Back focus on Lenses - Tamron 17-50mm and Sony 50mm SAL50-F14
Ok, so I've tested all my lenses, some many times, and found that the Tamron 17-50mm has back focus (focusing behind the AF point) at 17mm and the Sony SAL-50F14 also has back focus (but more noticeable because it's F/1.4 and at 50mm versus a WA 17mm).
The Tamron I suppose isn't too affected because at 17mm you wouldn't be using this at its MFD anyway. But it's there nonetheless.
The Sony is disappointing. It's a brand new lens and would expect Sony to have better quality control.
My very aggressive setup of batteries close together. 1" apart wasn't showing much. Spot Focus, AF on center battery. 2 sec timer on tripod.
TAMRON 17-50mm F/2.8 (shots at F/2.8)
above is 17mm showing back focus
above is 35mm, focus is OK
above is 50mm, focus is OK
above is 50mm @f/1.4 showing back focus
above is 50mm @ F/2 showing back focus
Question is, what should I do about these two lenses?
Regarding the Tamron, I think I can live with it unless anyone here things I should send it back to Tamron. It has ~5.5 years of warranty left.
Regarding the Sony, it's unacceptable and I need to either send it back to JR.com or send it to Sony for servicing (I don't believe I should have to pay for the shipping for their failure, it's brand new).
I definitely would not send both back at the same time, otherwise I wouldn't have anything to shoot with.
Could anyone also comment about Tamron and Sony's servicing and turnaround time.
Last edited by dr4gon; 01-16-2009 at 10:40 AM.
Canon 7D - 5D | 550EX - 430EX II - (2) PW FlexTT5 | 24-105 f4L | 70-200 f2.8L IS | 100 f2.8L IS | 50 f1.8 II