I agree.Originally Posted by rdenney
I agree.
“You often feel tired, not because you've done too much, but because you've done too little of what sparks a light in you.”
― Alexander Den Heijer, Nothing You Don't Already Know
Yes all that make a lot of sense. If one used a a computerscreen as backlight as I have seen some interest for one could at least easily try it by drawing a white line one pixel row at a time. It could be interesting to try I am just throwing some ideas around
Throwing ideas out there is a very good thing! Even if it's something the people don't check out immediately, it could turn out to be very useful down-the-road.
“You often feel tired, not because you've done too much, but because you've done too little of what sparks a light in you.”
― Alexander Den Heijer, Nothing You Don't Already Know
I have built a lightbox for flash. It works ok and is almost even but I am having trouble getting anything larger than 40x40mm even with my design. Ideally I would want something bigger so I can use the same backlight for full frame captures of a 6x7 negative or slide. Then If I need to i just move the camera closer and take a series of tiles. I started to look at dichroic light boxes. Could thhese be altered to have a flash as a lightsource?
What would be the best way to get a flash like speedlite really even across 6x7 is the question I guess.
I based my source on a De Vere light mixing box. The lighted area is approximately 250mm x 250mm.
“You often feel tired, not because you've done too much, but because you've done too little of what sparks a light in you.”
― Alexander Den Heijer, Nothing You Don't Already Know
ludvig, I think you would need what is commonly called a beam expander. It would be a simple condenser lens, or set, at some distance from the flash face - say a few hundred mm - and a diameter sufficient to easily cover the largest size image frame you are likely to use. The condenser set from a 4X5 D2 enlarger comes to mind. That condenser is a pair of convex/plano 150 mm diameter lenses face to face. This set might be placed 100 to 200 mm from the face of the flash; you'll need to experiment a bit with this. Also you will have to work on the uniformity of the light hitting the film. The further the condenser is from the flash the more even the light but the lower the intensity.
A second approach without using condensers is to just increase the distance between the flash and the film. I do this by bouncing the flash off a white card which sits at a 45 degree angle right under the film. The flash is at the end of a cardboard tube about 1 meter away from the white card. The white card is a good diffusion source so reduces the dust and particle imaging compared to the condenser technique.
Nate Potter, Austin TX.
I googled quite a bit and could not find a good description on how a de vere box is constructed. It seems to involve two lightsources and a mirror plus some diffusor? Do you have a picture I could look at?
I am looking into a good way to do the flash at a distance but the best would be to have it a bit more compact than 1 meter away!
Thanks for the suggestions.
Ludvig,
I'll take some pictures soon, both of a De Vere unit and of my light source.
“You often feel tired, not because you've done too much, but because you've done too little of what sparks a light in you.”
― Alexander Den Heijer, Nothing You Don't Already Know
Why can't we just adapt a standard lightbox previuosly used for viewing slides as a scanning platform mated together with a simple copy stand. They are color calibrated with a decent CRI number.
Previously, I had purchased a couple of Bowen Ilumitran side dupers used on ebay with the idea of using it to scan (with a DSLR), but never got around to setting it up.
Standard light boxes aren't ideal for two reasons. First, most have very noticeable hot spots. My Porta-Trace one certainly does. Second, at these magnifications vibration can be a real problem. If you have a Canon with the EFSC shutter mode (See: http://krebsmicro.com/Canon_EFSC/index.html), then you can probably do what you like, but if you don't have that super-low vibration shutter, then you probably want to avoid timed exposures in the 1 second to 1/15th of a second range. Using flash correctly minimizes the problems with vibration, but there might be issues with consistency, although that hasn't been a problem for me so far.
“You often feel tired, not because you've done too much, but because you've done too little of what sparks a light in you.”
― Alexander Den Heijer, Nothing You Don't Already Know
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