50mm f1.4 canon FD lens issue?

Dug out my 50mm f1.4 today and I was giving it a wipe down and notice this weird shape to one side, it doesnt really look like a crack and it's kinda hard to explain, any ideas? Thanks

 

Does it feel like a scratch when you clean it? Or is the surface smooth? Is it on the surface, or is it internal? Was it always there, or is it something new? Strange.

Does it feel like a scratch when you clean it? Or is the surface smooth? Is it on the surface, or is it internal? Was it always there, or is it something new? Strange.

I've never noticed it before but it's internal, it looks like a scratch but inside .very strange indeed!

Looks like a lubricant drip or some other fluid. Has anyone ever given this lens the naptha treatment?

Looks like a lubricant drip or some other fluid. Has anyone ever given this lens the naptha treatment?

I have no idea what that is ahah but the lens has never been serviced or maintained. Would there be any way to clean it? Thanks

As for cleaning, depends what kind of defect it is. If it is the coating, a cleaning will probably do no good. If it's some sort of residue, a cleaning may help. If it has no impact on your pictures, maybe the best thing is to do nothing at all.

It could be that the antireflection coating fell off. Or, as noted above, some lubricant on it would also cancel the effect.

 

The result is a small reflection where there shouldn't be one. You weren't expecting perfect photographs from a lens that old, were you?

 

A small reflection should have a small effect, though in some lighting conditions it might be big enough.

 

Being toward the outside, the effect should reduce as you stop down, though that reduces the use of an f/1.4 lens.

 

I suspect that the cost to fix is more than the value of the lens.

I have not seen anything like this on any of my old lenses. Something with the lens coatings seems possible.

 

I'd try some pictures with it and see if anything affects the image. If not, I'd just ignore it, but monitor it to see if it gets worse..

I have not seen anything like this on any of my old lenses. Something with the lens coatings seems possible.

 

I'd try some pictures with it and see if anything affects the image. If not, I'd just ignore it, but monitor it to see if it gets worse..

Was told by one camera shop that it was the start of lens separation and that it is a crack/stress fracure by another. Seems like the latter to me!

 

The picture above shows some detail that might suggest fungus (the right end).

 

However, as a old flint knapper, I'm skeptical that this is a fracture. Glass (and flint) typically crack from the edge and have shell-like ripples (Conchoidal fracture - Wikipedia)