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Post by Eric on Nov 9, 2012 1:33:56 GMT -5
Neutral density filters sometimes are not truly neutral. This is a test of a low cost set that I purchased from Amazon. It consists of: Graduated ND2 ND4 ND8, Full ND2 ND4 ND8 Filters, Filter Bag, Square Filter Holder, Square Lens Hood, and Complete Adapter Ring Set, 52, 55, 58, 62, 67, 72 and 77MM. This filter set compatible with Cokin P Series. Cost of this set was under $50.  This is my attemp to photograph a color wheel while adding filters to identify any changes in the color due to any off neutral coloration. To get started on this little project I needed a color wheel which I didn’t have. So off to the local arts and craft supply store to find and purchase one. They only had a very small wheel, not near as big as I had hoped. So, I left and headed over to Staples. After trying to explain a color wheel to one of the workers, he pointed me in the direction of their art area. Nope, no color wheel here ether. Well, at this point I was about to give up and head back home. There is also a Home Depot there and I had a few things I wanted to pick there unrelated to this project. I ended up in the paint area. I started to select some of the many color chips thinking that I could use some of those for checking the filter color shift. One of the workers asked if I needed any help. I asked if they had any color wheels for paint color selections. He said, “Sure, I have just what you need.” He came back with a rather large set of all the different colors they can make with a screw attached to one end that would allow the set to fan out in a large circle. This is what I ended up using for my test. I setup my light tent and used two daylight cfl that have a light temp of 6450 to illuminate the color wheel and other paint chip samples. The following set of photos are with the color offset due to the filters. I have a hard time telling the difference. This was my setup.  This photo is with NO FILTER.  This is with the ND8 filter.  This is with the ND8 + ND4 filters.  This photo is with all three ND filters, ND8+ND4 and ND2.  This color temp plot shows the shift in color temp as I added each filter.  This plot shows the shift in shutter speed as each filter was added.  For the money I believe this set does a good job and I would recommend it to anyone looking for a low cost set. Over this coming weekend I’ll take some photos using my welding helmet gold plated glass filters. I believe I have #9 and #12. These are dark very dark. I have used them for viewing the sun. I’ll share the data from these two filters. |
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Post by Karl Wertanen on Nov 9, 2012 1:48:45 GMT -5
Damn Eric. Good effort and good post.
I would like see the cokin in comparison... Just because the color shift is so terrible. I wonder if it would look any different and if direct sunlight would make any difference in results. That was when i had color shift issues. Direct morning and evening sunlight and in the sky.
Good post
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ronwarren
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Post by ronwarren on Nov 9, 2012 7:20:32 GMT -5
Great post. If you get a chance, could you post a link to where to find and purchase that filter kit? I'm poking around Amazon but I haven't found it, yet. Thanks, R
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Post by Eric on Nov 9, 2012 8:12:03 GMT -5
Thanks guys for the comments. Ron, try this www.amazon.com/gp/product/B00867PFZY/ref=oh_details_o03_s00_i00. Karl, I could be way off base here, but my 35+ years ago memory seems to be telling me that you can get a color shift with some film due to extended exposure times. So I have to ask if there is something on the web that confirm or discount this notion of mine? Karl, with your early morning sun, do you recall what color you were experiencing? I believe what ever the shift we should be able to duplicate it with the light tent setup. |
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Post by Karl Wertanen on Nov 9, 2012 8:37:58 GMT -5
I've since got rid of my cokin filters because it was so bad. Now that I use the Singh-ray filters in Cokins place, I no longer have the color shifts and I have not changed my process 1 bit. It's definately the filter. Cokin is notorious for it as many cheap filters are. The color shifts I was getting with cokin was a murky maroon color... I've heard some describe it as magenta but it looks maroon to me.
In order to prevent color shift due to reciprocity failure, every exposure on film over 2 seconds you are supposed to overexpose 1 stop (which can be a large amount of time in some circumstances) and that eliminates the recipeocity failure color shift. However it will not remove the color shift due to cheap ND's.
Edit: forgot to mention that you cannot see the color in the filter with your eye when you hold it up to different light. As soon as it was on the lens and an exposure taken, it was there. Even Daniel mentioned he experienced a color shift with his digital.
