topic 50 1.2L back-focuses with lateral focus points in EF & RF Lenses

50 1.2L back-focuses with lateral focus points

fausto — Mon, 06 May 2013 21:00:31 GMT

My 50mm f1.2l consistently backfocuses when I use lateral and corner focus points, focuses correctly when I use near center focus points.

I can adjust the problem through microadjustment (more or less 4 points), but in that case the lens front focuses with near center focus points.

I can tell it is not an issue of the camera (5dmk3) because it works fine with my 85mm 1.2L.

I am wandering if it is a normal issue with the 50mm 1.2L like the well known focus shift issue due to the "by design" spherical aberration (aberration left by design to improve bokeh).

Do anybody else is experiencing the same problem? Or is my copy defective?

Thank you so much for your replies (and sorry for my imperfect English!)

Fausto

Re: 50 1.2L back-focuses with lateral focus points

MiamiHEAT06 — Sat, 29 Jun 2013 21:17:03 GMT

Fausto,

I have been reading up on this specific problem with the 50mm f/1.2 lens in advance of purchasing this luxury lens. Canon support tells you that there is no such issue. However if you read reviews on Amazon.com or other sites that sell lenses, you can see expert comments on the back focus issue and having to micro adjust the lens to account for this issue when shooting wide open between f/1.2 and f2.0.. Apparently, the depth of field is so narrow, that you run into back and front focus issues sporadically. Check out some of the reviews on the lens on Amazon and you'll get a better field for this specific problem:

http://www.amazon.com/Canon-50mm-Lens-Digital-Cameras/product-reviews/B000I1YIDQ/ref=dp_top_cm_cr_acr_txt?ie=UTF8&showViewpoints=1

Let me know how it works out for you.

James

Re: 50 1.2L back-focuses with lateral focus points

ScottyP — Thu, 11 Jul 2013 22:00:45 GMT

The plane of focus is not flat, it is slightly curved on the 50 1.2. See Rogers's take:

https://www.lensrentals.com/rent/canon/lenses/normal-range/canon-50mm-f1.2l