[skid2964]

What would be the symptoms of a lens that has a lot of use on it?
Like one that has been used to take over 200,00 photos?
We are talking about a wide Sigma zoom auto focus lens.

[jatrax]

The photos will start to look more 'vintage' with curling edges and a slight sepia tone...............

Sorry, just joking.......

Are you seeing any difference? I have lenses from the 1950's that still work as new. Of course those are all manual. Things on a modern autofocus lens I would be thinking about would be the AF motor, if it has one. The aperture connection lever and mechanism might start to show some wear. Weather seals if there are any. Might need a CLA at some point but I am not sure that is as important as it used to be when lens helicoids had grease that would thicken up. Other than that, unless it is abused what can go wrong?

[victormeldrew]

How many photos it has been used for is essentially irrelevant, unlike a body. The act of taking an image does no damage.

The most important thing with a lens is how it has been cared for. If it has been stored in damp conditions, cleaned carelessly, dropped...even a very new lens could be ruined in no time. A well cared for lens could still be in excellent condition a century later having taken a million images.

However, with autofocus lenses, with an in-lens motor, sooner or later that motor will fail and so the act of using AF will bring it closer to that time. Also with zooms, the mechanics will wear, making the action sloppy and prone to creep. But with both issues it could be serviced and repaired if it is worthwhile, and be as good as new again.

[photoptimist]

The effects of wear include:

1. The aperture actuator becomes sticky -- impeding stop-down when you take a picture or re-opening at the end of the exposure. If it's affecting stop-down, you might get over-exposured images.

2. Slop or play in the AF system would increase -- you might notice slower focusing or a bit of rattle or jitter if the lens has to reverse focus direction. If the lens has a clutch for manual focusing, it might start slipping.

3. Zooming might become either looser, stiffer, or have more slop. Image sharpness might degrade over time if wear in the zoom mechanism means the internal elements are no longer in the precisely-best location.

4. Lettering on the lens barrel will wear off.

5. Dust will accumulate on the inside surfaces of the lens.

[abruzzi]

I would look for play in moving parts and in the mount.

[stevebrot]

I would look for play in moving parts and in the mount.

This ^^^

With the exception of the optics, your lens is a mechanical device and has wear-critical parts. A short list might include:

• Focus mechanism (both AF and manual focus), both tolerance and operation
• Aperture rings
• Aperture couplings
• Electrical contacts and switches (some of these are internal)
• The mount face
• Bayonet fittings for hoods
• Provisions for tripod mount

Steve

[jddwoods]

I have an F 28mm f2.8 which I bought new about 1990. After 27 years usage it is showing absolutely no signs of wearing out. If you take care of lenses I can see them lasting a long time. Even my DA17-70 which does not exactly have a stellar reputation is still working well after 9 years. I would expect that modern zoom lenses with in lens focus motors, especially SDM are more vulnerable to repair issues as Victormeldrew noted.

[Pioneer]

I have a very old Leica rangefinder with Elmar 50mm lens which I recently sent out for overhaul (definitely more involved than a simple CLA.)

The lens was built in 1935, as was the camera, and has been used a lot. The overhaul corrected some stickiness in focusing but the aperture ring still exhibits some sloppiness from wear. The lens is collapsible but it still locks solidly in place when extended. The infinity lock no longer actually holds the focus in place but has worn to the point where it can easily be pushed past the detent. The detent is now more of a suggestion than a real stop. There are some minor wear scratches on the front glass from cleaning, and aggressive cleaning may be the biggest mistake amateurs make with their lenses. The lens markings themselves are still readable as they were engraved, but if they had only been painted on they would have worn away entirely by now as there is obvious wear, almost a brassing color, on the lens itself though it is made of nickel.

Of course, these are all mechanical things but the optics are still impeccable. Aside from the light wear from lens cleaning the glass is very clean and the lens still takes marvelous photos. I use a lens hood to help prevent flare since this lens has no coating but this is not a big problem. There were only six glass air interfaces to affect the light passing through so flare was never a big problem with early Elmar lenses anyway. I never cease to be amazed at how good the photographs are from this old lens.

I also have some older Asahi Takumar lenses from the early M37 mount era that are also very, very nice, but they are not so old, nor are they obviously as used as this Leitz Elmar lens is. Obviously auto focus lenses have additional mechanical or electrical parts that are wear prone, but they should also hold up pretty well if they are well cared for and sent out for the occasional check up.

Certainly Leitz and Asahi Takumar lenses are examplars of superb build quality from their day, and I am not sure that Sigma has that same reputation. However, as has already been mentioned, a visit to a technician for a complete tear down, cleaning and careful reassembly may surprise you. Even if it seems a little slow or sloppy there is certainly many excellent photographs still to come from that glass.

[dmr]

I would not call it wearing out, but a K-mount zoom I love and I've had for decades has gone out of focus at infinity and has been sent to the shop. When at infinity it actually focuses in the foreground.

Another, a Pentax 28-80 kinda pops in and out of correct focus when it's switched between normal and macro mode. This was a camera show special so I'm not sure of the age, but it went in for an estimate as well and I'm not sure how much $$$ I want to put into that one.