Graduated Neutral Density filter question.

[CousinMadness]

Greetings,


I am heading home to Scotland in 3 weeks... you know... where even in summer the sky can be as bland as a white bed sheet :cry:

My question:

I am planning on purchasing a Cokin graduated ND filter to compensate for that washed out look. I have read that there are several strengths of ND tint and was wondering what one I should purchase.

The main content of my photography will be historical buildings.. Churches, Abbeys, Standing Stones etc. I do like the dramatic sky look... but don't want it to be so contrasty it looks like a B&W.

I will be using a Canon 300D with the EF-S 18-55 lens for the building shots.

Thanks.


CM.

[Todd Jacobsen]

Best ND filter for digital cameras:

Photoshop.

[Andy_T]

Maybe a polarizing filter would be more helpful for getting dramatic skies, but not adding a tint to the building in the middle of the picture.

Best regards,
Andy

[CousinMadness]

Best ND filter for digital cameras:

Photoshop.

Thanks Todd.

I will be shooting in large Jpeg format so I will already have lost some exposure compensation. RAW file sizes are just not feasable considering the amount of pics I will be taking. It's the bleed and the blue fringing I am hoping to get rid of first with a grad ND in the original image.

I can play with Adobe afterwards when I get back.

Plus I am still not an expert in fiddling with partial areas in Adobe. When there are trees involved against the skyline... I cannot seem to get the magic wand tool to work so that it will decrease the brightness of the sky without it looking like a jigsaw puzzle.



CM.

[CousinMadness]

Maybe a polarizing filter would be more helpful for getting dramatic skies, but not adding a tint to the building in the middle of the picture.

Thanks Andy,

I have used polarisers in the past with 35mm cameras... it works great when you have some blue sky and at 180 degrees to the sun. However, Scottish skies more often than not can be like a ruffled white bedsheet... bright and bland. I have to think of a way of getting the cloud texture to jump out.

I am not that proficient in Adobe yet.. but can sure learn if that's an option. You are right about the darkening aspect on a building especially if it has a large tower against a clear uninterrupted skyline..... ohhhh I am giving myself a headache thinking about it. :rolleyes:


CM.

[mdr]

I agree with that!

Photoshop is not the best ND grad! This will require two shots at different exposures, which doesn't work with moving subjects, particularly fast moving clouds, waves or leaves in the wind.

[HJMinard]

I agree with that!

Photoshop is not the best ND grad! This will require two shots at different exposures, which doesn't work with moving subjects, particularly fast moving clouds, waves or leaves in the wind.

Absolutely correct, because if you only take one shot of a high contrast scene, no amount of photoshopping will retrieve lost data (blown highlights or lost shadow detail). RAW helps, but lost data is lost data. The two exposure thing works well for a static scene, but you can't count on that.

If you're getting only one, I would recommend a 2-stop (.6) filter - soft edge for wide angle and hard edge for normal to telephoto (that's what the filter makers recommend, anyway). Hitech makes nice filters that fit the Cokin holders ... better than the Cokin filters but quite a bit less expensive than the Singh Ray's.

[Todd Jacobsen]

Plus I am still not an expert in fiddling with partial areas in Adobe. When there are trees involved against the skyline... I cannot seem to get the magic wand tool to work so that it will decrease the brightness of the sky without it looking like a jigsaw puzzle.
CM.

It's called layers. Don't mess with one layer when attempting to change just ONE part. Create a layer mask and you can adjust at will.

Hey, if anything, your trip will cause (force) you to learn more about PS.

Puting a filter on your DIGITAL camera affects CAPTURE. You can NEVER get that data back cause you never got it in the first place.

Except for polarizers (or UV which really don't do much except protection), I wouldn't mess with filters on your dslr. Buy the right PS plug-in, you don't even have to worry about polarizers either...

[Todd Jacobsen]

Absolutely correct, because if you only take one shot of a high contrast scene, no amount of photoshopping will retrieve lost data (blown highlights or lost shadow detail). RAW helps, but lost data is lost data. The two exposure thing works well for a static scene, but you can't count on that.

