Inconsistent aperture rings

Started Apr 2, 2014 | Discussions thread
photoreddi Veteran Member • Posts: 7,890
Re: Inconsistent aperture rings

jfw wrote:

DocetLector wrote:

I don`t agree with your post. First of all if you are talking about bucks - this lens has an aperture ring - just not marked and second those kind of people you describe are usually not using Fuji X cameras.

On the 10-24 constant aperture lens, I agree with you - seems nuts to omit the marks.

On the variable aperture lenses, let's run a quick mental simulation of the lens design that you are thinking of:

In, say, simulation alternative #1, we would be able to mechanically (i) set the lens for max focal length (ii) set the aperture to the widest (lowest f/stop). The result would be an unsupported aperture for the selected focal length - would you agree?

This would be, it would seem at least as 'confusing' as not having the lens marked.

So under, say, simulation alternative #2, we would have to do something to the simulation #1 design to either (a) prevent the unsupported aperture from being selected in the first place or (b) attempt to change either the focal length or the aperture to reach a supported combination. (b) would certainly be irritating design alternatve - so I can't see that being a reasonable design approach. Re: (a) its hard to imagine how this could be done in a way that would work with the lens not-powered-up, unless a mechanical approach was used. And I can certainly see such a mechanical approach costing money and adding weight.

Perhaps there are some errors in my reasoning, or I've not been creative enough to think of a good design alternative. But, given the above, not marking the aperture ring for a variable aperture lens does seem like the best design alternative among the options.

Not marking the aperture is becoming more common. Almost all of Nikon's current lenses are "G" lenses, indicating that they have no aperture ring. One of the reasons given is greater integrity, better resistance to moisture and crud entering the lens. This appears to be what Fuji does, except when they have aperture rings, the rings aren't mechanically connected. They're probably connected using magnetic detectors. This allows the lens to remain sealed but since there's no physical contact, there would be no way to know the aperture when the camera was turned on, since the detectors only detect magnet motion. That's why lenses that have true mechanical linkages can only have their aperture rings rotated over a small range before they hit a mechanical stop that prevents the ring from turning outside the aperture range. Fuji's aperture rings have no stops, and you can turn them 15%, 40°, 360° or 900° if you're persistent. The camera only detects the ring's motion, not its absolute position.

With this design, one way to make aperture markings on the ring effective would be to use a menu option to tell the camera what aperture the aperture ring appears to be indicating and then set the camera to match it. This would need to be done each time the camera is powered on unless the aperture detector remained active while the camera was powered off. But this would use more battery power and would add complexity, slow down the use of the camera, make it more likely for erroneous apertures to be unknowingly selected, and subject the camera to ridicule in reviews and by photographers as a Rube Goldberg device, if not a Franken-camera.

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