Thoughts on Nikkor 85mm f2 AI-S

[Roland Vink]

I observed another difference between the AI and AIS version that the focus ring on AI version moves a lot forward when focused to close distance. So the long DOF lines are needed.

DOF lines of AI and earlier lenses start with the narrowest DOF line pairs and progress outwards. They are usually in this order: green, red, yellow, blue, orange

AI-S lenses start with the widest DOF line pairs (smallest aperture) and progress inwards: orange, blue, yellow, brown.

The reason for the change is that AI-S lenses are designed to work in shutter priority and program modes. The bright orange minimum aperture reminds the photographer to use this setting when shooting in these modes, otherwise the full range of aperture settings won't be available to the camera.

Also note the AI-S DOF scale has at most 4 line pairs while earlier versions can have up to 5. This is because the focus throw of AI-S lenses is shorter, so there is less room for the DOF scale.

The AIS focus ring almost stays close to the white alu-ring so scale is still usable at close distance. The helicoid design must be quite different?   .....a lot more different than just 170 vs. 270 degree?

The focus ring has two helixes internally, one attached to the lower barrel with the aperture ring and lens mount, the other to the upper barrel with the optical unit and front filter threads. On many AI and earlier lenses the gradient of the two helixes is about the same, so when the focus ring is turned, about half the extension occurs with the focus ring, and half with the upper barrel. With most AI-S lenses, the gradient is different. The lower helix has a very low gradient, so the focus ring hardly moves forward at all, most of the extension occurs with the upper barrel.

This is not directly related to the focus throw. For example, the AI and AI-S 200/4 have the same focus throw, even though they have different types of focus ring. Also, the AI and AI-S both use the AI-S style of focus ring but have different focus thows.

[Roland Vink]

My copy is an Ai, but I don't think it is good at f2.

That looks out of focus. Maybe your lens doesn't quite focus to infinity, or do you see the same behavior at middle and closer distances?
My AI-S copy is sharp even at f/2.

[Zang]

It's actually because the focusing is linear that the focus scale is compressed near infinity and more generous at close range. This is can be a problem for macro lenses which cover a much greater focus range in the same focus throw, the range near infinity becomes very short. The only way around this would be to replace the linear helical focus action with a non-linear focus cam. The gradient of the cam would be shallow near infinity so the focus scale stretched out, and would become steeper at close range. However, focus cams are harder to make, can be less accurate and more likely to have some slack in the focus action, so are not often used, although cams are common in zoom lenses.

I am sure the focusing (or assembly movement) is linear. By nonlinear I meant the scale only meaning 10m is not twice the turning of 5m My point was when we add more throw, the close range usually benefits from it more than the far distance one. In my Zeiss Makro-Planar 100mm focusing from MFD to 3m takes almost the entire 345* and the rage from from 3m to infinity only takes the rest of 15*

[MEPER]

DOF lines of AI and earlier lenses start with the narrowest DOF line pairs and progress outwards. They are usually in this order: green, red, yellow, blue, orange

AI-S lenses start with the widest DOF line pairs (smallest aperture) and progress inwards: orange, blue, yellow, brown.

The reason for the change is that AI-S lenses are designed to work in shutter priority and program modes. The bright orange minimum aperture reminds the photographer to use this setting when shooting in these modes, otherwise the full range of aperture settings won't be available to the camera.

Also note the AI-S DOF scale has at most 4 line pairs while earlier versions can have up to 5. This is because the focus throw of AI-S lenses is shorter, so there is less room for the DOF scale.
The focus ring has two helixes internally, one attached to the lower barrel with the aperture ring and lens mount, the other to the upper barrel with the optical unit and front filter threads. On many AI and earlier lenses the gradient of the two helixes is about the same, so when the focus ring is turned, about half the extension occurs with the focus ring, and half with the upper barrel. With most AI-S lenses, the gradient is different. The lower helix has a very low gradient, so the focus ring hardly moves forward at all, most of the extension occurs with the upper barrel.

This is not directly related to the focus throw. For example, the AI and AI-S 200/4 have the same focus throw, even though they have different types of focus ring. Also, the AI and AI-S both use the AI-S style of focus ring but have different focus thows.

Thank you for the explanation.

