Solar filter or 10 stopper?

Peter69

Peter69

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20 March this year will have a solar eclipse.
Never tried to photograph one but Nikon say I should use a solar filter.
I checked to day and to stop the sun blowing out I need iso 100, 1/8000", f36 +7 stops of ND.

What would you guys use?
 
I thought a good test would being able to see detail such as sunspots on the sun's surface. That means you need to keep the surface of the sun well down from maximum exposure, and I didn't want to stop down more than f8 because on most of my lenses f11 is distinctly softer than f8. I found a ten stop ND filter wasn.t quite overexposed, but too close to max brightness for good detail resolution. So I stuck two 10 stops on (the cheap and very good XCSource 77mm 10 stop NDs) and got good exposures at around 1/60th on a tripod. I note that astrophotographers tend to recommend 16 stops for solar imagery.


Sunspots at 300mm f/8 1/80th sec (plus 2 big stoppers) by Chris_Malcolm, on Flickr

Two sunspots clearly shown, Tamron 70-300mm at 300mm.

On the other hand, if you want to photograph any of the surrounding scenery as context for the eclipse shot then you probably want it to a bit blown out.
 
@chris malcolm I see 20 stops gets a good image. It looks a little grainy though or is that the sun? The XCsource is good? They are much cheaper then others.
@michael23 How did the 50-500 perform? I'm torn between 70-200 & 150-500.
I'm not sure how to capture the event yet.
I will probably take multi shots of the eclipse and use a second camera to capture the scene as 4 stops just blows the centre of the sun out.
I've also go to get a location sorted because it will quite low in the sky 28degree I think
 
@dinners but are they any good? I posted to them above.
I will probably get an 82mm and a step down ring as I very very rarely use a filter in the big sigma. and may even shoot on the d7100 crop
 
Peter69 said:
@dinners but are they any good? I posted to them above.
I will probably get an 82mm and a step down ring as I very very rarely use a filter in the big sigma. and may even shoot on the d7100 crop
Click to expand...

I've not used one and they're relatively new.

I did start a thread about them a week or so ago.

The customer review comments on your Amazon link sound positive though.
 
Peter69 said:
@chris malcolm I see 20 stops gets a good image. It looks a little grainy though or is that the sun? The XCsource is good? They are much cheaper then others.
@michael23 How did the 50-500 perform? I'm torn between 70-200 & 150-500.
I'm not sure how to capture the event yet.
I will probably take multi shots of the eclipse and use a second camera to capture the scene as 4 stops just blows the centre of the sun out.
I've also go to get a location sorted because it will quite low in the sky 28degree I think
Click to expand...

It seemed to perform ok, though this was only one image, I didn't have the time to play around with apertures and exposures. I didn't get any sunspots though, the sun is rather quiet for those atm, as I was informed on stargazers lounge. The other option is baader astro solar film in a sheet if your handy enough to make your own filter up.

I am not really sure myself of what to do on the day, it's something I have never done before!
 
Peter69 said:
@chris malcolm I see 20 stops gets a good image. It looks a little grainy though or is that the sun? The XCsource is good? They are much cheaper then others.
Click to expand...

The sunspots are pretty faint, and I photographed it through light cloud and slihtly misty air which didn't help the contrast. Post processing has to seriously open up the relevant range to pick out the sunspots, which results in a lot of noise. But it's not all noise -- the sun's surface when you get down to viewing sunspots is always rather turbulently grainy. If there's any good sun between now and the eclipse I might have a go at image stacking to remove noise etc.. as the astrophotographers do.

Yes, the XCSsource is amazingly good! See post below for before & after images.

https://www.talkphotography.co.uk/threads/possible-bargain-10-stopper.570372/#post-6640637
 
I'm also quite interested in this thread and have a question.

I already have a circular 10 stop. Can I just screw a 6 stop in front of this?

Also, I use a Canon M so wouldn't be using an OVF, just the LCD screen.
 
