[sane-devel] Epson Perfection1640: testing focus (Flatbed)

[ael]

On Sun, Nov 07, 2021 at 08:16:42PM +0100, Wolfram Sang wrote:
> Please check if that works on your system as well.

I have been testing the focus setting on the 1640SU.
For the moment, I am testing without the TPU.
To do this I just changed 
dev->focusSupport = SANE_TRUE;
from SANE_FALSE in epson2-ops.c
and then made sure that I used only the values
FOCUS_ON_GLASS (64) or FOCUS_ABOVE_25mm (89)

I set up a target (actually an old DVD) propped up on one side so
it sloped from touching the glass on one side, and more than a couple
of mm above the glass on the other.

I could not tell the difference between the two scans.
So far as I could tell, the scanner was ignoring these focus settings
at least in the flatbed mode.

Of course, I checked the debug logs to ensure that the scanner
was accepting the focus commands.

I hope to repeat these tests with the TPU later today. I will have to
find a smaller sloping target to fit.

As I mentioned in an earlier note, I am beginning to suspect that the
1640SU has its own autofocus internally.

So it may be that the current epson2 version that leaves
dev->focusSupport = SANE_FALSE is fine. But let me check with the TPU.

ael