Author Topic: tale #85  (Read 1597 times)

richardHaw

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Dogman

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Re: tale #85
« Reply #1 on: March 28, 2023, 14:48:44 »
Thanks for this Rick.  Appropriately I just ordered a 55/3.5 AI yesterday. 
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John Geerts

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Re: tale #85
« Reply #2 on: March 28, 2023, 16:53:58 »
Thanks for the link Rick.  Interesting story of the famous 55/3.5 Micro with a typical Xenotar design

Akira

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Re: tale #85
« Reply #3 on: March 28, 2023, 18:25:58 »
Long time no see, Rick.  Hope you are doing well.  Thanks for the note.  Indeed, it is an interesting read.  I bought the last Ai version of this lens from Roland and completely happy with it.
"The eye is blind if the mind is absent." - Confucius

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Roland Vink

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Re: tale #85
« Reply #4 on: March 28, 2023, 23:05:21 »
Thank you, another interesting article although this one is very long and technical! :o

The AI 55/3.5 is a beautiful lens and it was difficult to part with it, but in the end I found the max aperture of f/3.5 a little too restrictive, and I did not like the hexagonal blurs caused by the 6-blade aperture.

Overall I found the AIS 55/2.8 a better lens for me, the f/2.8 aperture is acceptable and the 7-blade aperture gives blurs a more organic appearance. However this lens is not perfect either, background bokeh can be a little harsh and it flares when shooting into strong direct light.

Hugh_3170

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Re: tale #85
« Reply #5 on: March 29, 2023, 03:23:17 »
And it can leak oil all over the diaphragm once its grease breaks down - something that the 55mm f/3.5 does not seem to do.  A shame, as the 55mm f/2.8 is a good lens.  I know - have a couple of them.  :(

..........................................................

Overall I found the AIS 55/2.8 a better lens for me, the f/2.8 aperture is acceptable and the 7-blade aperture gives blurs a more organic appearance. However this lens is not perfect either, background bokeh can be a little harsh and it flares when shooting into strong direct light.
Hugh Gunn

Hugh_3170

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Re: tale #85
« Reply #6 on: March 29, 2023, 03:23:59 »
+1 from me on all points.  Thanks Rick.

Long time no see, Rick.  Hope you are doing well.  Thanks for the note.  Indeed, it is an interesting read.  I bought the last Ai version of this lens from Roland and completely happy with it.
Hugh Gunn

Roland Vink

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Re: tale #85
« Reply #7 on: March 29, 2023, 03:31:14 »
And it can leak oil all over the diaphragm once its grease breaks down - something that the 55mm f/3.5 does not seem to do.  A shame, as the 55mm f/2.8 is a good lens.  I know - have a couple of them.  :(
I have never had trouble with them. I have read that Nikon made some changes, maybe used different grease, so it is not a problem with later copies. Or maybe I am just lucky :)

Erik Lund

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Re: tale #85
« Reply #8 on: March 29, 2023, 09:35:46 »
Thank you! Good to see you here again - I have the late Ai version and I also have the f/2.8 no issues with oil or grease on the blades - Pretty sure it was a matter of the type of grease used and it was changed during the production runs of the lens.
I also had the Compensating version but it has been modified to death over the years, back when I was starting out chipping lenses in the F4 and F5 days  ::)
Erik Lund

Bernard Delley

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Re: tale #85
« Reply #9 on: March 30, 2023, 13:55:19 »
Thanks, Richard for this interesting link !
Tale #25 alludes to the request by professor Koana mentioned in the opening of the linked tale #85:
The Kanji characters used in those days had a larger number of strokes and required a resolving power several times higher than that needed for the letters of the alphabet for accurate identification.

