Damage to front lens elements - interesting article

[GrahamL]

Someone mentioned to me at the event last night that they'd suffered the unfortunate mishap of a camera mounted tripod falling, with the end result their protective filter had caused a scratch on the front lens element. My recollection is that the lens was a standard 24-70mm type zoom and though the scratch didn't appear to be affecting the use of the lens. They asked me if I knew whether it could be repaired. I said I had no idea, being fortunate to have only accidentally damaged a lens in other-ways. There question prompted me to look around for articles last night and came across this article that might be of more general interest:
https://www.lensrentals.com/blog/2016/12/front-element-lens-protection-revisited/

In summary the answer to the question posed seems to be: Yes, such damage can be repaired (professionally), but much depends on the price of the lens and lens replacement as to whether it's worthwhile. Such damage does not appear to be that rare, at least in the case of US rented lenses.

The argument about the use of a protective filter is an old one, but the comment on protective factor provided by using a lens hood is more novel as I get the impression a few folk don't always use one. Which given that they are normally provided gratis with the lens seems strange.

Be interested in what others think.

Graham

[Iggy]

The lens and camera dropped from waist height was a 24-105 Canon lens with lens hood doing a walk around Croydon
It landed on the lens hood that shattered probably protecting the lens and camera from damage as they continued to work well.
That same set up was probably dropped on another occasion while on holiday aboard when the front lens damage might have been done.
Iggy

[Compsec]

I have always viewed filters as general protection against weather. Cleaning a filter when its raining/snowing etc is much preferable to that a of a camera lens front element?

[Steve B]

Thanks for the advice to the anonymous (me) member who suffered a lens scratch last week. The 24-70mm lens had a lens hood and UV filter attached and the camera was mounted on a tripod about waist high. I turned round to zip up my camera bag and the tripod toppled over. The lens hood snapped and the filter splintered but when I managed to lift the filter glass off when getting home only some fairly small scratch marks were found in the centre of the lens.

I've taken some shots today and things seem to be ok, although yet to process on the Mac, so hope to have got away with cosmetic damage only. I'm a little disappointed the filter didn't absorb the impact better.

My research tells me that lens scratches can cause a little blurriness, especially where the scratch hits an edge in the composition and when using smaller apertures, and that there can be issues with lens flare. 'Useful' advice to be found on the web short of replacing the front element (expensive) or sending off for possible repair, includes: shooting at wider apertures, filling the scratch with black ink to deal with the flare issue, polishing or buffing the lens (with risk of losing anti-reflective coating and altering the curvature of the lens) - with variants of this including dipping a microfibre cloth in an alcohol solution and rubbing it in, ditto even toothpaste or peanut butter!

I shall not be trying any of these...

[Mike Farley]

I'm a little disappointed the filter didn't absorb the impact better.

It is possible that in this instance the filter has contributed to the damage suffered by the lens.

There are no right or wrong answers when it comes to filters, but it does help to know what problems you are going to encounter before they happen.

Personally, these days I usually do not bother. They can be useful to prevent unwanted grot getting onto the front element, but lens coatings are generally hard wearing and easy to clean. A microfibre cloth usually does the trick, sometimes combined with a lens cleaning solution for the harder to shift grunge. You also need to take into account that the filter is an extra layer of glass which will degrade image quality, even if imperceptibly. It pays to get the best you can afford.

Some people regard filters as being an easily replaced sacrificial element in the event of an incident such as the one you experienced, but there might be other less obvious problems as well. Follow the link to another LensRentals article and scroll down to where the MTF maps are shown for identical lenses. It is not hard to see which one has been dropped and requires repair, even if it is only an adjustment.

https://www.lensrentals.com/blog/2017/0 ... om-lenses/

That assumes the lens has been solidly built in the first instance. LensRentals recently documented the teardown of a Sony 70-200 lens which had been dropped and the focus no longer functioned. While it did not contribute to the focussing fault, they found that the internal construction of the consisted of two sections held together by a flimsy aluminium plate which had become distorted. The teardown was the longest and most complex which the LensRental team had undertaken and it required two articles to describe. The weak connecting plate was discovered in the first section and the cause of the AF malfunction in the second.

https://www.lensrentals.com/blog/2017/0 ... ss-part-1/

https://www.lensrentals.com/blog/2017/0 ... s-part-ii/

It is conceivable that the lens does not require repair and you can live with the damage to the front element. One test you could do, if possible, is to repeat one or more shots taken before the incident and compare them to see if there has been any degradation.