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by Tonka on Sat Feb 09, 2019 4:01 pm
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hello everyone,
Ive recently brought the siga 150-600mm sport for my D7200 and its been pretty impressive so far. AF speed has been impressively quick and the build quality is second to none but with regards to the quality of the photos i think they could be better. they are fairly sharp but i still think it has a long way to go. So im just wondering if anyone could give a detailed guide as to how i should go about calibrating it with the USB dock? do i have to do it at all focus distances at at all focal ranges? what focus target should i use? I'd be very glad if someone could help me out!
 

by E.J. Peiker on Sat Feb 09, 2019 4:29 pm
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Having calibrated over a hundred of these lenses they can be very sharp but it is a chore.  You absolutely must use the dock and the Sigma software and then it is at least two full iterations of 16 focus positions (distance and zoom setting).  It's pretty obvious what you need to do once you get the dock.  You simply calibrate for each of the positions but they interact with each other so you need to do at least a second round to really zero in on it.  I usually take about 4 hours and charge accordingly for my clients.  The focus target I use and recommend is the Lens align II with the extended long ruler.

In the end you get a focus calibration table that looks something like this - note that this is very different for every lens and camera combo so you can't use this one at all:
Image
 

by Tonka on Sat Feb 09, 2019 4:48 pm
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Thanks for the quick reply, i will try this out soon.
 

by Buckmaster on Mon Feb 11, 2019 10:22 am
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EJ, is it true that whatever number adjustment you come up with, you have to double it in the Sigma Software?  using a d500
 

by E.J. Peiker on Mon Feb 11, 2019 4:48 pm
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Nope not at all, they translate almost 1 to 1. Some people may be saying that because one adjustment affects another to some degree and after you get the initial values you have to redo it one more time to deal with overlap of the adjustments at different distances and focal lengths. It is best to do the initial adjustment using the exact values for each condition that you would plug into the camera and then redo it. More difficult to write than do but very time consuming and really not for people without math skills and some technical competence - they are likely to make things worse.
 

by Mike in O on Mon Feb 11, 2019 5:22 pm
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Ej...are you speaking about me?
 

by E.J. Peiker on Mon Feb 11, 2019 6:17 pm
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Mike in O wrote:
Ej...are you speaking about me?

LOL no of course not.  I have just done many of these lenses that were completely botched up by their owners and then they hire me to calibrate them and suddenly they like the lens :D
 

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