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Deleted
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Post by Deleted on Nov 9, 2012 10:37:56 GMT -5
yeah, I get a magenta/maroon color shift with my Cokins. Intrigued with this set though. I've been looking at eventually getting a kit to replace my cokins. These look cheap and no color shift. zoomed in, how is the quality still? While we are on ND Filter reviews, I did some pretty extensive testing on my Marumi 3 stop ND filter. You can see my results on my blog here -> www.danfrei.com/?p=14I really like the Marumi brand ND so much I got their circular polarizer and a protective filter from them and have all been great. |
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Post by Eric on Nov 12, 2012 9:58:40 GMT -5
In the quest to find lower cost ND photography filters, I decided to look into filters I have for one of my other trained disciplines, welding. In comparison most welding helmets used today are self-darkening filters. For the benefit of those unfamiliar, these self-darkening filters allow you to have the helmet on, looking through the filter to get ready to start welding, and as soon as the weld starts, the lens electronically darkens to protect your eyes. They work well, but give a monochrome view to what you are welding. On more critical welds, like on parts used on an aircraft, I personally like a fixed filter, like the ones pictured here. These filters allow a larger field of view and the manufacture claims they "Improved visibility to see the welding arc in true natural colors". This to me would suggest they are neutral density to truly show "natural colors." These are glass filters.  I ordered two new welding filters, Anchor Brand. I have a couple of these already but not in the shade levels of these two. The two I ordered were shade 9 and 12. When welding with a plasma arc it is suggested to use the darkest shade you can, yet still see what you are welding. For me, this is normally no higher than 11 and I try to go no lower than 10. Sometimes on thin material the power requirement is very low and a shade 9 is needed to allow me to see. The cost for these two filters, the Anchor shade 9 and shade 12, with tax and shipping to my home cost about $6. I compare these two filters to see how true to the claim of "natural colors" they are. For this test I use my light tent and two daylight cfl lights in the same fashion as the earlier write-up on filters made for photography.  The above photo with the two packaged Anchor Brand filters, are in my light tent lit with two daylight cfl bulbs. The photo below shows the untouched results with the Anchor #12 shade. As you can easily tell, the filter causes a strong green tint. The #9 gave a similar result.  In conclusion, these welding filters may work for photographing in black and white or viewing the sun, but for color photography I would choose something else. The green tint is more than can easily be corrected. This last shot shows the results of trying to white-balance correct the above image.  |
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Post by Karl Wertanen on Nov 12, 2012 10:13:16 GMT -5
Nice work Eric. Some good material for the blog.
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Post by Eric on Nov 12, 2012 10:35:19 GMT -5
Hey Karl, that’s one of my favorite words, reciprocity!  This word is common in the world of modal analysis, one of the many jobs I had in the past. For those that may not be familiar and want to know I think it would help to explain what this means. It has to do with the related affects from two or more different perspectives. In the modal analysis world, once reciprocity no longer applies it means that other unaccounted for factors or nonlinearities are affecting the results. Though I haven’t really thought about it, it would apply when the normal exposure calculation no longer works. To an old film photographers view point coming into the digital photography realm, I am finding new words to describe things compared to years past. Just one example and I would guess there are plenty more, what we once referred to film grain or graininess is now known as noise. This newer term "noise" makes since to me also working with digital analysis equipment for well over 35 years, it also applies to digital photography. I love talking bits and byte, though my wife finds them pretty boring!  |
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engineerd
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Post by engineerd on Nov 12, 2012 20:55:41 GMT -5
Great review! I'll have to check these out.
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Alfer
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Post by Alfer on Nov 14, 2012 16:43:17 GMT -5
Any recomendation on 9-10 stops that dont have any color cast? I have hoya nd400 and the blue cast is ruining every attempt on strobist photo im doing.
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Post by Karl Wertanen on Nov 14, 2012 21:22:55 GMT -5
Any recomendation on 9-10 stops that dont have any color cast? I have hoya nd400 and the blue cast is ruining every attempt on strobist photo im doing. I've heard high high remarks about the Lee Big Stopper (10 stop) and the Singh Ray Vari ND (a variable neutral density filter that you can change the ND density rating by turning the front of the filter like a circular polarizer). The Veri-ND is either 8 or 10 stops max... I can't remember for sure but it's one or the other. They are a bit pricey but I know people love them and i know the quality is there. Tiffen also makes really high quality glass filters but i have not heard of their 10 stop yet, but i never looked into it yet either. I don't have either but I will have one of those come spring time. Google search reviews on these filters and you might get an answer to your question. |
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Deleted
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Post by Deleted on Nov 15, 2012 1:06:47 GMT -5
Marumi, my current favorite brand of circular filters, has a 16 stopper for under 100. Multi-coated, glass. I have several Marumi filters and wrote a review on the 3 stopper I have from them linked in my post above if you care to read it. When/if I go with a "big stopper", I'll likely go with this theirs. www.amazon.com/Marumi-77mm-DHG-Neutral-Density/dp/B0068V25JE/ |
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Alfer
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Post by Alfer on Nov 19, 2012 3:57:20 GMT -5
Thank you for your reply guys. Just wanted to know if you have some experience with 6-10 stops filter. Looking into the big stopper also. Joey L uses the same filter but its too expensive for me right now. Again, thank you and great review
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Post by gtwhogger on Dec 7, 2012 18:18:22 GMT -5
Wish I would have seen this a few years back? but since then I chucked my Cokins and went with LEE
Nice review, thanks.
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