MFA for Sig 150-600 C, Different Camera Bodies

I have a 70D and a T4i. Of course I can MFA in camera on the 70D, and have the Sig adjusted for it. Here's what I discovered yesterday while out shooting birds. I decided for grins and giggles to put the Sig on my T4i just to see if there would be much difference with that of the 70D. What I discovered was the focus was way off. I do have the Sigma dock and could adjust it, however I'm concerned that in doing so would throw off the setting for my 70D. I've not attempted it yet, because if it does, I don't want to go through re-adjusting it for my 70D.

So does anyone know if I would MFA the lens via the dock for my T4i, would it affect my 70D?

Thanks..

Well you could keep a record of the correct settings for both cameras, and use the dock to set the lens up for which ever body body you plan on using it on. Unfortunatly you cannot have it optimised for more than one body at a time. From what you have said it looks as if the MFA settings for your two bodies might be at opposite ends of the range.

The other alternative is to set the lens up somewhere between the two bodies, that way you might get acceptable results on both.

Alan

Ok, I thought that I couldn't have it set for both. Yesterday was the first time I put it on the T4i, and was shocked at how far off it was. I'll keep that in mind, but doubt I'll use it on my Rebel. I just had it along with a shorter lens in case some birds were too close to use the big lens.
Thanks Alan.

T4i = no MFA, use the dock to calibrate the lens to the T4i.

Use MFA on the 70D to line up camera and lens.

Both cameras now focus the lens properly.

Done.

Yes it will probably affect the 70D focussing. This is a drawback of using the Sigma dock unfortunately. I had the same issue with the 5DS and 7Dmkii but got around this with FoCal however you do require the MFA facility on the camera and I don't know if this is available on the T4i; I suspect is isn't.

I have yet to get the 16 point MFA set up on my lens, the winter weather since christmas has not been ideal. I guess it depends on how consistent across the range the lens is. It may be that the in body calibration can manage the lens on the 70D, and use the in lens for the Rebel.

Alan

I guess I would question why you would use the lens on 2 crop bodies? I would adjust the lens for the body I would use most, which I assume would be the 70d due to a better AF system. Why waste concern , effort, and time on this issue at all if you are using the 70d and have lens dialed in for it?

TeamSpeed wrote in post #17906520
I guess I would question why you would use the lens on 2 crop bodies? I would adjust the lens for the body I would use most, which I assume would be the 70d due to a better AF system. Why waste concern , effort, and time on this issue at all if you are using the 70d and have lens dialed in for it?

Ok you asked, so here's my answer beyond just a simple, Because I wanted to....

I've seen some images posted by Malveaux recently, where he used a T4i with a 150-600mm. However I think he uses the Tamron. So I just thought I'd see if I could grab some images and compare. However since the focus was off, I was going to adjust it, and try again, but not if it would seriously affect the 70D.

you could set it for the t4i, and then try to set micro adjust with the 70D and the lens set up for the t4i

i've got a similar issue with my 120-300mm, it back focuses bad with my 120-300mm bare/at 300mm on the 70D, is fine on my 5Dc, and also fine with TC...i've done all my adjustments in camera with the 70D, but i'm not sure if i should play around with the dock more to see if i can get it better...i'm a bit intimidated by the dock adjustments to be honest...

DreDaze wrote in post #17906973
you could set it for the t4i, and then try to set micro adjust with the 70D and the lens set up for the t4i

i've got a similar issue with my 120-300mm, it back focuses bad with my 120-300mm bare/at 300mm on the 70D, is fine on my 5Dc, and also fine with TC...i've done all my adjustments in camera with the 70D, but i'm not sure if i should play around with the dock more to see if i can get it better...i'm a bit intimidated by the dock adjustments to be honest...

The dock works, but it is a total PITA in my opinion. I MFA'd my 120-300 Sport across the full 4x4 matrix for my 5D3, and then cross checked it against the 1D4 and found out that the 1D4 needed different values in 7 spots on the matrix. So I made two charts and for a while I would have to set up the 120-300 with the dock for the camera I planned to use. I labeled a lens cap to keep track which settings were in the lens at the time.

I've since sold of my 1D4 and I have just the 5D3 right now, but yeah......the dock can and does make Sigma lenses workable but at a price.

JeffreyG wrote in post #17906980
The dock works, but it is a total PITA in my opinion. I MFA'd my 120-300 Sport across the full 4x4 matrix for my 5D3, and then cross checked it against the 1D4 and found out that the 1D4 needed different values in 7 spots on the matrix. So I made two charts and for a while I would have to set up the 120-300 with the dock for the camera I planned to use. I labeled a lens cap to keep track which settings were in the lens at the time.

I've since sold of my 1D4 and I have just the 5D3 right now, but yeah......the dock can and does make Sigma lenses workable but at a price.

that's a good idea though, i'm not even sure why i didn't think of just setting it up for the two bodies separately...it doesn't take too long to hook it up to my computer, and it's not like i use the two bodies at once...it's usually just for portraits i'll take it with the 5D, but i'll use it for everything else on my 70D

i also wonder about it with the TC, because i feel like focus is pretty spot on for me there...but then i've also found out that my TC isn't supposed to be compatible since i have the new firmware...ugh, i'm a mess with this lens

sorry for taking things off topic OP