Using a graduated ND FIlter

[skywalkerbeth]

Hi

I bought my filter a few weeks ago and still haven't had the opp to use it.

I assume this is mostly for use in backlit photos, right? And additionally, more or less a flat landscape - i.e. no trees/buildings or anything close that's going to pop up in the middle and look odd since it would then be "half dark, half light", am I right?

I'm wondering if maybe I wouldn't have been better off learning how to shoot RAW and stitch two bracketed photos together, since there are some limitations to using the grad. filter. Then again, I also suppose that means only shooting on a tripod since the two photos must be exactly the same...

[sandpiper]

Then again, I also suppose that means only shooting on a tripod since the two photos must be exactly the same...

Not necessarily. If you are simply trying to get the sky to be less bright, they don't need to be in exact register (nor do they need to be in RAW). If you use AEB, and hold the camera reasonably steady, whilst the camera takes the three shots, they will be close enough.

Simply take one image for the sky, and one for the scene. Open them both and drag the 'scene' over the 'sky' image in PS (or other similar software), then gradually erase the sky area from the 'scene' to reveal the darker sky below. You will probably want a reasonable sized soft brush, and erase the main sky area 100% - but dropping the amount as you blend it in around the join with the main scene. As there is no fine detail in the sky, it won't show that they aren't in esact register.

Alternatively, you can use RAW and software for the two images, rather than bracketing shots when you take them. You need to make sure that you don't blow any highlights in the sky when shooting of course.

Just make two RAW conversions, one where you optimise the scene as normal, letting the sky wash out, the second where you optimise the sky and let the scene go dark. Then take these two seperate versions and combine as above. In this method of course,they WILL be in exact register, if that is required.

Hope this helps. It really is very easy once you have tried it a couple of times. Just watch the blend line to make sure that it is subtle.

[cfcRebel]

Hi

I bought my filter a few weeks ago and still haven't had the opp to use it.

I assume this is mostly for use in backlit photos, right? And additionally, more or less a flat landscape - i.e. no trees/buildings or anything close that's going to pop up in the middle and look odd since it would then be "half dark, half light", am I right?
It depends what type of GND filter you have, soft or hard. For mountain, or landscape with treeline, the soft GND works better. For seascape, hard GND is more appropriate. Take a look at this tutorial (http://www.inspiring-photography.com/forum/showthread.php?t=2332). It covers some basic knowledge of how to use GND filter.

[skywalkerbeth]

I tested it out yesterday - these were taken handheld - both handheld camera and filter. It was a quick test.

without graduated ND filter:

http://www.flickr.com/photos/skywalkerbeth/2320341375/

http://www.flickr.com/photos/skywalkerbeth/2321154490/

with it:

http://www.flickr.com/photos/skywalkerbeth/2320340811/

http://www.flickr.com/photos/skywalkerbeth/2321153996/

Thank you for the advice everyone - next time I'll have it set up correctly!

[cfcRebel]

Your samples above could use the hard GND, for example, since the horizon is quite straight. I assume you used the 2-stop filter listed in your sig for these images. A 3-stop GND might balance better the contrast between the sky and foreground but it's just a guess.
Have fun with the GND and look forward to seeing your work in the future.

[skywalkerbeth]

Hi

Thanks, I think you are right. But the two stop still helps!

I think also the hard would be better but the soft doesn't really detract does it? Mine is soft.

[iacas]

Your samples above could use the hard GND, for example, since the horizon is quite straight. I assume you used the 2-stop filter listed in your sig for these images. A 3-stop GND might balance better the contrast between the sky and foreground but it's just a guess.
Have fun with the GND and look forward to seeing your work in the future.
I have two 2-stop GNDs, and I sometimes just stack them in my Cokin filter holder. I like the added flexibility of having a 2 or a 4-stop... though it was mostly a mistake. I didn't think I had a 2-stop GND, so I bought the other. Had I thought about it, I might have gotten a 2-stop and a 3-stop. :)

Anyway, all I'm saying is "don't rule out stacking them."

Oh, and I've always found the hard ND filters tougher to use. The soft ones aren't soft for a very wide range, but they also won't draw lines on your camera. If you're off by a little with the hard ones, it can ruin an image. The soft ones have a bit more room to play, even on even, straight horizons, IMO.

[argyle]

You need a combination of hard and soft graduated filters. Hard for consistent, straight horizons (seascapes, etc) and soft for horizons that are uneven (mountains, trees, etc). The number of stops necessary will depend on the amount of light available. For example, if the scene has a bright sky that places the foreground in shadow, take a meter reading off the sky and one off the foreground. The difference in exposure will be the number of stops you'll need in a GND. These take a bit of practice to use as well. You'll also need to make use of your DOF button on the camera...this will help you to see where your line is BEFORE you press the shutter button. A good starting point is a 2-stop soft and a 3-stop hard GND. This will cover you for landscapes and seascapes. As far as using Photoshop...you can, but that takes practice too. I'd much prefer to get the image right in the camera than spend a few hours sitting in front of a monitor.

