Variable ND filters

Started by kihlbahkt, June 02, 2014, 07:07:24 PM

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kihlbahkt

Anyone have experience with variable neutral density filters? Sunny days are killing my brights. even at 100 ISO. I am trying to decide whether I go with sets of fixed density or variable. Variable sounds great, less filters to buy, less filters to carry and less fiddling with the cam to deal with super bright days. I need several sizes to cover my glass collection so I am leaning towards variable but would like any input about caveats or other aspects I should consider before I buy variable ND filters. Thanks.
600D x2

garry23

Think about focal length.

Wide Angle lenses and Variable NDs do not go well together, ie banding problems.

kihlbahkt

Thanks garry23. I will add that to the list of considerations.
600D x2

reddeercity

Not problem with a good quality Var. ND Glass, I use one all the time outside with primes or Zoom lens
and never had a problem with banding. Low quality ND glass will always produce problems.
Made sure the Glass is of very high optical quality as they range from $90 to $580 .
I use Promaster Digital HGX 77mm ND fader (same as Variable) but for Video,
http://www.promaster.com/products.asp?product=9350 , cost me in western Canada $199.00
I never leave the house without it when I do paid work. ;D

kihlbahkt

@reddeercity - Thanks for the testimonial and the link. Video is the main work for my cams so I will definitely give the Promaster series a good looking over. I noticed that the link is to HGX series which seems to have additional coating properties and is slimmer. I looked up Promaster vari nd at my local Mike's Camers but they dont seem to carry the HGX series. The HGX series seems to be top notch. The line available here in retail are much cheaper but not branded HGX. Any opinions on non HGX series quality? I may just give them a call to discuss.

edit: I did call and they have digital HGX variables for 49mm (52mm and 55mm)  thru 58mm, priced at 99usd to 120usd. Too bad I need 4 of them. Thanks for the info guys. I will likely start out with the 49mm since those are my fastest primes, which are OM lenses. I may buy a cheaper one to see how it performs on my canon lenses.It will be great to have more control of that pesky but critical sunlight.
600D x2

garry23

The x effect with WA lenses is well documented.

This is a gypsies warning so I will say no more.

;-)

kihlbahkt

No worries garry23. Your warning is noted.  :)
600D x2

ItsMeLenny

I thought variable ND filters work using polarisation, and that's why at wide angles it wouldn't work, just like a polarising filter doesn't.
I could be wrong though.

garry23

That's right, which is why you need to be sensitive to FL and amount of ND you dial in.

ansius

personally I'm in no favor for variable ND filters, because it takes time to get the polarizing and the nd effect right. I have set of regular, filters, and they don't care for the lens type. Especially with time lapses, where sun moves - it is not that easy to guess correct variable filter position so it would not crew up your picture. On the other hand - go for good barand with good reviews, cheep ones have more problems and at the end they have worsened the picture more than you gain.
Canon EOS 7D & 40D, EF-S 17-85mm IS USM, EF 28-300mm IS USM, Mir-20, Mir-1, Helios 44-5, Zenitar ME1, Industar 50-2, Industar 61L/Z-MC, Jupiter 37A, TAIR-3
http://www.ansius.lv http://ansius.500px.com

Walter Schulz

Quote from: ansius on June 03, 2014, 01:00:31 PM
personally I'm in no favor for variable ND filters, because it takes time to get the polarizing and the nd effect right.

There are Vari-NDs around where first quarter wave plate missing, topping the "sandwich" with the linear polarizer element. Those in fact do have this problem.

Again: This is a non-issue for a decent Vari-ND.
Decent means -> Quarter wave plate as first and last elements.


kihlbahkt

I am going to buy a Vari - ND today and run it thru its paces. If it does not perform to my satisfaction then I wont be using it and move on to normal ND filters. I totally appreciate the conversation around my question and the knowledge I have gained from asking it in this forum. I am also getting a screen hood to see what the hell I am composing and focusing in these bright day shoots. It would be cheaper to put a cardboard box on my head with a hole for the camera but then I might come off looking a bit silly probably.
600D x2

poromaa

I really like my variable ND-filter. Went through 100s of reviews and tests to find a good compromise between price and quality. I ended up buying a Tiffen 82mm Variable ND-filter + some adaptor rings (to use with all my lenses). It was quite expensive, but does not produce any reflections or blurriness to the image.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=360875292783

The filter works as both a polar filter and a variable nd. There is a slight color shift to blue/yellow depending on what angle it is in. Most ND-filters have this property. So if twisting it goes from clear to dark in blue-tint, then dark to clear in yellow tint. The color shift is very subtle and easy to correct. During this twist reflections in windows/water etc changes just as a circular polar filter does. So, this filter is kind of both a ND-filter and a polar filter (actually its two cir-polar filters on top of each other).