Peter69 said:
I see no reason why not.
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I decided to order some solar filter film in a 12" x 12" sheet and I'll make a couple of filters.

I have a couple of cheap UV filters that came with various purchases over the years so I'll take the plastic out of one of these and make a screw in filter. I'll also have enough left to make another filter for the Missus's telescope that I completely forgot about. She also has a Canon mount for it so might give that a go as well.
 
LeeRatters said:
I suppose it depends if you are taking a very close up of the sun itself or a wider view.
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If you're taking a wide view including a tiny sun you're likely to be heavily overexposing the sun, hence the danger is only burning a tiny hole in your sensor. Whereas if you have giant telephoto which can fill the frame with the sun's disc and your filters stop visible light but not IR then you risk burning the whole sensor.

So say the wise astrophotography experts. But the truth seems to be that solar filters are known to stop IR as well as visible light, whereas with other filters nobody knows. So why take a risk? But what is the risk? Where are the sob stories from silly photographers who shot the sun through a cheap 10 stop ND non-solar filter and damaged their camera sensor? How can we check the IR transmission of our existing ND filters to see if they're sun-safe?

I know solar film is relatively cheap. But that doesn't solve my problem. My problem is that I want to understand the physics. I want to know how to test IR absorption. My problem is scientific curiosity.
 
chris malcolm said:
If you're taking a wide view including a tiny sun you're likely to be heavily overexposing the sun, hence the danger is only burning a tiny hole in your sensor. Whereas if you have giant telephoto which can fill the frame with the sun's disc and your filters stop visible light but not IR then you risk burning the whole sensor.

So say the wise astrophotography experts. But the truth seems to be that solar filters are known to stop IR as well as visible light, whereas with other filters nobody knows. So why take a risk? But what is the risk? Where are the sob stories from silly photographers who shot the sun through a cheap 10 stop ND non-solar filter and damaged their camera sensor? How can we check the IR transmission of our existing ND filters to see if they're sun-safe?

I know solar film is relatively cheap. But that doesn't solve my problem. My problem is that I want to understand the physics. I want to know how to test IR absorption. My problem is scientific curiosity.
Click to expand...

I've taken probably hundreds of images with the sun in the frame without burning any holes in my sensors.
 
Firstly, it is very unlikely to damage the sensor unless you are aiming to burn it (f2 300mm 10 minutes will probably produce the desired affect when pointed at a full hot sun).
ND filters do publish graphs for the light transmission. as do UV filters. Some cameras have IR filters built in. The risk of damage is heat focused by a large fast lens.

Try this article
http://www.centralcoastastronomy.org/photographing-the-sun-by-lee-coombs/

I have no idea what you need to photograph non-visible light i.e. far red or UV
 
I don't know about Zomei. It looks to me as though XCSource buy stuff in to sell from different makers, so the quality of one of their kinds of filters is no guide to the quality of another. I found their 77mm 10 stop to be very good, not just very good for the price which is very cheap, very good at any price. I posted examples of its results here in another thread if you search.
 
I'm not an expert on photographing the Sun (despite my avatar) but I am interested in the eclipse, so I phoned a few specialist shops. I was advised that an ND or a combination of NDs is not the way to go as they dont stop IR radiation, the consequence of this is the camera overheating due to the lens acting like a magnifying glass held to the Sun. Its one thing to expose the sensor briefly and another to leave the camera aimed at the sun while composing a shot.
Also, you should be using live view and NOT the viewfinder.
That was the advice given to me.
 
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Funny, I'm just reading the Firecrest spec.
It specifies all IR light is blocked above 730nm.

