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Archive 2012 · Is "13" stops enough?

  
 
Jo Dilbeck
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p.1 #1 · Is "13" stops enough?


Ok, I know welders glass or eclipse glasses are best, but here's what I've got: Hoya ND16(4stops), 2xND8(3stops each), 1xND4 (2stops)and a polarizer(1-2 stops), total 13-14 stops of density. Will this work for shooting the eclipse at 6:30PDT? Can't see a damn thing looking through the filters off the lens, and glancing at the sun through the filters seems to be ok.

Any thoughts from the pros? I certainly don't want to fry the sensor in my camera, and will be using live view if this will work.

Jo



May 20, 2012 at 05:34 PM
RobDickinson
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p.1 #2 · Is "13" stops enough?


You multiply ND for exposure values.

i.e. two 3 stop filtes = 9 stops

But to shoot the sun you need about 40-50 stops + I think?

Know someone who shot sunspots with nd 64 at 1/8000th f14



May 20, 2012 at 05:43 PM
Pixel Perfect
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p.1 #3 · Is "13" stops enough?


RobDickinson wrote:
You multiply ND for exposure values.

i.e. two 3 stop filtes = 9 stops



That's not right Rob. You add the number of stops. You are right in that the effect of the filters is multiplied, but that's not the same as multiplying the stop values.

A 3 stop filter transmits 1/2^3 = 1/8th of the light. Put another one behind it, and it will transmit 1/8th of the light hitting it too, so all upi you get 1/8*1/8 = 1/64th the available light transmitted. But 1/64 is a six stop reduction. A 9 stop reduction is 1/512 reduction. This is the beauty of working with stops, you can just add them up.



May 20, 2012 at 06:22 PM
Photon
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p.1 #4 · Is "13" stops enough?


Whayne is of course exactly right about working with stops. One concern - I'm not sure how well typical photo ND filters block UV. I don't know about the sensor's vulnerability, but you say live view, so your eyes should be safe...


May 20, 2012 at 06:28 PM
Pixel Perfect
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p.1 #5 · Is "13" stops enough?


One problem with stacking ND's, is unless they are very neutral you quickly end up with strong colour casts, especially magenta it seems. You can fix it if you shoot RAW but it is something to be aware of. OF the reviews I've seen no ND is entirely neutral, at high enough density, and you do tend to get what you pay for.


May 20, 2012 at 06:43 PM
Jo Dilbeck
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p.1 #6 · Is "13" stops enough?


Yup, I get what I pay for, but since that's all I have to work with, as long as it doesn't fry my sensor, what have I got to lose?


May 20, 2012 at 06:47 PM
Tom K.
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p.1 #7 · Is "13" stops enough?


How would you like to do a 9 hour exposure and at the last second someone accidentally bumps into the tripod?


May 20, 2012 at 10:59 PM
Jeff_Stapleton
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p.1 #8 · Is "13" stops enough?


well...now that we've discussed...lets see some pictures


May 20, 2012 at 11:26 PM
Photon
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p.1 #9 · Is "13" stops enough?


Tom K. wrote:
How would you like to do a 9 hour exposure and at the last second someone accidentally bumps into the tripod?

If I had a scene set up and ISO/aperture/ND calculated for 9 hours exposure, I wouldn't really care if someone bumped the tripod at the last second. It would have no discernible effect on the image, being only 1/32,400 of the total exposure! Of course, if they wrecked my equipment I would care.



May 21, 2012 at 12:22 AM
Tom K.
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p.1 #10 · Is "13" stops enough?


Photon wrote:
If I had a scene set up and ISO/aperture/ND calculated for 9 hours exposure, I wouldn't really care if someone bumped the tripod at the last second. It would have no discernible effect on the image, being only 1/32,400 of the total exposure! Of course, if they wrecked my equipment I would care.


Now that is something that I did not know.



May 21, 2012 at 12:28 AM
Shutterbug2006
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p.1 #11 · Is "13" stops enough?


A fellow working in a camp in Norman Wells, BC, used a #11 green welding helmet lens and some duct tape to snap his shots. He posted them HERE


May 21, 2012 at 02:31 PM
stanj
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p.1 #12 · Is "13" stops enough?


I did fine with an NDX400 drop-in filter in my 400DO during full occlusion only, and with 19 stops on my 70-200 to even get sun spots and corona. Not that this helps you now


May 21, 2012 at 05:53 PM
mco_970
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p.1 #13 · Is "13" stops enough?


Jo - let's see the pics!!


May 21, 2012 at 06:16 PM
gpchase
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p.1 #14 · Is "13" stops enough?


Nice shots Stan..could a person use the Big Stopper and be safe ?


May 21, 2012 at 06:30 PM
stanj
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p.1 #15 · Is "13" stops enough?


gpchase wrote:
Nice shots Stan..could a person use the Big Stopper and be safe ?


How many stops is that? I can look at the sun with a 200mm with a 10 stop filter, but it's painful. With the 19 stops (3 stacked) it was a piece of cake. With the 400 looking into the full sun with only a 10-stopper is not something I would recommend, plus the 400 DO hates nothing like looking into direct light...



May 21, 2012 at 06:33 PM
mco_970
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p.1 #16 · Is "13" stops enough?


Nice shots, Stan! I like that you included the personal connection shots, too.


May 21, 2012 at 06:33 PM
Jo Dilbeck
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p.1 #17 · Is "13" stops enough?


I haven't had time to process my pix, but I used 1 16x, 2 8x and 1 4x ND filters. Put towel over lens and camera between shots, used live view only, and as far as I can tell from the LCD, everything came out ok. Of course, it's black sky, white sun, and black moon, honestly rather boring in the long term scheme of things to me. Once you've seen one like this, you've pretty much seen them all.

The most interesting part of my session was standing next to a couple from Florida who came all the way to Oroville CA to shoot the eclipse. We're going to share photos, I'm hoping they got some good ones because they were using true solar filters.



May 21, 2012 at 06:36 PM
gpchase
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p.1 #18 · Is "13" stops enough?


The Lee Big Stopper is 10 stops I believe. I recently picked one up but have yet to try it and would not care to suffer the results of pointing it at the sun if incorrect..


May 21, 2012 at 06:37 PM
stanj
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p.1 #19 · Is "13" stops enough?


gpchase wrote:
The Lee Big Stopper is 10 stops I believe. I recently picked one up but have yet to try it and would not care to suffer the results of pointing it at the sun if incorrect..


Depending on focal length you can be fine. I don't think it would be wise on a long lens, but with a 200 it will be painful but doable. Note that the max f-stop of the lens also matters, as you're looking thru the viewfinder wide open. A f4 lens will give you a full stop advantage over the f2.8 that I was using. It doesn't matter when taking the picture, but for LV or viewfinder it does. You can always dial in f11 or something and hold the DOF preview button, but you better not let go.



May 21, 2012 at 06:40 PM
mco_970
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p.1 #20 · Is "13" stops enough?


Jo Dilbeck wrote:
I haven't had time to process my pix, but I used 1 16x, 2 8x and 1 4x ND filters. Put towel over lens and camera between shots, used live view only, and as far as I can tell from the LCD, everything came out ok. Of course, it's black sky, white sun, and black moon, honestly rather boring in the long term scheme of things to me. Once you've seen one like this, you've pretty much seen them all.

The most interesting part of my session was standing next to a couple from Florida who came all the way
...Show more

I know what you mean about pix looking similar, but still interesting to me... The gear/technique behind the shots is of interest.

I was out working in the garden when it happened and all I felt was dizzy. Kind of like being drunk & wondering who turned out the lights.



May 21, 2012 at 06:46 PM
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