Loose Canon FD 24-35mm SSC aspherical?

I picked up this lens a little while back. After using it for a bit I’ve noticed fairly consistent and significant sharpness problems at the edges of the frame. This seems strange, as everything I’ve read about the lens indicates it’s a very good one. Last night I noticed that if I shake the lens gently front to back I can hear and feel things shifting inside. Is this an indication of a problem that would be causing the sharpness issues? If so, might it be repairable?

There's a possibility theres a loose retaining ring in there that would allow an audible rattle.
Should be an easy fix but getting to all the retaining rings MAY take major disassembly.
It may also be the first ring encountered.

I can't help you with your question, but did want to mention that any thread title that starts out with "Loose Canon" makes me want to read what follows.

MattKing said:

I can't help you with your question, but did want to mention that any thread title that starts out with "Loose Canon" makes me want to read what follows.

Click to expand...

+1

Ha! Didn’t think of that Matt. Afraid the question doesn’t quite live up to the hype.

Thanks for the tip John. I thought it was very unlikely the shifting is normal, but wanted to double check before taking it in. Sounds like it will be worthwhile to get it looked at.

-Aaron

artcarbuncle said:

I picked up this lens a little while back. After using it for a bit I’ve noticed fairly consistent and significant sharpness problems at the edges of the frame. This seems strange, as everything I’ve read about the lens indicates it’s a very good one. Last night I noticed that if I shake the lens gently front to back I can hear and feel things shifting inside. Is this an indication of a problem that would be causing the sharpness issues? If so, might it be repairable?

Click to expand...

The rattle is probably repairable (most things are) but it was never nearly as sharp as the primes it covers, particularly the 24. I doubt the sharpness issue has to do with the rattle.

Agree that it is likely repairable. I have an Auto Rokkor-PF 55/2 that had a loose optical assembly. All elements were loose as one solid unit. I disassembled the lens until I found one retaining ring loose. It held the optical train to the focusing helicoid. The ring was tightened and the lens functions as normal.

But this is a zoom lens, thus more complex and thus more difficult to repair, especially for someone unexperienced. Thus this likely is a case for a professional repairer.

I have no experience with this lens, but I own two zooms that actually came apart internally, requiring that they be opened up to fix them. Both SP Tamrons, a 60-300 and an 80-200. In both cases, they were an easy fix once I had opened the lenses up far enough to reach the sections that had come apart. With these lenses, it was element groups that had unthreaded themselves, so all I had to do was rethread them back and, using my spanner, give them a good tightening to insure they stayed put. These repairs were done about six or seven years ago, and two years ago, respectively, and everything has stayed put. With these two lenses, a visual inspection revealed the problem. So, before dismantling the 24-35, I recommend you perform a visual inspection of the lens's internals to see if you can find where things are amiss. If there are no visible issues, this means the problems most likely lies in the lens's barrel(s) and exterior, focusing and/or zoom collars, etc.