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Contax N24-85 overexposure problem

 
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bigkidneys



Joined: 11 Oct 2010
Posts: 8

PostPosted: Mon Oct 11, 2010 7:38 pm    Post subject: Contax N24-85 overexposure problem Reply with quote

Hello. I have tested and owned 3 copies of this lens and my most recent purchase seems to have a major problem with overexposure. I did not have this problem with my last 2 copies but this one if shooting with exposure at zero, comes out almost 1-2 stops overexposed on my 5D MKII. I have to consistently use -1 to -2 exposure compensation so that everything is not blown out. Have others had this problem before? I was told my copy has the latest firmware and the only thing I have done recently is add the EG-S screen. I have no issues with my other Contax and Zeiss lenses, it just seems to be this one. Any insight would be greatly appreciated. Thanks.

Jason
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conurus
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Joined: 15 Aug 2006
Posts: 795
Location: Vancouver, Canada

PostPosted: Mon Oct 11, 2010 9:17 pm    Post subject: Reply with quote

Jason,

Thank you for your problem report. Just to make sure, you have configured C.Fn IV: Operation/Others, 5:Focusing Screeen, to 2:Eg-S, right?

I guess I have to purchase a Eg-S and conduct some testing...

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bigkidneys



Joined: 11 Oct 2010
Posts: 8

PostPosted: Mon Oct 11, 2010 9:24 pm    Post subject: Reply with quote

Yes, I have that enabled in my custom functions section. I have not tried taking pictures against a solid white wall like you suggested to Arif in another post as it seems like we are both have the same issues. I will do that tomorrow and see what the histogram says. I have highlights enabled on my 5D MKII and when I shoot at 0 for exposure compensation the results are always bad with extreme highlights. I have noticed when I underexpose at either -1 or -2 I lose the highlights but the remaining areas are generally too dark. Just weird as I did not have this issue with another copy on the same camera. I am not sure if it has anything to do with it but this lens has the latest firmware and my previous copy did not. No issue with my other lenses as well. Thanks for the reply.
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arif



Joined: 18 Sep 2010
Posts: 15

PostPosted: Thu Oct 14, 2010 9:16 pm    Post subject: Reply with quote

i've read some articles indicating that because the focus screen is in the path of the meter it affects the exposure and more so on slower lenses.

I also read that with the split focus screens, that you should not use spot metering.

do you have another body that you can try it on? I am going to borrow a 7d and see if it over exposes also

keep me posted if you find a solution or cause

thanks
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arif



Joined: 18 Sep 2010
Posts: 15

PostPosted: Sat Oct 16, 2010 8:16 pm    Post subject: Reply with quote

hi

try placing the original focus screen back in. it worked for me.. not sure what it has to do with exposure metering .. but ... it seems to work with the original screen
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bigkidneys



Joined: 11 Oct 2010
Posts: 8

PostPosted: Sat Oct 16, 2010 8:50 pm    Post subject: Reply with quote

I actually did the same thing today as well and it works great too. We should mention it to Bo-Ming so he can tell others. Thanks again for letting me know. Was about to post my experience as well.
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