photoimager
Posts: 4,111
Stoke-on-Trent, England, United Kingdom
When those threads come up I always warn the person being directed away from using something that the people against using will not be paying the bill if it goes wrong.
Robert Jewett wrote: Very, very small. You can barely even see it. I jut wanted to come clean.
Some fine grain sandpaper might make it unnoticeable.
I shot film with a 90mm Zeiss lens on a Sinar for years with a fair sized chunk out of the front element, and no visible signs of it on the negatives.
Don't know if that works the same with digital??
Michael Fryd
Posts: 2,783
Miami Beach, Florida, US
Robert Jewett wrote: ...because I was taking images in Morocco where I specifically wanted a little lens flair...and got bumped into a terra cotta pot (24-70L).
And, I thought back to last month where I made fun of someone here saying he needed a UV filter in case he gets "shoved into a brick wall".
I thought, "Maybe...I should apologize."
Then I was like, "Naw."
J/K
I am not just going to stay out of all UV filter threads, I think.
Sounds like quite an impact. What makes you think a UV filter would have prevented the scratch?
Perhaps the pot would have broken through and you would have a scratched lens and a broken filter?
Filters do not provide a magic unbreakable barrier.
Theuns Verwoerd
Posts: 84
Christchurch, Canterbury, New Zealand
Michael Fryd wrote: Filters do not provide a magic unbreakable barrier.
No, but having specifically destroyed some filters (cheap ones I bought to repurpose their metal rings), I can tell you that those things are annoyingly hard to break. And then there's the one that sacrificed itself on a lens I dropped - filter shattered, lens without a mark.
They definitely have an impact on image quality, however.
The front element provides surprisingly low impact on image quality. It's more there for its light collection capabilities (being the largest element) ---- I have seen some TORE UP front elements that had no discernible loss in IQ.
no, theres an article where a guy smeared finger print and everything on the front element, then he even used a cracked lens front element and he had to work hard to make it show up' so yeah no worries & not puffing smoke.
something similar, so yeah if its not like this , then no worries.
I agree with Marquez...
Resale value is now way lower but in real world usability terms...
most scratches don't effect picture quality!
I worked photo retail in a super busy So. Cal. rental house and I saw some really,really beat-up,funky front elements...but the lenses were still usable and sharp enough for Pro use!!!
I don't know about it's affect on a digital sensor, but from a strictly optical standpoint, a small scratch on the front element would likely not affect the image at all. It would be worse if it was on the back element, but even then, it might not be visible.
In "Old Time" photography (film and old lenses) we many times have to deal with larger scratches and even chips in the glass. General concern is that with a chip, the non-normal glass surfaces can scatter the light differently, and filling in the chip with black ink helps solve that condition.
I suspect that your images would suffer much more with a cheap UV filter on your lens than a small scratch without the filter.
Did you miss the part where he said he wanted to have some lens flare?
To the people talking about big scratches and pieces missing from the front element not affecting the images.... Bullshit.
Unless your aperture is never smaller than 5.6, it's going to show up. I guarantee that if you're shooting at f/22, you're going to see every scratch or smudge on your lens. And dust particle on your sensor.
So, if you smashed your front element, just shoot everything at f/2.8 and you'll be fine.
@Good Egg Productions: I put a 1/8 inch scratch on the coating of a brand new 180mm lens for my RB67. You could easily see it with the naked eye. It happened the day I got the lens when I dropped it on a bed and it hit a key on my key ring. I rushed it over to a Mamiya repair center nearby. It was put on an optical bench and checked out at all apertures, from wide open to f32. NO visible marks were seen on the bench. I then tested it using VPS film. Ran the whole gamut of apertures. NO visible marks seen. For the next 30 + years I used that lens for portraits, usually at f5.6 with no marks from the scractch. I also used it at f22 hundreds of times shooting legal documents for court cases, such as checks, bonds, etc. NO visible marks from the scratch ever. I was lucky I know. The scratch was never buffed out, as I did not want to do anything to the coating on the front lens element. Of course, right after this incident, I purchased clear optical glass 77mm filters for my 3 RB lenses. Over the years, they got scratched up quite a bit but always protected the lenses.
Dan Dozer wrote: I don't know about it's affect on a digital sensor, but from a strictly optical standpoint, a small scratch on the front element would likely not affect the image at all. It would be worse if it was on the back element, but even then, it might not be visible.
In "Old Time" photography (film and old lenses) we many times have to deal with larger scratches and even chips in the glass. General concern is that with a chip, the non-normal glass surfaces can scatter the light differently, and filling in the chip with black ink helps solve that condition.
I suspect that your images would suffer much more with a cheap UV filter on your lens than a small scratch without the filter.
I'm sure there is a simple answer but I'm uncaffeinated so far today. Why is it that a small scratch doesn't show up but an equally small spot of dust will be show up as a lovely black spot that has to be cloned out? I've seen the videos about scratching breaking duct taping lenses and I even have one with a scratch that I've played with (but will never try to sell). But forget to get rid of the tiniest speck of dust and it will ruin your image every time. Someone explain this?
