ND and sound solutions for film at DVinfo.net

Martin Noboa · October 22nd, 2006, 06:33 AM

Hi, I’m new around here, and before shooting my first feature with an HVR a1, I wanted to have a couple of advices from you guys...2 things:

Planning to use ND filters to achieve at least a bit of shallow dof; in the 37 mm camera lens, and in the VCL-HG0737Y with the cavision lens hood (Filter thread: 82mm), but I’m not sure of the graduation I’d need, if 2f 4f 6f or 8f, no idea, and I’d be shooting on a road, countryside, city, day and night...so which ones would you recommend?

And secondly, I have a Me64 mic, which I plan to use indoors and outdoors in a boompole, and I also hasve an ATpro88 + the sony mic supply by the camera, but these two are not so hot so I’m planning on ordering a rode ntg1 or ntg2, to complement the Me64 and thus shoot with both mics indoors and outdoors (two mono mics) and then in post in audio mixing try to generate a stereo feeling... My question is, this audio setting is going to make a quality sound difference over going only ME64 on both xlr channels?

and that’s the situation, I have not much money to invest on an 35mm adapter, and as the shooting is the 25 of november, I decided to invest the small budget I have left in the rode + nd the filters + lens hood...

I appreciate your help

martin

Alex Thames · October 22nd, 2006, 09:17 PM

Filter thread 82mm? Isn't it 77mm?

Martin Noboa · October 23rd, 2006, 01:46 AM

yes, sorry, it´s 77mm, but that´s what I meant:

¨The Cavision LH77 Lens hood is made for the Sony VCL-HG0737Y lens, and allows you to attach 82mm filters to the inside of the lens hood¨

Tom Hardwick · October 23rd, 2006, 02:50 AM

Remember that your A1 already employs internal (and undocumented) ND filtration. These filters move in and out of the optical axis to keep the lens diaphragm working at its sweet spot of f/4, so unless it's exceedingly bright you'll not need to add more. If you feel you must shoot wide open for differential focus it might be better to up the shutter speed one notch to soak the last stop.

In fact, adding filters is always a problem with tiny 1"/3 chipped camcorders due the the pretty wide dof. If you must, have them as 37 mm filters, and not 77 mm further away from the front element where any imperfection will be recorded when you shoot into the light.

Remember too that if you add filters and use the standard hood you lose hooding efficiency because its internal depth is reduced. Oh, another thing. If you buy filters do make sure they're super multi-coated. You're adding a new fromt element to your camcorder, so it better be the best you can buy.

tom.

Martin Noboa · October 23rd, 2006, 04:12 AM

thanks tom. That´s was pretty clear...

And what about the mics?
Should I go for the ntg2 (mount on camera) and rec together with the ME64 (boompole) in two separete channels or stay with the ME64 and rec just one mono mic in rec ch select to channel 1

maybe add the sony mic supplied by the camera or the ATpro88, but I´m not too fan of these two...

Tom Hardwick · October 23rd, 2006, 04:28 AM

Martin, whatever you do you need to get the mics as close as possible to the voice you're recording. Shotguns are designed to be used up close in the same way as tie-clips.

So yes, mic on a pole is good and NTG2 backup on camera to the other track.

tom.

Alex Thames · October 23rd, 2006, 04:23 PM

I don't understand. Why use 37mm filters instead of 82mm (or 77mm or whatever)? How does 1/3" chip relate to the use of filters and depth of field? Wouldn't you see the imperfections regardless if it were 37mm or 77mm or 82mm filter?

I'm also confused what you mean by use 37mm filters instead of being 77mm away? The Y lens has a 77mm diameter. It doesn't put the front part 77mm away from the original lens.

How does putting filters on reduce the hooding efficiency?

And I really don't understand this deal with hoods anyways? I have never found it to be a problem at any zoom position. I mean, I think if you just put your hand to block stray light rays, you don't even need a hood? And I would think a hand is far less accurate than a hood. So I guess I'm confused how having a right aspect ratio hood and right length of hood affects anything? Could you explain further? Thanks!

Tom Hardwick · October 24th, 2006, 01:20 AM

That's a lot of questions Alex, but much better to ask than to carry on being confused.

