How do you meter AI/AI-S lenses with the Z?

Discussion in 'Nikon' started by BeBu Lamar, Oct 7, 2020.

  1. Of course with the FTZ how do you meter with AI lenses? How do you set the aperture in A and M mode?
  2. The camera has no control over the aperture, so you just set it with the ring. You can't have shutter priority because the camera can't change the aperture, though maybe auto-iso takes care of that; haven't tried it. I usually go manual for metering when I use my AiS lenses because I'm doing macro or something. I've found auto-iso is really your friend when using the older lenses.
  3. ShunCheung

    ShunCheung Administrator

    Since the Z bodies are mirrorless, you can switch on the live histogram, in either the EVF or the rear LCD. With the histogram, it is very easy to adjust the aperture, shutter speed, and sensitivity ISO manually to get the exposure you want. After all, it is digital; if the exposure isn't quite right, adjust again and capture another image. Few would use such a set up to capture any rapidly changing scene, anyway.
  4. But the bottom line is the Z can't meter with AI/AI-S lenses? Of course you can shoot without metering. But the manual said it can work in A and M and if the meter doesn't work how can it works in A?
  5. It certainly does meter and adjust exposure with my AiS lenses. You just need to choose a mode that allows it to change the shutter speed or the ISO to accomplish it. Or, go manual and use the histogram. Or, go manual with auto-iso. Turns out there are only a few ways not to have it adjust! People complain about the FTZ adapter, but I have no trouble working with it at all. Because it's mirrorless with an EVF, you find you don't miss the coupling as much as you might think.
    Last edited: Oct 7, 2020
  6. It does - you just have to add the lens info into the non-CPU menu. You won't get aperture information as the camera has no way of knowing it.
    With the aperture ring on the camera.

    Could someone with an FTZ adapter and a Ai/Ai-S lens (or pre-Ai) please check if the aperture closes down when you turn the aperture ring or if the aperture lever in the FTZ precludes this and only stops the lens down when the shutter release button is pressed? I would expect the lens to stop down when you turn the aperture ring - but the presence of that aperture lever gives me pause - Nikon would have to disable it in-camera when a non-CPU lens is mounted. I doubt that the FTZ adapter behaves any different with non-CPU lenses than any of the cheap F-to-Z adapters out there (which I assume do not even have that aperture lever).
  7. OK, I should probably read the instructions or better yet, Thom's book I got, but here's what actually happens with an Ai/AiS lens:

    auto-iso ON
    P mode is forced to A mode, camera chooses shutter and iso. You choose aperture with ring. Exposure should be correct.
    S mode is forced to A mode, same as above.
    A mode is A mode, still works same as above.
    M mode is M mode, you choose shutter and aperture with ring, camera chooses iso. Exposure should be correct.

    auto-iso OFF
    P mode is forced to A mode, you choose iso and aperture with ring, camera chooses shutter speed. Exposure should be correct.
    S mode same as above.
    A mode same as above.
    M mode is M mode, you choose everything and hopefully look at the histogram. Exposure is up to you choosing wisely.

    There is really only that one condition where the camera isn't metering and setting the correct exposure for you.

    There is nothing in the FTZ that affects the aperture. The lens physically stops down according to what you set with the ring. Through the miracle of EVF, you don't care if you have it set to adjust brightness. You'll see the DOF you're going to get.

    I don't know what the function of the FTZ aperture lever is, but the AiS ring does hit it when fully closed.
    NetR likes this.
  8. Thanks for checking Conrad. The aperture lever on the FTZ (or any Nikon DSLR) closes down the otherwise wide open aperture of a CPU-equipped lens at the moment of exposure or when you press the DOF Preview button (except for E lenses that have an electromagnetically controlled aperture) to either the f-stop selected on the aperture ring (if the camera menu has the appropriate option selected) or the value selected on (or by) the camera. The aperture lever on the FTZ engages the little spring-loaded tab inside the mount of the lens. The difference between Ai and Ai-S lenses is that the motion of that aperture lever is non-linear for Ai and linear (aka same amount for each stop) for Ai-S.
  9. That makes sense. I only have the one DX lens from my D200 and will investigate how the aperture works on that. From another thread, I didn't find any good reason to use the DX lens on the Z6, even though it worked exactly as you'd hope.
  10. So in M mode the meter doesn't work. It doesn't indicate over or underexposure? Also in A mode the camera automatically select the shutter speed but it doesn't tell you which one?
    Last edited: Oct 7, 2020
  11. Of course it works. You get to see the result on the bar graph or the histogram. And of course you see the shutter speed the camera has selected in the eye level or rear view screen. BTW, there's no "meter" like in antique cameras. The signal levels are read from the sensor. That's the "meter" and it's active all the time. The data is always presented to you unless you turn it off. I'm assuming the display can be turned off, but I've never tried since it would be sorta dumb not to see it.
  12. I'd be extremely surprised if any Z body metering stopped working with Ai/Ai-s lenses attached, because my Sony mirrorless bodies all meter perfectly with MF Nikkor lenses! That includes an 'old' NEX 6.

