uwa distort more in FF than in crop?


sfoto100

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#1
Hi

I was comparing the test results from photozone.de for tokina 11-16, sigma 8-16 on crop and canon EF 17-40 and 16-36 on FF, and it appears that uwa distort more in FF than in crop.

is it the case? if so, then uwa is better on crop than FF... at least in terms of distortion...

btw i find the tokina lens perform the best, but one downside is the lack ofMF button... i cannot use use AF and then switch to MF without affecting the focus. :(
 

Rashkae

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Nov 28, 2005
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#2
Well, you need to understand that the "sweet spot" effect still applies in terms of distortion. The base lens design is still as if it was an 11-18 in 35mm equivalent, but with less glass. ;)

For FF, I recommend the Sigma 12-24, very good distortion characteristics.
 

sfoto100

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#3
Well, you need to understand that the "sweet spot" effect still applies in terms of distortion. The base lens design is still as if it was an 11-18 in 35mm equivalent, but with less glass. ;)

For FF, I recommend the Sigma 12-24, very good distortion characteristics.
seems that Canon uwa lenses aren't that great leh... ;p
 

Kit

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#4
Hi

I was comparing the test results from photozone.de for tokina 11-16, sigma 8-16 on crop and canon EF 17-40 and 16-36 on FF, and it appears that uwa distort more in FF than in crop.

is it the case? if so, then uwa is better on crop than FF... at least in terms of distortion...

btw i find the tokina lens perform the best, but one downside is the lack ofMF button... i cannot use use AF and then switch to MF without affecting the focus. :(
For the sake of discussion, you first need to identify what kind of distortion you are referring to. Is it perspective distortions or curvilinear distortions?? Wihout establishing that, any discussion on distortions can be misleading and confusing. The former is an inherent propeerty of wide angles. The latter can be minimised with lens design.
 

sfoto100

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#5
For the sake of discussion, you first need to identify what kind of distortion you are referring to. Is it perspective distortions or curvilinear distortions?? Wihout establishing that, any discussion on distortions can be misleading and confusing. The former is an inherent propeerty of wide angles. The latter can be minimised with lens design.
i got the info from the site, it didn't state whether it is perspective distortions or curvilinear distortions leh...

it did mention SMIA TV distortion... u know what is that?
 

Rashkae

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#6
seems that Canon uwa lenses aren't that great leh... ;p
They're not known for their UWA lenses, true. They are very good in super telephoto though.
 

sfoto100

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#7
They're not known for their UWA lenses, true. They are very good in super telephoto though.
luckily there are 3rd lenses here to save the day....

sigh.. why Canon don't outsource their uwa to others lei ?


:devil:
 

Kit

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#8
They're not known for their UWA lenses, true. They are very good in super telephoto though.
luckily there are 3rd lenses here to save the day....

sigh.. why Canon don't outsource their uwa to others lei ?

:devil:
Well, or perhaps they are too well known for the UWAs..... in a wrong way :)

The new TS-E 24mm MK II and TS-E 17mm are reputed to be very good though.
 

Kit

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#9
i got the info from the site, it didn't state whether it is perspective distortions or curvilinear distortions leh...

it did mention SMIA TV distortion... u know what is that?
If its from the site then it should be referring to curvilinear distortions. They usually don't cover perspective distortions because its inherent in the design, its silly to even mention about them.
 

sfoto100

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If its from the site then it should be referring to curvilinear distortions. They usually don't cover perspective distortions because its inherent in the design, its silly to even mention about them.
wow.. u do know alot on uwa... so both can be corrected hor? "pai say" i didn't google lah...
 

Kit

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#12
wow.. u do know alot on uwa... so both can be corrected hor? "pai say" i didn't google lah...
Curvilinear distortions can be corrected or avoided with careful composing. Perspective distortions cannot be corrected but can be minimised with careful composing as well.
 

sfoto100

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#13
Curvilinear distortions can be corrected or avoided with careful composing. Perspective distortions cannot be corrected but can be minimised with careful composing as well.
tks alot
 

giantcanopy

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#14
seems that Canon uwa lenses aren't that great leh... ;p
i would not put it to that extent. kit has outlined some excellent wide lenses. Anyway the canon uwa are gonna be easily sharper than the sigma 12-24mm. The only thing being sigma is the only current maker of an autofocusing rectilinear wide angle lens at 12mm for FF sensors.

ryan
 

night86mare

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#15
For the sake of discussion, you first need to identify what kind of distortion you are referring to. Is it perspective distortions or curvilinear distortions?? Wihout establishing that, any discussion on distortions can be misleading and confusing. The former is an inherent propeerty of wide angles. The latter can be minimised with lens design.
photozone.de shows barrel distortion/pincushion distortion results.

so it's the latter, there is no reason why a lens test site would talk about horizontal/vertical perspective distortion... at least not a reputable one!
 

night86mare

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#16
i would not put it to that extent. kit has outlined some excellent wide lenses. Anyway the canon uwa are gonna be easily sharper than the sigma 12-24mm. The only thing being sigma is the only current maker of an autofocusing rectilinear wide angle lens at 12mm for FF sensors.

ryan
in general though, canon zooms have their distortion very poorly controlled.

everytime i see a curved horizon in naturescapes that curved, i know it came from a FF camera with 17-40 L. :bsmilie:
 

night86mare

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Curvilinear distortions can be corrected or avoided with careful composing. Perspective distortions cannot be corrected but can be minimised with careful composing as well.
yes, this is right.

anyways, why worry, just use ptlens, us$25 will correct your barrel distortion very well. :thumbsup:
 

Kit

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#18
in general though, canon zooms have their distortion very poorly controlled.

everytime i see a curved horizon in naturescapes that curved, i know it came from a FF camera with 17-40 L. :bsmilie:


You don't need to pair the 17-40 f/4 to find out about its curves. This is shot with a 10D :bigeyes:


In all fairness, the 16-35 f/2.8 MKII was much better in controlling barrel distortions but still pretty visible.


Then there came the Nikkor 16-35 f/4 which takes the cake. Its a semi-fisheye at 16mm I tell ya!!!
 

sfoto100

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#20
yes, this is right.

anyways, why worry, just use ptlens, us$25 will correct your barrel distortion very well. :thumbsup:
so if i use ptlens i can correct even the distortion produced canon 17-40, 16-35 izzit? :)

wa something new to me... learn something today tks alot
 

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