Micro adujust question on 6D

I have tried searching a bit and can't seem to find a thread on this subject so please excuse me if I missed something. Is it possible for a single lens to need correction for both back focusing as well as front focusing?

The reason I ask is that I just completed my first ever attempt at micro adjustment and ended up with my 24-105(Which I had thought was a bit soft) having values of -3 on the wide end and +5 on the tele end. Just wanted to ask if this was a common thing or if I may have messed up somewhere.

Isn't that WHY you can do both ends of a zoom?

I know that its possible for the adjustment to be different for each end. I guess I should rephrase my question as is it common or is it more likely that I messed up my adjustment

Actually what you found is very common.

After doing a test using 6 battery cells kept in a line at 45 deg to line of sight; my conclusion is that MA for my zooms is not critical and not required. This test may be critical for faster lenses.

GregoryF wrote in post #16130319
Actually what you found is very common.

Thank you very much that is what I was hoping for.

ssmanak wrote in post #16130474
After doing a test using 6 battery cells kept in a line at 45 deg to line of sight; my conclusion is that MA for my zooms is not critical and not required. This test may be critical for faster lenses.

It depends on the lens and the camera used. Since all lenses and all cameras are made to a certain tolerance or accuracy it is possible for the same lens to perform differently on separate cameras.

solepatch wrote in post #16129875
I know that its possible for the adjustment to be different for each end. I guess I should rephrase my question as is it common or is it more likely that I messed up my adjustment

It seems to be relatively uncommon, especially on L or more expensive lenses, to have that much different between the ends. On anything but the newest camera bodies, you are in a bit of trouble with a lens like that, since setting MFA for one end would leave the other end considerably far out and an avg value would leave both ends enough less than ideal to matter. I don't like it at all if (long end value - wide end value > 3). Luckily I haven't encountered that much.

Simply needing MFA is VERY common though, almost a guarantee I'd say.

I have left the MFA alone since I did the adjustment and it has helped out tremendously. Not really sure if the camera takes an average value or if it slowly progresses from one value to the other as you change focal lengths(this is what I assume it does) but it seems to have worked so no complaints.

wombatHorror wrote in post #16214289
It seems to be relatively uncommon, especially on L or more expensive lenses, to have that much different between the ends. On anything but the newest camera bodies, you are in a bit of trouble with a lens like that, since setting MFA for one end would leave the other end considerably far out and an avg value would leave both ends enough less than ideal to matter. I don't like it at all if (long end value - wide end value > 3). Luckily I haven't encountered that much.

Simply needing MFA is VERY common though, almost a guarantee I'd say.

My 24 - 105 has similar behavior and both my bodies are the older style MA. At wide angles even shooting wide open you have a pretty thick depth of focus, so you can get away with doing MA for the longer end of the zoom only.

solepatch wrote in post #16214347
I have left the MFA alone since I did the adjustment and it has helped out tremendously. Not really sure if the camera takes an average value or if it slowly progresses from one value to the other as you change focal lengths(this is what I assume it does) but it seems to have worked so no complaints.

Your assumption is correct, I've read this information from the camera. It makes a big difference compared to my 5d2 where you can only have a single adjustment for the lens.

Another thing to keep in mind is that at different focal lengths the MFA may be different. I know that's the case for my 50mm f/1.4. I did an adjustment for the distances I use most, it's +13 at minimal focus distance and a few meters out +8. So I ended up leaving that one at +11.

solepatch wrote in post #16129515
The reason I ask is that I just completed my first ever attempt at micro adjustment and ended up with my 24-105(Which I had thought was a bit soft) having values of -3 on the wide end and +5 on the tele end. Just wanted to ask if this was a common thing or if I may have messed up somewhere.

From memory, mine was -3 +6.