If you're getting only one, I would recommend a 2-stop (.6) filter - soft edge for wide angle and hard edge for normal to telephoto (that's what the filter makers recommend, anyway). Hitech makes nice filters that fit the Cokin holders ... better than the Cokin filters but quite a bit less expensive than the Singh Ray's.

HJMinard,

Agree that two shots are required to accurately expose a high contrast scene. But by adding a filter that affects capture, you are making an assumption that the photographer will get a BETTER picture by eliminating "data". This requires the photographer knows what he/shi is doing, and that the RIGHT data is being eliminated (vs the stuff you WANT to keep).

Nothing wrong with experimenting with filters, but I would DEFINITELY take multiple shots regardless, with filter, without, bracket exposure etc.

Anyone assuming a filter is going to solve problems, rather than CAUSE problems, better know when, where, and HOW to apply the filter. Otherwise, they are better off NOT using a filter.

[steven]

ND Filter does not eliminate any data.

It reduces the amount of light only. No data loss, unless you use it on a dark area.

But you you blow out the highlights no amount of PS can recover the detail lost. But with a ND Grad filter you can reduce the blow out to something in range.

[DaveG]

Greetings,


I am heading home to Scotland in 3 weeks... you know... where even in summer the sky can be as bland as a white bed sheet :cry:

My question:

I am planning on purchasing a Cokin graduated ND filter to compensate for that washed out look. I have read that there are several strengths of ND tint and was wondering what one I should purchase.

The main content of my photography will be historical buildings.. Churches, Abbeys, Standing Stones etc. I do like the dramatic sky look... but don't want it to be so contrasty it looks like a B&W.

I will be using a Canon 300D with the EF-S 18-55 lens for the building shots.

Thanks.


CM.


I've got both the G1 and G2 Cokin grad ND filters. I rarely use them mostly because they are the smallest Cokin filters and wouldn't fit on most of my Canon lenses. I can see the use for a graduated ND filter and my suggestion would be to get both (and there well be more than these two) in order to fine tune your shot depending on what you want to achieve.

If you shoot raw and get a pretty good exposure you can achieve some really good things in Photoshop without using the gradient tool or the grad ND filters.

What I do is to use Camera RAW to "decode" image and pay only attention to the shadows. I let the blown out sky stay blown out, and possibly make it worse. I get everything else the way I want it and send it over to Photoshop proper. Once there I save it as a .psd file. You must save it as something or you can't do what I'm about to do next.

I go back into Camera RAW and reopen the same shot (if I didn't save it in PS Camera RAW wouldn't let me reopen it). At this point I just pay attention to the highlights and let the shadows go where they want to. You will be amazed at how much good exposure there actually is in those "blown out" hightlights! Then I send that over to PS. Once there I choose SELECT, SELECT ALL, & COPY. I go to the first shot and create a new Layer and choose Paste.

Now the image with the nice sky is sitting over the other shot, and in PERFECT registration. I may want to switch the order of the layers but it depends on how I'm feeling as much as anything. In any case make sure that you are on the top layer. Then I take the eraser tool and erase the "bad" part of the top layer revealing the "good" layer underneath. You can adjust the opacity of the eraser tool so you can erase just enough to make the image look good to you, so it doesn't need to be all or nothing.

If I was you I'd try this technique now and see what you think. The biggest advantage is that it's free and if you are a Scot the "free" is right up your kilt.

[hikari]

[snip]
I am planning on purchasing a Cokin graduated ND filter to compensate for that washed out look.
[snip]
I will be using a Canon 300D with the EF-S 18-55 lens for the building shots.


Maybe I am completely off now....
The EF-S 18-55 lens has a rotating front element which rotates during focussing. This means that your graduated ND filter will be rotating as well when the camera focusses. So the filter may be in any position after focussing, which means that you will be quite busy with rotating the filter all the time so that the gradient is the way you want it to be. The way I understand it this lens is far from ideal when you want to use a ND filter or a polarizer.

[rdenney]

ND Filter does not eliminate any data.

It reduces the amount of light only. No data loss, unless you use it on a dark area.

But you you blow out the highlights no amount of PS can recover the detail lost. But with a ND Grad filter you can reduce the blow out to something in range.

