p.1 #1 · does any one own a sigma 300-800mm lens help reqired
hi im having trouble with my sigmonster and it would help to quize other users of this lens,
when i use it at 800mm wide open at 5.6 it is front focusing by about 25mm please note i am using the lens at its shortest focus range of 21 ft
when i drop down to 650mm no problems
when i use it at 800mm at f8 no problen because of the extra depth of field
are all the copys of this lens so bad if used at full mag of 800mm @ 5.6
all info will be of great help before i contact sigma as the lens has already been back for a calibration and came back no diffrence.
also iv tryed to calibrate to my 1dmk3 and iv gone to + 20 and its sill front focusing by about 5mm.
p.1 #2 · does any one own a sigma 300-800mm lens help reqired
I have the Sigmonster and have been happy with it; especially at the long end. I never experienced the issue you describe. Mine is one of the older models and I have frequently used it with a 1.4 TC as well as extension tubes.
I never did anything when using it with my 1d2. I also never tried adjusting the 1d4 when I got that body.
All in all it is one of my favorite lens; but I do use it on a big heavy tripod and a gimbal head.
You may want to go to pbase and look up liquidstone and ask him. He is the true master of the Sigmonster.
p.1 #4 · does any one own a sigma 300-800mm lens help reqired
I looked at your test shots. The closer ones definitely seem softer. One thing I would suggest is you lay the ruler flat at a slight angle so you can get a good idea about just where the critical focus spot is and just what the DOF is.
Also try both AF and MF and see if you can MF at the MFD, and the try and AF at the same distance.