It is the only one I have found so far though
 
Funnily enough, I've just made a solar filter with a 4" square sheet of Baader film. It's actually for my 4" reflector and I haven't tried it on a camera yet but I'll post a pic tomorrow if I get a chance.
Making a solar filter is very easy, all I did was to make a 3" round hole in a 4" plastic cap and sticj the film in place with duct tape. it's not pretty but works well. The advantage of Baader film over some solar filters is that the sun looks white and not coloured [is that colour temp.?] Plus it's cheap and it definitely beats the welding glass that I usually use, I thought the sun was green :)
 
I have the 16 stop version of the Hitech Firecrest here but not allowed to touch it until my birthday at the end of the month :mad:

Must make my solar filters over the next few days as well. I ordered the film from Rother Valley Optics which gives a more orangy image.
 
@Wissel I think you need to start arm twisting - 16 stop filter is (apparently) perfect for eclipse.
or you could wait until August 26 for the next one


IN 2026!!!!!
 
Chr1stof said:
I'm not an expert on photographing the Sun (despite my avatar) but I am interested in the eclipse, so I phoned a few specialist shops. I was advised that an ND or a combination of NDs is not the way to go as they dont stop IR radiation, the consequence of this is the camera overheating due to the lens acting like a magnifying glass held to the Sun. Its one thing to expose the sensor briefly and another to leave the camera aimed at the sun while composing a shot.
Also, you should be using live view and NOT the viewfinder.
That was the advice given to me.
Click to expand...

Can see the rational behind not using viewfinder, but, would liveview not leave the shutter open and subsequently expose the sensor?
 
How much IR does my 10 stop XCSource ND filter block? How safe will it be to photograph the sun through it?

Using the set up shown in the image below I measured the termperature of the soldering iron as 241C. I then stuck the filter in between iron and sensor and it measured as not even 0.1C above room temperature. An encouraging but not conclusive result. If the sun shows its face before the eclipse I'll have a go at measuring the temperature of the sun, and also measuring its warming effect on the filter, and the temperature of a hot spot focused with a magnifying glass on something black, with and without the filter interposed in the beam.


Is it safe to shoot the sun through my XCSource 10 stop ND filter? An experiment. by Chris_Malcolm, on Flickr
 
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Just remember, you're dealing with more than just the temperature generated by the sun, but also the various wavelengths of light. To be honest, I think it would be incredibly foolish for anyone to try to photography the eclipse, with just a 10 stop filter as protection.
 
johnnypanic said:
Just remember, you're dealing with more than just the temperature generated by the sun, but also the various wavelengths of light. To be honest, I think it would be incredibly foolish for anyone to try to photography the eclipse, with just a 10 stop filter as protection.
Click to expand...

We already know that a 10 stop ND filter reduces all the wavelengths of visible light by 10 stops. That is what it is designed to do. The only problem is the possibility that the ND filter doesn't adequately block enough of the infrared, leading to the possibility of the sensor, shutter curtain, etc. being heated to a damaging extent.
 
johnnypanic said:
Just remember, you're dealing with more than just the temperature generated by the sun, but also the various wavelengths of light. To be honest, I think it would be incredibly foolish for anyone to try to photography the eclipse, with just a 10 stop filter as protection.
Click to expand...
Did you see my post above regarding Firecrest? All frequencies above 730nm are blocked.
 
Hi Guys,

As an astronomer myself I would seriously not use a ND filter as it offers no protection whatsoever from UV and IR light. Cameras and lenses can be replaced but your eyes can not.

I would spend the money and get some proper solar film / filter. I would receommend Baader solar film or (my favourite as it gave a nice orange colour) Seymour Solar filters. I

Cheers,
Eddie
 
johnnypanic said:
Can see the rational behind not using viewfinder, but, would liveview not leave the shutter open and subsequently expose the sensor?
Click to expand...
I think they were assuming you would be using the correct solar filter, then you use live view in case the filter fell off or leaked etc
 
I've tried several 10-Stop ND filters and they all let through IR. I've tested them on my IR-adapted 20D and they tend to be about 6-stoppers for IR. And it's the IR that does the damage to sensors and retinas.

Here's now I made my solar filter - LINK.
 
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