Graduated Filter Setup

[Andrew Stannard]

Hi,

Haven't posted around here for a while - been annoyingly too busy for much photogrpahy! Anyhow, starting to get a bit more free time now.

I'm wanting to invest in some graduated filters for landscape photography with my 20D. I know with digital I can take 2 exposures and blend, but I'd rather spend my time photographing than behind photoshop. My current plan is to purchase the following:

Lee Filter Holder, 67mm and 77m wide angle adaptors, Hitech Graduated Filters.

Question is: Should I initially go for the Hard or the Soft?

I've read in a couple of places that with a 1.6x crop sensor a hard filter is more like a soft anyhow, so am a little confused.

Ignoring any sensor issues I am tending towards soft, but would appreciate any advice from someone using soft NDs on a 1.6x sensor.


Thanks,

 

[Ray West]

Hi Andrew,

As nobody who knows the specific filters has come forward, since a cropped sensor only covers the central part of the lens image circle, it follows that a graduated filter will only get its centre part used. Thus a hard filter will appear softer (only the centre of the filter will have an effect, that central region will be spread over the cropped image area, giving a softer effect, if you enlarge the cropped image to the same size as the full sized sensor. Now whether a hard filter on a crop sensor is as soft as a soft filter on a full size sensor, depends on the relative hardness to softness factor. Now, are you still confused? ;-)

Best wishes,

Ray

 

[Andrew Stannard]

Thanks Ray,

Been thinking about this some more and yep, still confused.

I think it must come down to FoV in the end though. If I'm using a 20mm lens on my 20D then the graduation effect ought to be the same as if I was using a 32mm lens on a 5D, after all the FoV will be the same and the filter isn't any further/closer to the lens in either case?

Unless there's something else that comes into play in which case the confusion will go deeper

 

[Bart_van_der_Wolf]

Been thinking about this some more and yep, still confused.

I think it must come down to FoV in the end though. If I'm using a 20mm lens on my 20D then the graduation effect ought to be the same as if I was using a 32mm lens on a 5D, after all the FoV will be the same and the filter isn't any further/closer to the lens in either case?

Correct. All the filter does is ultimately apply a density gradient over the entire projected image circle. On a 'cropped' sensor, only part of that entire image circle is used, so you won't get the minimum/maximum attenuation. The gradient used will determine how fast the overall transition will be, and with a 'cropped' sensor it will seem a bit more gradual because only part of the total transition is effectively used.

While I'm unfamiiar with the specific filters mentioned, I'd caution against the hard versions in general, unless you only shoot flat sky-lines.

Bart

 

[Ray West]

And the weather we've been getting here, you need to use it 'upside down' to lighten the sky ;-)

 

[Andrew Stannard]

And the weather we've been getting here, you need to use it 'upside down' to lighten the sky ;-)

Too right! There's no flooding here in Lancashire, but I've got friends in Tewkesbury and things are really bad there. I'm hoping were going to get an 'Indian summer' as I'm off down to Porlock at the end of August and will want to use my new filters

Bart - Thanks for your input. I think I'm going to start with some soft filters and then get a hard filter if I feel the need. Most of my use is likely to be on my 10-22mm, so we're talking a pretty wide FoV.