Ideal Canon Camera Settings

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Crispy
Posts: 14
Joined: 24 Apr 2015, 12:13
Number of books owned: 1500
Country: UK

Ideal Canon Camera Settings

Post by Crispy »

Hi

I am trying to use a script which was very kindly linked to from the forum, which allows a user to check their ideal Canon Camera settings. The script can be found here: http://www.mind2b.com/component/content ... a-settings

When I try to run it I get the following error mesage: U Basic 73 Parse Err

I am using Canon A1400s; has anyone else reported this error?
duerig
Posts: 388
Joined: 01 Jun 2014, 17:04
Number of books owned: 1000
Country: United States of America

Re: Ideal Canon Camera Settings

Post by duerig »

Crispy, I can't help you with that script, but I have been working on a user guide for the Archivist and there is a relevant section. Here is a draft:

Power Most cameras are battery powered because they are intended for mobile use. But you will be using them in a fixed position and changing a battery every few hours will quickly become troublesome. This is especially true if your battery location is not easily accessible after mounting and callibrating the position. Nearly every camera model has an AC adapter that you can purchase for it. Buy two when you are getting your cameras.

Mounting Each camera is mounted near the top of the imaging module facing the opposite page. The details of how to precisely position it are below, but the tricky thing is that the simple camera bolt shipped with the Archivist may not be enough by itself to mount your camera. If the cords or AC adapter on your camera are on the bottom, you need to make sure there is enough clearance. To do this you may need to buy a longer 1/4-20 bolt and some nuts and washers. If your camera mounting is tricky, please post to the forum or email help at tenrec dot builders for assistance.

White Balance The LED bulbs in the lighting module have a color profile of 'warm white' (2700 K). This means that the light they provide is skewed more yellow than blue. This means that you must set your white balance to 'Tungsten' on your camera. If you don't, the pictures be yellow tinted.

Focus Your camera can auto-focus when taking most scans. But the auto-focus can fail, especially when the center of the page is blank. If it does, you should manually focus your camera if possible. Be aware that each camera might need a slightly different focus even if they are the same model and the same distance from the page. Also, the ideal focus for the center of a page is slightly different than the ideal focus for the corners.

Zoom It is tempting to try to zoom in on each book as much as possible in order to maximize your effective use of the camera. But this is a mistake with the Archivist. Each time you change the zoom setting, you will have to recallibrate the position of your camera. Since callibrating your camera position precisely is so time consuming, it is better to pick a camera and zoom setting that provides sufficient resolution and leave it.

ISO In the Archivist, the pages will always be strongly and evenly lit. Low-light settings will simply reduce the quality of the image. Set the ISO to the lowest value your camera supports.

Aperture Most cheap cameras do not have aperture settings. If you are using a more expensive camera, then it is worthwhile to decrease the aperture size somewhat in order to make sure that both the corners and the center are always in perfect focus.

Shutter Speed Faster shutter speeds reduce the blur introduced by vibrations or other motions. Usually a value of 1/10 of a second is plenty fast enough for scanning.

Lens Distortion Every camera lens has slight imperfections which cause small distortions in the photographs. In addition, you will never get your camera to be completely perfectly positioned with respect to the page so the photo will be at a very slight angle. Often these artifacts can be hard to spot, especially if you aren't looking for them. But there is software that can be used to figure out the distortion on your setup and correct it after the fact. Only start looking into this when everything else is working.

-D
Crispy
Posts: 14
Joined: 24 Apr 2015, 12:13
Number of books owned: 1500
Country: UK

Re: Ideal Canon Camera Settings

Post by Crispy »

Hi Jonathon, thanks for this very detailed post; I've been experimenting with my setup this evening and have had some good results.

The image quality still isn't as high as I'd like though: I'm experimenting with a chdk script to slow my zoom down so that I can match the zoom level of both cameras. I've tried taking some pictures using the recommend settings in your post, without using a zoom, and the results weren't great; some page numbers and finer details were a bit fuzzy in the final output. This might also have been due to my aperture settings.


My settings are currently:

F-stop: f/3.2
Exposure time: 1/60 sec.
ISO Speed: ISO-10
Focal Length: 7mm
Max aperture: 3.34375.

I have been using the cameras' infinity focusing range to avoid having to measure the distance from the camera to the object in mm to use the CHDK control to lock the subject distance, but I will do some experimenting with this to see what might work better.

I did wonder whether there might be a way of physically moving the cameras closer to the platen, but this seems a bit excessive.
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