Scratches

[peoplemerge]

Like so many of us coming from a small format world, how much does scratches impact image quality on large format? I’ve held the belief that on a 35mm, a scratch to the front element won’t affect image quality at all, unless using flare to artistic effect (motion picture is the more important application) while a scratch to the rear element will have a major impact to the image.

I’ve wondered if the same can be said for large format or if the distance to the film plane and physics of lens design would make it less consequential.

 

[Sirius Glass]

Small scratches on the front of the lens for large formats should not have an effect, but they is always a chance that it does. Protect your lenses the best that you can. That can be done with filters on small formats, while care while handling larger lenses is a good way to start.

 

[xkaes]

Just like with smaller format lenses, much depends on the "scratches". If they are small and few, you have little to worry about. Keep in mind that with smaller formats you have to enlarge more to make the same size print -- so the magnification of the print makes a difference too. So does the f-stop that is used. Stopped down, the scratches are more likely to be apparent.

 

[peoplemerge]

Thanks for your responses. I hadn't thought of the aperture part of the equation, but now it does make a lot of sense. A large imperfection in the middle of the rear element with a small aperture is going to blur the image at the center of the film and send stray light all over. At a larger aperture, it'll be illuminated by more of the lens cell.

 

[loccdor]

Tons of fine scratches on the front element will give a glow effect. I found it happens at all apertures. But it has to be very scratched up, think hundreds of lines. It's actually really nice in some cases.

 

[Hanka73]

Like so many of us coming from a small format world, how much does scratches impact image quality on large format? I’ve held the belief that on a 35mm, a scratch to the front element won’t affect image quality at all, unless using flare to artistic effect (motion picture is the more important application) while a scratch to the rear element will have a major impact to the image.

I’ve wondered if the same can be said for large format or if the distance to the film plane and physics of lens design would make it less consequential.

Scratches on large format lenses can affect image quality, especially on the rear element, which impacts sharpness and contrast. Front element scratches are less noticeable due to the larger image circle but can cause flare or distortion.

 

[RalphLambrecht]

Like so many of us coming from a small format world, how much does scratches impact image quality on large format? I’ve held the belief that on a 35mm, a scratch to the front element won’t affect image quality at all, unless using flare to artistic effect (motion picture is the more important application) while a scratch to the rear element will have a major impact to the image.

I’ve wondered if the same can be said for large format or if the distance to the film plane and physics of lens design would make it less consequential.

We have lens designers at Photrio. They should answer that.

 

[Hanka73]

Tons of fine scratches on the front element will give a glow effect. I found it happens at all apertures. But it has to be very scratched up, think hundreds of lines. It's actually really nice in some cases.

Yeah, tons of scratches can give a cool glow effect, looks nice in some shots.

 

[beemermark]

Scratches on the front element creates diffusion and flare. A good lens hoods will help a lot. A black sharpie can be used to blacken out a deep scratch on the front element to prevent flare. I think most "scratches" are cleaning marks on the front element coating. A lens hod works wonders.