Perhaps. But I've been able to pull images up without blowing out highlights if I start with a one-stop underexposure compensation on my 10D. The images on the little screen look dark and flat, but they will allow some bold moves. I follow the opposite strategy I did for negatives: Expose for the highlights and process for the shadows.

But that leads to another suggestion: Don't use JPEG. I know that memory-card real estate is dear, but I'd rather go spend money on a passle of those $69 1-gig cards at Costco than give up all my ability to adjust the images after the fact. Or a digital wallet device (or laptop). Talk about giving up data! Shooting in 8-bit rather than 16-bit gives up most of your ability to expose for the highlights and process for the shadows.

We used grad filters on slide film because the film only had about five stops of dynamic range, and we had very little we could do after the fact to pull up the shadows, even with complex methods like contrast masking. The Canon DSLR's have a dynamic range more like 10 stops, and that should allow getting some pretty contrasty scenes recorded.

Here's an example:

http://www.rickdenney.com/images/san-juan-campanile-lores.jpg

My histogram was mostly bunched in the left half of the image, to make sure I didn't blow out the flare effect of the sun. But working from RAW, I was able to pull up that histogram really well, while still holding the highlights down enough to keep some detail in that flare. It's amazing what you can pull out of shadows.

Here's another:

http://www.rickdenney.com/images/san-jose-wavy-door-lores.jpg

In this one, I burned in the sunlit courtyard down to middle gray, and then pulled the curves up for the whole image to restore it back to the original brightness. Before doing that, the doorway was in deep shadow and had little discernable detail. There's no way in the world this shot would have been possible with slide film or a grad filter.

In neither case did I draw a sky selection. I did it all with the dodging/burning in tool and the curves. And starting with an image that had all the data in it in the first place (which means using RAW).

Rick "continually amazed by how much shadow information can be brought up to middle and highlight values" Denney

[DaveG]

Maybe I am completely off now....
The EF-S 18-55 lens has a rotating front element which rotates during focussing. This means that your graduated ND filter will be rotating as well when the camera focusses. So the filter may be in any position after focussing, which means that you will be quite busy with rotating the filter all the time so that the gradient is the way you want it to be. The way I understand it this lens is far from ideal when you want to use a ND filter or a polarizer.

Yeah, but you just grab the filter holder and rotate to the position you want. I used to do that with film camera shots all of the time.

Imagine a shot of a cabin. The right side of the image is full of cabin that goes from the bottom to the top of the frame. On the left hand side there's a chunk of overexposed white sky. I'd use a graduated blue or ND filter but have it come into the image at an angle. That way I didn't get a colour cast or a density change to the other side of the image that doesn't need it.

Anyway the rotating front element of the lens + the ND filter is a very minor annoyance and you'd have to fix it anyway whenever you switched from vertical to horizontal composition.

[roanjohn]

I thought graduated ND filter will only work when you have a straight horizon.......

Ro1

[PhotoEcosse]

I know what you mean about our skies; when they are blue they are BLUE and when they are grey, they are just plain dull!

I've been using a ND4 grad successfully for shots where the sky would have been blown out. I reckon I will partner it with a ND2 for slightly less effect or in extreme cases I can double them up in the same holder.

Pack your thermals, it has been snowing in Aberdeen all day. Brrrrrr!

[robertwgross]

RAW helps, but lost data is lost data.

We should all print out that phrase in 72-point font and paste it next to the histogram view on our cameras.

---Bob Gross---

[robertwgross]

I thought graduated ND filter will only work when you have a straight horizon.......

It works best and easiest when you have a straight horizon.

If you have something like a tree that interrupts the horizon, you can still use the grad ND filter, but you have to "play" with the result a little more to get what you want.

---Bob Gross---

[PhotoManMike]

Just be aware that the Cokin G1 & G2 grads aren't really ND, they're grey. I own a Cokin G1 which I bought in 1992 when I was living in Edinburgh, for exactly the reason you state, CM. Most of the time they were OK, but in a few shots (mainly when I had >50% sky or I overdid the filter effect) the greyness was obvious. At the time, I remember reading in the USENET rec.photo group that they reportedly sometimes gave a pink (!) color cast to slides. The plastic Cokin filters tend to scratch more easily as well, which is important if you're a klutz like me.

