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thechickencow
01-27-2008, 03:32 PM
I'm starting this thread with hopes that people with experience using these filters will be able to help us n00bs out.

Lets assume people can figure out how to put them on the camera, but go from there, i.e. lining up the edge, picking hard vs. soft edge, what stop filter to use, picking exposure, checking exposure, etc.

thomps6s
01-27-2008, 09:10 PM
Great post. I am interested in this as well. I never put much thought on it though, I always put them on and used them to benefeit the scene in front of me if I felt I needed to balance the exposure. Probably not the best tactic.

Stime187
01-27-2008, 09:32 PM
I thought I replied to this?

Anyways, great thread idea, I'll put together a reply when I get a few minutes.

uncle_git
01-28-2008, 03:37 PM
I've used various techniques for positioning grads - just remember to stop down to shooting aperture when positioning the grad as it will "move" as the camera stops down.

I've used gaffer tape or even a grey card held at the division line to help position the grad accurately in pre-dawn photo's

thomps6s
01-28-2008, 04:00 PM
I've used various techniques for positioning grads - just remember to stop down to shooting aperture when positioning the grad as it will "move" as the camera stops down.

I've used gaffer tape or even a grey card held at the division line to help position the grad accurately in pre-dawn photo's

Why would the Grad ND move when stopping down? Does your lens spin when you adjust your aperture?

uncle_git
01-28-2008, 05:56 PM
Nope - the actual grad line will move up and down the image - try it and see for yourself - tape paper or something over a lens and view it wide open - then use DOF preview to stop down.

I'm not sure optically WHY it does - but sure as a brick in the face hurts, it moves when you stop down.

So always position the grad with the lens stopped down to shooting aperture.

thechickencow
02-14-2008, 01:12 AM
I thought I replied to this?

Anyways, great thread idea, I'll put together a reply when I get a few minutes.

Did you get a couple minutes yet?

I've got my grads now and although I haven't taken them out of the box yet I'm excited to try them out.

Stime187
02-14-2008, 01:19 AM
Did you get a couple minutes yet?

I've got my grads now and although I haven't taken them out of the box yet I'm excited to try them out.

:lol: I'll hit this up tomorrow, Jay. I totally forgot about it.

Stime187
02-14-2008, 04:42 PM
I'll give this a quick rundown...

The Goal:

The goal of neutral density filters is to lower the dynamic range in a shot to an acceptable amount for your camera's sensor to capture. Sunsets, sunrises, etc are the primary uses.

You don't want the viewer to ever know a grad. ND was used in the shot, you have to learn to "hide" your grad. ND lines. This is completely doable and not very hard but a lot of people get discouraged when they're starting out. Most of my shots don't require any "touch up" but I do occasionally dodge part of the image in PhotoShop to remove signs of the filter. THIS SHOULD BE TOUCH-UP (!!), if you're spending more than a couple minutes, you did something wrong.

Soft vs. Hard:

Basically, there's two main types of Grad. NDs, soft line and hard line graduation. I use hard line when there is a distinct horizon or line of light that I can lay my grad. line across and have it blend in. I use soft line when the line I want to graduate isn't as distinct or there's something stopping me from my typical hard line.

I use hard line most of the time, in either a 2 or 3-stop variety.

Determining what filter to use:

If you want to get technical you can meter the dark area (the part you want to expose more) and the highlight area (the part you want behind neutral density) and determine the difference in order to select your filter, I don't do any of that.

I've gotten a decent feel for when to use what filter and I rely on my camera's histogram. If I put on a 2-stop and the highlights are still too hot with the shadows still too dark, I put on the 3-stop. If the 3-stop makes the dynamic range to narrow on the histogram or makes the image look unrealistic, I back off to the 2-stop. It's really a feel thing that just takes some experience playing with them.

