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Anisoplanatic effects can cause significant systematic photometricuncertainty in the analysis of dense stellar fields observed with adaptiveoptics. Program packages have been developed for a spatially variable PSF, butthey require that a sufficient number of bright, isolated stars in the imageare present to adequately sample the PSF. Imaging the Galactic center isparticularly challenging. We present two ways of dealing with spatiallyvariable PSFs when only one or very few suitable PSF reference stars arepresent in the field. Local PSF fitting with the StarFinder algorithm isapplied to the data. Satisfying results can be found in two ways: (a) creatinglocal PSFs by merging locally extracted PSF cores with the PSF wings estimatedfrom the brightest star in the field; (b) Wiener deconvolution of the imagewith the PSF estimated from the brightest star in the field and subsequentestimation of local PSFs on the deconvolved image. The methodology is tested onreal, and on artificial images. The method involving Wiener deconvolution ofthe image prior to local PSF extraction and fitting gives excellent results. Itlimits systematic effects to ~2-5% in point source photometry and ~10% indiffuse emission on fields-of-view as large as 28" x 28" and observed throughthe H-band filter. Particular attention is given to how deconvolution changesthe noise properties of the image. It is shown that mean positions and fluxesof the stars are conserved by the deconvolution. However, the estimateduncertainties of the PSF fitting algorithm are too small if the presence ofcovariances is ignored in the PSF fitting as has been done here. An appropriatescaling factor can, however, be determined from simulated images or bycomparing measurements on independent data sets.

Accurate photometry with adaptive optics in the presence of anisoplanatic effects with a sparsely sampled PSF