Some fine grain sandpaper might make it unnoticeable.
Horrible idea:
A scratch will diffuse perhaps 1% of the light hitting the lens. Whatever the proportion of scratch area to lens area is. Most of this light will be sent into black baffles and only affect image quality by it's absence.
A sanded, ground, polished, or however fared in AREA will diffuse a far greater portion of the light hitting the lens. Whatever the proportion of fared in area to lens area is. Much of this light will be sent to the sensor and noticeably affect image quality by distortion, contrast loss, flare, etc.
On the good side though it may convince you to replace the front element which otherwise had lost 1% of it's value before sandpaper abuse.
Richard Klein Photo wrote: @Good Egg Productions: I put a 1/8 inch scratch on the coating of a brand new 180mm lens for my RB67. You could easily see it with the naked eye. It happened the day I got the lens when I dropped it on a bed and it hit a key on my key ring. I rushed it over to a Mamiya repair center nearby. It was put on an optical bench and checked out at all apertures, from wide open to f32. NO visible marks were seen on the bench. I then tested it using VPS film. Ran the whole gamut of apertures. NO visible marks seen. For the next 30 + years I used that lens for portraits, usually at f5.6 with no marks from the scractch. I also used it at f22 hundreds of times shooting legal documents for court cases, such as checks, bonds, etc. NO visible marks from the scratch ever. I was lucky I know. The scratch was never buffed out, as I did not want to do anything to the coating on the front lens element. Of course, right after this incident, I purchased clear optical glass 77mm filters for my 3 RB lenses. Over the years, they got scratched up quite a bit but always protected the lenses.
Richard, I got a tiny spot of sap on my 14-24mm the first day I used it in the field. This thing was about the size of a half of the head of a pin. I could see it VERY easily when shooting at f/11.
Perhaps the length of the lens has more to do with it than the aperture, but seeing it on video at f/8 was unacceptable. Luckily, the camera shop was able to remove it with a cleaner.
Robert Jewett
Posts: 2,257
al-MarsÄ, Tunis, Tunisia
Drew Smith Photography wrote: I doubt you'll see it on your images.
Have you looked to see yet?
There is only one thing I notice. In all fairness: 1) Newish lens so I am not sure if it had this before or not 2) I rarely shoot into the sun like this...
But I don't think the lens flair in the lower right corner looked like this before:
The lens is a Canon 24-70 L on a Mark III. Can anyone tell me if they get the same thing?
I would think damage to your equipment would be expected, much as a contractor with a brand new pick up truck, till the first dent in the door, Its nearly impossible to get away clean forever. AS long as the damage does not compromise your photos live with it. My car has dings dents scratches and bird crap on it but still runs... barely... I spent all my money on camera stuff
A scratch will diffuse perhaps 1% of the light hitting the lens. Whatever the proportion of scratch area to lens area is. Most of this light will be sent into black baffles and only affect image quality by it's absence.
A sanded, ground, polished, or however fared in AREA will diffuse a far greater portion of the light hitting the lens. Whatever the proportion of fared in area to lens area is. Much of this light will be sent to the sensor and noticeably affect image quality by distortion, contrast loss, flare, etc.
On the good side though it may convince you to replace the front element which otherwise had lost 1% of it's value before sandpaper abuse.
I am sure the OP got the sandpaper suggestion(pun) as meaning his scratch would not show on the lens, among the scratches made by the sandpaper, and not realistically sandpaper the lens as a fix.
Michael Fryd
Posts: 2,783
Miami Beach, Florida, US
AVD AlphaDuctions wrote: I'm sure there is a simple answer but I'm uncaffeinated so far today. Why is it that a small scratch doesn't show up but an equally small spot of dust will be show up as a lovely black spot that has to be cloned out? I've seen the videos about scratching breaking duct taping lenses and I even have one with a scratch that I've played with (but will never try to sell). But forget to get rid of the tiniest speck of dust and it will ruin your image every time. Someone explain this?
Here's a simplistic overview of why dust on the sensor affects the image more than dust on the front element.
Imagine a front element 77mm in diameter. This has an area of about 47 square cm.
Image a large piece of dust, 2mm in diameter (about .03 square cm).
The area of the front element is about 1,500 times greater than the area of this rather large piece of dust.
Put that piece of dust on the lens, and you reduce the light falling on sensor by about 0.01% Hardly noticeable. Since light from each point on the front element reaches every pixel, the light is reduced evenly across the whole frame. There will be no noticeable difference in exposure.
Now put that 2mm piece of dust on the sensor. The pixels directly below the dust will get no light. The pixels away from the light will get the normal amount of light. The pixels near the edge of the dust will get a reduction that is influenced by the aperture. You will see an obvious black spot in the image. At smaller apertures, you will see a sharper and more pronounced edge. Wide open, there will be more light coming in from the edges, and this will go under the dust reducing the shadow. Remember, the dust is not on the sensor, but above it separated by a thin sheet of glass.
Thus dust on the sensor is a major problem. Dust on the front element, not so much.
