Backing Focusing 85L

Hello Guys,
Got my 85 L a few days back, found the images were soft at 1.2..., got a focus test chart printed and discovered that the lens was back focusing.
On my 7D, in MA sub menu i had to apply -13 correction to bring the focus on dot and now the result are acceptable.

Did a quick research and found that 1 out of 10 lens may need MA, some says all there lenses need a small MA. Now how much is an acceptable tolerance because -13 seems way too far from that middle point "0". Do i need to replace this lens or should continue using it because after spending so Ks of $$ the lens should work fine out of the box.

Pics of Before and After MA
Thanks
regards

I'd say you've got it dialed in perfectly. I wouldn't be too worried about sending it back or anything. After all, the whole point of having a +- 20 range is so you can use it.

If it was 18 or 19 I might be a bit worried. As you have it, it is fine.

Copidosoma wrote in post #15983759
I'd say you've got it dialed in perfectly. I wouldn't be too worried about sending it back or anything. After all, the whole point of having a +- 20 range is so you can use it.

If it was 18 or 19 I might be a bit worried. As you have it, it is fine.

a sign of relief! thanks

I agree. I have dialed in every lens I have. I don't think any 1.2 would ever not need any adjustment to make it perfect...
My 85 needs -8 and if I remember correctly my 50 needs -5

Not true. My 85LII is perfect at MA 0, and yes I have tested it. Zero is the best result with my copy!

I guess saying that all will need adjustment is a bit to the extreme. I'm sure there are some perfect couples out there.

My 85L is perfect on my 5D3, but front focuses fairly badly on my 7D. I'm going to print a focus chart as well. I'm not sure if its exactly a lens issue, but more so the combination of it with the body.

Christina.DazzleByDesi​gn wrote in post #15985586
My 85L is perfect on my 5D3, but front focuses fairly badly on my 7D. I'm going to print a focus chart as well. I'm not sure if its exactly a lens issue, but more so the combination of it with the body.

May be its an issue with my camera AF, and I might havent noticed on other L lenses bc of their deeper DOF. Now I will test my other lenses too. Do post you feed back

Silverstonev8 wrote in post #15985315
I guess saying that all will need adjustment is a bit to the extreme. I'm sure there are some perfect couples out there.

Rightly said

Bonbridge wrote in post #15985285
Not true. My 85LII is perfect at MA 0, and yes I have tested it. Zero is the best result with my copy!

So there are perfect copies as well.

My 85L needed a visit to Canon along with my 5D3. They had to fix both, and now it's a 0 MFA and pretty much dead-on. My 5D2 is a different story...

sportmode wrote in post #15985677
My 85L needed a visit to Canon along with my 5D3. They had to fix both, and now it's a 0 MFA and pretty much dead-on. My 5D2 is a different story...

how much were they off? What about the any other lenses you have and the 5D3

The camera might be at variance from perfect focus. The lens might be at variance from perfect focus. The combined resultant of both variances is what we MA. It's not just the lens.

turbolover wrote in post #15983746
Hello Guys,
Got my 85 L a few days back, found the images were soft at 1.2..., got a focus test chart printed and discovered that the lens was back focusing.
On my 7D, in MA sub menu i had to apply -13 correction to bring the focus on dot and now the result are acceptable.

Did a quick research and found that 1 out of 10 lens may need MA, some says all there lenses need a small MA. Now how much is an acceptable tolerance because -13 seems way too far from that middle point "0". Do i need to replace this lens or should continue using it because after spending so Ks of $$ the lens should work fine out of the box.

Pics of Before and After MA
Thanks
regards

I really like the result of your focus test. What chart did you use and can you walk me through on how to do it?

snake0ape wrote in post #15985702
The camera might be at variance from perfect focus. The lens might be at variance from perfect focus. The combined resultant of both variances is what we MA. It's not just the lens.

yeah true, but do this merit exchanging the lens or is this normal and my other copy may have similar issue

Kevinnho wrote in post #15985731
I really like the result of your focus test. What chart did you use and can you walk me through on how to do it?

there are many, google for focus test chart. After an extensive google search that kept leading me nowhere... this is the only thing I could find...Great explaination also... the chart itself is on page 18>

http://www.dphotojourn​al.com/focus-test-chart.pdf

Found this interesting article, It says at one place, "...And the funny part of all this is the more expensive wide aperture lenses are the ones most likely to show the problem, because their depth of field is so narrow and the in-focus portion of the picture is so sharp compared to the out of focus portion. That $200 f/5.6 zoom is not going to show a minor front focus problem because the depth of field is about half a mile. The $2,000 f/1.4 prime has a depth of field of a few inches and any problems are immediately evident (and the owner 10 times more invested in wanting a perfect lens)."
http://www.canonrumors​.com …-is-soft-and-other-myths/