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erian
3-Apr-2019, 15:43
How much would small scratches on the rear glass effect the final image?

189592

It is 400 f4, coverage about 8x10 to 11x14.

I understand that smaller the aperture the more but will ones like here display on the negative?

Pfsor
3-Apr-2019, 15:55
How much would small scratches on the rear glass effect the final image?


It depends on if you ask a seller or a buyer of the lens. Also, the effect is there (would be a miracle if it wasn't there) but more important is, if you're able to see the effect or not. Those scratches on the lens edge would let me sleep well as a buyer and a photographer, but not as a seller.

Luis-F-S
3-Apr-2019, 16:33
Only real way to tell is for you to try it and see if there are any effects. A seller will tell you it has no effect, and maybe it doesn't or maybe it does. L

domaz
4-Apr-2019, 08:29
One thing is for certain. Scratches on the lens isn't going to improve image sharpness, although maybe it improves "bokeh" and out of focus rendering? I had a lens that looks like it had been intentionally scratched that produced great out of focus rendering. Not sure if it was the lens or the scratches...

Pfsor
4-Apr-2019, 09:59
One thing is for certain. Scratches on the lens isn't going to improve image sharpness, although maybe it improves "bokeh" and out of focus rendering? I had a lens that looks like it had been intentionally scratched that produced great out of focus rendering. Not sure if it was the lens or the scratches...

Don't know, of course, what your definition of great out of focus rendering is, but me thinks that if the scratching produced visible effect on "out of focus" rendering, by the same logic it would also produce visible effect on the "in focus" rendering. Unless there is something like selective scratches optics.

Pere Casals
4-Apr-2019, 10:18
In my experience a lens has to sport a large amount of severe scratches to notice an effect.

Louis Pacilla
4-Apr-2019, 10:24
In my experience a lens has to sport a large amount of severe scratches to notice an effect.

+1

rdeloe
4-Apr-2019, 10:40
This is the classic Kurt Munger article on this topic... http://kurtmunger.com/dirty_lens_articleid35.html

I will say though that rear element scratches are more problematic than the front element damage that Kurt explored.

Eric Woodbury
4-Apr-2019, 11:22
As you stop down, you are using less and less of the outer part of the lens and only the center glass.

Also consider that a scratch doesn't cover much surface area so that a scratch doesn't do anything except for catch glints and stray refractions if illuminated (not cropped out by stopping down). That said, they are annoying.

e

Dan Fromm
4-Apr-2019, 12:10
Sigh. It all depends.

I have an 80/2.8 Xenotar that has the coveted "cleaned with coarse sandpaper" look front and rear. External surfaces only, not internal. It is just terrible, and at all apertures.

OP, you have the lens, try it out. Its the only way to know for sure.

pgk
4-Apr-2019, 12:24
I have a 90mm Elmarit-M with obvious coating damage on the front element. Its a very 'sharp' lens, but suffers from highlights bleeding into shadows as a result of the damage. I once had a Takumar 135mm with a deep scratch in the front element; once the scratch was filled with black ink this lens was absolutely fine and you'd never have known. Optical damage is something that can be disastrous but as Dan says, the only way to find out is to try out.