    MILC metering is done directly from the sensor. So as long as you have a lens attached that forms an image on the sensor, it meters. Doesn't matter what make or type of lens it is. Anything from Alpa to Zeiss will meter, just as long as there's a mount adapter for it.
    That's actually a bit backwards. The camera's aperture lever holds the aperture of the lens wide open until it's released just prior to exposure. The natural state of a Nikon-fit MF or non-E AF lens is with the aperture closed down.
    Last edited: Oct 8, 2020
  13. Thanks for the correction - that's what I meant to write but it's not phrased properly. A G lens OFF the camera is fully stopped down (E lenses are fully open) and lenses with an aperture ring are stopped down to whatever the selected f-stop is. Upon mounting, the camera aperture lever engages the tab at the back of the lens and opens the aperture fully; it's then allowed to close to the selected value when the shutter button (or DOF Preview button) is pressed.

    I would have been too - as I expressed in my post.
    The main difference is that there's no aperture lever in the adapter and hence the non-CPU lens is always at its set aperture - if the aperture lever in the FTZ would open the aperture of the lens upon mounting and only released it at the moment of exposure, metering of a non-CPU lens would be impossible as the camera has no way of knowing which aperture the lens is at; the result would always be for the lens fully open. So the FTZ has to act as if the aperture lever isn't present when a non-CPU lens is mounted.
  14. FWIW, I find knowledge of ancient film photography is still very useful in understanding the mechanics of exposure. That said, at a system level it can be better to think of a modern camera as a computer system that happens to be connected to an imaging sensor. The interconnection of aperture, shutter and ISO as they relate to light level can be anything the software was written to accommodate.
  15. I do not have a "Z"camera available so i cannot check, but IS there a mechanical aperture lever in a Nikon Z-series camera, or is it fully electronic, and is there only a lever provided in the FTZ adapter?

    OK Sorry , no aperture lever, this was already answered by Dieter , i was interrupted during the time i was typing this question..
  16. If I am not mistaken, then the motor to drive the aperture lever is in the FTZ adapter's tripod foot; there's no lever in the camera itself.
    c.p.m._van_het_kaar likes this.
  17. Thanx again for your answer, so there is no mechanical aperture whatever 0n a body either..

    (From an earlier answer in this treath : How do you set the aperture in A and M mode?
    With the aperture ring on the camera.)
  18. Though there is a motor in the FTZ, I don't think it has any effect with Ai/AiS lenses. People complain about how the adapter works with Ai/AiS lenses but, speculating, it makes sense that there's no automatic aperture control. Remember, these are mirrorless cameras. That means the sensor is always giving you the viewing image. Imagine if you mounted a fast lens wide open on a bright day or with high ISO set. The sensor would be completely overloaded and you'd see nothing because even a high shutter speed might not be high enough and/or the ISO can't go below 100. So, you don't want automatic aperture control. You need the aperture set for the conditions you're using it under, not wide open. These are not dSLRs and Nikon did the correct thing, probably the only reasonable thing, so everybody should quite complaining!
  19. But this same level can stop an AI lens down to the aperture set by the aperture ring or open it up to maximum aperture.
  20. I think that's correct, not sure, but AFAICT it's not programmed to do that, nor should it be. I suspect you can't control an Ai/AiS lens well enough to do the aperture tricks they do with the later lenses. Again, I'm just speculating.

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