magenta @ 50mm

misha · 05/03/07, 07:18 AM

i recently bought a pre-asph 50mm lux and getting the same magenta results as we all have at 15-35mm range. is that normal? i thought magenta was only an issue for wides?

thanks
m

adan · 05/03/07, 07:34 AM

Magenta IR contamination will happen on the M8 with any unfiltered lens. Focal length is not a factor.

The issue with wide-angles (<35mm) is that the corners turn green or cyan WITH IR-blocking filters (while the magenta is mostly eliminated), and therefore wides need coding to declare the focal length, and the corrective firmware (v. 1.1+) , in which case the camera can correct for the "cyan drift" after exposure.

The deal with your 50 is that, IF you get an IR filter for it, it will not show the green-corner effect, and thus will not require the 6-bit coding spots and any firmware corrections (unless you just want the focal length recorded in the metadata).

misha · 05/03/07, 07:48 AM

got it (i think)

.
thanks a lot for a quick and elaborate explanation.

misha

sean_reid · 05/03/07, 08:56 AM

Andy explained that well. The 50s will show a little bit of cyan drift but it's minor.

Cheers,

Sean

05/03/07, 07:18 AM	#1 (permalink)
misha Erfahrener Benutzer Join Date: 03/07/07 Posts: 173	magenta @ 50mm i recently bought a pre-asph 50mm lux and getting the same magenta results as we all have at 15-35mm range. is that normal? i thought magenta was only an issue for wides? thanks m

05/03/07, 07:34 AM	#2 (permalink)
adan Erfahrener Benutzer Join Date: 03/04/04 Location: Denver Posts: 1,115	Re: magenta @ 50mm Magenta IR contamination will happen on the M8 with any unfiltered lens. Focal length is not a factor. The issue with wide-angles (<35mm) is that the corners turn green or cyan WITH IR-blocking filters (while the magenta is mostly eliminated), and therefore wides need coding to declare the focal length, and the corrective firmware (v. 1.1+) , in which case the camera can correct for the "cyan drift" after exposure. The deal with your 50 is that, IF you get an IR filter for it, it will not show the green-corner effect, and thus will not require the 6-bit coding spots and any firmware corrections (unless you just want the focal length recorded in the metadata). Last edited by adan : 05/03/07 at 07:37 AM.

05/03/07, 07:48 AM	#3 (permalink)
misha Erfahrener Benutzer Join Date: 03/07/07 Posts: 173	Re: magenta @ 50mm got it (i think) . thanks a lot for a quick and elaborate explanation. misha

05/03/07, 08:56 AM	#4 (permalink)
sean_reid Erfahrener Benutzer Join Date: 11/17/04 Posts: 4,942	Re: magenta @ 50mm Andy explained that well. The 50s will show a little bit of cyan drift but it's minor. Cheers, Sean __________________ Sean Reid http://www.reidreviews.com

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