Sigma lens doesn’t stop down with adapter

[Atlantis]

I have this adapter https://www.bhphotovideo.com/c/product/1413049-REG/fotodiox_nikg_fxrf_lens_mount_adapter_for.html and I can use Nikon AF lenses on my Fuji XT3 and change the aperture with the ring.

But I can’t stop down this AF Sigma lens for Nikon https://www.bhphotovideo.com/c/product/802333075-USE/sigma_508306_70_300mm_f_4_5_6_apo_dg.html It is always at the wider aperture.

What is the Sigma lens lacking? Can I do something to make the aperture ring work?

 

[joe bosak]

These sigma lenses use an electronic connection to the camera, there is no aperture ring. You set the aperture from the camera. If you can't do that then (I think) it stays wide open.

A physical (as opposed to electronic) device like the adapter you are using, will do nothing on ths lens as regards apertture. There is no lever or whatnot on the lens for the aperture ring on the adpater to move.

I found similar with adapting my 105/2.8 macro in Sigma SA mount to a Sony A7. The MC11 adapter - which is an electronic adapter, for Sigma SA lenses to Sony E mount - only works with Sigma's "Global Vision" lenses as far as electronic connection goes; for others it's just a physical connector. The 105/2.8 predates "Global Vision" and uses a different coomunication protocol, so as far as my Sony A7 s concerned the lens is manual focus and wide open aperture.

 

[Atlantis]

Thank you!

Yes, I just saw that when I turn the aperture ring, I don’t see any diaphragm closing in the lens.

The adapter I have can work with Nikon G lenses (without aperture ring) by changing the position of a ring. But this Sigma lens can’t stop down even if I change the position of that ring (it is not a G lens, it is something different as you noted).

 

[ColSebastianMoran]

Atlantis, can you please show us a photo of the lens? Or it's exact model?

This sounds like trouble. I have had no trouble with Sigma Nikon mount lenses or with Nikon G lenses.

 

[Godfrey]

Thank you!

Yes, I just saw that when I turn the aperture ring, I don’t see any diaphragm closing in the lens.

The adapter I have can work with Nikon G lenses (without aperture ring) by changing the position of a ring. But this Sigma lens can’t stop down even if I change the position of that ring (it is not a G lens, it is something different as you noted).

Nikon G lenses have a mechanical aperture regulator, a lever operated by the body. Later Nikon lenses did away with the mechanical regulator and went to an all electronic aperture setting solution, just like Canon EF and many other modern lens systems. The Sigma lens is of this same type.

G

 

[Atlantis]

Atlantis, can you please show us a photo of the lens? Or it's exact model?

This sounds like trouble. I have had no trouble with Sigma Nikon mount lenses or with Nikon G lenses.

ColSebastianMoran,

It is the Sigma 70-300mm 1:4-5.6 D APO Macro for Nikon. It is not exactly the same one than the one from the link.

I tried the lens with a Nikon D80 and I think there is something strange. First, I didn’t get different exposures when I changed the aperture (I have to set the aperture ring at 22 and then dial the aperture on the D80). The EXIF was recorded with different F number, but the exposure was the same.

I kept trying. The autofocus seems to work well. But for some reason, at closer focusing distances, the camera didn’t shoot, even if it got focus. But then I was able to shoot at every focusing distance, and later it didn’t shoot again.

Also, the problem with exposure was solved magically (now the aperture changes the exposure).

What’s wrong? Could the adapter have broken the contacts or something? Or is it about not using the lens for a long time…?

 

[Atlantis]

When I wasn’t able to shoot at closer focusing distances… my bad. I forgot that I couldn’t shoot if it is out of focus due to minimum focus distance.

Now the D80 works well with the Sigma lens. And on the back of the lens I can see the diaphragm and if I push the aperture lever the diaphragm opens. Should I try the lens again with the adapter and the Fuji camera?

 

[shawn]

Is this your exact lens?

https://www.bhphotovideo.com/c/product/549304-REG/Sigma_5A8306_70_300mm_f_4_5_6_APO_DG.html

Look at the rear of your lens.

That metal tab at the 9 oclock position is to actuate the aperture. If you move that you should see the aperture change. There is a bar in your adapter that should move the tab as you turn the ring on your adapter. If the adapter isn't changing your aperture the bar isn't engaging with that tab for some reason.

If your lens doesn't have that tab on it then your mechanical adapter is not going to be able to adjust the lenses aperture.

Shawn

 

[Atlantis]

Previously, I tried this Sigma lens twice with the adapter and the XT3, and I wasn’t able to stop down.

But now I can. And I realized that the lens must be inserted only when the adapter ring is on one side (and not on the other side). Both times I tried previously, I imagine I must have inserted it with the ring on the wrong position. I really don’t know if that is possible. But if it is, I did in a way that pushed the lever in a way that block or cause trouble to the lever.

I am just guessing…

But the important thing is that the problem was solved.

Thank you!

 

[peterm1]

On any adapter for Nikon F mount lenses, the lens stop down ring on the adapter needs to be in what is often labelled the "open" position before the lens is mounted. This is then turned to "closed" after the lens is mounted and this actuates a mechanism in the lens which lets the lenses own aperture ring open and close the aperture.

Some adapters which are designed specifically for use with the later Nikon lenses that lack an aperture ring on the lens itself (S, G lenses ) use a specific lens stop down ring that is designed to operate like an aperture ring on a lens itself (if it had one). The rings on these adapters are generally marked in one stop increments to signify how much the lens is stopped down from maximum. If yours is not responding to this your first "port of call" should be to check to see if the aperture ring on the adapter works when it is set at the opposite extreme of its limit of travel, to the one normally set it at when you are about to mount the lens. If you have it set at the wrong extreme of its travel, the bar in the adapter's ring which moves the lenses aperture will not properly engage with it.