Grad filter discussion...

What is a reverse graduated filter?

since this thread is generating some very educational discussion, I changed the title to be a little more attractive

Reverse grads have a very abupt transition, becoming less dense towards the top of the filter. Standard grads have a less abrupt transition, becoming more dense towards the top of the filter.

3-stop standard grad

3-stop reverse grad

Ah, I see how that can be used. very cool! Thanks Marc!

I especially like a reverse grad when the sun is positioned very near the horizon.

Hey another related question - whats the difference betwen the cokin and singh-ray brands. I know singh-ray is pro-quailty stuff but is cokin really bad ?

No, I don't believe Cokin, Lee or most other less expensive grads are that bad (note: this is not often the case with most other filters and lenses). At worst, there may be the slightest of color casts and the optical quality and coatings with Singh-Ray glass can help reduce flaring/ghosting at times, but I'd say the differences are minimal at most. Singh-Ray is a small company owned by Bob Singh and they certainly care about customers and quality. The make all grad filters when ordered and offer pretty much any custom options you could want. Other reasons they may be more expensive. I do know photographers that use Cokin filters and are happy doing so and have never noted any major problems. I have never used them myself though.

Thanks Marc, I had ordered cokin filters and was hoping I had not made a mistake.

I have two 2-stop cokin soft grads and I'm not happy with the color cast. even when used with my one high-quality lens (70-200 f4L). The blues seem way off. Or... maybe I'm not using them correctly...? They are plastic so I figure that's probably got a lot to do with it. I think I have an example image on my hard drive at home. I'll post it in this thread if I can find it.

In any case, I'm saving my pennies to buy 1 and 3 stop singh-ray filters, and if I like them, I'll get a 2-stop as well. I have a cokin double-filter holder..

Even I have trouble with color casts, mostly magenta, with Singh Ray filters. Slight, but still a problem. At times it is impossible to stack filters or use a stong grad due to the cast. It seems to be a problem inherent of all grad filters. Some are better than others. Singh Ray is the best I've found, but not perfect. Like I said, I've never used Cokin but know people that have and were satisfied. I'm not completely satisfied with any of them all the time.

hmmm... sounds like maybe I'm using either too much filter, or using them when they're not necessary. I'll have to try some "filter braketing" in the future.

I'm terrible at using them. I find it very hard to see where exactly I'm placing the grad line. The only one I have is a 3-stop soft.

Stopping down the lens with the "Depth of field preview" button will help show where the grad line is so you can set it up where it needs to be. I've done this many times on my Canon cameras. Does Nikon have a "Depth of field preview"?

Yup, they do. I'll have to try to remember that trick.

Hard grads are best with digital cameras.. and will actually perform more like a soft. Bob Singh has a discussion of this on his site, and it is a good one to read....

I couldn't stand ND's on 1.6 crop cameras, but on full frame I kind of like them. Depends on situation. If the lights is changing fast and there is probably no time for too much bracketing filters are your only chance. I use Lee mostly, because I like their holder so much more then the darn cookin , but the filters are bigger and more expensive which is a downsize. When I like filters most is on the coast where they really can save you a lot of time on PC later on. Just my $0.02

After using a Cokin 2 stop soft edge with my Cokin p-mount and discovering a distinct pinky gray cast, I dumped it in favor of High Tech plastic, with hard egdes (2 and 1 stop). This photo was taken at Heceta Head with both filters stacked in the holder on a Nikon D70. Horizon shots really benefit from the hard edge, but use caution with direct light sources; for my wide angle lenses, I get best results after the sun has set. I also second the opinion that a good grad filter in camera can save some pp work, although this shot had some color correction and saturation help with Photoshop. :-)

I've got a pair of Hitechs and I love them. Little bit of an issue with static cling of dust particles, but a quick wipe usually solves the problem. Plus scratching isn't an issue.

Also, maybe this is a stupid question, but does the reverse grad thing only apply to screw-mount grads? Because you can just flip a mounted filter upside down, so it would either be a stroke of genius on behalf of the marketing department of filter makers to successfully market reverse grads (they could just sell the same thing packaged upside down)...or somebody is confused. Or is it just a term used to describe the reversing of a grad? I really only ask because the two shots Marc posted above look exactly the same to me.

Bryan, I think what Marc was saying is that the filter is densest in the middle, and lighter as you go "up"... Rather than being densest at the top and lighter as you go down.

Okay, so its a matter of how far from one end the transition starts? Standard filter has 1/3 - 1/2 darkened vs. reversed has 2/3-3/4 darkened, or something along those lines? The two I have are split down the middle more or less, so that's why it just sounded odd to me.