Filters can get awfully expensive, as you probably know. I don't know your skill or experience level, but no matter...before you drop a lot of cash on filters, its best to acclimate yourself to what they can and can't do. Here's a good link to some real good info:

http://www.bythom.com/filters.htm

[freaking102]

if you want to learn how to use ND filters, check out the articles on luminous landscape and nature photographers net.

[tomsem]

I was looking at getting a grad ND filter too. I was wondering how much I would use it do to the "straight line" nature of the transition. Looking through my landscape pictures there is not many with an absolutely straight horizon line. There is always an irregular subject that would then become light altered as well. I was thinking even the soft would have too big an effect on something you may not want altered in the picture. Having filters with both soft and hard transitions might help with that. Good tips and the links make for good reading. Thanks!

[Tareq]

Get 3-stop GND Hard Edge for the Sky and 2-stop soft GND for the foreground, i am sure you will be fine and doing alot
0.9 Hard and 0.6 soft are the most popular choice, i got P-series Hitech GND from 0.3 up to 1.2 all soft, i broke 1.2 in Scotland, but when i got back i ordered 4x5 Hitech GND 1.2 soft and hard and 0.9 soft, i may add few more later.

[Tareq]

I was using my soft even on those straight lines and i got good enough results, so you can use both soft or hard on any, but it is better to use Hard with uniform or straight horizon or any straight tilted line.

[Paul Pagano]

I like them a lot for sunsets. I use the soft ones since you can pretty much get away with the soft ones for anything.

[tomsem]

So with the soft transistions, they are pretty forgiving as far as not darkening a subject you don't want changed too much? For instance, I am thinking of a black bridge backlit by a cloudy sky. The bridge would be sort of cut in half, with the top half in the stronger graduated half with the sky. The supports would be in the weaker graduated part with the landscape half. I was thinking you would have too much of a two tone bridge and photoshop might be necessary. Then you may as well just not use a filter and photoshop the sky. Having never used these, just wondering what to expect of the soft transition.

[argyle]

To throw a wrinkle into the mix, a standard GND (either hard or soft) is not usually the best option for sunsets when the sun is at the horizon. You can blow out the horizon, while the sky would be darker, or set the demarcation too low and block too much of the sun. In these types of instances, a reverse GND would be the better choice. I didn't mention this in my previous post since I didn't want to overload you with advice, but as I said in my previous post, its best to become familiar with filters and their uses before dropping a lot of money on them.

Below is a sample pic showing what a GND can do for you. In this pic, I used two stacked GND's for a total of 5-stops. The cliffs at sunrise were extremely bright, and when exposing for them to avoid blowouts, the foreground went almost completely black. The two GND's allowed me to balance the exposure without losing any detail. Even with the 'soft' demarcation line, I was still able to avoid darkening the parts of the pic that jutted above the filter line.

http://northlake.smugmug.com/photos/225040252_F6jUM-XL.jpg

[tomsem]

Nice pic!! That mountain top is exactly the example I was thinking of. It looks like I am thinking the grads will make more of a "line" than it acutally does. Your shot blends in nicely. I am sure it takes practice to make it work but I can see where it would be useful. Thanks for your insight.

[sadatk]

http://flickr.com/photos/simplygeeky/2224766386/

[silverhalide]

Get 3-stop GND Hard Edge for the Sky and 2-stop soft GND for the foreground, i am sure you will be fine and doing alot
0.9 Hard and 0.6 soft are the most popular choice, i got P-series Hitech GND from 0.3 up to 1.2 all soft, i broke 1.2 in Scotland, but when i got back i ordered 4x5 Hitech GND 1.2 soft and hard and 0.9 soft, i may add few more later.

Are there any differences using a soft GND on a crop body vs a FF? It would seem to me that since the image size is smaller, you'd want a faster transition between the clear and darkened areas. Does this make sense?

Are there soft GND filters for crop bodies?

E.

[Tareq]

Are there any differences using a soft GND on a crop body vs a FF? It would seem to me that since the image size is smaller, you'd want a faster transition between the clear and darkened areas. Does this make sense?

Are there soft GND filters for crop bodies?

E.

it is not like that, it depends on the focal length.
you can use P-series GND for focal length say 24mm and above, but if you go below 24mm then you will see some vignetting, then you should use Z-pro or ultrawide GND filters [4x4 or 4x5] to avoid vignetting, doesn't matter you use those filters on crop or FF because you know that 10mm on crop body is equivalent 16mm on FF, so you can say that you will find differences between crop vs FF, but it may help sometimes as if you use 16-35 on FF then it is ultra wide, but if you use 16-35 then it will be wide or very close to ultrawide but you know you should use same equivalent focal length to compare between bodies.
I hope i did explain it clearly.

