Can I Use Non-AI Lenses On My Modern DSLR?

This question seems to come up quite a bit so I felt I would take a short second to address it. The question is:

Can I use older, Nikon F-mount, what we retroactively call "Non-AI" lenses, on my modern DLSR. 

The short answer is: ONLY IF, the rear-most lip of the lens does not interfere with the AI tab, located on a rotating ring that is just outside the camera mount. In many cases however, this lip will interfere with the tab, ramming into it, and it can actually damage your DSLR.

There are a lot of great resources out there which cover the histories of Nikon's mount systems and the variations. I will try to link some at the bottom of this page. But for the impatient, the crash course is simply ensuring that the lens you wish to mount does not contact the AI tab located on the camera.

Nikon AI Mount (N/AI)

In the image below, you see a Vivitar 90mm f/2.5 (N/AI mount) mounted on a Nikon D750. This (1) is the indexing tab located on the lens mount, at the base of N/AI lenses. As you rotate the aperture ring to set it, this pushes the camera tab (2) further in it's rotation, telling the camera information about what aperture is being used.

These N/AI lenses have no electronic linkage to the camera so, after simply mounting the lens, the camera has no information about what lens is being used, what the maximum aperture is, etc. There is a solution for this. By navigating to the Wrench Icon in your menu and selecting "Non-CPU lens data" you can manually enter the focal length and aperture of the lens you are using. Now that the camera knows where to begin, it can calculate, via that little tab linkage between the lens and camera, what aperture you are using, as you rotate through different apertures.

Next, I have my Sigma 50mm f/1.4 Art lens mounted on the Nikon D750. This lens is akin to Nikon's "G" mount lenses. The "G" stands for "gelded", which essentially refers to the removal of the manually adjustable aperture (and thus the AI tab) on the lenses. Since modern lenses communicate with the cameras electronically, there was no longer a need to maintain this linkage (Though, some users dismayed over this since these newer lenses now possess less backwards compatibility because some of the older film cameras cannot communicate with lenses electronically - it was all mechanical.). As you can see, the rear portion of the mount, clears the AI tab (3). It is said, though I have never owned any, that some older Non-AI lenses, especially those by third-party manufacturers, such as Vivitar, while not AI lenses, didn't have a very long rear mount and would clear the tab. These lenses can safely be used.

Conclusion

Now that you have seen what the Auto-Indexing linkage looks like. You can hopefully see what is meant about ensuring the back of the lens doesn't collide with the AI tab on the camera. To the original question: Can I use [Insert Lens] on my DSLR? You need to ensure the lens mount clears this tab, and doesn't ram into it when mounted. As long as this tab is free, you can use the lens. Albeit, at reduced functionality of an AI lens, or modified Non-AI lens (machined to index with the camera correctly).

How I Nearly Missed Capturing Something Beautiful, While Thinking About Buying More Camera Gear

That lamp post is killing me! Only so much you can do while driving...By the time I made a second pass, the fog had changed.

I love gear. Many photographers do. For many of us, using the tools are as much of the experience as achieving our final product, beautiful, purposeful imagery. We are constantly, however, reminding ourselves and each other, gear is designed for an eventual purpose. And while we love to "nerd out" and talk shop on the forums, we ultimately own the stuff, to accomplish a goal. To make images. This is just another reminder.

Last week, I had just left work and I was witness to a rare-ish weather event. And even though I bring my camera along with me each day for just such occasions, I was feeling tired and mentally began making excuses for why stopping wasn't that important. At the same time, I began thinking about stopping by the camera store on my way home to see if anything new had appeared in their used gear case. It was at that moment that I recognized the irony of the situation and the inner dialogue went something like this. Wait, so you're not going to go capture this incredible visual event that you've never seen before because you feel tired? You've never seen this before in the 5 years you have been making this drive. Oh, good, better idea, go to the camera store and buy more gear to carry around and not make images with. Great idea, guy.

And for a tad background, I live in a wonderfully convenient, kempt mid-western suburb. And while I can appreciate the many virtues of living there, it's hardly a photographically inspiring place. In contrast, I work 40 miles away, in an historic rivertown, Alton, IL, along the Mississippi River. The town is built up the the bluffs which skirt one side of the river and is home to a beautiful suspension bridge which has become a symbol of Alton. My point is, for me, there's a much higher chance I will find things of interest to photograph in the town where I work, than when I get home. Therefore, I bring my camera with me every day.

So, in getting back to the story, I made it a couple miles before my inner monologue successfully shamed the lazy part of me into turning back. I'm glad I did. As you can tell by this point, the weather event which I referred to, was fog. And not just any fog, a low-lying blanket which was sweeping toward the city at the moment I was leaving work. The result was a half-revealed, previously frozen landscape, reminiscent of a windy tundra.

Clark Bridge from the Alton marina

A shot of the bridge from the Missouri side of the river. The city of Alton is located off-camera to the left.

The granary pictured is located just before the town of Alton. A road to the right of it leads back into town. To the left, houses can be seen located up at the top of the bluffs. 

Admittedly, the images aren't mind-blowing. Though, I do especially love the last couple posted here. After a short while, the fog enveloped the city and things looked like a typical, uniform fog. But I'm glad I got out and made images. And as always, we make many images, some better than others. I shared some of these with some co-workers and the images gave them great joy. And in the end, that is another facet of image making. As the maxim goes, we are our own worst critics. I'm happy that my work could be enjoyed by those around me.

So that is how I almost went to look and lust after gear, instead of using what I have, to do the very thing it was designed to do. 

In the interest of keeping with the tech aspect of this blog though, I will share these images were made with the Nikon D750 and the Nikon 24-120mm f/4G ED VR. This combo has proven an excellent solution for grab-and-go scenarios. Had I known about the fog, I would have definitely brought something longer for more detailed images of the houses on the bluffs, but we do what we can! Images were processed in LR.