Wanted: Dummies Guide to ND Grads

Dr_Q

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After a long long time researching and then forgetting about it I've got myself a set of soft ND grads. Last night I was at the point where I didn't even know how to fit the filter holder to the camera properly (in fact I put it on backwards and was wondering why it didn't fit too well...) but today I decided to give it a bash. This was using a HiTech 0.3 ND grad.

Annoyingly straight out of camera the shots were really lacking contrast which you can see if you click CLICKY. I played around with exposure correction and I think I've managed to portray the scene pretty accurately. I also have a screenshot of the photograph in lightroom CLICKY.


https://pic.armedcats.net/d/dr/dr_q/2009/01/18/grad1.jpg

I've tried to talk to as many people as I can about this and I have gotten a few different answers. Some people say that the grad has lessened the contrast in the photograph to make sure all of it is within the dynamic range of the sensor (kind of logical but I don't know...) Others have said that it was the way that I took these photographs in the first place. I got everything set up and metered with the grad on instead of metering the foreground or subject, locking the exposure and then using that exposure with the filter on again. It has also been suggestion that I could have gotten a similar photograph without a grad at all and that the conditions used weren't at all ideal for this sort of experiment.
 
They might reduce contrast a little bit simply because you're adding extra glass, but I don't think they're specifically designed to do that. Metering with the filter on is the correct way to do it. We're talking about TTL metering here, after all.

I'm going to go with "wrong subject" on this one. This particular subject and composition looks like it may have been better served with a CPL (Circular PoLarizer). With the sun to your right (I think?), the sky would have darkened nicely and been well within the dynamic range of the sensor, especially with the reflections on the water.

I typically use my grad ND to retain sky detail and/or provide a graduated effect in situations where a CPL won't work (cloudy days, shooting at angles other than 45 degrees to the sun).

Oh, yes, also important: if you're using a regular screw-on mount filter on your lens, it will only graduate in the centre. If you're using it on a zoom lens, it will typically only work near the wide end of the lens. The only effect it will give you at longer focal lengths is darkening. For fixed lenses, it depends on the design, but it will usually work.

Since you talk about a "holder", I'll assume you have a cokin rig or something similar. The only-down-the-middle limitation doesn't apply here, but what focal lengths you can use the filter at depends on how soft or hard the graduation is.

Here are some examples where I've used my grad ND. Notice that they are mostly at wide angles where a CPL would have had no effect.

https://pic.armedcats.net/e/ep/epp_b/2009/01/18/2008-11-19_Wavy_Fence.jpg

https://pic.armedcats.net/e/ep/epp_b/2009/01/18/2008-11-19_Wood_Shed.jpg

https://pic.armedcats.net/e/ep/epp_b/2009/01/18/2008-09-03_Old_Shed_in_the_Blistering_Sunset.jpg

https://pic.armedcats.net/e/ep/epp_b/2009/01/18/2008-10-10_Cool_House_Beneath_the_Clouds.jpg

https://pic.armedcats.net/e/ep/epp_b/2009/01/18/2008-10-26_Another_Old_Shed.jpg

https://pic.armedcats.net/e/ep/epp_b/2009/01/18/2008-10-26_Dump_and_Truck.jpg

https://pic.armedcats.net/e/ep/epp_b/2009/01/18/2008-11-01_Old_Blue_Tractor.jpg

https://pic.armedcats.net/e/ep/epp_b/2009/01/18/2008-11-06_Artful_Train.jpg

https://pic.armedcats.net/e/ep/epp_b/2009/01/18/2008-11-26_Untitled_Sunset.jpg
 
Thanks for the reply epp_b, I use HiTech 85mm filters in a Cokin filter holder. I bought a set of 3 but just to start with I used a 0.3 soft grad. This is only a 1 stop grad so none of the results are going to be that dramatic but I was still quite surprised at what happened here. The sun was behind me and to the right when I took this. I think I will try some more experimentation as I really don't feel I've got things right this time. I could blame the filter here but to be honest I don't really want to (what can go wrong anyway? :p).
 
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