[Hangbot]

I have a soft .9 GND and love it. I take it everywhere. Usually I just hold it in front of the lens because when I mount the holder, you can see it when zoomed out to 17mm.

[Tareq]

I have a soft .9 GND and love it. I take it everywhere. Usually I just hold it in front of the lens because when I mount the holder, you can see it when zoomed out to 17mm.

Yes, you are right, but do you use 17mm on a full frame? and do you use P-series holder? If you use Z-pro holder than i think you can't see or very hardly you will see the holder at 17mm, i tried it on 10-22 at 10mm on 30D and i don't see that holder [only very very tiny vignetting corners appears few times due to my wrong screwing maybe].

[Hangbot]

I'm using the P-series holder on a 30D and a 40D. With the 17-55 I can see the holder until around 20mm. But even with the vignetting from it, the benefits of the GND outweighs it when you need it:)

[silverhalide]

it is not like that, it depends on the focal length.
you can use P-series GND for focal length say 24mm and above, but if you go below 24mm then you will see some vignetting, then you should use Z-pro or ultrawide GND filters [4x4 or 4x5] to avoid vignetting, doesn't matter you use those filters on crop or FF because you know that 10mm on crop body is equivalent 16mm on FF, so you can say that you will find differences between crop vs FF, but it may help sometimes as if you use 16-35 on FF then it is ultra wide, but if you use 16-35 then it will be wide or very close to ultrawide but you know you should use same equivalent focal length to compare between bodies.
I hope i did explain it clearly.

You explained equivalent focal lengths well enough, but that wasn't really what I was getting at. I'm not concerned about the vignetting, but rather how soft the transition is, and whether that varies with body type. Let me try again...

A soft GND filter transitions from clear to dark over the distance of (for the sake of argument, let say) 25 mm. For some arbitrary lens, with a diameter of 77 mm, on a full frame body, that means the bottom 1/3 of the image hitting the sensor is clear, 1/3 has some degree of darkening, and 1/3 is solidly darkened.

On a crop body, where only the center part of the image circle is used, does the 25mm of transition represent a more gradual transition in the image? Since we're only using the center part, perhaps this would be 1/4 of the image clear, 1/2 in transition, 1/4 dark.

Perhaps the attached diagram would help. Here you see that on a crop sensor, almost the entire image is taken up by the transition area.

So, my question comes down to: With a crop body, do you need a GND with a sharper transition than when using a FF body?

E.

[Tareq]

You explained equivalent focal lengths well enough, but that wasn't really what I was getting at. I'm not concerned about the vignetting, but rather how soft the transition is, and whether that varies with body type. Let me try again...

A soft GND filter transitions from clear to dark over the distance of (for the sake of argument, let say) 25 mm. For some arbitrary lens, with a diameter of 77 mm, on a full frame body, that means the bottom 1/3 of the image hitting the sensor is clear, 1/3 has some degree of darkening, and 1/3 is solidly darkened.

On a crop body, where only the center part of the image circle is used, does the 25mm of transition represent a more gradual transition in the image? Since we're only using the center part, perhaps this would be 1/4 of the image clear, 1/2 in transition, 1/4 dark.

Perhaps the attached diagram would help. Here you see that on a crop sensor, almost the entire image is taken up by the transition area.

So, my question comes down to: With a crop body, do you need a GND with a sharper transition than when using a FF body?

E.

I see, i have to check my Geneva Paris photos as i was using only 30D and 350D with GND filters and CPL sometimes.
And i have Scotland photos where i was using 5D with same GND [P-series].

[iacas]

So, my question comes down to: With a crop body, do you need a GND with a sharper transition than when using a FF body?

No... I prefer to look at it a different way, by changing the field (angle) of view. In other words, you just need the same equivalent field of view on the crop camera.

Just as with other things, that means getting an equivalent lens.

So a 24mm lens on a full-frame camera... means you need a 15mm lens on a crop (1.6) body camera. Thus, the angle of view will be the same and thus, the transition size will appear the same.

At least, I think this is all true. The math works out on the 10-22 vs. the 16-35, after all. At 10/16, the angle of view is virtually identical (it's off by about half a degree).

[Blue S2]

I use a 3-stop soft for most of my landscape work. I find this to be generally pretty good at opening up the ground enough while providing a proper or slightly dramatic sky.

Check out the Singh-ray stuff. http://singh-ray.com

They also make reverse ND grads for sunsets. Very cool stuff, very high quality.

[nicshow]

I thought I read on here to use the middle slot on the holder but while shooting recently, I got a reflection on the top corners of the filter so I moved it to the slot nearest the lens. Which slot do all of you normally use?

Nic