Loss of sharpness in Canon 100-400?

Cporosus1 · May 1, 2020

Hello everyone,

I have a question to ask- is it possible for a lens (in my case, the Canon 100-400) to lose sharpness? I have been using this lens since 2008 (it is the "dust pump" model not the newer one) and I have traveled all over the world with it (Australia, Belize, Brazil, Costa Rica, Indonesia, Singapore, South Africa, Sri Lanka, etc. some multiple times). Despite a few superficial blemishes from years of wear, there does not appear to be anything mechanically wrong with it. However, over the last couple of years, I've noticed it just doesnt "nail" some of the shots that it would have before. It seems I need to be almost entirely still to get a sharp wildlife shot, whereas before I could be moving or on a boat, etc. and still get the shot. Should I give up and get a new lens or do you think a cleaning may help? Can accumulation of dust inside the lens cause this? I don't think it is the camera itself. I have a Canon 7D Mark II and I purchased it much more recently (November 2016) and my smaller lens doesn't have the same problem.

Thanks!

tirediron · May 1, 2020

It's unlikely to be dust, but it could very likely be missed focus due to wearing of components. A twelve year old lens with a lot of miles on it could easily have developed some "slop" causing images not to be tack sharp. Have you tried setting up some test shots? Mount the rig on a tripod, use optimal settings (>1/500 sec, >8) and then try manually focusing and auto-focusing on the same target, 50 - 100' away. If it's sharp in the manual focus and not the auto-focus, then it could either be wear, or your AF calibration is off a hair. If it's soft in both of them, it's likely wear.

Cporosus1 · May 1, 2020

Thank you. I will try that. If it is wear, is it possible to have the worn parts replaced or would I need to buy a new lens?

Original katomi · May 2, 2020

Not sure where you live but after the tests and you decide it’s the lens wear
Contact canon and ask for both prices and Note... authorised .....dealers who could do the repairs.
Once you have the prices you could look at repair or replace.
For uk canon
Digital Cameras, Lenses, Camcorders & Printers - Canon UK
I am sure if you ask others here will post a link to canon in their location

Designer · May 2, 2020

Cporosus1 said:
Can accumulation of dust inside the lens cause this?

I doubt it. Typically, internal dust will degrade the contrast of a lens.

jcdeboever · May 2, 2020

After test as @tirediron directed, if it fails to your comfort on both applications, you should consider sending it in for repair. I assume it would be less than buying new glass.

tirediron · May 2, 2020

Assuming the lens is repairable; I ran in to a situation with my 300 2.8 a couple of years (which was about the same age) and Nikon simply laughed; they had no parts with which to repair it. Of course Canon is an entirely different ball game, but give the age, repairs may indeed be a challenge.

photoflyer · May 3, 2020

If you have a camera with dual pixel autofocus, try focusing in live view. If it is sharp then try autofocus micro adjustment. I had to do this with one lens/body combo and perhaps over time, wear may necessitate this in your case. Just an idea.

BTW, I just got the latest version of that lens...wow! If you do need to replace it, you will really enjoy wearing out the new one.

photoflyer · May 3, 2020

Oh, and post here what you find so we can learn from your experience.

Derrel · May 3, 2020

Are the lensmount attaching screws all snug?

Raw photographer · May 9, 2020

I'm having the same problem with my lens, it was always tac sharp when i bought it, now it seems to be just a bit softer, but my lens is not even a year old, i've just learnt to deal with it.

photoflyer · May 9, 2020

Raw photographer said:
I'm having the same problem with my lens, it was always tac sharp when i bought it, now it seems to be just a bit softer, but my lens is not even a year old, i've just learnt to deal with it.

Are you using the same camera now as when it was new?

Raw photographer · May 9, 2020

photoflyer said:
Raw photographer said:

I'm having the same problem with my lens, it was always tac sharp when i bought it, now it seems to be just a bit softer, but my lens is not even a year old, i've just learnt to deal with it.

Click to expand...

Are you using the same camera now as when it was new?

No i'm using a way higher quality camera, but even when i was using my old camera it still wasn't as sharp as when I first bought it, i swear when i got the lens it could have taken on an L series lens easily, but now not so much.