great results until i add GCP

[Alan]

hi
my workflow using sony nex7 16mm lens, 60% overlap, add photos, align, create dense cloud, mesh and then texture, end with an non geo reference model, that is very clean I then add very accurate GCPs, thats when things start to go wrong, i get lots of noise, and errors are quite high, i use gradual selection and reoptimise, errors drop but so do points, have spent weeks reading up on this, but cannot seem to get around it, any suggestions
many thanks

[Alexey Pasumansky]

Hello Alan,

Please post the screenshot of Ground Control pane (source values). Probably, you are using both camera and marker coordinates while they are in the different coordinate systems.

[Alan]

hi, sorry for the delay in replying, no not using camera co ordinates at all, have the average errors down to about 1.2 metres, if I try to bring this down, through gradual selection then points that are needed disappear causing problems
cheers
ps, wont allow me to attach an image

[Alexey Pasumansky]

Hello Alan,

Then please send the screenshots to support@agisoft.com.

[Alan]

will try again with attached screengrab

[Alan]

Ah that worked, no png's allowed have had clean results, but with larger errors, images are 6000*4000 with 65% overlap, soon as I try bring the error down to an acceptable level, goes all noisy, lots of spikes etc I use 4 for tie point accuracy and 0 for marker accuaracy, as I use a total station for marker location, sub cm accuracy,m any suggestions