I've only used this filter a handful of times since returning to the US, and I think if I felt I still really needed the effect I'd splurge for a Singh-Ray "Galen Rowell" filter or one of the other high-end glass filters.

Mike

[Todd Jacobsen]

ND Filter does not eliminate any data.

It reduces the amount of light only. No data loss, unless you use it on a dark area.

But you you blow out the highlights no amount of PS can recover the detail lost. But with a ND Grad filter you can reduce the blow out to something in range.

Yeah but....

Why don't you just bracket the shot? It's really six of one, half dozen of the other. You either lose data in the shadows or lose data in the blown highlights.

Getting the ND filter to ONLY affect the sky is pretty tough. You're hoping everything else it affects, you didn't get lost.

If you're just trying to adjust exposure, do it with bracketting and the layer using PS.

[HJMinard]

Yeah but....

Why don't you just bracket the shot? It's really six of one, half dozen of the other. You either lose data in the shadows or lose data in the blown highlights.

Getting the ND filter to ONLY affect the sky is pretty tough. You're hoping everything else it affects, you didn't get lost.

If you're just trying to adjust exposure, do it with bracketting and the layer using PS.

Yes ... but ... that only works if: you have your tripod with you (handheld won't work) and absolutely nothing in the scene is moving (clouds, leaves in the wind, people, etc.).

[Lesmac]

I disagree totally with the concept of using PS as a substitute for ND grads, it takes far too long , why make work for yourself, slipping on a grad takes a couple of minutes.
Cokin grads are cheap and cheerful, but generally do the job, I agree the greys can sometimes be off.
I use Lee filters, which are far more neutral, but mainly for their size, I found with the cokin P filters I couldn't stack filters wothout vignetting on 17-40 lens (1DS MKII)
Les
http://lesmclean.photoblink.com/
Some samples odf Scotland in my gallery (some taken with ND grads)

[steven]

I love to use PS to do a ND effect when I have a tripod and a static shot.
It works wonders.

But there are still times that that technique does not work.

Using RAW process twice, once for highlights, once for shadows is an interesting idea and I'll have to give that a try (I shoot all RAW). But there are still times when I have had more dynamic range than could be captured with a single picture, even with RAW.

[SnJPhoto]

I have a LEE - 4" X 6" - 2 stop soft gradient filter and love using it. If you practice you can use it without a holder. I would recommend practice with it before you "need" it. the first few shots I used toomuch of the dark end of the filter. It is now a standard item in my travel bag. It cost about $70,but worth it inmy opinion.

Cheers.

Scott

[CousinMadness]

It's called layers. Don't mess with one layer when attempting to change just ONE part. Create a layer mask and you can adjust at will.



Thanks again Todd.

I went into the City this afternoon and bought a Cokin G2 graduated. I have used Cokin before 15 years ago when I came to Canada, my original 49mm thread adapters are still in Scotland.

I took some shots in downtown London Ontario today... and spent the last 3 hours fiddling and tweaking in Adobe. I am getting used to the layer idea Todd... but it's so darned difficult to capture a whole area. I keep using that magic tool... and "add to selection" about 20 times till it's filled up.

I'm not sure what a layer mask is.... I am clicking on "layer" then "new adjustment layer"... then when all is fiddled with... flatten layers.

I noticed some deterioration on the edges after I did a saturation increase.. is this normal? The sky was perfectly blue here today... so no need to test the new filter. This is exactly the kind of tearing I see when there is 4 stops difference between the wall of a building and the sky.

I first saw some before and after images on photopost site using grad ND and thought... hey that would solve my problems. As usual in these forums, I am learning that there is more than one way to fry an egg LOL.

Thanks for your help, and to everyone else if I don't answer your posts.


Cousin M.

[CousinMadness]

Thanks to everyone who replied to my thread. I am learning a lot from everyones ideas and personal preferences.

Today was sunny here in eastern Canada... so not the best day to test the ND theory but I did practice some of your Adobe suggestions to squeak out the best in an image.

Here's a screen shot (not the best way to show quality)... of the original image and after some saturation, straightening and masking the sky and grass separately.

