Nick in the rear elment of a lens

[paul_sharratt]

How much would a 1 mm nick just off center on the rear element of a

Hassleblad 150mm sonnar lens effect the sharpness of the images.

I'm considering a great price on a used lens and will use it for

portrait and landscape images. Thanks for all input.

[peter_white2]

Filled with black paint, not a bit.

[Aoresteen]

Can you shoot some film with it first? My bet is you can't tell the difference.

[berg_na]

My 100CF also has some small nicks near the center of its rear element, but they don't appear to have much effect the image quality at all, even when shooting against bright light sources.<p><center><img src="http://img201.exs.cx/img201/8150/100cf5ds.jpg"></center>

[dave_moeller]

Peter has give you the right solution. If you don't want to do anything, then try shooting with the lens to see if the image is degraded. Chances are that you won't see any degradation unless you're shooting into the sun. If you fill the nick with something black as Peter mentions (I prefer India Ink), then even shooting into the sun won't be a problem.

 

Small nicks in lenses like this substantially impact the market value of the lens, but rarely have any effect on the actual usefulness of the lens. And fixing the problem when there is one takes all of about two minutes of your time and an hour or two of waiting for the ink to dry fully.

 

(By the way, my preferred method for filling in these kinds on nicks is to use a toothpick. Just rub the end of the toothpick on something hard until it's a bit frayed, drag your fingertips over the frayed end to pull off any loose bits of wood, dip the tip of the frayed end into the ink, then place the ink in the nick. If you get ink outside of the nick you're blackening, it can be removed easily with a lens tissue for the first minute or two.)

 

If you're buying this lens to use and the price reflects the nick in the lens, then buy it. If, on the other hand, you're buying it as an investment, pass on it and find a pristine example.

[tito sobrinho]

Ha! The nick on the rear element of a Hasselblad lens, reflects a slip of the improper "tool" when unjamming the body. A practice done by newbie photographers and or a so called "technicians" at an over the counter camera store.

[cpj]

Use flat black quick drying laquer for just enough paint to fill the nick. The India Ink also

works well and we used to use that 40 years ago. Nobody, regadless of whether or not

they use a microscope on your prints, will be able to see any difference between an image

shot with a filled nick in a lens and the same type lens without a nick.

 

Remember the diagrams of how the lens is designed to precisely focus the light coming

from "infinity" onto the film plane. As long as there are no reflections created by the nick

in the glass, you still have 99.9% or more of the lens contributing to the image formation.

 

The effect created by the 1 mm nick will be so far out of the the plane of focus that it is

immaterial. A nick on the rear element probably focuses two feet behind the camera if it

comes into focus at all. The practical effect is like shooting a portrait with a 150mm lens

of a subject 8 feet away with a wide open aperture and having something even as bright as

a traffic light 300 yards in the background. There will be no detectible degradation of the

image at all.

[paul_sharratt]

Received the lens today. The 1mm nick turns out to be about the size of the head of a pin. Looks like its only a nick in the coating and so I'm pleased that this tiny imperfection reduced the cost of the lens more than 50%. Thanks for everyone's input.

[frank_ainsworth]

I bought a 100mm CF on eBay, described as "excellent", only to discover a 1mm nick at the edge of the lens.

 

I knew it wouldn't affect the image in a discernible way, but was angry because I'd bid a top secondhand price to secure the lens, as no mention was made of the damage to the optics.

 

The vendor also offered a "bargain" sample of the same focal length, separately, and described that has having a chip. It sold for a lot less. When I received my lens, I assumed that I'd been sent the "bargain", in error.

 

In my mind , I don't expect anything described as "excellent" to be served with chips. I hope you gave your vendor good feedback for their honest description of your lens. My guy got off lightly with no online comment from me. He knows who he is...