Are variable ND filters worth the cost?

OrionsByte · May 13, 2011

I've got some birthday money burning a hole in my pocket and was thinking about investing in an ND filter, just because there have been times I wished I had one and didn't (though I realized today that even my CP filter could have stopped me down at least a little, but I digress).

Since my "need" for this is a little open-ended I want to get something fairly flexible, and while I think I could probably get away with a .6 or .9, I was curious to know whether the variable ND filters are worth it for the flexibility, or if they tend to interfere with image quality.

I'd love to hear some opinions!

My most likely use-case for these would be slowing the shutter speed down to flash-sync speeds in bright daylight for outside portraits, but I'd also love to be able to do some slow-shutter shots of water and such in the daylight as well.

Robin Usagani · May 13, 2011

I wouldnt get .6 i think. Just get .9. 3 stops is about right for what you need.

Big Mike · May 13, 2011

FYI, using them to 'slow the shutter speed down' for outdoor flash shots, probably isn't the best idea. The ND filter will block the flashed light as well....requiring you to use more and more flash power.

Sure, it could be helpful if you want to shoot at large apertures in that situation...when you don't want to stop down the aperture.

OrionsByte · May 13, 2011

Big Mike said:
FYI, using them to 'slow the shutter speed down' for outdoor flash shots, probably isn't the best idea. The ND filter will block the flashed light as well....requiring you to use more and more flash power.

I was aware of that, but thanks for the reminder.

Sure, it could be helpful if you want to shoot at large apertures in that situation...when you don't want to stop down the aperture.

That's basically what I had in mind. Like I said though, I don't have a terribly specific use for it yet.

Schwetty's probably right though, a .9 would be easy to compensate for if it was a little too dark for whatever specific purpose I was using it for at the time, and if I needed something more dense at some point in the future I could always pick one up.

KmH · May 13, 2011

If you have a .3 (1 stop), and a .6 (2 stops), ND filter, by stacking you also have a .9 (3 stops)

If you have the .3, .6, and .9, by stacking the filters you also have a1.2 (4 stops), a 1.5 (5 stops), and a 1.8 (6 stops)

Robin Usagani · May 13, 2011

how many can you stack? eventually you will see the ring when you shoot wide?

OrionsByte · May 14, 2011

Well after careful thought and consideration, plus the fact that it was all the camera store had in stock, I picked up a .9. :lol:

I also bought a new umbrella and a dome diffuser for my flash. Put them all together to play around this morning. I meant to take a photo of my setup but I forgot. Basically I had the light stand with the umbrella out on the balcony which is off of our bedroom. My camera was on a tripod on the other side of the bedroom, about 12 feet or so away from where I stood out on the balcony with my 55-200mm at 122mm. I triggered the camera with my IR remote, and the flash was triggered with the popup flash.

1. ISO 200, f/8, 1/60, flash at 1/2 power:

2. ND8 filter, ISO 400, f/5.6, 1/60, flash at full power:

You can clearly see that the ambient light was reduced by a stop (-3 stops from the ND filter, +1 from the increase in aperture, +1 from the increase in ISO = -1). Bumping up the flash power by a stop compensated for that so the flash exposure was the same.

Now obviously I could have achieved the exact same results just by taking the shutter speed from 1/60 to 1/125 and leaving everything else alone, but this was more of a mental exercise for me, and I wanted to use the new filter. Yay for experimentation!

Despite the ugly model with morning hair, I'm pretty happy with the results of these, even if they were just tests.

The first one is way better though, both because of the lighting ratio and because of the DOF. C&C welcome if desired.

KmH · May 14, 2011

Schwettylens said:
how many can you stack? eventually you will see the ring when you shoot wide?

Not all ND filtes are round, and screw onto the front of a lens, but yes, if you stack the round kind vignetting can occur.

Robin Usagani · May 15, 2011

dude.. you have ND filter, shoot it to the max aperture. Thats why people use ND filter. Shooting it at F8 and F5.6 doesnt do anything but using more battery juice. People use ND filter because they cant shoot wide open with off camera flash (no HSS or FP) or when they want to do slow shutter on a bright day.

OrionsByte · May 15, 2011

Schwettylens said:
dude.. you have ND filter, shoot it to the max aperture. Thats why people use ND filter. Shooting it at F8 and F5.6 doesnt do anything but using more battery juice. People use ND filter because they cant shoot wide open with off camera flash (no HSS or FP) or when they want to do slow shutter on a bright day.

f/5.6 is my max on that lens at that focal length, but yeah I should try some with my 1.4.

I really had NO reason to put the ND filter on yesterday, other than that I wanted to try it and go through the exercise of compensating for it.

Village Idiot · May 15, 2011

Schwettylens said:
dude.. you have ND filter, shoot it to the max aperture. Thats why people use ND filter. Shooting it at F8 and F5.6 doesnt do anything but using more battery juice. People use ND filter because they cant shoot wide open with off camera flash (no HSS or FP) or when they want to do slow shutter on a bright day.

A 3 stop may not be enough. Just going off the top of my head with the settings from the last photo, going from ISO 400 to 200 is one stop and SS 1/60 to 1/250 is a touch over two stops. Going f/5.6 to f/2 is two stops, for a total of three. Any lenses faster then f/2 are going to have a brighter exposure. If he's shooting in brighter light, that will exacerbate the problem. I picked up a 6 stop for that reason, but I also have flash packs to compensate for needing more power to help with that 6 stop.

OrionsByte · May 15, 2011

Well I did some more messing around today to open up the aperture. I used my 50mm 1.4 but shot at f/2 because the DOF was just too thin any wider than that. So with the ND8, I shot at f/2 1/60 ISO 100 with the flash at 1/4. I also took some test shots of a stuffed animal at f/1.4.

Village Idiot said:
Schwettylens said:

dude.. you have ND filter, shoot it to the max aperture. Thats why people use ND filter. Shooting it at F8 and F5.6 doesnt do anything but using more battery juice. People use ND filter because they cant shoot wide open with off camera flash (no HSS or FP) or when they want to do slow shutter on a bright day.

Click to expand...

A 3 stop may not be enough. Just going off the top of my head with the settings from the last photo, going from ISO 400 to 200 is one stop and SS 1/60 to 1/250 is a touch over two stops. Going f/5.6 to f/2 is two stops, for a total of three. Any lenses faster then f/2 are going to have a brighter exposure. If he's shooting in brighter light, that will exacerbate the problem. I picked up a 6 stop for that reason, but I also have flash packs to compensate for needing more power to help with that 6 stop.

It should be enough for now, for me anyways. Given my settings above, I have room for at least an extra couple stops of ambient light before I run in to my sync speed again. It's pretty overcast today so on a sunny day I may have a bit more trouble.

I was thinking, even on a "sunny 16" day, the ND8 filter would let me stop down to f/5.6 at ISO 200, or f/4 at ISO 100. For outdoor portraits that may not be ideal, but it's still a lot better than f/16. As far as slow running-water type shutter speeds in bright light, I'd be using a smaller aperture for landscapes anyways, so I think it's pretty doable. As usual when I buy new camera toys, I'll use it until my needs and skill outgrow its limitations.