Nikkor 18-70 DX + pol filter. Avoiding vignetting.

[dave_osborne]

I've got a 18-70 DX (on a D200) which I use mostly for its wide end and often

use a polarizing filter.

 

Currently I use at B+W 72mm(long story) pol filter on a 67-72 step up ring and

get a bit of vignetting @ 18mm.

 

Not sure if it's the thickness of the stepup ring which is doing this so wanted

to ask if anyone uses a 67mm pol filter and is vignette free @ 18mm?

 

And if you are exactly which make of pol filter do you use?

 

Cheers,

Dave.

[Jerry_]

At 18mm the polarizer "effect" may not be exactly what you want (with film,) anything wider than 24mm gives un-even results in the sky with a circular polarizer filter. That said, try to keep anything "important" out of the corners if you are going to use the circular polarizer filter at 18mm.

[dave_osborne]

18mm = 27mm equivalent field of view on a D200 so it isn't really hugely wide.

I've no problem with the variation of the polarisation effect, just looking for someone who uses a 67mm pol filter on this lens @ 18mm to let me know whether they get vignetting or not.

[shineofleo]

18mm is not so wide, or you can get a slim version of the cpl? which may not have a front thread.

[aaron l]

Your step up ring is probably what's causing it. If you get the correct sized filter, you won't see this. I have a UV filter on mine always and don't get vignetting. I use a Cokin P holder with a Singh-Ray polarizer and get a tiny bit of vignetting. Once I chop the corners off the holder, that will not be a problem any more.

[dave_osborne]

Thanks Aaron, that's what I was looking for.

A polariser's a little thicker than a UV filter but sounds like it may be better without a step-up ring.

 

Now to find someone to swap a 72mm for a 67mm!

[Ed_Ingold]

The step-up ring moves the filter further from the lens, reducing it's effective diameter. A thin polarizer may not be thin enough. However, a normal polarizer (with an threaded front) of the right size is not likely to vignette on a DSLR. I've had trouble with step-rings even on normal lenses with film.

 

The 18-70 may vignette somewhat without a filter at all. Point it at a blank sky at wide aperture some time, and check the densitometry in Photoshop.

[photo5]

I use a 67mm Moose Filter (Polarizer with 81A combined) on my 18-70mm and haven't noticed a vignetting problem.

 

Dave<div></div>

[photo5]

Oops, I attached the wrong image, sorry about that.

 

Dave<div></div>

[Peter_in_PA]

BUT...

 

If you do invest in a new polarizer, I'll bet a thin one at 77 with a 67-77 step up ring would

still not vignette with a thin polarizer and then you'd have the right size for if you ever buy

any "pro" lenses. It could save you money in the long run. (I use a 72-77 on my 18-200 and

get no real vignetting from one filter attached at 18.) But don't shoot wide open, because

then you WILL vignette anyway, because the lens just does that wide open.

[dave_osborne]

Cheers Peter... it is a bit of an annoying expense trying to work out which is the best filter size for your particular selection of lenses innit.

I guess using 77mm is probably the best way to future proof but step up rings do annoy me.

Good point about the f3.5 vignetting.. that might actually be what I was seeing - I need to do some experiments.

Cheers again.

[sam_bennett1]

I have the 18-70 lens on my D70s. I can confirm that there is no viginetting with a 67mm circular polarizing filter at 18mm.

 

Hope this helps,

 

Sam