Hi Dm1dave, The set up was 200 f5.6 focal distance 550mm (sigma 120-300 f2.8 with Sigma 2X TC EX DG D300) It might be slow but I use a Mafrotto 724B (not so good for) no mirror lock up. I don't know my level. Thank you.
>Can we see one of your test images? I can't up load images yet. >If you are not seeing a difference the problem is probably >something other then a focus issue. May be. >Tell us how you set up the test... 550mm focal distance( D300 sigma 120-300 f2.8 sigma TC 2X) >What tripod and head are you using? or are you handholding? Manfrotto 724B (not good for) >Are you using mirror lock up? No >What is your aperture and shutter speed?
200 f2.8>Also people may be able to provide more useful help if you >fill out your profile so that we know your experience level >and what equipment you have available. I don't know my experience level.Thank tou.