Select count of timestamp formatted field in short date format to give number of rows
Since the column type is a datetime and this is SQL Server 2016, converting it to a date is easy :
SELECT CONVERT(Date,[SCAData].[dbo].[Camera].[DTUpdated]) AS Date_Updated,
COUNT(DTUpdated) AS No_of_Rows 
FROM [SCAData].[dbo].[Camera]
GROUP BY CONVERT(Date,[SCAData].[dbo].[Camera].[DTUpdated])  
ORDER BY 1; 

If you really want to do it via an VARCHAR field, just do it like that :
SELECT CONVERT(VARCHAR(10),[SCAData].[dbo].[Camera].[DTUpdated],105) AS Date_Updated,
COUNT(DTUpdated) AS No_of_Rows 
FROM [SCAData].[dbo].[Camera]
GROUP BY CONVERT(VARCHAR(10),[SCAData].[dbo].[Camera].[DTUpdated],105)  
ORDER BY 1;