Scratched rear element = ruined lens?

Horatio

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Recently came across a lens for sale that has several visible scratches on the rear element. How badly would this compromise IQ? I saw a YouTube video last year where someone deliberately scratched the front element of a lens until the IQ became objectionable. IIRC, it took quite a lot of abuse before IQ suffered. I’ll try to post a photo later.
 

awty

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Depends where it is and how badly. Wide open it may increase flare. If its in the middle it might affect image when stopped down. Usually rear element has much more impact on the image than the front element.
 

Dan Fromm

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Try it out. If you don't like what it does, fill the scratches with India ink.
 

KinoGrafx

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Keh has one that’s not all scratched up right now for $237, just for reference
 

Nitroplait

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I would buy it for $100 just for fun if I didn’t already own one. Scratches on wide lenses are more likely to impact results - and on the rear element even more so. The results from this lens will be negatively impacted, the question is just how much.
$200? Move along.
 

Huss

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Scratches on the front element - at worst it can increase flaring if the sun/light source is angled just so.
Scratches/marks on the back element? A huge deal. That definitely will cause image degradation.
You can test this yourself by putting a piece of lint/hair/make a mark with a removable marker in a non destructive way if you wish on the back element of your test lens.
It will be noticeable.

$200 is the going rate for this lens if it is in great shape from a private seller.

This guy is asking $210 for one in great shape:
https://www.fredmiranda.com/forum/topic/1687178/0?keyword=20mm#15499303
 

TheFlyingCamera

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I have a Cooke Series II 10.4" Anastigmat that has significant scratches to the glass on both front and rear elements, and the barrel looks like a very patient dog eventually got tired of chewing on it. But it is capable of this:



and this:



and even this:



So if you can get the price down on that lens, I'd use it in good health.
 
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