Is this physical vignetting or is this called something else?


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zoossh

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Nov 29, 2005
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#1
When using this setup from inside to outside,

1. a sigma 10-20mm lens,
2. a 77mm B+W MRC UV filter normal thickness,
3. a 77mm to 82mm step up ring adapter,
4. a cokin 84mm square filter holder,
5. a singh ray 84mm square filter

i got this problem of the filter holder edge coming into the view from 10-13mm,

at 12mm, jpeg small, downsize 25%, saved in jpeg max quality 300DPI,
noticed the left and right wide-end edge



from what i read, there are 3 types of vignetting,
http://en.wikipedia.org/wiki/Vignetting

- Mechanical (or physical) vignetting
- Optical vignetting
- Pixel vignetting

and vignetting refers to a reduction in image brightness in the image periphery compared to the image center.

my confusion is - does vignetting only refers to a reduction in image brightness (i.e. uniform graduated darkening at the corners)? my picture above shows that at 10-13mm, the wide angle will capture undesirable objects in the peripheral field, which includes my filter holder, which is not a reduction in image brightness but a capturing of light and details, including the shape and form of my filter holder. so is that considered a physical vignetting or is it called by another term.

by taking off component by component, i realised that this below setup
1. a sigma 10-20mm lens,
2. a 77mm B+W MRC UV filter normal thickness,
3. a 77mm to 82mm step up filter
does not produce the above problem. but i wonder if i use a thinner UV filter, would it reduce the above problem to may 10-11mm of focal length instead? does the feature of the lens (i.e. the optical vignetting) plays a part in contributing to this kind of problem or are they totally separate issues?

also in another picture, i caught this.
also at 12mm, jpeg small, downsize 25%, saved in jpeg max quality 300DPI,
notice the wave at the top,


if i didn;t rem wrongly, the cokin filter has 3 slots from anterior to posterior for 3 filters at any one time, i put my filter in the farthest and most anterior slot, and i think it cast the filter holder shadow on the filter, causing this wave. i adjusted it to the nearest and most posterior slot, and that disappeared.

i would like to ask those who use other 84mm square filter holder, whether the above problems is a design defect in cokin filter or is it uniform throughout various 84mm square filter holder? can i solve the problem by upgrading on the filter holder?
 

pai

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Nov 24, 2004
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#2
i dunno what u call it lah. but the main thing is to get rid of the problem right? :angel:
the lens does affect the extent, e.g. more likely to happen on APS crop lens than on full-frame lens, more likely to happen at wider focal length, smaller aperture. but much more useful to look at your filter setup.

yes, using a slimmer UV filter should reduce the problem. in fact many people would advise you not to stack filters, and to take the UV filter off if you're going to use the cokin holder.

also, do you really need a three slot filter holder? cokin has a wide-angle holder that only has one slot. it's much slimmer and thus you're less likely to have this problem. about the same price as the regular holder. or u can take a penknife or something and cut away the extra two slots from your current holder.

why not bring your camera and lens to the shop and try this to see how much this will help? can see on the lcd screen.
 

sabbatical

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Jun 17, 2004
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#3
Yes, definitly looks like you would need a bigger Cokin filter holder to accomodate your wide angle lens. Also means you need to get the bigger filters to fit. :p

Your second problem seems to be flare, might not be a problem from the filter, but getting the filter as close to the lens as possible would help, then again it is best to get equipment that fits your lens properly.
 

Denosha

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Dec 25, 2003
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#4
Pai is right about the wide-angle holder. The normal 3-filter holder will also vignette on my 10-22 but the wide-angle holder won't (if i take out my UV filter as well). By step-up filter I suppose you mean the ring adapter for the filter holder right?
 

zoossh

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#5
pai said:
i dunno what u call it lah. but the main thing is to get rid of the problem right?
yah, but wanted to know what it is called to aid communication next time.

pai said:
also, do you really need a three slot filter holder?
no i dun. but at that time, that is the only filter holder cathay have. i dun think they dun other 84mm square filter holder, so thinking of importing one. however without hands on can only enquire from users from clubsnap who used them. cokin holder is light but very flimsy. dunno if other brands holder would be much better and worth the upgrade.
 

zoossh

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#6
sabbatical said:
Yes, definitly looks like you would need a bigger Cokin filter holder to accomodate your wide angle lens. Also means you need to get the bigger filters to fit. :p

Your second problem seems to be flare, might not be a problem from the filter, but getting the filter as close to the lens as possible would help, then again it is best to get equipment that fits your lens properly.
the flare, you are referring to that wave like reflection from my cokin holder on the singh ray filter?

and dun think i will upgrade to bigger filters. the 84mm singh ray filters cost me almost $400....
 

pai

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#7
zoossh said:
no i dun. but at that time, that is the only filter holder cathay have. i dun think they dun other 84mm square filter holder, so thinking of importing one. however without hands on can only enquire from users from clubsnap who used them. cokin holder is light but very flimsy. dunno if other brands holder would be much better and worth the upgrade.
i bought a cokin wide-angle holder at cathay just a few months ago. maybe they told u they only have one kind of holder when they meant they only have cokin holders, but not other brands? maybe you could check with them again, save the hassle and expense of ordering from overseas.

