[TheWengler]

Staff note: This post may contain affiliate links, which means Pentax Forums may earn a small commission if a visitor clicks through and makes a purchase. If you would like to support the forum directly, you may also make a donation here.

---

I'm planning on purchasing either the Pentax or Tamron variant of this lens soon. I've been reading lots of formal and user reviews before making my purchase and I came across something that concerned me. One of the user reviews stated that when this lens is used with a filter it has severe vignetting at the wide end and when filters are stacked they creep into the shot. Since I only saw this once so I'm wondering if this was just an isolated case or if it's a problem that doesn't get mentioned. I plan in using a 67mm circular polarizer with an adaptor on this lens. It's a regular Hoya filter, not the slim kind that lacks the front thread. I'm not planning on stacking filters so that isn't so much of a concern for me. Has anyone with this lens experienced this problem?

[clawhammer]

I don't have that particular lens, but it wouldn't surprise me to get some vignetting at the wide end with a cp-l. you might be able to get away with it by using the adapter, but it's hard to say until you try. I'd take your adapter and cp-l into a store, do a test shot wide open at the wide end and see what you get both with the adapter/filter on and with it off as well.

[Canada_Rockies]

I'm planning on purchasing either the Pentax or Tamron variant of this lens soon. I've been reading lots of formal and user reviews before making my purchase and I came across something that concerned me. One of the user reviews stated that when this lens is used with a filter it has severe vignetting at the wide end and when filters are stacked they creep into the shot. Since I only saw this once so I'm wondering if this was just an isolated case or if it's a problem that doesn't get mentioned. I plan in using a 67mm circular polarizer with an adaptor on this lens. It's a regular Hoya filter, not the slim kind that lacks the front thread. I'm not planning on stacking filters so that isn't so much of a concern for me. Has anyone with this lens experienced this problem?

One thing that I and others have done in the past with really, really wide lenses such as this is to use a filter adapter ring to increase the filter size. They are used to adapt, for example a 52mm filter to a 49mm filter ring on the lens. The better ones only extend past the filter threads by the thickness of the metal they are made of, and then the larger filter is further out from the lens' field of view.

This is not necessarily an inexpensive way to go. I will be saving up to get a 77 > 82 adapter for use with my 12-24, then I need an 82mm polarizer, which is not exactly the least expensive filter on the planet.

[TheWengler]

One thing that I and others have done in the past with really, really wide lenses such as this is to use a filter adapter ring to increase the filter size. They are used to adapt, for example a 52mm filter to a 49mm filter ring on the lens. The better ones only extend past the filter threads by the thickness of the metal they are made of, and then the larger filter is further out from the lens' field of view.

This is not necessarily an inexpensive way to go. I will be saving up to get a 77 > 82 adapter for use with my 12-24, then I need an 82mm polarizer, which is not exactly the least expensive filter on the planet.

Well I was planning on doing that already but only because I already have a 67mm filter. I had no idea if it would hurt or help the situation. If it helps then that's great news. Thank you for the replies.

[heatherslightbox]

On my last vacation, I tried using my 62mm CPL with the Tamron version and, yes there was quite a bit of vingnetting at the wide end. I was disappointed--especially after having spend $459 on the thing. Needless to say, that isn't enough of a reason to get rid of it, though, as it produces pretty nice pics.

I've got a 72mm CPL that's just been sitting around after I got rid of the lens I had originally bought it for--that filter will now be going back into my camera bag after I get a 62-72 step-ring for it.

I love step-up rings.

Heather

[TheWengler]

On my last vacation, I tried using my 62mm CPL with the Tamron version and, yes there was quite a bit of vingnetting at the wide end. I was disappointed--especially after having spend $459 on the thing. Needless to say, that isn't enough of a reason to get rid of it, though, as it produces pretty nice pics.

In another thread you mentioned having problems with vignetting while stacking a CPL on top of a UV filter. Did you have problems with the CPL alone or just while stacking?

