topic Re: Grad ND Filters in EOS DSLR & Mirrorless Cameras

Grad ND Filters

Lillieb — Thu, 27 Oct 2016 16:39:18 GMT

first time buyer off ND Grad Filters for my EOS 6D - some advice would be very welcome. Thank you.

Re: Grad ND Filters

Waddizzle — Thu, 27 Oct 2016 16:45:12 GMT

@Lillieb wrote:
first time buyer off ND Grad Filters for my EOS 6D - some advice would be very welcome. Thank you.

I don't use graduated ND filters. You can add digital filters in post that can do the same thing, and with even greater precision. You can shape the filter, and use multiple overlapping filters to achieve the precise effect you need.

About the only real use I would have for an ND filter is if I were in a situation where I was shooting with a very wide aperture and had too much light, which is actually pretty rare. I have experimented with photographing the Moon with them, too.

Re: Grad ND Filters

RobertTheFat — Thu, 27 Oct 2016 16:56:22 GMT

@Lillieb wrote:
first time buyer off ND Grad Filters for my EOS 6D - some advice would be very welcome. Thank you.

As with a polarizer, don't buy any lens whose front element rotates when the lens is zoomed or focused.

Re: Grad ND Filters

kvbarkley — Thu, 27 Oct 2016 17:36:19 GMT

If you really want one, use one with an external holder so that the graduation can be adjusted up and down to hit the horizon.

I agree with Wadizzle. Don't bother with the filter, simply take a bunch of exposures and put them together in post - possibly with HDR software.

Re: Grad ND Filters

TTMartin — Thu, 27 Oct 2016 22:22:47 GMT

@Lillieb wrote:
first time buyer off ND Grad Filters for my EOS 6D - some advice would be very welcome. Thank you.

There are very few filters that can not be duplicated with digital post processing.

A gradient ND filter is not one of them.

The only filters that can not be duplicated with digital technique are a polarizing filter and a regular ND filters.

So my advice would be to skip buying on and save some money.

Re: Grad ND Filters

Waddizzle — Fri, 28 Oct 2016 00:56:54 GMT

@TTMartin wrote:
@Lillieb wrote:
first time buyer off ND Grad Filters for my EOS 6D - some advice would be very welcome. Thank you.
There are very few filters that can not be duplicated with digital post processing.

A gradient ND filter is not one of them.

The only filters that can not be duplicated with digital technique are a polarizing filter and a regular ND filters.

So my advice would be to skip buying on and save some money.

Here is an example of using digital filters in post processing, instead of an ND filter.

Notice the appearance of the falling water. I didn't use an ND filter to achieve the effect on the water. In addition, I also brightened up the water cascading down the steps with a few Radial Filters. This water was moving very quickly, and the photo was about a half second exposure, shot at f/22. The most glaring "flaw" were the dark areas, which were cleaned up in post using Lightroom.

Re: Grad ND Filters

ebiggs1 — Fri, 28 Oct 2016 14:02:51 GMT

As most of the consensus form above is, filters are mostly obsolete. Learning and how adapt you are at post processing is by far the best way to go.

"The only filters that can not be duplicated with digital technique are a polarizing filter and a regular ND filters."

This statement is only true depending on how well you know how to use editors like Photoshop or not. This person probably doesn't know how. I agree a polarizer is likely the most difficult to master in post but it is possible. It does take advanced skills in PS and a lot of time so I generally still use a polarizer, occasionally. However I never use any of the several dozen filters I had for my film gear. They now collect dust and are doing a fine job of it.

A gradient filter is one of the easiest filters to duplicate in post. It even has a tool built in. An ND usually requires layers to accomplish but is also possible. The polerizer requires the use of channels and layers.

Re: Grad ND Filters

kvbarkley — Fri, 28 Oct 2016 14:08:15 GMT

So Photoshop can reveal what is behind a blown highlight caused by a reflection that a polarizer can remove?

Amazing!

http://www.bobatkins.com/photography/technical/polarizers.html

Note the picture with the frog.

Re: Grad ND Filters

RobertTheFat — Fri, 28 Oct 2016 14:20:35 GMT

@ebiggs1 wrote:
As most of the consensus form above is, filters are mostly obsolete. Learning and how adapt you are at post processing is by far the best way to go.

"The only filters that can not be duplicated with digital technique are a polarizing filter and a regular ND filters."
This statement is only true depending on how well you know how to use editors like Photoshop or not. This person probably doesn't know how. I agree a polarizer is likely the most difficult to master in post but it is possible. It does take advanced skills in PS and a lot of time so I generally still use a polarizer, occasionally. However I never use any of the several dozen filters I had for my film gear. They now collect dust and are doing a fine job of it.

A gradient filter is one of the easiest filters to duplicate in post. It even has a tool built in. An ND usually requires layers to accomplish but is also possible. The polerizer requires the use of channels and layers.

