Exposure Lock and ND Filter at DVinfo.net

Kevin Samborn · May 28th, 2006, 07:49 PM

Hi-

I have an Optura 30, and I'm trying to understand how to use a Neutral Density filter. I'm a relative novice at this, so I apologize if this is a naive question. I've read the manual many times, and I don't completely get it.

I guess my question is, if possible, do I need to set the exposure completely manually? Or, do I simply let the camera automatically set the exposure, and then I use the Exposure Lock to manually make adjustments?

Does it make a difference with or without the Neutral Density filter?

(I am trying the ND filter for two different things: 1) very shallow depth of field in normal conditions, and 2) getting better color out of my subjects when making ski movies - I don't care if the snow is blown out! I'm practicing in the summer...)

Thanks,
Kevin

Vic Macky · May 29th, 2006, 01:15 AM

A good first step is to check out this link http://www.cs.mtu.edu/~shene/DigiCam...filter-ND.html as it gives you the general idea of how neutral density works. It maybe for slr or dslr cameras but it will give youthe idea on how neutral density works and should answer your question whether it makes a difference.

Since im still a newbie i can't really say much about the exposure. i'm sorry about that but as far i understand exposure you only adjust it when there is an under or overexposure on your subject.

There are other members here who are more knowledgeable i'm sure they will give more inputs as they read your post.

Michael Wisniewski · May 29th, 2006, 10:38 AM

Use the Optura 30 like you normally would, you don't have to do anything special when using the neutral density filter.

The Optura 30 can create a shallow depth of field but the effect is very limited. The ND filter will help you achieve this in bright conditions by letting you open the aperture.

To enhance the shallow DOF effect on the Optura 30:

open the aperture in bright light
- by using a high shutter speed and/or the ND filter
- by manually making the exposure brighter
zoom-in to your subject
get them close to the camera
put some distance between your subject and the background.

Kevin Samborn · May 29th, 2006, 02:26 PM

Thank you very much, Michael-

One follow up / two questions:

To open the aperture, if I choose

- "by using using a high shutter speed and/or using an ND filter" - does the camera open the aperture automatically? I would think yes
- "by manually making the exposure brighter" - this means by choosing Exposure Lock and then increasing the exposure, right? So, I have to be careful if the camera has already chosen the "optimal" exposure, I guess. Or do you mean something else.

Again, thank you.

Michael Wisniewski · May 29th, 2006, 09:49 PM

Quote:

Originally Posted by Kevin Samborn

"by using using a high shutter speed and/or the ND filter" - does the camera open the aperture automatically?

Yes, in both cases, the Optura 30 will automatically open up the aperture, unless it's ridiculously bright. You can open the aperture manually by selecting a shutter speed: 1/60 - 1/2000, then use the Exposure Lock to increase the exposure.

Tom Hardwick · June 13th, 2006, 05:16 AM

The Canon has internal ND filtering and considering the size of the chips you should be wary of using external NDs, unless they're super multi-coated, spotlessly clean and well hooded.

Uping the shutter speed quickly leads to CCD smear on the 30, so beware taking this route. So yes - let the camera decide in auto, then lock in that setting for your shot. Don't let diaphragmm bounce spoil the shot just because a black car or a white shirt fleetingly crossed your frame.

tom.

Kevin Samborn · June 13th, 2006, 11:30 AM

Hi Tom-

Thanks for your info.

One question - how do I turn on the internal ND filter in the Optura 30? Is it switchable?

Thanks,
Kevin

Tom Hardwick · June 13th, 2006, 11:51 AM

No, it's not switchable. The ND is a tiny sliver of a filter, positioned very close to the diaphragm blades so that the edge of the filter is completely out of focus on the chip, and even small intrusions of the filter soak light from the whole frame.

As light levels increase the more the filter intrudes into the light path. So the lens goes to f/4 or thereabouts, then the internal ND will take over, probably soaking the next three stops. So an exposure that would need 1/50th at f/11 will actually be 1/50th and f/4 plus lots of ND. This happens in auto as well as manual, but of course you're not told about it, even on replay.

This gives much sharper pictures, because diffraction at small apertures (smaller than f/4) with very short focal lengths is very damaging to resolution.

tom.