i think it's quite common to use the cokin holder even if you're using more expensive filters. ppl pay more for better filters, because it affects the picture quality, so stuff like neutral colour, scratch resistance, matter. the holder, as long as it does its job, can already. but if you don't like the cokin one, can try other brand, just remember to get the wide-angle version, as that will help take care of the main issue, which is the vignetting (mechanical, in your case). sturdiness is just gravy.

happy hunting :)
 

GOMUS

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Jan 10, 2006
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#8
Friend, i have this problem with my 10-22mm Canon too.

if i shot with 10mm, u put on two screw-on filters: UV + Polarise, I saw the edge ring. but i use single filter, this problem i can get rid. I guess it is the angle of the lens, will reveal your filter or your filter holder.

Readind from Singam's lens review,http://ephotozine.com/equipment/tests/testdetail.cfm?test_id=362: "Sigma have done a good job here, with the lens sporting a 77mm filter thread, not a huge size for an optic this wide. And the front element does not protrude, so that close fitting filters can be used.

We tried a Cokin Z-Pro system on the lens and found that, fitted normally, there was no vignetting if the holder was oriented in the same way as the hood is fitted. However, it did vignette at 10mm with the holder in a normal position when taking landscape shots. (Disappears between 11 and 12mm) With the holder reversed, leaving just the single slot, this problem was overcome. Sigma does state in their multi-language leaflet that only one filter should be used and thicker ones ‘may’ cause vignetting. "

see if it is helpful!! So why dont get a screw on filter or hold by your hand.

When u take that pic?? Never ask me? I am free this weekend, any shoot tomorrow?
 

zoossh

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Nov 29, 2005
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#10
GOMUS said:
Friend, i have this problem with my 10-22mm Canon too.

if i shot with 10mm, u put on two screw-on filters: UV + Polarise, I saw the edge ring. but i use single filter, this problem i can get rid. I guess it is the angle of the lens, will reveal your filter or your filter holder.

Readind from Singam's lens review,http://ephotozine.com/equipment/tests/testdetail.cfm?test_id=362: "Sigma have done a good job here, with the lens sporting a 77mm filter thread, not a huge size for an optic this wide. And the front element does not protrude, so that close fitting filters can be used.

We tried a Cokin Z-Pro system on the lens and found that, fitted normally, there was no vignetting if the holder was oriented in the same way as the hood is fitted. However, it did vignette at 10mm with the holder in a normal position when taking landscape shots. (Disappears between 11 and 12mm) With the holder reversed, leaving just the single slot, this problem was overcome. Sigma does state in their multi-language leaflet that only one filter should be used and thicker ones ‘may’ cause vignetting. "

see if it is helpful!! So why dont get a screw on filter or hold by your hand.

When u take that pic?? Never ask me? I am free this weekend, any shoot tomorrow?
one of the weekdays when i managed to finish off my work at 5-6pm. my working hours not very regular....

tomorrow got to work 10-6pm. shall we try matilda house or somewhere near hougang? but before that, let me check with my gf.
 

zoossh

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#11
by the way, i'm forced to use a square filter as graduated filters need to adjust up and down according to the horizon. and yah, i enjoy both the soft edge 3 stop and the 2 stop reverse hard edge.
 

GOMUS

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#12
zoossh said:
one of the weekdays when i managed to finish off my work at 5-6pm. my working hours not very regular....

tomorrow got to work 10-6pm. shall we try matilda house or somewhere near hougang? but before that, let me check with my gf.
i dont mind matlida...tomorrow any chance?
 

zoossh

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Nov 29, 2005
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#13
what do people use to cut the filter holder without causing a dangerous jagged edge? can i use a sharp art penknife?
 

Artosoft

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Aug 31, 2005
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#14
zoossh said:
what do people use to cut the filter holder without causing a dangerous jagged edge? can i use a sharp art penknife?
After you cut it with sharp art penknife you can use sand paper to remove the jagged edge.

Regards,
Arto.
 

zoossh

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#15
Artosoft said:
After you cut it with sharp art penknife you can use sand paper to remove the jagged edge.

Regards,
Arto.
too tough, unable to cut thru.
 

Artosoft

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#16
zoossh said:
too tough, unable to cut thru.
Use metal jigsaw, a jigsaw to cut metal, but it is ok to cut hard plastic. Or, use solder to melt it down. Afterthat you can use sand paper to remove the jagged edge.

Regards,
Arto.
 

dr34mc4st3r

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May 2, 2003
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#17
best is go buy those 3-in-1 diy kit consiting of wood engraving tools, soldering iron and hotknife. the hotknife makes a more clean cut compared to using the soldering iron
 

Denosha

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#18
dr34mc4st3r said:
best is go buy those 3-in-1 diy kit consiting of wood engraving tools, soldering iron and hotknife. the hotknife makes a more clean cut compared to using the soldering iron
Have to buy things just to cut the filter holder, might as well just go and buy the slim holder and try to sell off the old one cheap (since it seems u've already attempted to cut it :bigeyes: ).
 

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