APO Corrected 1.35x Scanner Lens For $20 PrimeFilm 3650u

[Lou Jost]

"All slides MUST be oriented in such a way that the slide is in landscape position."

From the online manual. Though I don't know how they define landscape mode...

I have a paper manual for my Coolscan 5000 which I still use, will check it.

Edit: Also, the Coolscans accept film strips, so they have to be optimized for scanning along the long dimension.

[Lou Jost]

Hm, the manual doesn't clearly say anything about that, but the strip film holder only accepts normal strips 24mm across; their length is indeterminate (between 2 and 6 frames long).

[RobertOToole]

The 3650u, which is a mid-range scanner, does the same thing, though since I have not stripped one yet I'm not sure of the particulars. Robert quotes 1.35x but I'm not sure how that is calculated. Perhaps the 3650 has a much longer sensor? Robert?

The 3650U scans the 36mm dimension of the slide, not the vertical portion, that I know for sure. That is different than other scanners. I believe I have a picture of the orientation if anyone is curious.

Got the 1.35x magnification number by dividing the sensor width by 36mm and reversing it to go past 1x. I tested some closer to 1x and the corners were soft.

Robert

[ray_parkhurst]

Hm, the manual doesn't clearly say anything about that, but the strip film holder only accepts normal strips 24mm across; their length is indeterminate (between 2 and 6 frames long).

Both the 1800u and 3650u accept film strips as well, same orientation as "landscape" for slides.

[ray_parkhurst]

The 3650u, which is a mid-range scanner, does the same thing, though since I have not stripped one yet I'm not sure of the particulars. Robert quotes 1.35x but I'm not sure how that is calculated. Perhaps the 3650 has a much longer sensor? Robert?

The 3650U scans the 36mm dimension of the slide, not the vertical portion, that I know for sure. That is different than other scanners. I believe I have a picture of the orientation if anyone is curious.

Got the 1.35x magnification number by dividing the sensor width by 36mm and reversing it to go past 1x. I tested some closer to 1x and the corners were soft.

Robert

I have not opened up the 3560u, but the 1800u has a 22mm sensor length. So it would be 0.61:1 in normal operation, or 1.64:1 in reverse. I assume the 3650u has a longer line sensor, so if the 1.35:1 is correct, then in normal operation the scanner is operating at 0.74:1, and the sensor is 26mm long.

[RobertOToole]

These are just record images made with a mobile phone, and were not taken to be posted online.

Top shows the mirror, bottom shows the removed sensor.

[ray_parkhurst]

Looks identical to the 1800u, except the plastic is black vs the 1800u's tan.

Edited to add: The sensors look to be about the same length. When you measured 26mm, was it the entire length of the sensor chip? The 1800u sensor is also 26mm long, but the active RGB portion is only 22mm. The rest is bondpads for interconnect.

[RobertOToole]

I have not opened up the 3560u, but the 1800u has a 22mm sensor length. So it would be 0.61:1 in normal operation, or 1.64:1 in reverse. I assume the 3650u has a longer line sensor, so if the 1.35:1 is correct, then in normal operation the scanner is operating at 0.74:1, and the sensor is 26mm long.

Honestly don't remember Ray but I do have the sensor here, let me check. Okay the sensor mask window, where the sensor is exposed, is 27mm wide, not sure how much of the sensor element is actually active though.

Tested the 3650U lens at a couple different mags and 1.35x seemed to work best. I normally do that with scanner lenses just to be sure.

Curious to see how that LS-30 works out.

Robert

[Lou Jost]

The Nikon scanner accepts filmstrips inserted in the short front end of the scanner, while the 3650U accepts filmstrips going through the short axis of the scanner.

Robert, when you say the 3650U scans the 36mm dimension, do you mean it moves the lens along the 36mm dimension? That would be the same as the Nikon scanner I have. In that case, the scanner lens would have a FOV of 24mm.

It is hard to imagine a scanner that would be designed to accept filmstrips yet with lens and sensor covering 35mm. This would waste lots of resolution, unless there is something I am not thinking of.

Edit: I posted this while Robert was adding the images above; now that I see his images of how the scanner works, I see it is very different from the Nikon scanner. I don't understand how that could work, but there it is!

[RobertOToole]

Looks identical to the 1800u, except the plastic is black vs the 1800u's tan.

The PrimeFilm 7200u/7250u should be similar, even the optical resolution according to he test on filmscanner.info!

[ray_parkhurst]

The Nikon scanner accepts filmstrips inserted in the short front end of the scanner, while the 3650U accepts filmstrips going through the short axis of the scanner.