One common use of a polarizer is to get rid of reflections on water, exposing what lies below the surface. And a ND filter can be used to prevent blown highlights. How do you propose to perform those tasks in post-processing, no matter how advanced your skills are and how much time you're willing to spend?

Re: Grad ND Filters

ebiggs1 — Fri, 28 Oct 2016 14:29:38 GMT

I suppose neither of you read this, " I agree a polarizer is likely the most difficult to master ..." It does depend on how advanced you are in the use of PS.

In some cases HDR is used to enhance the ND filter effect. Highlights can easily be captured and even the very darkest parts in a shot.

I don't intend on giving a class on how to use PS here on the Canon forum. If you want to learn how to use PS check into courses by some of the best like Ben Wilmore. There you can learn how. You can even put a frog where a frog can't be seen!

Re: Grad ND Filters

RobertTheFat — Fri, 28 Oct 2016 14:41:00 GMT

@ebiggs1 wrote:
I suppose neither of you read this, " I agree a polarizer is likely the most difficult to master ..." It does depend on how advanced you are in the use of PS.
In some cases HDR is used to enhance the ND filter effect. Highlights can easily be captured and even the very darkest parts in a shot.
I don't intend on giving a class on how to use PS here on the Canon forum. If you want to learn how to use PS check into courses by some of the best like Ben Wilmore. There you can learn how. You can even put a frog where a frog can't be seen!

You're conflating the word "difficult" with the word "impossible". Adding a frog is not the same thing as exposing a frog that is already there. Ask the photographers who have been kicked out of journalism for inserting or deleting an item in a scene.

Re: Grad ND Filters

ebiggs1 — Fri, 28 Oct 2016 15:10:38 GMT

B from B,

"You're conflating the word "difficult" with the word "impossible".

Not really. My take is it is possible. Factual wasn't part of the question. It is "possible" to even make a photo with out the camera. Let alone with out any filters!

Re: Grad ND Filters

TTMartin — Fri, 28 Oct 2016 19:36:00 GMT

@ebiggs1 wrote:
As most of the consensus form above is, filters are mostly obsolete. Learning and how adapt you are at post processing is by far the best way to go.

"The only filters that can not be duplicated with digital technique are a polarizing filter and a regular ND filters."
This statement is only true depending on how well you know how to use editors like Photoshop or not. This person probably doesn't know how. I agree a polarizer is likely the most difficult to master in post but it is possible. It does take advanced skills in PS and a lot of time so I generally still use a polarizer, occasionally. However I never use any of the several dozen filters I had for my film gear. They now collect dust and are doing a fine job of it.

A gradient filter is one of the easiest filters to duplicate in post. It even has a tool built in. An ND usually requires layers to accomplish but is also possible. The polerizer requires the use of channels and layers.
If you have a reflection of cars in the street in a window, there is no way you can simulate the effect of a polarizing filter eliminating that reflection and showing you what is inside of the building.

While you can simulate slow shutter speeds that you get using an ND filter by layerying photos of a waves or a water fall, I don't believe you can effectively simulate the shallow depth of field of using a wide f/1.4 aperture on a sunny day where you needed an ND filter to get the shutter speed below 1/8000.

Re: Grad ND Filters

ebiggs1 — Fri, 28 Oct 2016 20:48:10 GMT

You need to learn how to use Photoshop. If you don't take a college level course, you can get some good insights on the net. Better yet invest in the courses by Ben Wilmore. He is amazing.

I don't intend on giving a PS tutorial here on the forum.

Re: Grad ND Filters

RobertTheFat — Fri, 28 Oct 2016 21:03:36 GMT

@ebiggs1 wrote:
You need to learn how to use Photoshop. If you don't take a college level course, you can get some good insights on the net. Better yet invest in the courses by Ben Wilmore. He is amazing.
I don't intend on giving a PS tutorial here on the forum.

As some perceptive commentator once said, "When you find yourself in a hole you can't get out of, stop digging."

Re: Grad ND Filters

TTMartin — Fri, 28 Oct 2016 23:33:32 GMT

@RobertTheFat wrote:
@ebiggs1 wrote:
You need to learn how to use Photoshop. If you don't take a college level course, you can get some good insights on the net. Better yet invest in the courses by Ben Wilmore. He is amazing.
I don't intend on giving a PS tutorial here on the forum.
As some perceptive commentator once said, "When you find yourself in a hole you can't get out of, stop digging."

Yep

As for Photoshop tutorials, my daughter has a Bachelor's Degree in Visual Communication Design which includes extensive training in the entire Adobe Creative Suite and works full time in that field, if I decide I need any training in Photoshop I'll just ask her.

Re: Grad ND Filters

ebiggs1 — Sat, 29 Oct 2016 14:05:26 GMT

"... I need any training in Photoshop I'll just ask her."

