B&H Used Department has this extremely difficult to find item: https://www.bhphotovideo.com/c/product/802286036-USE/pentax_slide_holder_1x_...981&

I adore mine and it works really well. I wrote up a sample of my experiences with the item and it's in the reviews here on the forum: PENTAX Slide Holder 1x, K reviews - Pentax Camera Accessory Review Database

If you have slides or negatives from the film era, in my opinion, this is the best option to digitize them!

[reh321]

Woo hoo! Rare "get", glad some of my discussion in the reviews helped in some small way! The extension tube was the solution for me on the crop sensor.

A system like this is the only way I could envision a "hundred thousand" image copy session. Be careful to retain the Kodachrome color palette if possible. Your digital settings will almost certainly alter the colors and I'm not sure that shooting RAW and batch processing will prove to work well since color cast in the images will vary depending not only on the film but on the light conditions when the originals were shot. To work with hundreds of thousands of images means trying to individually "massage" each image as a RAW capture would require decades of your time! Experiment a bit with the neutral Kelvin settings which could retain atmospheric conditions--like sunsets--in the originals without too much change.

Good luck with your project!

Additionally, you seem to be planning for the highest resolution RAW files you can possibly get on all the copies. Since max resolution would likely only be of value for images selling to a publisher or for extremely large prints, I can't believe that even a tiny fraction of those hundreds of thousands of images would merit such treatment. I'd copy the 200 or so images that might be sale-worthy with large RAW files if you are so inclined but with various film emulsions all shot presumably in differing natural light you will not be able to batch process for color cast. This makes adjusting for color cast while shooting the far better option to save you a few decades of post processing time. And note that though I'm not a true professional photographer I have sold more than 1000 images for publication including full page glossy images and cover photos and I'm 'fessing up here--I'VE NEVER SHOT A RAW IMAGE NOR POST PROCESSED A SINGLE RAW IMAGE. I've sold 30x40" prints for several thousand dollars and shoot primarily for support materials for my articles and books and nowadays paid blog content and I've never been able to come up with a single reason to even consider shooting RAW. I don't shoot snapshots but all well planned and dialed in JPEG's (I select color rendition through several methods provided in our cams--often through choices like the Reversal Film option or Kelvin scale). Sorry to ignore the truth about RAW offering more range for change, but I'm only interested in saleablility and shooting RAW has absolutely nothing to do with the marketability of images! But though not shooting RAW I go overboard to make in-camera settings work for me...I go so far as to bracket white balance on key images to avoid having to do it in post. But that's my bent. The fun of photography is we all get to choose our own "bent"

---------- Post added 01-08-22 at 11:57 AM ----------

Couldn't resist doing a little math.
150,000 images at one minute per copy equals a year and a quarter of full-time 40 hour work weeks to copy them all. And that's at a blazing one minute per image for the copy and processing.
At a more realistic 3 minutes per image that would be 4 years of copy work at 40 hours a week!

If you don't push and take your time and choose to post process each RAW image and it takes a reasonable 5 minutes per image you are looking at over 6 years of working 40 hours a week!

Probably forced to batch process and lose the individual color cast of each image to ever complete the project?

I had several thousand slides to digitize. I had already owned a Pentax copier thirty years ago - when I was trying to turn all media into slides - and rejected it for various reasons.

I found the Nikon scanner to work the best, because it’s multi-pass method allowed it to use parallax to eliminate dust, spots, and scratches, but when examining the results at 200%, I discovered that it would develop alignment problems. Not wanting to ‘go broke’ paying for intermittent CLA, I also got a Plustek “8100” and an Epson “V600”. Each of them has issues of some sort.

[yucatanPentax]

I had several thousand slides to digitize. I had already owned a Pentax copier thirty years ago - when I was trying to turn all media into slides - and rejected it for various reasons.

I found the Nikon scanner to work the best, because it’s multi-pass method allowed it to use parallax to eliminate dust, spots, and scratches, but when examining the results at 200%, I discovered that it would develop alignment problems. Not wanting to ‘go broke’ paying for intermittent CLA, I also got a Plustek “8100” and an Epson “V600”. Each of them has issues of some sort.

Did you ever hit on a solution? Tried the individual slide copier (holder) devices for a DSLR? I think my slides likely number in the hundreds. I used to discard any that weren't what I thought at the time were "great" or "perfect." Probably threw away something that might be useful in the digital era.

[reh321]

Did you ever hit on a solution? Tried the individual slide copier (holder) devices for a DSLR? I think my slides likely number in the hundreds. I used to discard any that weren't what I thought at the time were "great" or "perfect." Probably threw away something that might be useful in the digital era.

Right now I’m using an Epson “v600” then editing at 200% to clean up the scans {it does leave dust, spots, and scratches, even with “ICE”}.
My computer has Linux installed, so I use my wife’s Win 10 laptop {no CD drive}.
If I had a Win 10 box or a Mac with a CD drive, I would probably use the Plustek, but that is too complicated right now.

[normhead]

I had one years ago in my AV department, where the AV club could use it. It was always set up and never a waste of space.