>Why use 37mm filters instead of 82mm?

OK. The A1's zoom lens probably has 12 elements in the lineup. Adding a filter adds another element and brings with it the chance that it's not perfectly clean (both sides) and of course each piece of glass adds a small amount of flare. Lots of filters out there are completely uncoated, and this adds a whole lot of flare.

Last Friday I shot as second cameraman at a wedding, using Bob's VX2000. I noticed he had an uncoated 'protective' UV filter on his lens and within 20 seconds I could demonstrate the losses incurred, and had him unscrewing it immediately. He took the one off his PD170 as well, as he simply had not realised how they could degrade his image quality so.

The dof of the A1 when used at the wide-angle end of the zoom can easily extend from a cm or so in front of the lens to a few metres, even allowing for the internal ND that limits the aperture to f/4. When this happens, dust on the filter can be easily seen as you shoot into the light. Using a 77mm filter even further away from the chips means the dust and imperfections are all the more in focus, and the degredation all the more obvious. See what I mean?

Many cameras (TRV900, VX2000 etc) have the hood bayonetted onto the camcorder's lens barrel. That's fine, no problem. But just imagine that you screwed 10 filters onto the front of the lens - now they'd protrude from the front of the lens hood, and it would be perfectly useless at shielding the lens.

Of course you'd never dream of doing this, but I'm just showing you that every filter you add reduces the hood's efficiency.

A camcorder's lens hood is only efficient at the wide-angle end of the zoom anyway, and at any other focal length it loses efficiency. So yes, hooding the front element with you hand is a good idea - always remembering of course that you're seeing an overscanned v/finder image and you could well be obsuring part of the full frame.

Remember that a lens hood is doing one job only (maybe two if it keeps raindrops off) - and that is to stop non image-forming light hitting the front element.

I do a quick demo with my students. I get them all to look straight at me across the room, keeping their eyes fixed on mine. When asked, they all say yes, they can indeed see the overhead fluorescent lights even though they're not looking up at them.

This light is hitting their corneas and it's exactly the same with a camera's front element. I now pull on a peaked cap, completely blocking out the overhead lights as I look back at them. My eyes now give more accurate exposure as well as the image of the class having less flare (our corneas are not multi-coated).

Sorry to have gone on so long. If you'd been with me for 10 minutes Alex I'd have convinced you that the lens hood is the cheapest, lightest, best accessory you can buy, full stop.

tom.

Alex Thames · October 26th, 2006, 02:09 AM

Thanks for the explanations. They make perfect sense, and you don't have to convince me to get a sunshade because I already have one - the LH77 from Cavision. So far, I haven't noticed any flaring unless shooting virtually directly at the sun. This is even with noticeable spots on my Y wideangle lens, which I really should clean, but I don't have any cleaners.

I want a filter for a few reasons - for the filtered effect and for protection, although I'm thinking that protection isn't much help because for the super-multi-coated filters, they cost just as much as the Y lens, so it's investing $1 to protect $1 (roughly). Absolutely useless.

Now I'm still unsure why an aspect ratio of the sunshade has any effect though. Could you explain that?

Also, if the shade is most effective at the widest angle, then why not have an extremely long sunshade so that even when zoomed all the way in, the shade would still prove effective?

Finally, about the overscanning - not a problem on the A1 as it has the all-scan option to view the entire frame.

Tom Hardwick · October 26th, 2006, 02:41 AM

Modern lens coatings are a lot tougher that they were 30 years ago and cleaning with a micro-fibre cloth is all that's needed. Sparingly and gently though.

You can't have a lens hood that effectively hoods the telephoto end of the zoom or you'd vignette the image (see inside the hood) as you zoomed back towards wide.

Hoods are designed for one purpose only - to keep non image forming light off the front element. So it needs to be accurately aspect ratio shaped to do this most effectively and efficiently.

tom.