Usually I set my lens to a nice apperature (3.2) and then a low iso 100. then i twist the ND until i only have minor areas of over-exposure (ETTR) to gain as much DR as possible.

Walter Schulz

Quote from: poromaa on June 03, 2014, 09:00:23 PM
(actually its two cir-polar filters on top of each other).

I bet it is not! Rather a linear polarizer on top of a circular.

jimmyD30

Thanks for all your input guys, I've been using medium quality variable NDs on normal range lenses and didn't think the wide angle might cause a problem, so now I'll go test them out before needed on a shoot :)

garry23

The issue is not NDs but variable NDs that make use of a linear and circular polarizer.

I have personally seen the negative impact with a 10mm lens on an APS-C.

As others have said you just need to watch what you dial in, ie don't be too aggressive.

poromaa

Quote from: Walter Schulz on June 03, 2014, 09:28:21 PM
I bet it is not! Rather a linear polarizer on top of a circular.

Oh, i didn't know? :) I have to say that I have never understod how circular polariser would worked anyway. Made me look it up. Seems like all "circular-polarizers" consists of one linear polirized glass and one cir-pol.glass ? Find the whole thing to be quite strange - like quantum mechanics.

kihlbahkt

So the initial verdict is a big winner. I purchased a 49mm Promaster HGX Variable ND for 99usd today. My Variable ND candidate lenses dont fall into the wide angle range so concerns raised by garry23 should not impact me. I am generally shooting wide angle indoors/set where an ND is not likely to be required. It appears to provide exactly what I need. Time will tell. I also bought a hoodman hood loupe, model ch32 @ 99usd. It is collapsible and has no direct way to attach to the cam and it designed to be held up for viewing purposes. I think they sell a rubber band as an accessory. I attached mine with a quick assemblage of three "street" rubber bands and BOOM!, all done. So the combo of the hoodman and the vari nd will improve my outdoor shoots for sure. I will be shooting this weekend outside so I am pumped to not squint to see my lcd, or try to (uselessly) cover with my hand, as well as, keeping that shirt/face/prop from blowing out. Thanks to everyone for their input. My 200$ investment should serve me well.
600D x2

ItsMeLenny

Which is probably why cheap variable ND filters can be blurry.
Because cheap polariser filters are hell blurry.
Discovered that after wasting $20.
Which I wonder if circular polisers are blurrier than linear.
Doesn't matter which you buy if you're shooting manual.

kihlbahkt

It is an interesting filter and the polarization factor is there, for obvious reasons. Just before full open there is a tiny little range that will make my digital TV screen content disappear while everything else looks the same so it looks like the TV is not on. I also did some experimentation with panning from dark to bright while giving the vari-nd an artistic and well timed twist and had some satisfactory results with keeping exposure levels at a suitable levels. Very similar to auto exposure on a camcorder without changing the ISO or aperture. I have not used on water or glass reflections but figure that there is polarization in play all the time with this filter, or at least when specific angles are set. Still thumbs up for this vari-nd. It also has potential for in camera fade to black/fade from black, which is something I did not think about previously.
600D x2

Walter Schulz

Quote from: poromaa on June 03, 2014, 11:52:16 PMSeems like all "circular-polarizers" consists of one linear polirized glass and one cir-pol.glass ?

A circular polarizer is just a linear polarizer followed by a device "scrambling" the waves from linear polarisation to circular. Thus they may reflected or passed by the main mirror as intended. Linear polarized waves could be reflected at all (or passed by at all) this main mirror which will mess up phase detection AF (the old-fashioned one like described here) and exposure metering when used outside liveview or movie mode.
The scrambling device is called "quarter wave plate".

Most people don't have problems with the concept of linear polarization. When it comes to circular polarization imagination fails and blank stares will occur. And I'm quite one of those, too.

Ciao
Walter

poromaa

Quote from: Walter Schulz on June 04, 2014, 07:02:35 AM
A circular polarizer is just a linear polarizer followed by a device "scrambling" the waves from linear polarisation to circular.

Thanks for that explanation! Couldn't really find out what that circular thing did. Just ended up in texts about linear polarising filter. Thanks!