Changing projection of geotiff file (raster data) in QGIS?

After downloading an SRTM geotiff (DEM) from USGS's website, I would like to convert it from GCS to a projected coordinate system. After opening it in QGIS:

1. 
   

   Is that enough if I simply just click on 'save as...' and set CRS from WGS84 to the preferred PCS?

   
   


2. 
   

   Or should it be done like 'Raster > Projections > Warp'?

   
   

(I feel like it is not that easy and there is a trick somewhere...)

Answer

Save As ... only works for vector data.

Raster > Projections > Warp is dedicated for rasters. The reason behind are the many options you may need for reprojecting (and resampling) raster data.

In the background, GDAL ogr2ogr and gdalwarp are used respectively.