October 22nd, 2006, 06:33 AM	#1
Martin Noboa Regular Crew Join Date: Oct 2006 Location: paris Posts: 55	ND and sound solutions for film Hi, I’m new around here, and before shooting my first feature with an HVR a1, I wanted to have a couple of advices from you guys...2 things: Planning to use ND filters to achieve at least a bit of shallow dof; in the 37 mm camera lens, and in the VCL-HG0737Y with the cavision lens hood (Filter thread: 82mm), but I’m not sure of the graduation I’d need, if 2f 4f 6f or 8f, no idea, and I’d be shooting on a road, countryside, city, day and night...so which ones would you recommend? And secondly, I have a Me64 mic, which I plan to use indoors and outdoors in a boompole, and I also hasve an ATpro88 + the sony mic supply by the camera, but these two are not so hot so I’m planning on ordering a rode ntg1 or ntg2, to complement the Me64 and thus shoot with both mics indoors and outdoors (two mono mics) and then in post in audio mixing try to generate a stereo feeling... My question is, this audio setting is going to make a quality sound difference over going only ME64 on both xlr channels? and that’s the situation, I have not much money to invest on an 35mm adapter, and as the shooting is the 25 of november, I decided to invest the small budget I have left in the rode + nd the filters + lens hood... I appreciate your help martin

October 22nd, 2006, 09:17 PM	#2
Alex Thames Major Player Join Date: Feb 2006 Location: New York Posts: 508	Filter thread 82mm? Isn't it 77mm?

October 23rd, 2006, 01:46 AM	#3
Martin Noboa Regular Crew Join Date: Oct 2006 Location: paris Posts: 55	yes, sorry, it´s 77mm, but that´s what I meant: ¨The Cavision LH77 Lens hood is made for the Sony VCL-HG0737Y lens, and allows you to attach 82mm filters to the inside of the lens hood¨

October 23rd, 2006, 02:50 AM	#4
Tom Hardwick Inner Circle Join Date: Mar 2003 Location: Billericay, England UK Posts: 4,711	Remember that your A1 already employs internal (and undocumented) ND filtration. These filters move in and out of the optical axis to keep the lens diaphragm working at its sweet spot of f/4, so unless it's exceedingly bright you'll not need to add more. If you feel you must shoot wide open for differential focus it might be better to up the shutter speed one notch to soak the last stop. In fact, adding filters is always a problem with tiny 1"/3 chipped camcorders due the the pretty wide dof. If you must, have them as 37 mm filters, and not 77 mm further away from the front element where any imperfection will be recorded when you shoot into the light. Remember too that if you add filters and use the standard hood you lose hooding efficiency because its internal depth is reduced. Oh, another thing. If you buy filters do make sure they're super multi-coated. You're adding a new fromt element to your camcorder, so it better be the best you can buy. tom.

October 23rd, 2006, 04:12 AM	#5
Martin Noboa Regular Crew Join Date: Oct 2006 Location: paris Posts: 55	thanks tom. That´s was pretty clear... And what about the mics? Should I go for the ntg2 (mount on camera) and rec together with the ME64 (boompole) in two separete channels or stay with the ME64 and rec just one mono mic in rec ch select to channel 1 maybe add the sony mic supplied by the camera or the ATpro88, but I´m not too fan of these two...

October 23rd, 2006, 04:28 AM	#6
Tom Hardwick Inner Circle Join Date: Mar 2003 Location: Billericay, England UK Posts: 4,711	Martin, whatever you do you need to get the mics as close as possible to the voice you're recording. Shotguns are designed to be used up close in the same way as tie-clips. So yes, mic on a pole is good and NTG2 backup on camera to the other track. tom.

October 23rd, 2006, 04:23 PM	#7
Alex Thames Major Player Join Date: Feb 2006 Location: New York Posts: 508	I don't understand. Why use 37mm filters instead of 82mm (or 77mm or whatever)? How does 1/3" chip relate to the use of filters and depth of field? Wouldn't you see the imperfections regardless if it were 37mm or 77mm or 82mm filter? I'm also confused what you mean by use 37mm filters instead of being 77mm away? The Y lens has a 77mm diameter. It doesn't put the front part 77mm away from the original lens. How does putting filters on reduce the hooding efficiency? And I really don't understand this deal with hoods anyways? I have never found it to be a problem at any zoom position. I mean, I think if you just put your hand to block stray light rays, you don't even need a hood? And I would think a hand is far less accurate than a hood. So I guess I'm confused how having a right aspect ratio hood and right length of hood affects anything? Could you explain further? Thanks!

