Practical advice on Nikkor 55 1.2 SC Auto

[Bjørn Solberg]

Having had digital camera for about a year(D3s) and beeing a fullblooded amateur, I have not yet found a solution on the following problem: This lens works perfectly on all stops exept the 1.2. On 1.2 the flash sign lights up, and when I press the release button, mirror stays up until I either press release button again, or turn aperture ring back to a higher number than 1.2. In the menu I can define lenses without CPU, but how does the camera get this information? I am aware further reading will probably enlighten me, but if an answer is easily available here on NG, it's better. Adding a random picture taken with the lens today.

[Bjørn Rørslett]

Is the lens AI-modified or otherwise AI-compatible?

[longzoom]

Remove the lens, set aperture to f/16, mount the lens back, slowly. If aperture is already open at full, but the lens is not clicking confirming it sets inside its space, and needs extra turning to do so, with more effort, the lens's aperture lever needs more space, or this lever is too long and touching camera's inner details. If you have skills, you may remove extra metal on this lever yourself, if not, ask technician. In any case, do not use this lens till situation  resolved, to avoid damage to the body. Good luck!  LZ

[Bjørn Solberg]

The lens clicks smoothly in place, also at f 16.

I admit there is a steep learning curve, and attach photos of the lens, the height difference around f 8 is the Ai?
I assume then the problem will  be related to the lens, and not some wrong settings on the camera?

[Bjørn Rørslett]

The lens is AI or AI-modified by a factory kit, so should pose no problem at all.

Rotate the aperture ring to see whether the aperture opens or closes. Check that the aperture lever (the small pin sticking out on the rear of the lens) can move freely. When you release it, the lens should immediately close down to the actual setting.

Go to the camera menu and check the settings for a non-CPU lens. It should read "Lens no 1, focal length 55 mm, max. aperture f/1.2". If not, dial in the correct data and ensure the entry is saved. When you mount the lens, the aperture read-out on the camera should show the various f-numbers as you rotate the aperture ring.

If you instead get the F-- display, an error message, or the camera locks up and refuses to fire, you need to change the setting for aperture control under Custom Settings. There is a main entry for Controls and in a submenu, you will find the option to make the aperture ring default instead of the dial on camera. Select that option. It will not interfere with the control of any AFS/G lens (those without aperture ring) as the camera logic automatically falls back to the camera dial for such lenses. Quite clever

When everything is sorted through the camera set up, your lens should function and meter on your D3S. However, be aware that when using Live View, you might have to reset Aperture Control to be camera dial. That first FX generation had some peculiarities in the manner LV was implemented. My D3S is loaned to a friend at present so I cannot check further with my own 55 lens.

[Bjørn Solberg]

Thanks a lot, thorough, detailed and with patience as always. I will report back.

[Roland Vink]

In the menu I can define lenses without CPU, but how does the camera get this information?

Follow the instructions given by Bjørn above. Once you have entered and saved the non-CPU lens details, you must manually select the non-CPU entry to match the lens attached, so the camera "knows" which lens is being used.

If you have only one non-CPU lens this is no problem, define Lens no.1 and leave the camera on that setting. When an AF lens is used the camera will know what lens is used. When you switch back to your manual lens it will default to the non-CPU setting saved in the camera.

If you have multiple non-CPU lenses, you will need to manually change the non-CPU lens setting to match. If you regularly use non-CPU lenses it may be useful to add the non-CPU setting to your "My Menu", so it is easier to find. I use manual lenses a lot, so on my D600 I assigned the Fn button the non-CPU lens settings, when I change lenses I just press the Fn button and rotate the command dial to bring up the correct lens settings.

This is not a perfect solution, I sometimes forget to change the setting so the wrong aperture and focal length is stored in the EXIF data. The only fool-proof solution is to add a CPU to your lens, although the 55 1.2 SC is one of the most difficult (nearly impossible) to modify.

[Bjørn Rørslett]

In the menu I can define lenses without CPU, but how does the camera get this information?

Actually a very interesting question that really needs a long explanation. Suffice it at this point to say that the mechanical coupling provided by the aperture stop-down lever is the essential component. The additional information is provided by the entry in the non-CPU menu, or by the CPU of a modified lens.

[Bjørn Solberg]

Yes, the lens now shows up as 55 1.2 in the camera, great!

Under Controls I go down to f8 customize command dials, where I out of 4 submenues choose   aperture ring setting, then I get two options in the submenu and I choose aperture ring, and press OK. When I go back one step, the aperture  ring setting still displays OFF, whilst on the other four menues  (on the same "page")  they change to ON when I do a change.

This can mean I have another setting on the camera (wrong) that prevents the change I want?

