View Full Version : Tachihara 8x10 fresnel "double image"

24-Feb-2007, 04:55
I just received my Tachi 8x10, and I'm playing with it a bit. I have one issue with the "ground glass". It seems to have a "latent" image that stays the same whatever the angle of view, but it also has a "floating" image that changes with the position of your face relative to the glass, and that "floating" image has a slightly different focus AND angle of view than the other. It's also quite a bit brighter.
At first I tought it was some sort of reflection, but even under the darkcloth, and even using a loupe I get this overlap.. It's sort of like a rangefinder double-image, but instead if heloing the focus, it ruins it :D

So I'm wondering if my "fresnel" has a problem, like the frosted side that is no longer frosty enough ? Maybe the previous owner cleaned the glass (that is actualy plastic) with something that cleaned it a bit too much?

Is it a common problem ? can it be fixed ?

Ernest Purdum
24-Feb-2007, 11:53
My guess is that the fresnel may be in the wrong position relastive to the groundglass.

Alan Davenport
24-Feb-2007, 12:51
Check to see if someone has put the fresnel on the wrong side of the groundglass. The Tachihara 4x5s have the fresnel on the back side (toward the photographer) and I doubt they'd change that for a different size.

24-Feb-2007, 16:55
Hmm. here the "Tachihara" label is on the clear "glass" that is over the "ground glass" fresnel.
The "ground fresnel" ground side (the focus plane) is toward the lens, the fresnel part is toward the photog, and the clear "glass" is over it to protect it (and bear the label)

So I /assumed/ this is the right way ?

I temporarily switched over to a plain ground glass to get around the problem...

Alan Davenport
24-Feb-2007, 18:07
Yep, that's how the 4x5 is assembled. I'd forgotten that they have the fresnel on the back side of the GG. Haven't had mine apart since I dropped it in the creek.

Don't ask.