Questions on the crippled Nikon N80.
I refer to crippled in the sense that it will not meter with AIS lenses. Meanwhile bodies such as the 2000, 6000, & 8000 series, as well as the F90, F100 and Fm10 among others will meter with them in reduced capability mode. Since all AF lenses have chips in them and obviously the AIS lenses don't, it leads me to believe that it has something to do body. In the N80 if the AF lens isn't set to the minimum aperture the camera displays the "FEE" warning. Do the above mentioned bodies display the same warning with a AIS lens, or is it a custom menu option to use the AIS models? Basically I'm wondering if there is a mechanical nature to this problem or if it is inherent to the thin film board and a selectable option to even use the lens.
The N80/F80 lacks the AI meter coupling tab, so it has no idea what aperture the lens is at. If you want to use non-CPU lenses on it, it isn't the best choice unless you have a handheld meter.
Look at the mount (the outside of the mount, specifically) on bodies that support manual lenses like the F90 and you'll see the AI coupling tab. That is completely missing on the F80/N80.
Jim MacKenzie - Regina, Saskatchewan, Canada
A bunch of Nikons; Feds, Zorkis and a Kiev; Pentax 67-II (inherited from my deceased father-in-law); Bronica SQ-A; and a nice Shen Hao 4x5 field camera with 3 decent lenses that needs to be taken outside more. Oh, and as of mid-2012, one of those bodies we don't talk about here.
Favourite film: do I need to pick only one?
It's part of the problem that Nikon didn't change the F mount when they switched over to AF. This is a good things but as needs arise they have to change the way lens and body interface. Including all of the interfaces would be too expensive so the lesser model only have the lasted interface. For example the lower end Nikon DSLR don't have the AI coupling so they can't meter with AI lenses but also they don't have the coupling to drive the lens for AF so the lens has to have built in motor and the N2020 did have the coupling to drive the lens for AF but not the electrical interface neccesary to use lenses with built in motor. Canon changed the entire lens mount in one scoop which made many of its customers mad but in the end it was a good decision.
Originally Posted by waynecrider
Disagree. Changing the lens mount and making ALL the old lens obsolete vs. Nikon, some lens/bodies loose some functions however, still can make images.
Originally Posted by Chan Tran
Example, I use ALL my old Nikon lens with my D70s, even though I manually adjust the settings. Nikon was more thoughtful regarding the investment their customers made in the Nikon line.
Depends on your perspective. Canon apparently felt their hands were tied in trying to make the old FD lens mount work with the new technology. Their decision to drop FD angered a lot of people (myself included; I had just purchased a new T90 as my first camera) but the resulting EOS design became the market leader.
Originally Posted by fotch
Ultimately, corporations are in the business of making money. Canon's business decision has worked out for them, and for their customers. Nikon's business decision has led to a lot of forum postings questioning the compatibility of various gear. For my own part, I'm a bit wary of buying Nikon gear because I'm never sure what works with what, and in which modes, nor do I understand why or why not. So I stuck to AF-D lenses for my F4, and if I ever get that F6 I'm dreaming of I'll be limiting myself to G-series lenses.
Right now in Spain they're holding the Running of the Bulls,
followed by the Soiling of the Pants, and the Burying of the Idiots.
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My original question is basically a theoretical exercise for fun. I obviously know the AIS lens won't meter, I just want to know what crippled it. As has been stated, the Ai tab is the culprit. Ok, let's go from there.
Originally Posted by PhotoJim
After I posted the original question I took a further look at the lens mount. Again, what I am after is trying to determine if the body could meter at all with a AIS lens set at minimum aperture and what that determining factor is.
PhotoJim is right in the respect that the Ai tab, which is at the 1 o'clock position on a N90, is the determining factor in manual operation with a AIS lens; Outside of telling the camera that the lens is set at the smallest aperture for operation in the program modes. I do not know the extent of program operation with a AIS lens. I believe it's restricted.
The N80 body on the other hand has a lever at approx the 7:30 position that tells the camera that the lens is set at the minimum aperture. A AIS lens will make that contact. So with that in mind, and the fact that the Fee warning doesn't disappear on the N80 with a AIS lens set at minimum (in this case F22) what the camera is apparently seeking is a response from the AF chip. My question is, what that response is.
If you go to this link you'll see Fig 17A which shows the 5 pin out of a earlier Nikon body like the N80
So on this diagram 1a is power and 1e is common for AF focusing and maybe for power to the chip. I'm questioning what b, c and d are. I'm not big into electronics, but I generally thought "C" serial clock times a response. "B" and "D" I have no idea. Generally thinking "B" or P1/P2 is a switch or a path for Auto focus. I'm thinking the thin film board sends a signal to P1 and looks for a response from P2 such as circuit is closed or maybe AF focus is attained, although I thought that was a body cell determination. "D" is a question. Maybe someone here with knowledge in electronics can entertain some idea?
I know that at one time someone was chipping the AIS lenses. Since they are manual focus, the chip could only pass a signal. I don't think it would be a focus signal cause how do you fix that. It would just have to be perhaps a aperture signal. Not having a trashed AF lens to dissect I can only conjecture that it is a electro-mechanical switch, or a tab in the lens moves a lever on a switch. Who know's.
The N80 would need to know the maximum aperture of the lens. It would get this value by communicating with a CPU lens. It needs the value for matrix metering as the matrix metering algorithm needs to know the absolute brightness of the scene. It also need max aperture value to display the aperture with its LCD. The F5 and F100 can't do matrix metering, P or S mode with AI-S lens but they can meter in CW or spot mode because their AI coupling tells them how many the stops the lens will close down when the actual exposure is made. The N80 doesn't have this coupling either so it can't do that either. It could do stop down metering if Nikon decided to do so but they didn't.
I'm waiting on a response from company that chips lenses. In the meantime I ran across this information which list lenses and the ability to chip them.
The 4th paragraph down talks about the crippled bodies.