Help need focussing my Tachihara..

snaggs · Apr 1, 2007

Twas a nice cloudy day on saturday morning, so I took my wife down to the park a few shots.

My problem is.. that with the Peak 10x suction loop that I bouht with my camera.. I just couldn't get it into final focus. I could see when the ground glass snapped into focus without the loop... but with the loup on the eyes (on the ground glass).. they were always mushy and never snapped into focus like I expected.

Is this the loop? Like the diopiter adjustments you need to make on an SLR? Too much magnification?

Regards,

Daniel.

Amund · Apr 1, 2007

Too much magnification, try 4x-ish....

Bob F. · Apr 1, 2007

Times-four to times-six seem to be favorite, but I keep a x10 plastic loupe in the bag for emergencies and it is usable: you just have to try to ignore the grain of the glass.

You may have a problem with focus. The loupe needs to focus on the other side of the ground glass which is about 2mm beyond the base of the loupe. If the loupe is designed for looking at film on a light table, the focus will be set to be at the base, not 2mm beyond it. The loupe is allegedly designed for use on a view camera but possibly only by adding a sucker foot to a standard x10 loupe so it's not clear where the point of focus may be. Ten-times magnification suggests a very narrow focusing range so the natural variation in the height of the rubber foot under differing pressure alone may cause problems. Looks like a pretty rubbish design to me, but WDIK?!...

I'd take the foot off and try it without and see if you can get sharp focus that way, possibly by holding it off the glass slightly, or not...

Good luck, Bob.

roteague · Apr 1, 2007

Did you use the loupe backwards?

dickie vaara · Apr 2, 2007

I also doubt it's the loup. I have a Tachihara as well, and I own a fairly inexpensive 8X loup made by Horizon. It adjusts like the eyepiece on a set of binoculars, for varying eye strengths; so I asjust it for viewing negs, and re-adjust for different surfaces. You might look into that brand, or one that works similarly. Otherwise, the rubber foot trick that Bob F. mentioned sounds like a solution.

Richard
--------------------------------------------------------------------------
"Shooting digital is about as creative as turning on the radio......."

roteague · Apr 2, 2007

Check to see you are using the loupe correctly. From your description, it sounds like you are using it backwards - it is exactly what happens when I use my Toyo loupe upside down.

photographs42 · Apr 2, 2007

I don’t think it’s possible for it to be the camera. 10x is pretty strong, although that’s what I use, but it depends on your eyes, the texture of the GG, and whether or not you have a fresnel lens on the GG. If you have a fresnel, the 10x might be too strong because the magnified image of the fresnel lines get in the way or the magnified texture of the GG can get in the way also.

Try this. Hold a piece of printed matter (you know it is in focus) up to a window on a sunny day and use the loupe to view the print. It should focus when the loupe is separated a few mm from the surface. Do you wear glasses? If so the loupe needs diopter adjustment, but even, then it won’t work very well if it is too strong.

Jerome

Jon Shiu · Apr 2, 2007

Hi, if you can see it snap into focus without a loupe, then you can work much more quickly and intuitively. Practice without the loupe and you will get a feel for how the contrast on a bright edge changes when it comes into to focus. I don't use a loupe, but then I'm pretty nearsighted and don't wear my glasses when focusing.

Jon

photographs42 · Apr 2, 2007

There is also this.
http://www.largeformatphotography.info/forum/archive/index.php/t-947.html
Jerome

Campbell · Apr 6, 2007

It's probably a combination of the 10x loupe and the Fresnel lens on the Tachihara. Fresnel lenses are great for brightness but the lines in them can make them a little hard to focus (except the Maxwell screen). I'd suggest a different loupe, like 4x, or maybe just try using some strong drugstore reading glasses.

snaggs · Apr 9, 2007

I think it was the rubber suction cup which was causing the problem, or maybe I did have it back to front. All went perfectly yesterday!

Daniel.

Help need focussing my Tachihara..

Privacy & Transparency

Privacy & Transparency