# Choosing the right GND Filter



## edurieux (Mar 11, 2016)

Hello guys,

I'm more and more interested in landscape photography so I decided to purchase a filter kit. I do not buy the kit for a special kind of pictures, I just want a polyvalent kit that can suit most situations.

I am shooting most of the time with the 6D with a 17-40L or the 50A. 

I bought the Formatt Hitech holder with two Firecrest 100mm square filters, a 4 stop and an 8 stop.
I am currently wondering which GND I can take to complete my kit. The soft grads seems to be more polyvalent than the hard grads, but I may be wrong.

Next, what is the real practical difference between the 125mm and the 150mm filters ?

And finally, what density would you choose ? I usually bracket with a 2ev shift (-2, 0, +2) so maybe a 4 stops would be a good choice ? What do you think ?


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## kaihp (Mar 11, 2016)

edurieux said:


> Hello guys,
> 
> I'm more and more interested in landscape photography so I decided to purchase a filter kit. I do not buy the kit for a special kind of pictures, I just want a polyvalent kit that can suit most situations.
> 
> ...



As I understand it, the hard grads are usually used with Tele lenses, whereas the soft ones with wide angle lenses. I grabbed both, and as far as I recall, I tend to use the hard grad the most, even on Wide-angle lenses.


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## Valvebounce (Mar 11, 2016)

Hi edurieux. 
I think the hard vs soft grad is mainly down to what the scenery is like, seascapes, flat prairie, hard horizon hard grad, rolling hills, mountains, uneven tree line, soft horizon soft grad. 

Cheers, Graham.


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## edurieux (Mar 11, 2016)

Thanks for your answers.



Valvebounce said:


> I think the hard vs soft grad is mainly down to what the scenery is like, seascapes, flat prairie, hard horizon hard grad, rolling hills, mountains, uneven tree line, soft horizon soft grad.



Exactly, that is why I think the soft grads are the most appropriate as first GND.
What do you think about grads and size ?


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## Zeidora (Mar 11, 2016)

I have sets (1,2,3 stops) of both and use hard at least 80% of the time, including WA shots. I hardly use 1 stop (OD 0.3), but use 2 and 3 stops about equally (OD 0.6 and 0.9).

Re width, depends on your lenses. There should be specs out there from the filter manufacturer. I do fine with 4" on my 21 with 82 filter thread on FF (90 degree angle of view), and even on LF with a 72 mm (110 degrees).


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## edurieux (Mar 11, 2016)

Zeidora said:


> I have sets (1,2,3 stops) of both and use hard at least 80% of the time, including WA shots.



I guess I will have to get both hard and soft filters then !



Zeidora said:


> Re width, depends on your lenses. There should be specs out there from the filter manufacturer. I do fine with 4" on my 21 with 82 filter thread on FF (90 degree angle of view), and even on LF with a 72 mm (110 degrees).



I am not wondering about width, I know the 100mm size is enough for most lenses.
But the rectangular GNDs comes in two sizes : 125 and 150mm, And I wonder what is the difference on the field.


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## ahsanford (Mar 11, 2016)

Seascapes, hard horizons do well with hard grads.

Many other applications with uneven horizons might do better with soft grads (or bracketed compositions if you subject allows, wind isn't an issue, etc.). 

For grad strength, check out this basic method (1:59 - 2:35 or so in this video) but I'd recommend spot metering off your 6D's center AF point as a best practice if you go this route. I usually need 2-3 stops between foreground and sky when I use grads, but it depends on what you shoot and what time of day you shoot it.

And the biggest caveat I can give with front-filtering: if you have the ultra-ultra-wide angle sickness (which many on this forum do) -- say if you shoot in the 11-16mm FF range -- *read up on filter system vignetting before you commit to pricier filters*. 

With vignetting and front filters, everything is an 'it depends' phenomenon (FL principally, but also the specific lens in question, how much you want to stack ND / ND Grad / CPL, etc.), but generally things go to hell under 16mm FF as a rough rule. If you want to shoot wider than 16mm FF with front-filtering (or ever want to someday), it might be best to invest in specialized larger format filters/holder like Lee's SW150 or Wonderpana's FreeArc system to avoid hard intrusions in your FOV. Those systems are pricier across the board and require larger bag space to do the job, but they uniquely solve a tough problem.

Thankfully, I don't have the U-UWA sickness and the Lee 100mm system (likely similar to your Hitech setup) completely covers me down to 16mm and I'm fine. 

- A


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## jprusa (Mar 11, 2016)

I have the set of 1-3 stop hard filters but made the mistake of getting a 4 stop reverse GND and the others are hardly ever used.


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## MrFotoFool (Mar 11, 2016)

As already stated or implied, hard edge filters only work if the horizon is straight. If you photograph at the ocean or in flat plains, this is fine, but for most uses I think a soft edge is more practical.

Though I do not do HDR myself, I imagine many photographers are now doing this instead of using graduated ND filters. The obvious advantage is it works well with uneven horizons, such as mountains.

I used to have a Cokin grad (the larger "pro" size). I never bought the holder, I just held it up to the lens with my hand. I barely used it and got rid of it. Now on the rare occasions I need something like this I do a long exposure and just hold my hand or a black cloth in front of the upper part of the lens for the first half of the exposure. Not always precise, but it works surprisingly well.


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## Deleted member 91053 (Mar 11, 2016)

edurieux said:


> Hello guys,
> 
> I'm more and more interested in landscape photography so I decided to purchase a filter kit. I do not buy the kit for a special kind of pictures, I just want a polyvalent kit that can suit most situations.
> 
> ...



Don't forget the reverse grads that Formatt make. I am not a great user of filters but a friend has one of Formatt's reverse grad filters. I have used it and we both agree that this is a far more useful graduated filter type than the normal graduated filters as it eliminates the darkening at the top of the frame and reduces over bright horizons. They are not cheap but VERY well worth investigating.
I would happily dump all my existing grads for one or two of these!


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## ahsanford (Mar 11, 2016)

johnf3f said:


> Don't forget the reverse grads that Formatt make. I am not a great user of filters but a friend has one of Formatt's reverse grad filters. I have used it and we both agree that this is a far more useful graduated filter type than the normal graduated filters as it eliminates the darkening at the top of the frame and reduces over bright horizons. They are not cheap but VERY well worth investigating.
> I would happily dump all my existing grads for one or two of these!



I've never used a reverse grad. Aren't they principally for sun-in-frame sunrise/sunset shots? Do they serve any purposes beyond that?

- A


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## Deleted member 91053 (Mar 12, 2016)

ahsanford said:


> johnf3f said:
> 
> 
> > Don't forget the reverse grads that Formatt make. I am not a great user of filters but a friend has one of Formatt's reverse grad filters. I have used it and we both agree that this is a far more useful graduated filter type than the normal graduated filters as it eliminates the darkening at the top of the frame and reduces over bright horizons. They are not cheap but VERY well worth investigating.
> ...



I never thought of using one for a "Sun in Frame" shot - you have got me thinking now!
I have only used my friends reverse grad a couple of times (on FF with a 24-105) and I thought it gave a more even rendition of skies/clouds rather than the bright horizon and progressively darker skies that conventional grads tend to give.
The trouble with graduated filters is that we all have different expectations and experiences but, for what it's worth, I am no longer looking for conventional grads - I want reverse grads but they are pricey!


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