Robert, when you say the 3650U scans the 36mm dimension, do you mean it moves the lens along the 36mm dimension? That would be the same as the Nikon scanner I have. In that case, the scanner lens would have a FOV of 24mm.

It is hard to imagine a scanner that would be designed to accept filmstrips yet with lens and sensor covering 35mm. This would waste lots of resolution, unless there is something I am not thinking of.

Edit: I posted this while Robert was adding the images above; now that I see his images of how the scanner works, I see it is very different from the Nikon scanner. I don't understand how that could work, but there it is!

The 1800u and 3650u indeed scan such that the 36mm dimension is aligned with the line sensor. Edited...this is the case when the slide is placed in the holder in "landscape" orientation.

Edited to add: I wrote while you were editing...the design of the 1800u/3650u is pure genius, very compact and accurate.

[ray_parkhurst]

Going back to older Nikon scanners, is the LS1000 worth looking into? There is one on eBay for $20.

[viktor j nilsson]

Thanks for the tip, Robert. I've been looking for Minolta and Nikon scanners for a while, but the prices have become crazy (and I like bargains too much).

Inspired by this thread I put in an €10 offer for a Reflecta i-Scan 1800 without power adapter. The offer was prompty accepted. Looking forward to trying it out, based on Beatsys picture it looks like a very useful lens for that magnification range. Makes sense if it would be the same lens in the 1800 and 3200 scanner, and that they only updated the sensor.

Btw, the FCC ID of the i-Scan 1800 I bought is LXH-P0005-U.
This ID seems to be shared by several scanners: Mediax DiaScanner 1800, MICROTEK FilmScan 1800, PrimeFilm 1800, Pacific PrimeFilm 1800. Not sure how informative FCC IDs are, though.

Glad you found the thread useful.

Let us know how it works out and how you manage to mount it.

Thanks for the ID info.

Best,

Robert

Got the Reflecta i-Scan 1800 film scanner in the mail the other day. Today I found some time to pick it apart. The lens looks slightly different from your 3650u lens. Mine has three rectangular notches on the sensor side, and a paint mark on the side facing the film. Can't post pictures right now, will do later when I have time. (Won't be as nice as your epic gummi-bear photo!).

I somewhat temporarily mounted it inside a rms parfocal extender (a 12mm long empty rms-threaded tube that I use to put short-barrel Lomo objectives on my microscope). A layer of tape or two made it a snug fit. I was a little surprised to see how little extension was necessary to get 1.35x mag.

Pictures look really clean so far, no loCA or laCA that I can see on the camera screen (don't have my computer here at the moment).

I like it, it's very cute. I look forward to seeing how it works in practice. It nicely fills a gap in my objective collection will allow me to use my horizonal (bellows+finite microscope objectives) setup for a wider range of subjects

[ray_parkhurst]

I took out the lens from my non-functional PrimeFilm 1800u, and it has two notches like Robert's 3650u lens, but in slightly different positions. It also has a blue paint mark toward the film.

Seems there are different versions of lenses, even among similar models.

Still have not shot with it. I'll need to rig up a camera mount to make it work given its short FL won't support bellows.

[jcb]

I have been dissecting 2 Reflecta i-scan 1800 (both made in Taiwan with the same part number 3882B452, another id number stated as 3620026 and FCCID LXH-P0005-U). They are quite similar from the outside but quite different inside.
To recognize them :

• One has 5 screws on the bottom. The on/off switch is located at the back in the upper colored part of the case. it sports a brass lens manufactured in a traditional way (lenses are held by brass threaded rings)
  One has 4 screws on the bottom. The on/off switch is located at the rear in the lower white part of the case. The optics look like a different formula with lenses glued or otherwise set in place in a very thin aluminium barrel. The external plastic parts look similar (same global shape and color) but on closer inspection are really different and indicate a very different manufacturing.

I also dissected a Microtek film scan 35 (named film color scanner on the bottom label) that had exactly the same item number 3882B452 and FCC ID LXH-P0005-U and is exactly the same as the Reflecta with 5 screws on the bottom with (color apart) the same plastic case. Lens is the same as in the Reflecta with 5 screws.
Now about the lenses.

• The better looking brass barrel lens looks different from the one shown in the original post :
  • the 2 grooves are located further to the rear of the lens (opposite the paint mark)
    total length is 16.4mm
    diameter is 14.4mm
  The aluminium barrel lens looks also different :
  • the front of section of the lens where the paint mark is seems finely knurled
    total length is 14.7mm
    diameter is 14.4mm

Optical quality of both lens types is as yet untested but I expect very little from the aluminium barrel one seeing how flimsy the barrel seems.[/list]