which is worse?

[R Paul]

Hi

I was wondering about something simple: Would a scratch on the front element of a lens cause more harm to an image than one on the back element?

Thanks

r paul

[Chrismat]

A scratch on the back element would be worse because it is closer to the film plane. The further away from the film the less noticeable a scratch would be (as long as it isn't too bad).

[BobD]

If the scratch is on the front, everyone will see it and think you are a bad photographer for using a scratched lens.
However, if the scratch is on the rear, no one will see it and your status will be unaffected.

Therefore it is far better to have scratches on the rear of the lens.

[36cm2]

Chrismat is right, but Bob D is funny.

[JLP]

I don't have any lenses with a scratch on the front but i do have a Nikon 90 f4.5 LF lens with a pretty visible chunk of glass missing almost at the center of the rear element. The lens performs exceptionally well and i have never seen any problems in the photos taken with this lens. Can't explain how that is possible but just shows that small imperfections don't make much of a difference except on the sales price.

[jordanstarr]

...is this a trick question?

Neither matters if it doesn't effect the image.

But in seriousness, the front does not matter as much because of the amount of diffraction of light as it passes through each element hides any flaws better. Because in normal conditions, light will be "perfect" until the end element, (and assuming the rear is with the stratches) the problems that arise cannot be subdued by other lenses "correcting" it's flaw. That being said, I've shot plenty of lenses with marks on both front and rear with no "real" consequences noticed on film. For example, I just made an 11x14 print from a shot on my 50mm lens that has residual mould marks on the inside of the front element, cleaning marks and stratches on the front element and coating spotting on the front and rear elements. I held it up to an 11x14 print from a perfect 35mm lens and NO ONE IN THE WORLD would be able to tell the condition of the two lenses based on the photographs. As a result, I never shy away from saving a few hundred dollars on user-grade lenses with a mark here or there.

[revdocjim]

You might be surprised what you can get away with when it comes to scratches.
And interesting test!

[Too old to care]

You might be surprised what you can get away with when it comes to scratches.
And interesting test!

That is truly amazing. Thanks for posting this. I will stop worrying about every piece of dust on my front lens from now on.

[rich815]

While it all makes sense in theory I think the scratch on the rear is better and have shot lenses with such scratches with seemingly no issues. The front scratches make the lens more prone to flare in my experience.

[Prof_Pixel]

I think the scratch on the rear is better and have shot lenses with such scratches with seemingly no issues. The front scratches make the lens more prone to flare

That is my understanding as well.