15mm Ltd and Square Filter Systems

Started Jun 10, 2011 | Discussions thread
Tan68
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Re: 15mm Ltd and Square Filter Systems, notes
In reply to johnny_rico, Jun 12, 2011

i use the 49mm filter with glass out as an adapter for Cokin thin-mount P-series holder. you do want to use the "thin" holder.

i have also used the 49mm ring to hold a 67mm polarizer. the 67mm works okay... if i remember right, i used both the polarizer and the grad-ND for the for the second picture...

i did use both a 67mm polarizer and grad-ND for the light house. you see just a tiny bit of vignette at the top. but i would not have a 1 second exposure without both filters. i used the polarizer to cut light as i don't on a 49mm ND.

i had the 67mm polarizer for other lenses. i thought the greater diameter might enable it to work with the 15mm and it works okay at smaller apertures. i don’t think a smaller polarizer such as a 58mm or 52mm would work well. yes, a 49mm polarizer would be best, gut the 67mm is what i have right how... so, just making note it is useable...

i think a square filter with a 49mm "adapter ring" works well. if you don't typically use the full 3:2 aspect ratio and crop to 4:3, then vignette is a non-starter.

when you get a 49mm filter to use as an adapter, the 49mm filter will stick out past the retracted hood. just a little git. some have posted they sanded down the filter so it sits flush with the retracted hood.

i like to use a filter holder rather than hold filters by hand. holding them by hand is a viable solution, but i like the holder so i can position the filter and then wait for the time to take the picture. a holder also helps with repeatability if precise positioning is preferred...

also, look here:
http://forums.dpreview.com/forums/readflat.asp?forum=1036&message=34910683

the link above has measurements for vignette. in this post, i did not test the polarizer plus square filter. the square filter alone does not vignette much and would vignette less if i bothered to shave my 49mm "adapter ring". also, when i did this test i only had a 67mm Cokin holder adapter. i used a 49-67mm step up ring and Then the Cokin holder adapter! i now have a 49mm Cokin holder adapter and, without the step up ring, vignette should be less. also, for less vignette when i want to use a polarizer, i could use a 49mm polarizer in place of the 49mm "adapter ring". then, i should have little vignette. however, i don’t own that 49mm polarizer...

the vignette in the lighthouse picture below is because of the added polarizer! the polarizer is a "thin" design.

in the post, you see little thumbnails. vignette in the thumbnails is horrible!!! this is because my flash did hot evenly illuminate the upper left hand corner so ignore the darkness in most of the frame.

PS

i poured a glass of water oh my keygoard ahd this is what i get with ho correctiohs. if ahy odd spellihgs slipped through, i apologise.

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