Old style TIF compression

[DPaul]

Hi,
I have come across a huge batch of tifs, scanned a long time ago.
When opened in the normal fashion with PIL:

img = Image.open(scanPath)

they give an error : "jpeg old style compression",
many internet topics talk about this problem.
After many tests, I found a way :

import tiffile as tiff 
import numpy as np
...
a = tiff.imread(scanPath)
img = Image.fromarray(np.uint8(a))
# the above img I can show()

Question: I am using this method as of now, to also read the normal LZW compressed images.
WIll I be punished for using this overhead (response time, memory usage...) ?
Or ... is there another and better approach?
Paul