ProOptics 12K Line Scan Lens

mjkzz · Post by **mjkzz** » Tue Jul 31, 2018 5:50 am

Ran into this lens at surplus shop, I was told it is a 12K line scan fixed focus lens made by Korean Prooptics. So I looked it up and found its specs:

http://www.prooptics.co.kr/AF12k1_25x.html

According to the spec, it has M44x1 thread at the end of it, so I had to order a custom part, converting M44x1 to M52x0.75, then I used a M42-to-M52 filter ring adapter then mount it on some extension tubes to make it at 1.29X.

Test setup is as below: 3 degrees of freedom (roll, tilt, and yaw) on the subject and one degree of freedom on the camera (forward and backward).

With some tinkering with those 4 degrees of freedom, I got a picture as close I can. I think the "fuzziness" in the picture is due to bad printing, rather than focus. So maybe Robert's silicon wafer is good test here as the etchings are razor sharp.

I think it is pretty good corner to corner (except vignetting pointed by arrow, probably caused by my tubing -- in the spec it says CCD size of 86mm).

mjkzz · Post by **mjkzz** » Tue Jul 31, 2018 5:56 am

100% crop of the grid, almost no distortion, though I wish the printing of the scale is sharper . . .

corners

ray_parkhurst · Post by **ray_parkhurst** » Tue Jul 31, 2018 6:22 pm

Nice find! I'd use it in reverse at ~0.75x to image Cents. Perfect focal length. Any way to mount it in reverse?

mjkzz · Post by **mjkzz** » Tue Jul 31, 2018 9:49 pm

I think so, the front has M38x0.5 thread (guessed), so reverse mounting it is possible if you can get an adapter for it.

mjkzz · Post by **mjkzz** » Wed Aug 01, 2018 1:02 am

still at 1.29X, some kind of coin. full image in TIFF format

some details 100% crop

Beatsy · Post by **Beatsy** » Wed Aug 01, 2018 2:48 am

How long is the total package (from camera mount to front of lens)? Do you think it would push to higher mag? The coin closeup looks really sharp, which implies it might.

That looks a really nice find. Congrats.

mjkzz · Post by **mjkzz** » Wed Aug 01, 2018 4:48 am

thanks, the length of the lens is 72mm and total extension is about 129mm for the Sony A7III to get 1.29X magnification. I think it is pretty sharp, I just need to find something to shoot with

mawyatt · Post by **mawyatt** » Wed Aug 01, 2018 4:31 pm

Nice, now you just need a 3/2 96MP sensor to keep up with this lens

Best,

mjkzz · Post by **mjkzz** » Wed Aug 01, 2018 5:17 pm

mawyatt wrote:Nice, now you just need a 3/2 96MP sensor to keep up with this lens

Best,

Hahaha, but how did you get those figures? 3/2 and 96MP?

mawyatt · Post by **mawyatt** » Wed Aug 01, 2018 8:24 pm

3/2 ratio @ 12k pixels per line. So 12K by 8K , or 96MP

Best,

mjkzz · Post by **mjkzz** » Thu Aug 02, 2018 7:15 am

oh, thanks Mike, I was confused by 3/2, I thought you meant 3/2 inch sensor. I think only a medium format camera can do 96MP.

I need to stop reading stuff here, after reading these line scan lenses, all the sudden I see there are 3 shops selling lenses like this one, I normally just go pass them

mawyatt · Post by **mawyatt** » Thu Aug 02, 2018 8:29 am

A little geometry and algebra will yield a 3/2 ratio medium format sensor of ~40.77mm by ~27.18mm with 3.398 micron square pixels which will fit Nikon's new Z mount (49mm diagonal) will give ~96MP.

This is certainly within the reach of modern sensor technology, and I'm betting we'll see a Nikon medium format sensor camera based upon the new Z mount in the coming years, maybe not 96MP for starters but possibly ~58.56MP with D850 size pixels (4.35um).

Best,

mjkzz · Post by **mjkzz** » Thu Aug 09, 2018 7:07 pm

added an aperture assembly, now it is at f/6.3 (one stop below its fixed aperture).

Lou Jost · Post by **Lou Jost** » Thu Aug 09, 2018 9:08 pm

This is for a very large sensor, 83mm across, with 7um pixel size. It isn't designed for small pixels or high-megapixel normal-sized sensors. That's why it has a relatively slow aperture.

A 35mm sensor that would match the design specification should be about 5000 pixels across. In other words, your Sony sensor is outresolving the lens.

Still, nice results!

mjkzz · Post by **mjkzz** » Thu Aug 09, 2018 9:15 pm

The Sony A7 III has 6um pixel (6000x4000), so compared to 7um resolving power, sure.

Thanks.