[Confused]

Hi TheWengler

I imagine it's technically possible that if you 'stacked' a 62mm polarizing filter in front of a 62mm UV/Skylight filter, you might experience some slight vignetting at the extreme 18mm wide-end of Pentax/Tamron's 18-250mm Di II superzoom.
However, there are two easy solutions to avoid this pitfall:

a) unless you enjoy seeing undesirable internal reflections in your images, temporarily remove & store the UV/Skylight filter, replacing it with the polarizing filter as and when required or

b) purchase a 62-72mm step-up-ring and add a 72mm polarizing filter. Bear in mind however that the large diameter polarizing filters can be incredibly expensive nowadays, unless you can get hold of a decent secondhand one.

I would probably select option b) in order to avoid the irritating and time-consuming requirement of post-processing affected images. You may not be aware that vignetting can easily be removed in most of today's photo-editing software packages !

Best regards
Richard

---

Last edited by Confused; 12-09-2007 at 05:56 PM.

[TheWengler]

Hi TheWengler

I imagine it's technically possible that if you 'stacked' a 62mm polarizing filter in front of a 62mm UV/Skylight filter, you might experience some slight vignetting at the extreme 18mm wide-end of Pentax/Tamron's 18-250mm Di II superzoom.
However, there are two easy solutions to avoid this pitfall:

a) unless you enjoy seeing undesirable internal reflections in your images, temporarily remove & store the UV/Skylight filter, replacing it with the polarizing filter as and when required or

b) purchase a 62-72mm step-up-ring and add a 72mm polarizing filter. Bear in mind however that the large diameter polarizing filters can be incredibly expensive nowadays, unless you can get hold of a decent secondhand one.

I would probably select option b) in order to avoid the irritating and time-consuming requirement of post-processing affected images. You may not be aware that vignetting can easily be removed in most of today's photo-editing software packages !

Best regards
Richard

I think I'm going to go with option B. I already have a 67mm CPL. Anyone have an idea what the quality differences are between the different brands of step up rings?

[Duh_Vinci]

I'm sure there are some difference, not sure how dramatic... For a long time I've been using rings from eBay Seller: sainidigital: Lenses Filters, Camcorder Accessories items on eBay.com , I find their quality top notch, and precision of thread and finish flawless (whoever makes them...)

Regards,
D

[jmdeegan]

Are there a lot of sample photos for the 18-250? I checked the pentax photo gallery, since I like sorting through their images, and it isnt there yet, and I dont know if any other sights filter by lens....

debating something like this, or upgrading my existing variety--ie, going to the 16-50 replacing the kit lens, adding the 50-135 replacing part of the 50-200, and then finding some new lens for the 135-200 i'd give up.

but, having one lens meaning i dnt need to swap lenses (not to mention being more affordable) would be appealing too. would love to see some examples, if anyone can share and point me to them

thanks

[TheWengler]

Are there a lot of sample photos for the 18-250? I checked the pentax photo gallery, since I like sorting through their images, and it isnt there yet, and I dont know if any other sights filter by lens....

debating something like this, or upgrading my existing variety--ie, going to the 16-50 replacing the kit lens, adding the 50-135 replacing part of the 50-200, and then finding some new lens for the 135-200 i'd give up.

but, having one lens meaning i dnt need to swap lenses (not to mention being more affordable) would be appealing too. would love to see some examples, if anyone can share and point me to them

thanks

Flickr: The The Tamron-based 18-250 zoom Pool

[jmdeegan]

thanks

decisions decisions.....

[Confused]

Hi TheWengler

Try this link for step-up rings:

lens filter Step up ring set 49-52-55-58-62-67-72-77mm - (eBay.ca item 320190658910 end time 08-Dec-07 19:10:25 EST)

Best regards
Richard

[rfortson]

This lens has vignetting even without the filters. I still like the lens, but I noticed it right off. I was coming from a FF 28-300 Tamron, and that didn't really have any vignetting.

I just figure it's one of the compromises you'll pay for this lens, but it's still very convenient, and the image quality suits my needs fine.

I see someone posted my Tamron 18-250 pool on Flickr. That should give you plenty to sort through. My entire set of Peru picture on my Flickr stream were taken with the 18-250. You'll see some vignetting in there on some shots as well.