Vial, back Focus on Sigma 18-50 f2.8

[Duron]

was testing the Back Focus of this lens, sigma 105 coz my Sigma 18-50mm f2.8 has back focus problem. Just wanted to confirm that it's not the D5D problem

sigma 105mm, focus on front Vials

sigma 18-50 @ 50mm f2.8 focus on center Vial

if i return the lens to SC, i wonder what will they fix here?

 

[Timber Wolf]

Hello. Hmm. For Minolta lenses they will take a photo of a test chart, measure the amount of back focus and ask Japan side to burn a chip with the updated parameters to correct for backfocus. Takes about maybe a week or two for the chip to come over, then they'll install it and your lens should be okae liao.

Cheers =)
QX

 

[rOnGrEn]

Hello. Hmm. For Minolta lenses they will take a photo of a test chart, measure the amount of back focus and ask Japan side to burn a chip with the updated parameters to correct for backfocus. Takes about maybe a week or two for the chip to come over, then they'll install it and your lens should be okae liao.

Cheers =)
QX

hey QX...does it cost anything if the lens is under warranty ? how about past warranty?

and the threadstarter says its his sigma lens that has problem... u have any experience with sigma lens backfocusing or anyone else recalibrated their 3rd party lens be4?

Thanx in advance!

 

[TME]

Duron, this is OT but what is the stuff in those vials?

The second shot looks backfocussed but are u sure that the vials are not too close to one another so that the camera mistakes the vial to the right of the centre one as what u want to focus on? Might want to decrease the number of vials and spread them out so that the center sensor only focuses on the centre vial and the left and right vials are sufficiently far away to prevent this kind of 'mistake' on part of the camera.

 

[s00n]

Hi all,

What about the back focal for KM 17-35 lens?
I am encounter alot of back focal issue when the back ground is shining.
is there a way to repair it?