Disclaimer: this is a simplified explanation. Many details have been omitted.
Here's a simplistic overview of why dust on the sensor affects the image more than dust on the front element.
Imagine a front element 77mm in diameter. This has an area of about 47 square cm.
Image a large piece of dust, 2mm in diameter (about .03 square cm).
The area of the front element is about 1,500 times greater than the area of this rather large piece of dust.
Put that piece of dust on the lens, and you reduce the light falling on sensor by about 0.01% Hardly noticeable. Since light from each point on the front element reaches every pixel, the light is reduced evenly across the whole frame. There will be no noticeable difference in exposure.
Now put that 2mm piece of dust on the sensor. The pixels directly below the dust will get no light. The pixels away from the light will get the normal amount of light. The pixels near the edge of the dust will get a reduction that is influenced by the aperture. You will see an obvious black spot in the image. At smaller apertures, you will see a sharper and more pronounced edge. Wide open, there will be more light coming in from the edges, and this will go under the dust reducing the shadow. Remember, the dust is not on the sensor, but above it separated by a thin sheet of glass.
Thus dust on the sensor is a major problem. Dust on the front element, not so much.
Disclaimer: this is a simplified explanation. Many details have been omitted.
all totally understood but I was asking about dust on the lens that I forget to remove.
Michael Fryd wrote: A spec of dust on the front element won't leave a spot in your image.
A spec of dust on your sensor typically will leave a spot in your image.
I see the spots all the time whenever I forget to clean my lens before a shoot. Its not so bad in the studio and can be cloned out. But shooting landscapes and having to crop a bit the spot becomes a monster bug crawling across the image. I'd post one but its too ugly to put anywhere.
EDIT: I remembered one where I didn't care since it was for non-photographic purposes
Michael Fryd wrote: Put that piece of dust on the lens, and you reduce the light falling on sensor by about 0.01% Hardly noticeable. Since light from each point on the front element reaches every pixel, the light is reduced evenly across the whole frame. There will be no noticeable difference in exposure.
Now put that 2mm piece of dust on the sensor. The pixels directly below the dust will get no light. The pixels away from the light will get the normal amount of light. The pixels near the edge of the dust will get a reduction that is influenced by the aperture. You will see an obvious black spot in the image. At smaller apertures, you will see a sharper and more pronounced edge. Wide open, there will be more light coming in from the edges, and this will go under the dust reducing the shadow. Remember, the dust is not on the sensor, but above it separated by a thin sheet of glass.
Thus dust on the sensor is a major problem. Dust on the front element, not so much.
Well explained!
Now a big dirty translucent fingerprint smudge on 1/4 of the lens... LOL!
Bad news!
The more I look at that Robert, the more I think it may be just a small chip right where the small red circle is.
The way that it kinda split the colors between red and yellow, and throws a "tail" in line with the sun's rays, is almost like there's a different curvature in that small area (where the red is)...like a small chip might produce.
Michael Fryd
Posts: 2,783
Miami Beach, Florida, US
ArtisticGlamour wrote: The more I look at that Robert, the more I think it may be just a small chip right where the small red circle is.
The way that it kinda split the colors between red and yellow, and throws a "tail" in line with the sun's rays, is almost like there's a different curvature in that small area (where the red is)...like a small chip might produce.
I think a lens hood may mostly solve it.
Like filters, a scratch or chip can contribute to flare and reduced contrast.
The standard advice is to fill in the scratch/chip with a black sharpie. This eliminates any scratch/chip induced flare or contrast loss. As already been discussed, a few dust specs or sharpie marks on the front element have an extremely minimal impact on the image.
The advantage of the filter is that it can quickly be replaced. The economics frequently suggest the filter won't save you money.
Asume you have five lenses, and buy five $100 high quality protective filters. You encounter a situation where the filter sacrifices itself to prevent your front element from being scratched. You replace that filter, and have now spent $600 on protective filters.
Had you not bought filters, a front element repair would likely cost less than $600.
If you treat that that scratch with a sharpie, you save even more.
Assuming you scratch 20% of your lenses (or less) it's much cheaper to pay for the occasional repair then to pre-pay for filters.
If you never scratch a lens, then you save even more by avoiding filters. If you routinely scratch your lenses, then you may want to examine your technique. A $5 lens cap costs much less than a $100 filter, and provides better mechanical protection.
Michael Fryd wrote: The standard advice is to fill in the scratch/chip with a black sharpie. This eliminates any scratch/chip induced flare or contrast loss. As already been discussed, a few dust specs or sharpie marks on the front element have an extremely minimal impact on the image.
Robert Jewett
Posts: 2,257
al-MarsÄ, Tunis, Tunisia
Michael Fryd wrote: The standard advice is to fill in the scratch/chip with a black sharpie. This eliminates any scratch/chip induced flare or contrast loss. As already been discussed, a few dust specs or sharpie marks on the front element have an extremely minimal impact on the image.
Great suggestion...but, I can't seem to find a black Sharpie anywhere in Tunisia!!!
LOL!
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