Update py/ngff_zarr/to_ngff_zarr.py

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: thewtex

py/ngff_zarr/to_ngff_zarr.py

@@ -988,8 +988,12 @@ def to_ngff_zarr(
         # Get the chunks - these are now the shards if sharding is enabled
         chunks = tuple([c[0] for c in arr.chunks])
 
-        # For TensorStore, shards are the same as chunks when sharding is enabled
-        shards = chunks if chunks_per_shard is not None else None
+        # For TensorStore, calculate shards based on chunks_per_shard when sharding is enabled
+        shards = (
+            tuple(c // s for c, s in zip(chunks, chunks_per_shard))
+            if chunks_per_shard is not None
+            else None
+        )
 
         # Determine write method based on memory requirements
         if memory_usage(image) > config.memory_target and multiscales.scale_factors: