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yunr · 10-27-2016, 12:14 PM

Hello everyone, I was thinking to mount a polarized filter on my 20-40mm lens, but it seems there isn't any filter at this size that would fit on this lens? Any suggestions on which filter/adapter rings/or other options to make it work?

Thanks,
Bob

Saltwater Images · 10-27-2016, 12:48 PM

Hi, I believe to circular size for the HD DA 20-40 is a 55mm thread. B&H has quite a 55mm polarizer selection: Polarizing Filters | B&H Photo Video

**Wingincamera** · 10-27-2016, 12:52 PM

I use a 55 to 77 step up ring, because my largest lens uses a 77mm filter. I have 77mm ND & polarized filter that I use with it. I have these two also in the 49mm, since that is what most of the Pentax lens use.

Step Up Rings | B&H Photo Video

cpobuttons · 10-27-2016, 12:59 PM

you have to remove the hood to install the filter...

Adam · 10-27-2016, 01:52 PM

With a filter on I doubt the hood is even necessary. 55mm is the size you want.

MikeW · 10-27-2016, 04:26 PM

Yes, 55 is what you want after you remove and then replace the hood. BUT, maybe you want to do a step-up ring as suggested by Wingincamera. I really like this lens, but it tends to flare even with the very skimpy hood on. So, I'm thinking that it could use either a deeper hood or a step-up ring, plus deeper hood.

Saltwater Images · 10-27-2016, 05:06 PM

The best question to answer before you purchase a polarizer or step up rings (if needed) is what size filter thread do your other lenses have? In my case; the 4 lenses I use the most HD DA 21, HD DA 40, HD DA 70 and D FA 100 Macro WR - all have a 49mm filter thread. I purchased one good polarizer and one good variable ND filter - I have covered a lot of bases with 2 filters, keeping my kit light and investing in better accessories.

If you have lenses with a couple of different thread sizes - which ones will you want to put a polarizer on? Get a polarizer to fit the largest thread size and step up rings to make the polarizer fit lenses with smaller thread sizes. You'll capture better images spending a few extra dollars on a good polarizer and inexpensive step up rings as opposed to buying several cheaper polarizers in different thread sizes.

lytrytyr · 10-27-2016, 06:37 PM

Originally posted by MikeW

I really like this lens, but it tends to flare even with the very skimpy hood on.

That has not been my experience, in almost three years of using the lens.

Outis · 10-28-2016, 04:21 PM

Originally posted by lytrytyr

That has not been my experience, in almost three years of using the lens.

Yeah, I don't get flare, either.

10-27-2016, 12:14 PM	#1
yunr New Member Join Date: Jul 2012 Location: U.S. Photos: Albums Posts: 18	filter size for DA 20-40mm Hello everyone, I was thinking to mount a polarized filter on my 20-40mm lens, but it seems there isn't any filter at this size that would fit on this lens? Any suggestions on which filter/adapter rings/or other options to make it work? Thanks, Bob

10-27-2016, 01:52 PM	#5
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 51,608	With a filter on I doubt the hood is even necessary. 55mm is the size you want. Adam PentaxForums.com Webmaster (Site Usage Guide \| Site Help \| My Photography) PentaxForums.com server and development costs are user-supported. You can help cover these costs by donating or purchasing one of our Pentax eBooks. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, KEH, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

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10-27-2016, 12:48 PM	#2
Saltwater Images Veteran Member Join Date: Nov 2014 Location: Newfoundland Photos: Gallery Posts: 501	Hi, I believe to circular size for the HD DA 20-40 is a 55mm thread. B&H has quite a 55mm polarizer selection: Polarizing Filters \| B&H Photo Video

10-27-2016, 12:52 PM	#3
Wingincamera Loyal Site Supporter Join Date: Oct 2012 Location: Pine Haven, Wyoming Photos: Gallery \| Albums Posts: 1,182	I use a 55 to 77 step up ring, because my largest lens uses a 77mm filter. I have 77mm ND & polarized filter that I use with it. I have these two also in the 49mm, since that is what most of the Pentax lens use. Step Up Rings \| B&H Photo Video

10-27-2016, 12:59 PM	#4
cpobuttons Senior Member Join Date: Feb 2013 Location: Norwich, Ct Posts: 139	you have to remove the hood to install the filter...

10-27-2016, 04:26 PM	#6
MikeW Veteran Member Join Date: Jan 2008 Location: Indiana Photos: Gallery Posts: 437	Yes, 55 is what you want after you remove and then replace the hood. BUT, maybe you want to do a step-up ring as suggested by Wingincamera. I really like this lens, but it tends to flare even with the very skimpy hood on. So, I'm thinking that it could use either a deeper hood or a step-up ring, plus deeper hood.

10-27-2016, 05:06 PM	#7
Saltwater Images Veteran Member Join Date: Nov 2014 Location: Newfoundland Photos: Gallery Posts: 501	The best question to answer before you purchase a polarizer or step up rings (if needed) is what size filter thread do your other lenses have? In my case; the 4 lenses I use the most HD DA 21, HD DA 40, HD DA 70 and D FA 100 Macro WR - all have a 49mm filter thread. I purchased one good polarizer and one good variable ND filter - I have covered a lot of bases with 2 filters, keeping my kit light and investing in better accessories. If you have lenses with a couple of different thread sizes - which ones will you want to put a polarizer on? Get a polarizer to fit the largest thread size and step up rings to make the polarizer fit lenses with smaller thread sizes. You'll capture better images spending a few extra dollars on a good polarizer and inexpensive step up rings as opposed to buying several cheaper polarizers in different thread sizes.

10-27-2016, 06:37 PM	#8
lytrytyr Pentaxian Join Date: Nov 2011 Photos: Gallery \| Albums Posts: 4,310	Originally posted by MikeW I really like this lens, but it tends to flare even with the very skimpy hood on. That has not been my experience, in almost three years of using the lens.

10-28-2016, 04:21 PM	#9
Outis Veteran Member Join Date: Apr 2014 Location: Cambridge, MA Posts: 935	Originally posted by lytrytyr That has not been my experience, in almost three years of using the lens. Yeah, I don't get flare, either.

filter size for DA 20-40mm

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