Sigma AF 75-200mm f/3.8

General
I found this lens at a bargain price and thought to give it a try. Autofocus 200mm and f/3.8? That sounds almost too good to be true. And sadly it is - although not for the reasons you might be thinking! Read on, and you'll see what's the problem with this lens.

Pros/Cons
+ autofocus, 75-200mm, and f/3.8 constant? And for a price around $40? You're kidding, right?
+ more than decent image quality. Stopped down, I'd actually call it very good!
+ mechanically sturdy

- serious compatibility issues with digital Nikons (read "Final Verdict")
- autofocus unreliable, hunting a lot (could be related to the compatibility issue)
- old design, questionable aesthetics (if you care about that stuff)


Intended Users
Great for:

• IF the compatibility issues can be rectified, this is an amazingly capable, fast telezoom for peanuts!
• Do-it-yourself people who aren't afraid of fixing and tweaking (again, referring to the compatibility issue)
• Even as a manual focus lens, it makes sense - to a lesser extent, though.

Not for:

• entry-level cameras. Autofocus (assuming the compatibility problem is solved) still requires a body motor
• those who want to get a lens and start using it right away. It doesn't work with modern Nikons!
• sports/action. I don't trust the autofocus (again, it could be a compatibility issue)

Optically, it's fine, really. Especially stopped-down couple of stops. I used my copy as a manual focus lens, after covering the contacts with tape

Final Verdict
OK, so you probably want to know what the heck is this compatibility problem I keep babbling about, right? Well, this is a lens from the mid-80s. A lot has happened since in camera technology. And although all Nikkor lenses are still perfectly compatible with all modern Nikon bodies, the same is not true for all third party lenses. This Sigma is one of the unlucky ones, as the chip doesn't communicate properly with the camera body. Trying to mount this Sigma on your digital Nikon, you either get an error message, or an aperture reading of f/1. Autofocus is unreliable, exposure is unreliable, or it might not work at all.

Is there a solution? There is, but it's not very sense-making in terms of value (considering the cheap price of this lens). The easiest thing would be to send the lens to your local Sigma support center and ask them to rechip it. There is a chance they might say no, I suppose (this is an old lens). Another solution - especially for those who aren't afraid of a little DIY work - is to rechip it yourself. There are some chip modules out there you can find and attempt it. Again, though, it isn't very sense-making.

The cheapest (well, free!) solution is to cover the five contacts with isolation tape. Then, your lens becomes a manual focus lens (you still have metering if you have an upper-level body). Is it worth it? Well.... I will have to say no. For roughly the same money, you can get either a Nikon Series E 70-210 f/4 or the great Nikkor 200mm f/4. Both are superior in terms of optical quality, mechanical quality, and ergonomics.


Not to mention, a cheap AF-S lens is a much, much better solution in terms of overall balance. A Nikkor AF-S VR 55-300mm might not be f/3.8 at 200mm, but it's better optically, it has reliable (and functioning!) autofocus, and it adds VR.

For FX users, the Nikkor AF-S VR 70-300mm is the way to go. Again, you lose a bit of max. aperture but you gain so much more.