Good idea.

Re: Grad ND Filters

TCampbell — Sun, 30 Oct 2016 15:56:08 GMT

Back on the topic of ND grads...

The grads typically come in 1 stop, 2 stop, and 3 stop versions... and they also use have an option for a "hard edge" vs. a "soft edge" grad.

The 1, 2, and 3 stop difference indicates how much light is blocked by the half of the filter that is tinted. The idea is that you'd meter the light area (presumably that would be the sky) then meter the dark area (presumably that would be the foreground) and note the difference in the exposure. This tells you which grad strength to select.

Next is the issue of "soft" vs. "hard". Both filters have a gradual transition (hence the name "grad") but a "hard" grad has a rapid transition from clear to dark whereas the "soft" has a much slower transition. If you're shooting a scene where with a very clear and clean separation of foreground vs. sky (the scene has a horizon line) then a "hard" edge grad usually is the better choice. If the scene has no strong "horizon line" (elements from the foreground cross the horizon and reach into the "sky" part of the shot) then a "hard" edge grad would look wonky because you'd notice foreground objects having a very obvious transition point. A "soft" edge grad is gentle enough that the viewer probably wont notice the objects are darkened near the top (or whichever direction you decide to orient the filter).

For a full-frame camera, the 100mm filter width (4") is the appropriate size (they do come in sizes).

You'll need a filter holder... Cokin makes them and Lee Filters make them. Lee Filter is a high-end brand, their filters are better and their holders have more options. Cokin will be cheaper (they're a budget name) and they wont have as many options. However... for the basic 100mm (4" width) holder, they'll both work well.

Lastly... can you do this in post-processing or do you need the real filter?

That last question is really an issue of total dynamic range. What you definitely don't want to do is allow the information in your image to "clip" (aka "blown" highlights is usually the problem.) That means if you look at the histogram that represents the distribution of data in your image, the histogram often resembles something that looks like the silhouette of a mountain range on a graph. If one side of that "mountain" is chopped off (either at the left or right edge of the histogram) then it means you lost data that can never be recovered (that's something you cannot fix in Photoshop... unless you're a talaneted artist and can make a really convincing fake.)

This means that if your camera has enough dynamic range to capture whatever the scene needs, then you don't need a physical filter. If the exposure range of the scene exceeds the dynamic range of the camera then a filter would be helpful as it buys you several additional stops worth of range.

Ernie mentioned the use of HDR (HDR = High Dynamic Range photography). In HDR you should use a tripod and the subject should preferably not be moving. You'll take several photographs of the same subject... but each photograph is taken using a different exposure. One of the photographs should be taken using the overall recommended exposure (if you use "evaluative metering" then you use the suggested exposure). Typically you would take at least two additional photos... one is usually deliberately over-exposed by a few stops (often 2 or 3) and the other is typically underexposed by a few stops.

You can then "merge" the three shots. The camera evaluates the middle exposure and finds the brightest and darkest pixels. It then borrows pixels from the over-exposed and under-exposed versions of the shot to integrate into the final exposure and this creates a result where nothing is over-exposed or under-exposed.

I'm not sure about the 6D, but several cameras have a built-in HDR mode. There are many options as to how you process an HDR image and some look rather surreal while others look natural. It is possible to make HDR exposures that look very convincing (they don't "look" like HDR shots) and this is a way to get the shot without using filters at all.

But the one caveat to HDR is that it really helps if nothing in the scene is moving. If objects are moving through the scene then you don't get three (or more) shots with identical scenes (just different exposures) but you end up with three completely different shots that creates "ghosting" problems (like a double-exposure) when you try to merge them. Some of the better software has anti-ghosting algorithms that try to detect and correct this. Since a shot taken with a grad ND filter gets everything in a single exposure, object movement in the scene is not a problem.

Re: Grad ND Filters

Peter — Sun, 30 Oct 2016 19:20:21 GMT

@Lillieb wrote:
first time buyer off ND Grad Filters for my EOS 6D - some advice would be very welcome. Thank you.

I use Tiffen ND grad made of glass. I use Lee filter holder. Glass is expensive but will last the rest of your life if you don't drop it. Formatt-Hitech also makes glass filters.

This picture was taken with a plastic filter from Hitech (Formatt-Hitech these days) with hard edge. My plastic filter has lots of scratches and you can see the reflections from the sun in the middle. Also notice the dark part abote to the right in the picture.

Re: Grad ND Filters

Mitsubishiman — Sun, 30 Oct 2016 21:22:22 GMT

I agree with every comment, I only utilize a good CP - Hoya, and Hoya NDs, however my only reason for an ND is a very long exposure that I need to stop beyond the camera setting.

I went to a photo class where the two instructors were big on external grad NDs, after seeing what most PPS vendors have I never understood with the flexibility they have why one would bother.