V1U and Protective Filter at DVinfo.net

Alex Raskin · June 9th, 2007, 12:46 AM

So the theory goes that it's always good to protect your lens by putting a neutral UV filter on it.

Question: won't that extra glass introduce extra reflections and other imperfections, readily visible in HD resolution?

Serena Steuart · June 9th, 2007, 12:54 AM

The filters have anti-reflection coatings, so you won't get reflections. You might if you had a strong light (e.g. the Sun) striking the lens, but then you get all manner of internal reflections. It's true that any extra glass absorbs light, which is the reason astronomers make efforts to cut optical elements to a minimum. However in video 1-2% isn't going to be noticed. Imperfections? That's why filters are made with optical quality glass and are expensive.

Marcus Marchesseault · June 9th, 2007, 01:02 AM

HD resolution isn't all that amazing that minor lens flaws are blatantly obvious. However, it is possible to get reflections from bright sources. It's not a bad idea to add a protective filter, just be aware that you may have situations where you might need to remove it to prevent what looks like a flare. I'm using the Cokin P filter system and I got a clear UV filter for rough service. The good thing about square filters is that they are very easy to remove and it only takes a second. They can be switched or replaced quickly for changing conditions. Also, larger circular filters are expensive and the square filters can be very cheap if you get the plastic (resin) kind.

Alex Raskin · June 9th, 2007, 08:13 AM

I have not used matte boxes before. Cokin P system looks attractive though.

What are the advantages/disadvantages of Cokin P vs regular screw-in filters?

One disadvantage I see is that I will no longer be able to use V1U's camera hood as supplied with the cam.

The advantages seem to be... faster filter changes? and maybe a more professional look of the rig? what else?

Back to the UV filters: this guy

http://www.bhphotovideo.com/c/produc...in_Filter.html

does not have the usual description such as anti-reflective multicoating etc., which is what I'd normally want for the glass filters. How to choose the right resin filter?

Alex Raskin · June 9th, 2007, 08:48 AM

Found this site about Cokin filters, seems very informative and objective:

http://www.geocities.com/cokinfiltersystem

Marcus Marchesseault · June 9th, 2007, 08:22 PM

The advantages of the Cokin filters are affordability and quick changes. I actually think the polarizer is a decent filter, but the square resin are not coated. I haven't been that impressed with coated filters as there is still a reflection but it turns the color of the coating. A hood is the only thing that will stop flares and glass reflections in the lens. In the worst case scenario, all filters need to be removed from the lens and screw-on filters make that difficult. Yes, multi-coated filters are better, but they aren't going to allow you to shoot into the sun without reflections.

The resin UV and ND filters are so cheap that they are practically disposable. I keep them as clean as possible and it seems like I might get away with using the glass polarizer and an ND filter without too much trouble. In a nasty environment, I would even add a clear filter and remove it as it gets contaminated.

Another advantage to all square filter holders in general is the ability to position the filter precisely in front of the lens. A gradual filter is best used when it can be aligned with the bright part of the scene. For example, in a landscape shot the area of gradation would be aligned with the horizon. Round filters just can't do this at all.

Filters aren't a casual endeavor. I think it is probably wise to get a system of cheap filters and learn exactly what you need first before you spend a thousand dollars on a mattebox and basic filter kit. An entire Cokin setup only costs about $100 (holder kit, polarizer, ND grad, UV) and it is a great learning tool even if you end up buying a high-end system later.

EDIT

I checked out that link and it does look very useful. I forgot the primary reason I decided to change to square filters until I went there. With a square filter system, all your filters can be used with any camera as long as you buy an adapter ring for those cameras. You can also get some of that effect with round filters by getting filters all of the largest size you might use and using step-up rings on your smaller lenses. That's why I got the 72mm circular Ultra Contrast 3 filter. I couldn't find a contrast filter for the Cokin system so I put the round contrast filter behind the square filters. I chose 72mm because it is the same size as my 35mm lens adapter and the same as many other HDV cameras.

Alex Raskin · June 10th, 2007, 07:11 AM

Many thanks Marcus, I appreciate your detailed explanation!

June 9th, 2007, 12:46 AM	#1
Alex Raskin Trustee Join Date: Sep 2003 Posts: 1,435	V1U and Protective Filter So the theory goes that it's always good to protect your lens by putting a neutral UV filter on it. Question: won't that extra glass introduce extra reflections and other imperfections, readily visible in HD resolution?

