Will the sun damage lens coatings? I shot the eclipse. Would have preferred to use my 400 f/2.8 but I did not have a large enough filter to cover the front element. I used my 100-400...

Robertl594 Loc: Bloomfield Hills, Michigan and Nantucket

I shot the eclipse. Would have preferred to use my 400 f/2.8 but I did not have a large enough filter to cover the front element. I used my 100-400 because I had a 77mm solar filter.

My question is, my 400mm uses a 46mm drop in filter just in front of the camera, not in front of the front element, will the sun damage the elements and coatings in front of the filter? I did not want to take the chance of damaging my lens, so I did not use it. I have ordered some sheet filters large enough to cover the front element in the future.

Thank you for answers.

Here are a few I was able to get.

azted Loc: Las Vegas, NV.

Nice work. The solar flares are very well defined!

Earnest Botello Loc: Hockley, Texas

Great set, Robert. I am not an expert, but unless you leave the camera sitting pointed at the sun for a many, many hours in one place I doubt that the lens will be damaged in any way using it for a few minutes.

Orphoto Loc: Oregon

I have never heard of coating damage, always only shutter curtain and/or sensor. Highly unlikely glass elements would be adversely affected. Will be curious to see how the henhouse reacts here.

Longshadow Loc: Audubon, PA, United States

Orphoto wrote:

I have never heard of coating damage, always only shutter curtain and/or sensor. Highly unlikely glass elements would be adversely affected. Will be curious to see how the henhouse reacts here.

I'll agree with you.

MJPerini

Robertl594 wrote:

I shot the eclipse. Would have preferred to use my... (show quote)

Nice pictures !
I think you did the right thing by being cautious. I do not think lens coatings per se would be damaged , but I did read an advisory from Canon never to use the filter drawer for solar filters, only front mount filters. The reason is that the IR from the sun can generate large amounts of heat, and THAT could definitely cause damage

wdross Loc: Castle Rock, Colorado

Robertl594 wrote:

I shot the eclipse. Would have preferred to use my... (show quote)

The main problem with a drop-in filter is getting it out fast enough for totality. There is a chance depending on where the aperture iris is for possible damage to it and depending on how strong the light is concentrated on the filter itself (overheating, cracking), but they usually are located far enough away from the most concentrated light and tend to be sturdy enough. But there is a chance for damage depending on their locations in the lens. Obviously, killing the light levels before any of the lens elements start concentrating the light is the best way to go.

chrisg-optical Loc: New York, NY

Robertl594 wrote:

I shot the eclipse. Would have preferred to use my... (show quote)

I doubt it is an issue for the short amount of time the event happens. Sensor/shutter damage is more likely than coating damage. Some eclipse photogs will place cardboard over the lens when not exposing, or use the lens cap.

DirtFarmer Loc: Escaped from the NYC area, back to MA

Robertl594 wrote:

...My question is, my 400mm uses a 46mm drop in filter just in front of the camera, not in front of the front element, will the sun damage the elements and coatings in front of the filter? I did not want to take the chance of damaging my lens, so I did not use it. I have ordered some sheet filters large enough to cover the front element in the future...

I seriously doubt that solar exposure would damage your lens coatings. After all, you go out and about with your lens frequently. What does it matter whether you are pointed at the sun or not. The sun light falls on your lens unless you are pointing away from the sun.

The only way that damage would be likely is if the solar disk were focused on a part of the lens. Otherwise, normal exposure to sunlight will not affect it.

cahale Loc: San Angelo, TX

Robertl594 wrote:

I shot the eclipse. Would have preferred to use my... (show quote)

I can't answer that with reasonable certainty. I do know that I do not have a sufficiently dark neutral density filter to do the job. I do, however, have a large variety of them, and overcame the problem by stacking a bunch of them. Worked like a charm - both camera wise and allowing me to observe through them. Sometimes serendipity is served by pack-rattiness.

bhapke

I don't know from personal information but did hear on a podcast by an astronomer and photographer that you should not use any filter that doesn't cover the front of the lens. He specifically mentioned that drop-on filters were not suitable.

dwmoar Loc: Oregon, Willamette Valley

bhapke wrote:

I don't know from personal information but did hear on a podcast by an astronomer and photographer that you should not use any filter that doesn't cover the front of the lens. He specifically mentioned that drop-on filters were not suitable.

+1

nervous2 Loc: Provo, Utah

Very nice shots.

User ID

I keep protective filters on all of my lenses to protect the coatings from from solar radiation.

Robertl594 Loc: Bloomfield Hills, Michigan and Nantucket

MJPerini wrote:

Nice pictures !
I think you did the right thing by being cautious. I do not think lens coatings per se would be damaged , but I did read an advisory from Canon never to use the filter drawer for solar filters, only front mount filters. The reason is that the IR from the sun can generate large amounts of heat, and THAT could definitely cause damage

Thank you! Not sure if you are right, however you makes total sense. I will not use a drop in filter! I did order one of these from Amazon to make a filter for the front element. 8"x8" Solar Filter Sheet for Telescopes, Binoculars and Cameras
https://a.co/d/jfEQe6W