I still have a lot to learn about fiddling in Adobe... but I will be using my Grad ND wisely where conditions warrant it in Scotland. Thanks for all your advice.



Cousin M.

[jukas]

In neither case did I draw a sky selection. I did it all with the dodging/burning in tool and the curves. And starting with an image that had all the data in it in the first place (which means using RAW).

Rick "continually amazed by how much shadow information can be brought up to middle and highlight values" Denney


If you open either of these images in PS and look at the white areas theyr'e all showing up as 254/254/254 that's as close as you can get to pure white without being there. Does that mean you properly exposed and then intentionally blew out the highlights?

Sorry, but I love my Grad ND filters, unless you have an incredibly static subject and you take exposure readings beforehand there's just too much of a chance of something in the image changing or you moving the tripod. Raw gives you a ton to work with, but you'll always get a better result if you get the exposure right the first time.

[rdenney]

If you open either of these images in PS and look at the white areas theyr'e all showing up as 254/254/254 that's as close as you can get to pure white without being there. Does that mean you properly exposed and then intentionally blew out the highlights?

Sorry, but I love my Grad ND filters, unless you have an incredibly static subject and you take exposure readings beforehand there's just too much of a chance of something in the image changing or you moving the tripod. Raw gives you a ton to work with, but you'll always get a better result if you get the exposure right the first time.

Yes, I intentionally blew out the highlights. If there's no detail there, i'd rather it be paper white than dull gray. In targeting, I might pull them back in if I see that my printer posterizes at the gamut boundary.

But I've taken similar pictures on Velvia, with the result that the highlights are blown out in the same way, but the shadows are in complete silhouette. And the parts that are not blown out would be. In the doorway picture, I pulled the sunlit courtyard down to middle gray, and then pushed the whole image back up so that the blown-out portions were white again. That's a major move in photoshop, and absolutely requires starting with a 16-bit file.

I shot that same doorway about 15 years ago using a large-format camera and black-and-white sheet film, with full zone system measurement and control. I was unsuccessfuly at retaining any useful detail outside the doorway, and without some contextual detail, the image looks quite strange.

I pay close attention to the histogram in the field. That way I know what I have. You'll see two humps--one for the sky and one for everything else. Both humps must be complete on the histogram. If they are, you can do what you need to do in Photoshop. If you can only get one or the other, then it's time for extraordinary measures, including grad filters. I'm surprised how rarely that happens.

Here's an image where I did not intentionally blow out the highlights. This would have been a very difficult image on Velvia without a grad filter:

http://www.rickdenney.com/images/st_helens_zenitar_johnston_ridge_extreme_lores.jpg

My beef with grad filters is that the graduation is usually quite visible. The results can be very pretty, but they are still quite obvious to me. It is very difficult to hide the effects of the graduation with subsequent Photoshop manipulations. With slide film, it's the only tool you have--the transparency has to stand on its own. We can do more with digital images, though. In the natural scene, the line between sky and earth is usually a lot sharper than a grad filter, but too irregular to put on a filter. In the image above, a grad filter would have put a gradation on the cloud and spoiled the effect of the scene, at least for me.

Rick "who has narrowed the valley between two humps on a histogram dozens of times without a grad filter" Denney

[DaveG]

Just be aware that the Cokin G1 & G2 grads aren't really ND, they're grey. ...

Mike


But what could they be if they aren't grey? They HAVE to be grey to be a neutral density filter. At one end you have clear and at the other end pure black. A faded pure black is grey. My concern would be that they aren't grey but have some colour cast.

I suspect that you are "seeing" grey when a small aperture and close up focusing is taking place. That way the filter is coming into focus.

[Jon]

They're not neutral grey. There's some colour cast.

[DaveG]

They're not neutral grey. There's some colour cast.

Exactly. But Mike's suggestion, as I understood it, was that grey did not yield neutral density filtration. It was the grey itself not a colour cast in the grey that was the problem. My point was that the filter HAD to be be grey in so far as grey has no colour cast and is only restricting the light, not the colour of the light, from hitting the film/sensor.

I also agree with you that the Cokin ND filters have some colour cast in them.

[Jon]

I think the problem with filters advertised as "grey" is that they aren't neutral. I got my grads from Singh Ray.