Also the AI vs. AI-S version of the 85/2 moves the lens unit same distance which is expected as the lens design is same.
As the focus ring does not move much with AI-S lenses there are no needs for the long DOF lines so it makes sense with the short lines on alu-ring.
It makes sense to always have same color (orange) on smallest aperture on AI-S lenses.
On AI-lenses the "red" aperture color looks "pink" to my eyes :-)

[Roland Vink]

Correction, I meant to say: This is not directly related to the focus throw. For example, the AI and AI-S 200/4 have the same focus throw, even though they have different types of focus ring. Also, the AI and AI-S 50/1.4 both use the AI-S style of focus ring but have different focus thows.

And yes, the colours of the AI and AI-S DOF scales are a bit different. On AI and earlier lenses the red is more pinkish and the orange is dull. On on AI-S lenses the red is brighter and the orange is is almost fluoro in some cases

[Bent Hjarbo]

I have now tried my 85 f2.0 Ai on my Z6, as I might get better focus AF on long distance.
The trees in the distance look a bit more focused than om my previous attempts with th Df.
I also tried on more close up.
Z6

[MEPER]

I just opened the door and shot some images with AI 85/2 at f/2 using Z50.
It does quite well at f/2.
A couple of test images with 100% crops.
Still strange with those very different reviews in the past.
Maybe the cropped sensor makes vintage lenses look much better (apart from blurring the background).

[MEPER]

One more where I focused at the red waste containers for batteries.
If sensor had more resolution the very small lettering may be readable.

[Robert Camfield]

One more where I focused at the red waste containers for batteries.
If sensor had more resolution the very small lettering may be readable.

For a given focusing distance and defined aperture, observed resolution is largely determined by image size and optical qualities. Here, resolution delivered by the 85mm f2.0 is quite good, particularly for f2.0...which affirms Roland's comments. As mentioned, Nikon shortened focus throw for many of the prime AIS lenses...like many, I generally prefer the longer throw AIs. An exception is the 2nd generation (5/5) 35mm f2.8 AI lens: the exceptionally short throw was extended for AIS counterpart.

The tidy dimensions of the 85 f2.0 AI/AIS certainly makes for an attractive package though my experience conforms to the consensus view: image quality is disappointing...perhaps there's considerable sample variation for Nikon's 2nd generation 85s.

Robert

[MEPER]

I have only one sample more which is the AIS version. I tried it a few minutes ago with similar test targets as with AI version at f/2. Today the light was stronger so faster shutter speeds.
Performance seems similar using the AIS. A couple of images with 100% crop. The last one I focused at chimney.

[MEPER]

To have something to compare with (just for fun) I tried an old Nikkor-H 85/1.8 with similar test target. First image at f/1.8 and second at f/2. It "clears up" a bit from 1.8 to 2.
This lens has always been my favorite. I have an AI'ed H-C version which I have used a lot with film. But here the single coated version is used.

[Robert Camfield]

To have something to compare with (just for fun) I tried an old Nikkor-H 85/1.8 with similar test target. First image at f/1.8 and second at f/2. It "clears up" a bit from 1.8 to 2.
This lens has always been my favorite. I have an AI'ed H-C version which I have used a lot with film. But here the single coated version is used.

The 85 F1.8 H C appears to obtain higher resolution than either of the 85 F2.0s, thus confirming the consensus view.  Thanks for comparisons...Robert

[Dogman]

Maybe it was just my particular lenses but in the 1980s I shot with both Nikon and Leicas.  I had a new Leitz 90mm Summicron I never learned to like very much.  When compared to my old 85/1.8 Nikkor, the Summicron was softer and had less resolution and contrast.  I sold the Summicron but kept the 85mm Nikkor until it was worn so badly it was coming apart.  I never tried the ƒ/2 version but I have the wonderful (big and heavy) 85/1.4D that I love dearly.

[MEPER]

As I also have the AF 85/1.4D I made similar images today at 1.4 and also at 2.0.
Even that it can't autofocus the aperture can be set from camera and there is focus confirmation from the focus points (turning from red to green). It seems accurate.
My lens has a bit of dust between the two rear lenses. I wonder it if could be a DIY-job to blow it away. The rear lens just looks like a flat glass surface.

Even with a bit of dust this lens seems to do quite well.

[Roland Vink]

I compared my AIS 85/2 (first) with my AI converted K 85/1.8 (second). At medium-close distance it does show less contrast and more bleeding of highlights into dark areas. The 85/1.8 may be also a little sharper, which is surprising since it is an older design. Maybe the old reviews are right, the 85/2 was intentionally given lower contrast to make it more flattering for portraiture.