Drew, I'll time a scan sometime soon.
Here's a d600 shot of a Stouffer step wedge. I've listed the densities of the steps, along with the green sRGB channel and LAB L values when the file is taken into Photoshop.
Drew, I'll time a scan sometime soon.
Here's a d600 shot of a Stouffer step wedge. I've listed the densities of the steps, along with the green sRGB channel and LAB L values when the file is taken into Photoshop.
“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
Here's a res chart shot with the D800E using a Schneider 80mm f/6.7 Apo Macro. Magnification is 1:1 give or take a few pixels.
It looks to resolve the same whether it's a .tif, .jpg or .gif.
Last edited by Daniel Moore; 25-Oct-2013 at 18:55.
It looks like Group 6 Element 2 is resolved. That's 3650 spi.
“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
Drew, using a 3 second exposure delay I captured 25 frames of a 4x5 scan in three minutes 8 seconds. I'm moving the stages at very nearly 30mm per sec.
Here's a resolution test using a D7100 and Magnagon 75mm f/5.6:
Looks to me like group 6 element 5 is resolved putting it at 5160 spi. Yikes!
An outstanding result. Thank you for doing the test!
“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'm currently in the middle of designing a scanner using the Actobotics system. Its rather like a precision Erector set. The design will use 4 of their slider kits, two for each side of each stage, with stiffening elements and joining plates where necessary. I plan on using a stepper motor from Spark Fun to drive each stage. I plan to use a shaft to connect the two sides of a stage together so that they can be driven together. I contacted them a short time ago regarding stepper motor mounts and they said that the mounts were being finalized and would be available soon. This should make is possible to mount a NEMA face motor to the slider kit. There would be one motor per stage.
Since the rails are on the sides, this makes it possible to make a platform with an aperture through with light would shine for the "exposure". The light source could then be very small, only slightly larger than the capture area. The camera and light source would be stationary. A very high quality light source could be used. This should result in the most even illumination across all sections of the negative. This also removes the weight of the light table from the stages so the stages would not care much additional weight. This idea might require negative carriers with glass in order to ensure that the negatives remain flat. If flatness or other technical problems make the aperture concept unworkable, the "moving light table" concept can always be used in its place.
A slider kit is $120, so the cost of the scanner will be more than $500, excluding the camera, lens, etc. I think it should be less than a new flat bed scanner, which is why I started looking at this concept, as well as resulting in higher quality scans than a flat bed scanner could produce, I assume. I have a Sketchup model put together of the concept and will put that on my Dropbox if people are interested. I appreciate comments and feedback regarding the suitability of this approach. I have yet to consider how the camera would be mounted but assume a gantry could be constructed to hold it.
Regards,
Rob
My flickr stream
Slight correction to my other post: I meant two slider kits per stage, one per side of each stage.
My flickr stream
I'd love to see the sketchup file, sounds fascinating. I'm now working on a circuit board for Scanduino which should be adaptable to many systems such as this.
Sounds like a good system. My only reservation concerns the " The light source could then be very small, only slightly larger than the capture area." In my experience that will lead to significant light falloff at the edges of the sampled area.
“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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