October 24th, 2006, 01:20 AM	#8
Tom Hardwick Inner Circle Join Date: Mar 2003 Location: Billericay, England UK Posts: 4,711	That's a lot of questions Alex, but much better to ask than to carry on being confused. >Why use 37mm filters instead of 82mm? OK. The A1's zoom lens probably has 12 elements in the lineup. Adding a filter adds another element and brings with it the chance that it's not perfectly clean (both sides) and of course each piece of glass adds a small amount of flare. Lots of filters out there are completely uncoated, and this adds a whole lot of flare. Last Friday I shot as second cameraman at a wedding, using Bob's VX2000. I noticed he had an uncoated 'protective' UV filter on his lens and within 20 seconds I could demonstrate the losses incurred, and had him unscrewing it immediately. He took the one off his PD170 as well, as he simply had not realised how they could degrade his image quality so. The dof of the A1 when used at the wide-angle end of the zoom can easily extend from a cm or so in front of the lens to a few metres, even allowing for the internal ND that limits the aperture to f/4. When this happens, dust on the filter can be easily seen as you shoot into the light. Using a 77mm filter even further away from the chips means the dust and imperfections are all the more in focus, and the degredation all the more obvious. See what I mean? Many cameras (TRV900, VX2000 etc) have the hood bayonetted onto the camcorder's lens barrel. That's fine, no problem. But just imagine that you screwed 10 filters onto the front of the lens - now they'd protrude from the front of the lens hood, and it would be perfectly useless at shielding the lens. Of course you'd never dream of doing this, but I'm just showing you that every filter you add reduces the hood's efficiency. A camcorder's lens hood is only efficient at the wide-angle end of the zoom anyway, and at any other focal length it loses efficiency. So yes, hooding the front element with you hand is a good idea - always remembering of course that you're seeing an overscanned v/finder image and you could well be obsuring part of the full frame. Remember that a lens hood is doing one job only (maybe two if it keeps raindrops off) - and that is to stop non image-forming light hitting the front element. I do a quick demo with my students. I get them all to look straight at me across the room, keeping their eyes fixed on mine. When asked, they all say yes, they can indeed see the overhead fluorescent lights even though they're not looking up at them. This light is hitting their corneas and it's exactly the same with a camera's front element. I now pull on a peaked cap, completely blocking out the overhead lights as I look back at them. My eyes now give more accurate exposure as well as the image of the class having less flare (our corneas are not multi-coated). Sorry to have gone on so long. If you'd been with me for 10 minutes Alex I'd have convinced you that the lens hood is the cheapest, lightest, best accessory you can buy, full stop. tom.

October 26th, 2006, 02:09 AM	#9
Alex Thames Major Player Join Date: Feb 2006 Location: New York Posts: 508	Thanks for the explanations. They make perfect sense, and you don't have to convince me to get a sunshade because I already have one - the LH77 from Cavision. So far, I haven't noticed any flaring unless shooting virtually directly at the sun. This is even with noticeable spots on my Y wideangle lens, which I really should clean, but I don't have any cleaners. I want a filter for a few reasons - for the filtered effect and for protection, although I'm thinking that protection isn't much help because for the super-multi-coated filters, they cost just as much as the Y lens, so it's investing $1 to protect $1 (roughly). Absolutely useless. Now I'm still unsure why an aspect ratio of the sunshade has any effect though. Could you explain that? Also, if the shade is most effective at the widest angle, then why not have an extremely long sunshade so that even when zoomed all the way in, the shade would still prove effective? Finally, about the overscanning - not a problem on the A1 as it has the all-scan option to view the entire frame.

October 26th, 2006, 02:41 AM	#10
Tom Hardwick Inner Circle Join Date: Mar 2003 Location: Billericay, England UK Posts: 4,711	Modern lens coatings are a lot tougher that they were 30 years ago and cleaning with a micro-fibre cloth is all that's needed. Sparingly and gently though. You can't have a lens hood that effectively hoods the telephoto end of the zoom or you'd vignette the image (see inside the hood) as you zoomed back towards wide. Hoods are designed for one purpose only - to keep non image forming light off the front element. So it needs to be accurately aspect ratio shaped to do this most effectively and efficiently. tom.