20171104_0014_Working_20200327_3200dpi.jpg
20181104_0014_Master_202001011_20201025_Working_4000dpi
“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'd seen Daniel's project before, but not yours. I'm taking a shortcut by using one of the cheap chinese CNC kits and re-purposing it.
Yep, that's a good option.
Daniel's design was compact and very sturdy, as the system clamped the lens in place.
I used a Velmex 4000 unislide to position the camera + lens system. That was more complex and expensive, but it allowed me to change out lenses. I tried about 20 different lenses, and I ended up preferring a Rodagon D 75mm 1x lens at 1x magnification. I expect there are better options now...but even with the ancient 55 Nikkor, the system outperformed an Epson flatbed, and that was tested using resolution targets and stepwedges for density measurements. My system outperformed the Epson by about 1 stop more dynamic range. Today's cameras can likely do significantly better, and that's not even considering multiple exposures and different exposure levels. I tested that back then too, and it gave great results, but it did require a lot of extra exposures and processing.
“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
Which is the best setting for the V850? In my test of it vs a Howtek 8000, I did the scans on my V850 using Epsonscan. The first scan was done at 4800 ppi reduced to 4000 for the first comparison set. The second scan was done at 2400 as I found for some reason it was sharper after sharpening than the 4800 scan. That could be an error on my part. Both scans were adjusted to set the clipping points only.
Here's the complete thread for the comparison of the v850 vs Howtek 8000.
https://www.largeformatphotography.i...ghlight=howtek
Flickr Home Page: https://www.flickr.com/photos/alanklein2000/albums
Did I have to reduce the 4800 to 2400 first? to 3200? something else?
Flickr Home Page: https://www.flickr.com/photos/alanklein2000/albums
I honestly don't know myself. I've been doing various tests, trying to reduce the number of variables, but I've lacked *ahem*... focus.
Personally, the variables for me are holder height (reasonably sure I've got that one nailed down), scan resolution, down-sampling, and film quality-- and right now, I'm not convinced my negatives are of sufficient quality to make definitive judgments.
The way to reduce the ppi is to do a 2x2 binning. This is different than resizing in photoshop or other programs. 2x2 binning turns 4 pixels into a super pixel. Reducing the file using photoshop or epson scan will yield inferior results. To my knowledge only Vuescan offers this option unless you use a different program.
Focus is number one. From there, scan at the highest resolution you can do and then do a 2x2 bin before saving. That takes a 6400 to 3200. Vuscan is the only program I know that can do that right now. If you have to save the file and use a different program, you will need to keep the file just south of 4gb for a tif file. Do not compress, even if you use lossless.
Don't buy into the scan only for the size/s you plan to print out. The smaller the dpi the more information you throw away. Which is not true for binning.
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