So I think the next step should/could be, I test the lens on another camera, just to eliminate a possibility, although it appears smooth  and the aperture lever works perfectly from 16 to 1.2, and I do take pictures on all settings (correctly) exept 1.2, where the problem still is as described in initial post. The seller of the lens have used it on a Canon camera using adapter, but  the adapter "was broken", so maybe some force have been used, but not easily seen.

I admit my skills in handling and knowing the menues have tripeled during this exercise; labels progress.

[knb]

I do not own the D3S, but a D700 (probably similar menu settings). The setting that you mention here (Aperture setting: Sub-command dial/Aperture ring) has no meaning for a lens without a CPU. It will always default to the aperture ring. For a lens with both a CPU and an aperture ring, it will have an effect. At least this is how the D700 behaves. My Df behaves similarly for AI-lenses without a CPU. The correct maximum aperture for the lens must of course have been selected in the Non-CPU lens data menu, which it seems that you have done now.

This sounds like some sort of a mechanical problem with the lens. Is it possible that something can short-circuit any of the CPU-contacts on the camera side when setting the aperture to f/1.2? Just a wild guess...

[Bjørn Rørslett]

The explicit setting of aperture control by the lens gets a meaning once the camera is set up for non-CPU lenses. At the very least one observes, and the camera records, the actual aperture setting.

What these Nikons won't do is allowing access to "P" and "S" exposure programs, unless the lens has a CPU. Both modes will fall back to "A" with any non-CU lens. Since 99.9% of my manual lenses have a CPU, that default response is rarely seen by me, but I do know of its existence

[Bjørn Rørslett]

---- This can mean I have another setting on the camera (wrong) that prevents the change I want? ---

Nope. The aperture selection control is a little counter-intuitive as it says "off" whilst the real message is "you have switched off the *default* behaviour". Something obviously was lost in translation there.

Would be much better if the readout was either "Aperture control: Camera" or "Aperture control: Lens". The alternatives for the control of aperture are equivalent in my opinion. The preference should be up to the user (if the lens offers its own aperture ring, otherwise the setting is moot).

[David H. Hartman]

I did a test to demonstrate that it is important to enter the correct data for a non-CPU lens when relying on the meter in a Nikon dSLR...



This was shot with a Nikon D2H and a 105/2.8 AIS Micro-Nikkor. Deliberately entering the wrong non-CPU data, wrong aperture gave incorrect exposure. This isn't exposure compensation this is giving the meter disinformation.

The test photos above were shot with a Nikon D2H. It would be a good idea to confirm that this is still the case with a more recent camera (basic science concept). I don't see why it would not but still it never hurts to double check. It was shot with an AIS lens. I don't think an AI lens matters either (with non-CPU lenses, i.e. not chipped). The caption didn't say but I'm sure all were shot at an aperture setting of f/2.8.

Dave Hartman

I've never used custom settings to require setting the aperture with the aperture control ring on the lens. I probably tested this with my F5 and didn't keep using the setting. The F5 defaulted to center-weighted metering with AI and AIS lenses the way I set it up. The fingers know that an AI or AIS lens needs the aperture set on the lens and an AF, AF-D, AF-S or G type lens requires setting the aperture on the camera body. The fingers have yet to encounter an E type lens.

I understand but have no experience that with chipped AI lenses that it is important use the aperture control ring on the lens. A change in the AIS lenses would [was] made to accommodate the Nikon FA. I know the concept but the words escape me (dyslexia).

I seem to remember that some fast or super speed lenses require exposure compensation with certain viewing screens. The 55/1.2 AI might be one of those lenses.

Hope something here helps,

Dave Hartman

I've just finished my 3rd cup of coffee and the brain should be fully active soon. I'm on the road again...

[Bjørn Rørslett]

Thanks for your experimental evidence, Dave !! This is exactly what one would expect if the lens was f/2.8 and the wrong max.apertures were entered so the final closing of the lens iris would be obfuscated..

Dave, the term you were searching for is "linear aperture control". AIS lenses have this feature. Any SE, AF, AFD, AI-P, AF-P, G, AFS or E lens by definition is   natively AIS. Thus in the final reckoning only AI or AI-modified lenses, sharing a non-linear movement of their aperture, have to be steered by the aperture ring on the lens itself. However, the maximum accuracy of lens stopping down still is with the aperture ring, if it exists, set to the desired position. Time-lapse photographers and film makers have been aware of that fact for a long time thus prefer lenses with an aperture ring

[David H. Hartman]

Yes, "linear" was the word I could not bring up so I couldn't write "linear aperture control." 

On another forum in another life people were saying that entering the correct maximum aperture in the non-CPU data was not important hence the test above.

Dave