Telecentric Scanner-Nikkor ED LENS: Nikon 8000 ED lens

RDolz · Post by **RDolz** » Mon Jan 14, 2019 3:20 pm

As I was not clear what was happening with the Coolscan 8000 lens, in non-telecentric mode, I decided to do a test in direct and reverse mode for magnifications ranging from 0.70X to 1.15X

In the end I was able to take the test this weekend. I did the test for the following magnifications (approx.): 0.70 / 0.80 / 0.90 / 1.00 / 1.15 /

As a summary: for 1X or smaller increases, my Coolscan 8000 is better in direct mode than in reverse.

1.15X is the only case that gives a better image quality in reverse mode than in direct mode. It matches Lou's assessment:

Lou wrote:The two magnifications being discussed here, 0.9x and 1.12x, are very close but are on opposite sides of the 1:1 mark, so it makes sense that the best orientation for 0.9x is the reverse of the best orientation at 1.12x.

In the central area the differences are practically negligible. On the other hand, the difference can be seen in the edges of the images.

I enclose the summary images. From left to right:

0.70 / 0.82 / 0.90 / 1.00 / 1.15

The direct mode corresponds to the upper crops.

Center:

Left side:

What I do observe is, in direct mode, a small increase in glare at lower magnifications.

Best regards

ray_parkhurst · Post by **ray_parkhurst** » Mon Jan 14, 2019 3:36 pm

Please remind me...which orientation is "direct" vs "reverse"?

RDolz · Post by **RDolz** » Mon Jan 14, 2019 3:54 pm

I'm sorry, "Direct" is the position in which the lens was mounted on the scanner, the face that looked at the sensor of the scanner looking at the sensor of the camera. That is, the position in which it was designed to obtain the best performance.

Reverse is the position shown in the image of the initial setup of this post, in which you can see on the face that looks at the object the word "sensor". In telecentric mode and at 1.12X I obtained better results in the "Reverse" mode.
.

ray_parkhurst · Post by **ray_parkhurst** » Mon Jan 14, 2019 7:37 pm

RDolz wrote:I'm sorry, "Direct" is the position in which the lens was mounted on the scanner, the face that looked at the sensor of the scanner looking at the sensor of the camera. That is, the position in which it was designed to obtain the best performance.

Reverse is the position shown in the image of the initial setup of this post, in which you can see on the face that looks at the object the word "sensor". In telecentric mode and at 1.12X I obtained better results in the "Reverse" mode.
.

So the end of the lens with less space to the body center goes toward the sensor. I'll call this the "short end".

If m<1, long end should point toward the subject
If m>1, the short end should point toward the subject

Correct?

RDolz · Post by **RDolz** » Tue Jan 15, 2019 3:10 pm

ray_parkhurst wrote:So the end of the lens with less space to the body center goes toward the sensor. I'll call this the "short end".

If m<1, long end should point toward the subject
If m>1, the short end should point toward the subject

Correct?

Yes, it is correct, in my test:

"Reverse": short end ( and paint dot) towards the subject for magnifications greater than one.

"Direct": Long end (three rings) to the subject for magnifications less than or equal to one.

Although previously I associate the short end with two rings, I only specify three rings in the long end, because for the short part there are two versions, as you can see on Robert's website:

https://www.closeuphotography.com/scann ... r-ed-lens/

"........and 2 different versions of the 14 element lens as you can see in the image below. Right now I am pretty sure the two 14 elements are different designs. The only things that I can see that are similar are the lens coating color and the dimensions of the middle section that is used to mount the lens into the scanner chassis. Differences? Front element diameter, overall length, number of lens sections, thickness and position of sections. ...."

The Coolscan lens that I have has two rings in the short end.

Also on Robert's page, you can observe the "direct" position with the three rings towards the mirror, that is, towards the subject that in this case is the slide.

https://www.closeuphotography.com/how-t ... 00-scanner

etalon · Post by **etalon** » Wed Jan 16, 2019 11:48 am

Hi Ramon,

thank you for that further test. It shows clearly, what be expected: The 0.9x for direct mode and 1.15x for reversed mode would give the best results.

Can you tell, how much the space between the barrel end and the camera sensor in direct mode at 0.9x is?

Thanks again,
Cheers Markus

RDolz · Post by **RDolz** » Wed Jan 16, 2019 1:32 pm

etalon wrote:Can you tell, how much the space between the barrel end and the camera sensor in direct mode at 0.9x is?

Hi, Markus: The space between the barrel end and the camera sensor in direct mode at 0.9x is, approximately, 133 mm. The distance between the front of the lens and the subject is 150 mm.

Best

etalon · Post by **etalon** » Wed Jan 16, 2019 1:37 pm

Thanks, Ramon!

Cheers Markus

etalon · Post by **etalon** » Sat Jan 19, 2019 1:51 am

Hello gents,

I was looking for some pics taken with that 8000 lens, but I couldn‘t find that much. I don‘t mean testchart pics, but macro pics taken from users of that lens. Maybe I did the wrong search. Can any user of that lens provide me some links or results of his or others work?

Thank you!

Cheers Markus

Olaf G · Post by **Olaf G** » Sun Jan 20, 2019 10:22 am

Haven't had the opportunity to use it that often but I will post more...

https://www.flickr.com/photos/62289058@N03/albums

etalon · Post by **etalon** » Tue Jan 22, 2019 1:04 pm

Olaf, thanks for your great pics. I‘m really astonished, how less guys take pics with that beautyful lens, even the lens was called superb...

Since today, I have finished the assembly of my scanner nikkor 8000 and I‘m really impressed of the quality of that lens. Sharpnes, resolution and completely free of any chromatic abberation at a really low magnification of 0,92x! That‘s exactly, what I was looking for.

Here is my very first pic with that beautyful lens. I hope, it is ok for Ramon, posting it in his thread...

https://www.mineralienatlas.de/viewF.ph ... 1548185859#

It‘s a Uranophane specimen from Shinkolobwe/DR Congo. FoV is 18.5mm at the long side. It‘s a 80 layer stack with 100um step size. Postprocessed with PS CC2018.

Thanks for all the infos to that outstanding lens, which let me buy one!

Cheers,
Markus

Lou Jost · Post by **Lou Jost** » Tue Jan 22, 2019 1:15 pm

I'm very glad to see people using this lens. It is indeed excellent.

RDolz · Post by **RDolz** » Tue Jan 22, 2019 3:39 pm

Olaf, I was pleasantly surprised by the images you have achieved using the coolscan in a conventional way ... dazzled by the telecentricity, the stacking and sttiching, I had never thought of this way of using it.

etalon wrote:Here is my very first pic with that beautyful lens. I hope, it is ok for Ramon, posting it in his thread...

Markus, is a fantastic image, and an ideal subject to show the capabilities of this lens. Those fine crystals of Uranophane are wonderful. What lighting do you use?

By the way, I read that this mineral is radioactive

Lou, .. you are one who have caused that some of us to use this lens, ..

best

Lou Jost · Post by **Lou Jost** » Tue Jan 22, 2019 5:36 pm

I'm very happy to see my former lens being used so well!

Olaf G · Post by **Olaf G** » Wed Jan 23, 2019 10:58 am

etalon wrote: Here is my very first pic with that beautyful lens.

Outstanding work, Markus!
I am looking forward to seeing more pictures taken with that lens.