Holder:

Lots of people use filter holders and lots of people hand-hold the filters. I do both at times, but I prefer a holder. Basically, you put the filter in the holder, and line up the dark part over the highlights and the clear part over the shadows in the shot. You do this by adjusting the filter up and down while watching the graduation line and rotating the filter side to side to hit certain angles.

Lots of people use the DOF preview button to do this but I never and don't plan on starting. I can see the filter and place it fine without that and in my opinion, that's just an extra step to complicate things.

Handling:

Yes, they are filters, you should be semi-careful with them. But to be honest, mine get abused and yours will get scratched/blemished/covered in finger prints. It happens, don't worry about it. The filters will be fine and still function.

----

Anyways, I'm sure someone can pick this apart for things that are "wrong", but the above works well for me and if you have any questions or want clarification, just ask. I pretty much wrote that off the top of my head so I'm sure I left plenty of details out.

Hope it helps.

thechickencow
02-19-2008, 10:28 PM
So you typically don't worry too much about a dust spot or two on the filters when you're shooting, or do you clean them before a shot?

Mine are dirty, and I haven't even used them yet!

Stime187
02-19-2008, 10:34 PM
So you typically don't worry too much about a dust spot or two on the filters when you're shooting, or do you clean them before a shot?

Mine are dirty, and I haven't even used them yet!

Sometimes I wipe them off before I shoot with them, that's as much cleaning as they ever get.

Ask Mike (Rowan611) on here about my old set, he owns them now. He can tell you mine were pretty messed up. Nothing too bad, but certainly not clean and pretty. They still work awesome though.

It really doesn't matter in my opinion. I have a new set and they'll be just as screwed up before too long.

Colorblinded
02-19-2008, 11:17 PM
I'll give this a quick rundown...

The Goal:

The goal of neutral density filters is to lower the dynamic range in a shot to an acceptable amount for your camera's sensor to capture. Sunsets, sunrises, etc are the primary uses.

You don't want the viewer to ever know a grad. ND was used in the shot, you have to learn to "hide" your grad. ND lines. This is completely doable and not very hard but a lot of people get discouraged when they're starting out. Most of my shots don't require any "touch up" but I do occasionally dodge part of the image in PhotoShop to remove signs of the filter. THIS SHOULD BE TOUCH-UP (!!), if you're spending more than a couple minutes, you did something wrong.

Soft vs. Hard:

Basically, there's two main types of Grad. NDs, soft line and hard line graduation. I use hard line when there is a distinct horizon or line of light that I can lay my grad. line across and have it blend in. I use soft line when the line I want to graduate isn't as distinct or there's something stopping me from my typical hard line.

I use hard line most of the time, in either a 2 or 3-stop variety.

Determining what filter to use:

If you want to get technical you can meter the dark area (the part you want to expose more) and the highlight area (the part you want behind neutral density) and determine the difference in order to select your filter, I don't do any of that.

I've gotten a decent feel for when to use what filter and I rely on my camera's histogram. If I put on a 2-stop and the highlights are still too hot with the shadows still too dark, I put on the 3-stop. If the 3-stop makes the dynamic range to narrow on the histogram or makes the image look unrealistic, I back off to the 2-stop. It's really a feel thing that just takes some experience playing with them.

Holder:

Lots of people use filter holders and lots of people hand-hold the filters. I do both at times, but I prefer a holder. Basically, you put the filter in the holder, and line up the dark part over the highlights and the clear part over the shadows in the shot. You do this by adjusting the filter up and down while watching the graduation line and rotating the filter side to side to hit certain angles.

Lots of people use the DOF preview button to do this but I never and don't plan on starting. I can see the filter and place it fine without that and in my opinion, that's just an extra step to complicate things.

Handling:

Yes, they are filters, you should be semi-careful with them. But to be honest, mine get abused and yours will get scratched/blemished/covered in finger prints. It happens, don't worry about it. The filters will be fine and still function.

