ND Grad Questions

[Draken]

I wanna get an ND grad since i do alot of ladscape photography and i understand this will solve my blown out sky issue. But they come in 0.3, 0.6 and 0.9 so which one is for me? and how do i meter correctly in order to determine which one i use ? i a complete noob when it comes to Metering the scene so any help on how to do that would be awesome

cheers,


Mike.

 

[kundalini]

Here's a read from Thom Hogan on filters in general, but he does speak of Grad NDs.

I can't find some other links I've seen before, but use the search function at the top right. There has been discussion on these filters. I'll bounce back if my memory returns.

 

[ksmattfish]

Every 0.3 is 1 stop. It depends on the lighting conditions you encounter, but I'd guess that a 3 stop grad ND would be a good place to start. You may find that if you leave your camera in the default segmented metering mode that it does fine with the filter on. If not remove the filter and meter the foreground.

 

[Draken]

Every 0.3 is 1 stop. It depends on the lighting conditions you encounter, but I'd guess that a 3 stop grad ND would be a good place to start. You may find that if you leave your camera in the default segmented metering mode that it does fine with the filter on. If not remove the filter and meter the foreground.

so do i meter the foreground only ? or that and the sky ? im still confused lol

 

[tirediron]

I would recommend the purchase of a . 3 and .6 or 1 and 2 stop ND grads, which will give you three stops if used together, but much more versatility than a single 3 stop on it's own. With respect to metering, always meter the scene without the filter, put the filter on, and expose. You may have to adjust a little bit either way, but that's the beauty of digital.

 

[Joves]

I would recommend the purchase of a . 3 and .6 or 1 and 2 stop ND grads, which will give you three stops if used together, but much more versatility than a single 3 stop on it's own. With respect to metering, always meter the scene without the filter, put the filter on, and expose. You may have to adjust a little bit either way, but that's the beauty of digital.

This is the best solution. You will have to shoot with them to learn to use them effectively. But hell it is didgital so it is no big deal. Much better than learning in the film days.

 

[Draken]

awesome thanks guys i know i meter the foreground but where abouts im really noobie at metering and really dont know what to do :-( also since im getting my Sigma 10-20mm im not sure using two ND grads will be a good idea due to vignetting is that true ?

thanks Again,

Mike.

 

[tirediron]

awesome thanks guys i know i meter the foreground but where abouts im really noobie at metering and really dont know what to do :-( also since im getting my Sigma 10-20mm im not sure using two ND grads will be a good idea due to vignetting is that true ?

thanks Again,

Mike.

I would suggest matrix/wide-area metering, but again, a lot will depend on the range between bright and shadow. With respect to the issue of multiple filters, are you planning to use screw-ins or gel types? I recommend the gel types, esp. for ND Grads as that gives you the flexibility to move the graduation anywhere in the frame, and will allow you to stack multiple filters with no vignetting.

 

[Garbz]

Well if you're shooting landscapes I certainly would recommend saving your money first, or at the very least experimenting with the following to try and find out what type of an ND Grad filter you really need:

Tripod. Multiple exposures as if you're about to do a HDR. Photoshop.

In photoshop pick the exposures. The original and the -1EV for example for the sky. Then blend them together with a gradient mask.

The advantages:
- It is truly neutral, no cheap grad filters introducing colour casts or being imperfect.
- You can adjust the gradient after shooting.
- If you took multiple exposures you can choose the strengths of the effect.
- COST! Good ND Grad filters which are nicely linear and neutral do come at quite a price.

The disadvantages:
- You need a tripod.
- Does not work for moving objects which span across where the gradient effect starts and ends.
- Some people have a fear of photoshop.

 

[ksmattfish]

so do i meter the foreground only ? or that and the sky ? im still confused lol

With the filter off meter the foreground only, and then meter the sky only. Count the difference in stops. If you want your sky to be brighter than middle gray subtract 1 stop from your count. Now you know what strength grad ND you need to use. Put the filter on, and set your exposure based on the foreground readings.

Or just leave the filter on, compose and meter the entire scene. Take a test shot and see if it works okay. Modern, TTL, segmented metering (the default setting on most DSLRs) shouldn't have problems dealing with the filter assuming you've chosen a grad ND that's close to the right strength (most of the time I think you'll find a 3 or 4 stop grad ND does the trick).

Stacking filters can cause problems such as vignetting and flare (decreased contrast and saturation), etc... On the other hand if you want to fine tune the exposure your choice is to buy one of every strength grad ND you'll ever need, or stack filters.

Personally I like the technique Garbz describes. Besides the problems with filters in general, my landscape compositions rarely fit the straight line through the center that grad NDs allow for. When I'm shooting landscapes I almost always use a tripod so it's easy to make an exposure to optimize the sky, and make another exposure that optimizes the foreground, and mask them together in processing. If I don't have a tripod processing multiple photos from a single raw file is an option.

This composition doesn't fit a typical, screw-on, grad ND filter.

 

[Steph]

A few comments about ND filters and the way I use them (I shoot slide film with a MF camera):

-Meter a midtone in the foreground. Meter the sky. Calculate the difference in stops. Substract one and that gives you the strength of the ND filter (I found this to be a good method with good success rate to have a well balanced sky wihtout using a handheld spotmeter). Use the meter reading from the foreground for the shot.
-I find a 2 stop filter to be the most useful (although I sometimes use 1 and 3 stops ).
-Rectangular filters are much more versatile than screw-on ones (you can place the transition ND/clear wherever you want).
-Some filters are more neutral than others. I find that Cokin ND filters tend to give a purple cast to the sky (BTW, they are not sold as ND filters but as grey filters). Filters from Formatt and Lee are more expensive but truly neutral in my experience.

 

[tirediron]

-Some filters are more neutral than others. I find that Cokin ND filters tend to give a purple cast to the sky (BTW, they are not sold as ND filters but as grey filters). Filters from Formatt and Lee are more expensive but truly neutral in my experience.

Actually, they're referred to by both terms on the Cokin webiste:

http://www.cokin.com/filtres2.html?=#121

 

[Steph]

Actually, they're referred to by both terms on the Cokin webiste:

http://www.cokin.com/filtres2.html?=#121

You are right. The rest of my comment about the Cokin filters is still valid though.

 

[tirediron]

You are right. The rest of my comment about the Cokin filters is still valid though.

I think that's debatable; I've personally never noticed the effect, but I have heard many reports of it...

 

[Alex_B]

A few comments about ND filters and the way I use them (I shoot slide film with a MF camera):

-Meter a midtone in the foreground. Meter the sky. Calculate the difference in stops. Substract one and that gives you the strength of the ND filter (I found this to be a good method with good success rate to have a well balanced sky wihtout using a handheld spotmeter). Use the meter reading from the foreground for the shot.
-I find a 2 stop filter to be the most useful (although I sometimes use 1 and 3 stops ).
-Rectangular filters are much more versatile than screw-on ones (you can place the transition ND/clear wherever you want).
-Some filters are more neutral than others. I find that Cokin ND filters tend to give a purple cast to the sky (BTW, they are not sold as ND filters but as grey filters). Filters from Formatt and Lee are more expensive but truly neutral in my experience.

totally agreed + good recipe for using an ND grad, good summary.