What happens to aperture when you take off Nikon G type lens?

[milosh]

Hello everyone,

As the title says, I am wondering what happens to aperture when you take a Nikon G type lens off camera? Does the aperture go wide open, or it closes down, or it stays like it was last set in camera?

I am asking this because I'm considering whether or not to buy a Nikon lens to Pentax adapter from eBay, which would allow me to use my Nikon lenses on my old Pentax Program A SLR. But, the problem is that two out of my three lenses are G type, without an aperture ring. So, is there any way to get around this?

Thanks

[OsmosisStudios]

They stop all the way down. You can test this by holding the lens with both caps off looking through the front at a light source. on the back is a small tab: moving it side to side will open/close the aperture. When the lens isnt sprung on the body (dismounted or not connected to a Nikon AF body) it closes right down.

I'd also check to see if the adapter you buy interferes with this tab.

[firebox40dash5]

Originally Posted by OsmosisStudios

I'd also check to see if the adapter you buy interferes with this tab.

It shouldn't interfere, since the aperture prong isn't exclusive to G lenses.

[OsmosisStudios]

Originally Posted by firebox40dash5

It shouldn't interfere, since the aperture prong isn't exclusive to G lenses.

Never hurts to be carefuly

[milosh]

Thanks for the info, I guess then that using G type lenses like this is out of question. They should make an adapter with aperture ring, with which you could manually set the aperture. Hm, I'm wondering if anyone thought of that..

[Lipjam]

I've had the Nikon 18-200mm G lens for about 2 years and it has served me well. In fact it has be my main lens with the exception of a 11-18mm wide angle. Truth be told I believe it is the best all purpose lens out there at the moment. Well with one caveat: It's a bloody G-lens! Use a tele convertor and it becomes a black hole. I am getting into Macro photography and this is where I discovered the Nikon's Achilles heal. Well maybe a bit unfair because it doesn't claim to be a macro lens, but I am disappointed that this lens has such a limitation.

The fact is I cannot use it with my tele-convertor because the aperture closes right down. I have used it for static items with long exposure times but this would never work with wildlife.

I ramble... the reason I contributed to this thread was because in my search for an aperture adapter I found this:

Nikon G - Canon EOS Adapter


I know this thread is not for Canon but if it is possible for Canon why not other mounts... I thought the Nikon mount wold have been the easiest to make?

[firebox40dash5]

I'm going to take a guess the reason it doesn't exist is because the thickness required would basically turn such an adapter into an extension tube, or would require optics (and more thickness and cost). IIRC, the sensor-mount distance on Canon bodies is slightly shorter than on Nikon, so there's room for an adapter like the one you posted without affecting the focusing distance.

I don't know what kind of TC you're using, but either Sigma or Kenko TCs are supposed to work with the aperture lever... though they may not correctly report the changed focal length or aperture to the camera. The Nikon converters would require you to machine the lens mount slightly to fit a lens with a max aperture smaller than f/2.8, and may interfere with the rear element of your lens.

[Lipjam]

Firebox

I had a good look at what is happening when I mount the lens on the TC and you are absolutely right. The aperture lever on the lens does does operate and I can see the Iris on the G lens opening.

The problem seems to be a lever on the S5Pro mount. This lever moves from 2 to 11 o clock. On a lens with an aperture ring there is a notch (about 5cms wide) below the F numbers on the body of the lens. This notch catches the lever on the TC and pulls it across to 11 o clock as the lens is mounted and locked. This in turn moves the lever on the S5Pro. On a G lens this notch is missing and the lever does not get pulled across. When I manually pull it across there is a lot more light entering the camera and it takes a decent photo. I am not sure of the function of this lever but it obviously affects metering.

Any advice gratefully received.