June 9th, 2007, 12:54 AM	#2
Serena Steuart Major Player Join Date: Jun 2006 Location: Studio Alnitak, Melbourne, Victoria, Australia Posts: 640 Images: 3	UV filter The filters have anti-reflection coatings, so you won't get reflections. You might if you had a strong light (e.g. the Sun) striking the lens, but then you get all manner of internal reflections. It's true that any extra glass absorbs light, which is the reason astronomers make efforts to cut optical elements to a minimum. However in video 1-2% isn't going to be noticed. Imperfections? That's why filters are made with optical quality glass and are expensive. Last edited by Serena Steuart; June 9th, 2007 at 12:57 AM. Reason: To complete answer

June 9th, 2007, 01:02 AM	#3
Marcus Marchesseault Trustee Join Date: Nov 2005 Location: Honolulu, HI Posts: 1,961	HD resolution isn't all that amazing that minor lens flaws are blatantly obvious. However, it is possible to get reflections from bright sources. It's not a bad idea to add a protective filter, just be aware that you may have situations where you might need to remove it to prevent what looks like a flare. I'm using the Cokin P filter system and I got a clear UV filter for rough service. The good thing about square filters is that they are very easy to remove and it only takes a second. They can be switched or replaced quickly for changing conditions. Also, larger circular filters are expensive and the square filters can be very cheap if you get the plastic (resin) kind.

June 9th, 2007, 08:13 AM	#4
Alex Raskin Trustee Join Date: Sep 2003 Posts: 1,435	I have not used matte boxes before. Cokin P system looks attractive though. What are the advantages/disadvantages of Cokin P vs regular screw-in filters? One disadvantage I see is that I will no longer be able to use V1U's camera hood as supplied with the cam. The advantages seem to be... faster filter changes? and maybe a more professional look of the rig? what else? Back to the UV filters: this guy http://www.bhphotovideo.com/c/produc...in_Filter.html does not have the usual description such as anti-reflective multicoating etc., which is what I'd normally want for the glass filters. How to choose the right resin filter?

June 9th, 2007, 08:48 AM	#5
Alex Raskin Trustee Join Date: Sep 2003 Posts: 1,435	Found this site about Cokin filters, seems very informative and objective: http://www.geocities.com/cokinfiltersystem

June 9th, 2007, 08:22 PM	#6
Marcus Marchesseault Trustee Join Date: Nov 2005 Location: Honolulu, HI Posts: 1,961	The advantages of the Cokin filters are affordability and quick changes. I actually think the polarizer is a decent filter, but the square resin are not coated. I haven't been that impressed with coated filters as there is still a reflection but it turns the color of the coating. A hood is the only thing that will stop flares and glass reflections in the lens. In the worst case scenario, all filters need to be removed from the lens and screw-on filters make that difficult. Yes, multi-coated filters are better, but they aren't going to allow you to shoot into the sun without reflections. The resin UV and ND filters are so cheap that they are practically disposable. I keep them as clean as possible and it seems like I might get away with using the glass polarizer and an ND filter without too much trouble. In a nasty environment, I would even add a clear filter and remove it as it gets contaminated. Another advantage to all square filter holders in general is the ability to position the filter precisely in front of the lens. A gradual filter is best used when it can be aligned with the bright part of the scene. For example, in a landscape shot the area of gradation would be aligned with the horizon. Round filters just can't do this at all. Filters aren't a casual endeavor. I think it is probably wise to get a system of cheap filters and learn exactly what you need first before you spend a thousand dollars on a mattebox and basic filter kit. An entire Cokin setup only costs about $100 (holder kit, polarizer, ND grad, UV) and it is a great learning tool even if you end up buying a high-end system later. EDIT I checked out that link and it does look very useful. I forgot the primary reason I decided to change to square filters until I went there. With a square filter system, all your filters can be used with any camera as long as you buy an adapter ring for those cameras. You can also get some of that effect with round filters by getting filters all of the largest size you might use and using step-up rings on your smaller lenses. That's why I got the 72mm circular Ultra Contrast 3 filter. I couldn't find a contrast filter for the Cokin system so I put the round contrast filter behind the square filters. I chose 72mm because it is the same size as my 35mm lens adapter and the same as many other HDV cameras.

June 10th, 2007, 07:11 AM	#7
Alex Raskin Trustee Join Date: Sep 2003 Posts: 1,435	Many thanks Marcus, I appreciate your detailed explanation!