause heating problems (or fires!) with softboxes, umbrellas, and the like. For this reason you may prefer to work with strobes. If you get strobes then you also need a way to trigger the strobes from your camera. You can NOT use the on-camera flash to light the blueprints or to trigger the strobes, as this will create bad reflections in your image.
Make sure you set the white balance on the camera correctly for the light you are using so that the blueprints come out the correct color, otherwise they may end up a very strange shade. (Scanners automatically configure the white balance of their scans for their own light but with a camera you need to do this manually as the camera has no knowledge of the type of light you are using. Auto-white balance is not very accurate.)