May 28th, 2006, 07:49 PM	#1
Kevin Samborn New Boot Join Date: Apr 2006 Location: Swampscott, MA Posts: 14	Exposure Lock and ND Filter Hi- I have an Optura 30, and I'm trying to understand how to use a Neutral Density filter. I'm a relative novice at this, so I apologize if this is a naive question. I've read the manual many times, and I don't completely get it. I guess my question is, if possible, do I need to set the exposure completely manually? Or, do I simply let the camera automatically set the exposure, and then I use the Exposure Lock to manually make adjustments? Does it make a difference with or without the Neutral Density filter? (I am trying the ND filter for two different things: 1) very shallow depth of field in normal conditions, and 2) getting better color out of my subjects when making ski movies - I don't care if the snow is blown out! I'm practicing in the summer...) Thanks, Kevin

May 29th, 2006, 10:38 AM	#3
Michael Wisniewski Wrangler Join Date: Jul 2002 Location: Makati, Metro Manila Posts: 2,706 Images: 32	Use the Optura 30 like you normally would, you don't have to do anything special when using the neutral density filter. The Optura 30 can create a shallow depth of field but the effect is very limited. The ND filter will help you achieve this in bright conditions by letting you open the aperture. To enhance the shallow DOF effect on the Optura 30: open the aperture in bright light by using a high shutter speed and/or the ND filter by manually making the exposure brighter zoom-in to your subject get them close to the camera put some distance between your subject and the background. __________________ "Ultimately, the most extraordinary thing, in a frame, is a human being." - Martin Scorsese

May 29th, 2006, 01:15 AM	#2
Vic Macky New Boot Join Date: May 2006 Location: usa Posts: 14	A good first step is to check out this link http://www.cs.mtu.edu/~shene/DigiCam...filter-ND.html as it gives you the general idea of how neutral density works. It maybe for slr or dslr cameras but it will give youthe idea on how neutral density works and should answer your question whether it makes a difference. Since im still a newbie i can't really say much about the exposure. i'm sorry about that but as far i understand exposure you only adjust it when there is an under or overexposure on your subject. There are other members here who are more knowledgeable i'm sure they will give more inputs as they read your post.

May 29th, 2006, 02:26 PM	#4
Kevin Samborn New Boot Join Date: Apr 2006 Location: Swampscott, MA Posts: 14	Thank you very much, Michael- One follow up / two questions: To open the aperture, if I choose - "by using using a high shutter speed and/or using an ND filter" - does the camera open the aperture automatically? I would think yes - "by manually making the exposure brighter" - this means by choosing Exposure Lock and then increasing the exposure, right? So, I have to be careful if the camera has already chosen the "optimal" exposure, I guess. Or do you mean something else. Again, thank you.

June 13th, 2006, 05:16 AM	#6
Tom Hardwick Inner Circle Join Date: Mar 2003 Location: Billericay, England UK Posts: 4,711	The Canon has internal ND filtering and considering the size of the chips you should be wary of using external NDs, unless they're super multi-coated, spotlessly clean and well hooded. Uping the shutter speed quickly leads to CCD smear on the 30, so beware taking this route. So yes - let the camera decide in auto, then lock in that setting for your shot. Don't let diaphragmm bounce spoil the shot just because a black car or a white shirt fleetingly crossed your frame. tom.

June 13th, 2006, 11:30 AM	#7
Kevin Samborn New Boot Join Date: Apr 2006 Location: Swampscott, MA Posts: 14	Hi Tom- Thanks for your info. One question - how do I turn on the internal ND filter in the Optura 30? Is it switchable? Thanks, Kevin

June 13th, 2006, 11:51 AM	#8
Tom Hardwick Inner Circle Join Date: Mar 2003 Location: Billericay, England UK Posts: 4,711	No, it's not switchable. The ND is a tiny sliver of a filter, positioned very close to the diaphragm blades so that the edge of the filter is completely out of focus on the chip, and even small intrusions of the filter soak light from the whole frame. As light levels increase the more the filter intrudes into the light path. So the lens goes to f/4 or thereabouts, then the internal ND will take over, probably soaking the next three stops. So an exposure that would need 1/50th at f/11 will actually be 1/50th and f/4 plus lots of ND. This happens in auto as well as manual, but of course you're not told about it, even on replay. This gives much sharper pictures, because diffraction at small apertures (smaller than f/4) with very short focal lengths is very damaging to resolution. tom.