This will not apply to all cases for sure. And each broken item is unique in it's breakage, and requires different strokes for different folks to complete the repairs. But what I had found here was undamaged glass and some shattered plastic body elements on an otherwise said to be functional late model lens. Nothing too serious! This was a best case scenario for a dropped ultra wide with the bulbous front element.
Looked like the previous owner had managed to only shatter the lens hood, inner facial ring and most of the plastic body mounts for the lens hood. All things considered these plastic pieces do appear to hold the bulbous front element in place somewhat. I got lucky and the winds of fate delivered to my door a eBay deal so good some may consider it a steal!
but it's risky, this could have easily been a bad deal for me to have to recover from.
Step 1: Inspect for Further Damage, Replace the Permanent Hood
Upon arrival via post I took a closer look and saw the adjustment screws for the outer lens elements were still solidly intact. And I had 4 opposing positioned lens hood mounting screw studs left to install the new hood onto!
Of course every break is different and this is only my encountered scenario. But it turned out to be a wickedly simple fix to install the new lens hood and screw cover as pictured above OEM parts from sigma.
Since replacing the plastic mount hardware required a much more involved tear down of the lens barrel, I decided it worth a try just putting all the pieces together and giving it a test.
- There were 4 screws holding bits of remaining lens hood from the drop, I unscrewed them with a proper drive and mounted the new hood with the 4 screws.
- After mounting the hood element, i simply had to pressure fit the inner surround that goes between lens element and lens hood. this is fragile so don't be an ape about it, if pressure fit fails you, try screwing it in, just be sure to use something like a clean micro-fiber cloth between the lens and anything your using to push it in, the glass didn't scratch or break during a fall! no need to bust it now that were putting it all back together again...
- In my case, I had to adjust the AF in camera for the lens as the lens was front focusing by nearly 2 inches. Not sure if that is an aftereffect of the drop, online forums are abound with how to and not to program these new ART series lens' via USB dock and sigma software. But I did the adjustment to AF in camera as I only have one body that i'll be using the lens with. And didn't want to hastle with the sigma dock programming of the lens itself.
Step 2: Enjoy the New Lens!
I've been quite pleased with the lens thru it's quick and occasional squeaky HSM. It's currently the fastest piece of glass in my collection and has given me a newfound appreciation for out of focus backgrounds, and with 20mm there is always alot of background... even at the minimum focus distance.
Goes to show a willingness to DIY a fix can save quite a few $... I ended up getting this lens half price with the replacement broken pieces included in the purchase price.