Hello Luka.
If you use las2dem or blast2dem a buffer is needed and then things are a bit more complex. If you use lasgrid or lascanopy then you can do this as follows:
Generate a usual 50 centimeter raster:
lasgrid -i ..\data\fusa.laz -step 0.5 -o fusa_50cm.asc
more fusa_50cm.asc
ncols 500
nrows 500
xllcorner 277750.000000
yllcorner 6122250.000000
cellsize 0.500000
NODATA_value -9999.0
-9999.0 45.34 45.07 -9999.0 42.40 -9999.0 42.42 42.42 42.41 [...]
Generate a 50 centimeter raster shifted by 25 centimeter:
lasgrid -i ..\data\fusa.laz -step 0.5 -grid_ll 0.25 0.25 -o fusa_50cm_shifted_25cm.asc
more fusa_50cm_shifted_25cm.asc
ncols 501
nrows 501
xllcorner 277749.750000
yllcorner 6122249.750000
cellsize 0.500000
NODATA_value -9999.0
-9999.0 -9999.0 -9999.0 -9999.0 -9999.0 -9999.0 42.42 42.42 42.41 -9999.0 42.43 [...]
Should work the same with TIF.
Martin @rapidlasso