Interestingly tale #85 mentions modulation transfer functions "MTF" in some detail:
" Now we'll take a quick look at MTF characteristics. I'll cover the results seen at 30 lines/mm. First, reaching 87%, MTF value is very high at the center of the frame at a distance of infinity, but gradually drops toward the edges. Contrast still measures approximately 55% at a height of 50% the total image height, and remains approximately 33% at the extreme edges. On the MTF chart, the image-plane average value is highest at a magnification of -1/30× suited for shooting portraits. However, the variation from those at infinity is very small. There is no deterioration in MTF characteristics from near infinity to a magnification of around -1/10×, which makes the Micro-Nikkor Auto 55mm f/3.5 an excellent all-purpose lens for standard focal lengths. The peripheral MTF peak begins to move in the negative direction in accordance with changes in the curvature of field as we move closer to achieve a magnification of -1/10× or greater. As a result, MTF characteristics of the same plane appear to deteriorate. However, as I mentioned earlier, depth of field is extremely shallow with close-up photography. As such, the only flat subject that would lie on the same plane is a newspaper. When photographing a three-dimensional object, the MTF value for the focus position at each image height is what's important. Therefore, a perfectly flat image plane is not really necessary. I found Wakimoto's design to be outstanding in that respect as well. "

The statement " a perfectly flat image plane is not really necessary " towards the end is a bit surprising in view of making micro fiche copies of Kanji text.

In march 2020 I made MTF measurements for my 55mm f/3.5 micro Nikkor. As usual in Bayer green spectrum at imaging ratio 1:33 for 10, 20, 30,40 and 50 cycles/mm. fullt race is meridional direction and dashed sagittal. Its through focus from front focus 64mm left to back focus 64mm to the right, and also stopped down at f/5.6 and f/8 in addition.    I would say that stopped down to f8 there is not much left to be wished by the standards of today. 

If you consider this lens to reproduce old 35mm slides, imaging ratio 1:1, then there is a practical advantage to modern micro Nikkors with internal focus.
For this old lens, with the internally fixed lens group to be extended for focus, a special case arises at imaging ratio 1:1. The object sensor distance is at the minimum (~ 4f ). Precise focus can be obtained by either moving the object or the camera, but not with the focus ring ! The focus ring adjusts the precise imaging ratio in this special case.
A modern lens with internal focus (changing focal length) behaves differently. You can auto-focus for conveniently get focus accurate enough. And the object sensor distance acts primarily on the imaging ratio as usual.


richardHaw

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Re: tale #85
« Reply #10 on: March 30, 2023, 14:00:53 »
55/3.5 is a masterpiece  :o :o :o

Roland Vink

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Re: tale #85
« Reply #11 on: March 30, 2023, 21:52:45 »
I need to dig up my old instruction booklets for this lens, but I am fairly sure they says that optimum performance is achieved at 1:10 magnification ratio, where the focus distance is about 0.66m. Tale #85 suggests the best performance is highest at 1:30 but the variation is very small from infinity through to 1:10, with performance dropping at closer distances. I suppose that more or less agrees with the instruction book :o

The article also says "the same optics and basic design survived for nearly 20 years", but it is commonly said that the early versions (preset and compensating) are optimised for close range and don't perform so well at far distances. Later versions (Micro-Nikkor-P, K and AI) were adjusted slightly to be more balanced, sacrificing some close-range performance for better all-round performance.


Birna Rørslett

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Re: tale #85
« Reply #12 on: March 30, 2023, 22:20:31 »
The weird-looking 5.5cm f/3.5 Micro-Nikkor from early '60s went to 1:1 and definitively did not have a truly flat field. I was surprised of this back in  its time.  The later 'compensation' Micro-Nikkor 55mm f/3.5 had, however, but only achieved a max. of 1:2 and according to the accompanying pamphlets was optimised for 1:10. Its performance at infinity was acceptable, but far from stellar. Later versions performed better towards infinity and likely traded a slight reduction in the near range to achieve this.

They tweaked the design from 5/3 to 5/4 (if memory serves) over time from the first 1:1 Micro to later generations.

Bernard Delley

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Re: tale #85
« Reply #13 on: March 31, 2023, 11:06:32 »
I got an old thread here
https://nikongear.net/revival/index.php?topic=224.msg1511#msg1511
where I made up a special test object for 1:1 testing and showed the evidence.
I found no significant sharpness difference between
AI Micro Nikkor 55mm f/3.5  #1010505
compensating Micro Nikkor 55mm f/3.5 # 271483
maybe the test could be a bit refined and improved (do not light all RGB patches everywhere), and the full images shown at 50% at least.
Anybody with different 55mm f/3.5 versions can do such a test. I would be interested to look at results.

Erik Lund

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Re: tale #85
« Reply #14 on: April 03, 2023, 09:46:46 »
That was a trip down memory lane re-reading that thread  :o :o :o ;D
Erik Lund