ND4 + ND8 vs. no ND = no difference?

[PhilD]

I have bought ND4 and ND8 for Cokin P and when I stack them both I don't see much difference in bright light? What am I doing wrong? I want more uniform pictures, I don't want highlights fighting with darks.

Yes Cokin is a cheaper alternative to the circular filters but shouldn't they make a difference? They reduce the shutter speed a lot so I can get closer to 1/50 but image-wise there's not much difference.

Thanks

 

[delaney]

Make sure your shutter/aperture is locked.

 

[PhilD]

Make sure your shutter/aperture is locked.

In manual mode it only seems to make the image darker when I put the filters and then I have to compensate.

 

[Ben_B]

ND filters are not to make the image more uniform they are to make it darker so you can have your aperture wider open in brighter light to keep shallow DOF without having to raise the shutter speed, and also to avoid closing the aperture too far and losing image quality due to diffraction. I don't think they'll help you get a more uniform image. You can try reducing contrast all the way on the custom film mode settings.

You might be thinking of graded ND filters which have a darker part at top (usually) than bottom, and are used for wide shots with lots of sky visible (balancing it.)

 

[PhilD]

You can try reducing contrast all the way on the custom film mode settings.

It does make some difference but not enough for my taste... any way to dial it down even more than -2?

You might be thinking of graded ND filters which have a darker part at top (usually) than bottom, and are used for wide shots with lots of sky visible (balancing it.)

Yes but since I do a lot of run & gun, gradeds are useless for me. Or maybe I'll try them just to see.

 

[Ben_B]

It does make some difference but not enough for my taste... any way to dial it down even more than -2?



Yes but since I do a lot of run & gun, gradeds are useless for me. Or maybe I'll try them just to see.

I wouldn't.

I do mostly filmmaking not run and gun so if I am having dynamic range problems I just throw more light up on my scene and stop down (not always practical in daylight outdoor though.)

That said for run and gun outdoor you will want ND filters, but they can't magically make the camera have better dynamic range. One thing I would recommend is being aware of where the sun is in the sky, etc, and try not to shoot into, but rather with your back to it; your subject will be brighter and the sky will be darker!

 

[delaney]

Also for run & gun a nice little trick for outdoors is to attach an ND2 and CPL this becomes a variable ND with the ability glare reduction as a bonus. Not the most control but still fast and easy to change.

 

[Ben_B]

Not sure what kind of shooting you're doing but this being summer we get a nice long magic hour at end of day when sun has gone down but it's still bright out...very even lighting everywhere, no shadows, no highlights, and a sky at a similar brightness to everything else...great fun shooting then.

 

[Mike@AF]

Also for run & gun a nice little trick for outdoors is to attach an ND2 and CPL this becomes a variable ND with the ability glare reduction as a bonus. Not the most control but still fast and easy to change.

An ND filter with a CPL filter becomes a variable ND? I don't think so. You'd need two CPLs or a CPL and a linear pola.

 

[delaney]

An ND filter with a CPL filter becomes a variable ND? I don't think so. You'd need two CPLs or a CPL and a linear pola.

Opps, yeah... I meant a CPL and a LP. Typing faster than I'm thinking obviously.

 

[nathankw]

As I understand it ND's are designed not to change the picture at all, except to reduce the amount of light. So if you compensate with shutter / aperture, the image itself won't change.

Perhaps what you want is a low contrast or ultra contrast filter:
http://www.tiffen.com/contrast_filters.htm

Anyone had any experience of using them with the GH1?

 

[Ozpeter]

So if you compensate with shutter / aperture, the image itself won't change.

Changing shutter speed and/or aperture does in itself change the image, which is the whole point of using the ND filter (to allow you to do just that).

 

[nathankw]

Yes, absolutely. But the ND itself should leave the picture unchanged so that you can get the benefit of changing the DoF or the motion blur without changing balance of the picture.

 

[PhilD]

As I understand it ND's are designed not to change the picture at all, except to reduce the amount of light. So if you compensate with shutter / aperture, the image itself won't change.

Perhaps what you want is a low contrast or ultra contrast filter:
http://www.tiffen.com/contrast_filters.htm

Anyone had any experience of using them with the GH1?

From seeing this it seems that it's nothing I can't do in Photoshop.

 

[PhilD]

Opps, yeah... I meant a CPL and a LP. Typing faster than I'm thinking obviously.

Do you know how variable ND works with Cokin? Do you stack the linear pola farther to get less ND or something?

 

[dvbrother]

From seeing this it seems that it's nothing I can't do in Photoshop.

True, but by applying the filter in front of the lens, as opposed to in post-production, the quality of your final image should be, in theory, better. If you apply a low contrast look in post, you are essentially lifting the shadows, which with the GH1's AVCHD compression, you run a serious risk of revealing compression artifacts and other unwanted noise. With a low con filter in front of the lens, this problem will not happen. Personally, I don't like the low contrast look. It doesn't add dynamic range in my opinion. It just makes everything look milky.
A circular polarizer may help you get what you want, considering it can cut the glare off of bright objects. In theory, that may allow you to iris up a bit and therefore the darker parts of the image get brighter without blowing out the highlights.

 

[PhilD]

A circular polarizer may help you get what you want, considering it can cut the glare off of bright objects. In theory, that may allow you to iris up a bit and therefore the darker parts of the image get brighter without blowing out the highlights.

What should I get between a circular and linear polarizer? The linear is cheaper and I've heard the only difference is that the linear doesn't allow DSLRs to focus properly (DSLRs excluding the GH1 apparently)

 

[Ben_B]

Yes excluding the GH1. Are you going to be taking mostly photos or videos? If you're doing photos have you looked indo HDR photography? I think you can do a mild version of the effect to get what you're trying to get. I have been experimenting with doing video composites and adding the sky into my wideshots with something kind of like the HDR technique (shooting two or more exposures.) Works nicely, but only for ultra wide shots with no camera movement.

 

[PhilD]

Yes excluding the GH1. Are you going to be taking mostly photos or videos? If you're doing photos have you looked indo HDR photography? I think you can do a mild version of the effect to get what you're trying to get. I have been experimenting with doing video composites and adding the sky into my wideshots with something kind of like the HDR technique (shooting two or more exposures.) Works nicely, but only for ultra wide shots with no camera movement.

Yes I have heard of HDR but to me the effect has to be very subtle otherwise it looks like a framegrab from a videogame.


I've found this:
http://www.popphoto.com/Reviews/Accessories/Filter-Factor

Double polarization

That's what I need!

 

[yslee]

For compatibility's sake I believe a CPL is better, so you can use them with any future SLRs or cameras.

Now, I just want to stress what others have said already; if you want to increase dynamic range you'll need to be careful when setting up your shot. The ND stands for Neutral Density, and there's a reason why it's called Neutral!