----

Anyways, I'm sure someone can pick this apart for things that are "wrong", but the above works well for me and if you have any questions or want clarification, just ask. I pretty much wrote that off the top of my head so I'm sure I left plenty of details out.

Hope it helps.My use of them is pretty similar to this. I just don't have the holder yet.

Don't worry too much about the condition of the filter or a few dust spots. It's impossible to keep them spotless and flawless for most people who are really using them. It'll be way out of focus anyway so as long as no light is falling on them you'll likely never notice the crap on them or damage done to them as long as it's not excessive.

another
02-20-2008, 10:15 AM
Lots of people use the DOF preview button to do this but I never and don't plan on starting. I can see the filter and place it fine without that and in my opinion, that's just an extra step to complicate things.


That's very surprising to me, cuz your stuff looks great; you're obviously placing the filters in the right place but the following is absolutely true:


the actual grad line will move up and down the image - try it and see for yourself - tape paper or something over a lens and view it wide open - then use DOF preview to stop down.

I'm not sure optically WHY it does - but sure as a brick in the face hurts, it moves when you stop down.


I have to thank Bryan Peterson (http://www.amazon.com/Understanding-Exposure-Photographs-Digital-Updated/dp/0817463003/ref=pd_bbs_sr_1?ie=UTF8&s=books&qid=1203518901&sr=8-1) for clearly explaining what the DOF preview does and now I use it religiously. When you look through your viewfinder you are seeing the scene wide open, no matter what you have your aperture set to. When you press the DOF preview the camera stops down to your aperture setting. When you preview DOF you will see the filter line move. It does not stay where you see it through the viewfinder.

I whipped up a quick page to show the extremes of this. (http://18ideas.com/filters/) The default images are as I saw them through the viewfinder (large aperture). If you mouseover the small aperture it will swap the image(s) to what the camera shot at that aperture. It's obvious the filter line moves ... and moves in relation to the difference of apertures. Meaning, there is less movement if you chose f/8 instead of f/32 for example.

(Note: a 3-stop hard grad was used. In the bottom image, the grad is just above the trees when viewed wide open - notice it blends perfectly, you would think after looking through the viewfinder that you were setup properly)

Now, a couple things here ... 1) I'm on a mac and that javascript/css magic looks fine in Firefox and Safari. No idea how the page will display in IE. 2) I'm massively ignorant of all things camera-related. Everything I've posted above is what I've learned from reading about DOF preview and filters. The images, and the filter movement, happened on a Nikon. If there is a magical camera out there that for some reason actually stops down the viewfinder to your aperture setting, then the above will not hold true (the filter line would remain where it is in the viewfinder) but I've never heard of a camera acting that way. 3) Lastly, I'm not trying to start any kind of argument here ... I was just shocked to read that Scott doesn't use DOF preview yet seems to place his filters perfectly (and I know he's not shooting wide open). Hopefully my comments, and sample images, have explained the issue well enough for filter newbies to know what they have to look out for ... unless Scott wants to pass along some of his Jedi training on how to take a perfect shot without using DOF preview!

-kevin

SlvrScoobie
03-02-2008, 10:27 AM
Its most likely due to the change in focus. When you place the filter over the lens wide open, you see the filter at some amount of out of focus distance, between where the lens is, and where good focus starts. Lets say on an infinitely far away object on a 70mm lens, at 2.8 that that distance is 100m away. If you think about it as distance * oof = a specific amount of vertical distance the graduated filter will take up from 0%->100% of its graduated density.
Now when you stop down this OOF area decreases as DOF increases, so now your good focus starts @ 25m. As this increases the vertical density change area is now smaller, since the filter is 4X more in focus.
Since our eyes view things like density in a logarithmic step, but the manufacturers probably make these with a linear change from 0-100%, when you stop down your actually making that 4X smaller portion more visible, and since were probably using it where the line is around 18% gray (or 1/2 density) when we stop down, that 18% is now shifted due to the change in the vertical density distance.
Did I make sense?