Tachihara users - rear standard help

[welly]

Hello all,

Question about my Tachihara 8x10, specifically the rear standard. Is there a way of getting both sides of the standard to focus at the same time rather than independently as it appears to work? I'm always concerned that one half of my image is going to be out of focus (slightly). When I'm working under the dark cloth and wanting to focus, it's a little awkward. Or perhaps I need to just figure out using the front standard to focus. But I seem I recall last time I tried, it wouldn't move back far enough hence me using the rear standard to focus. I'm using a 300mm Fujinon lens with it.

Thank you!

welly

[Heroique]

It sounds like a complex focusing issue, so if you gave a concrete example and made it as visual as possible, it might help...

For example, what's your subject and the distance?
Where do you want the plane of best focus?
How wide do you need the DOF?
Starting from a neutral set-up, what movements are you using?
What remains out of focus on the GG?
Will a narrower aperture help?

We have so many experts of technique here, a little more info would put them into action.

[Leigh]

I __assume__ yours is the same as mine, purchased new two years ago. The two sides move independently.

There's no way to make them move in unison other than to design an accessory for the camera.

If it's just a question of perpendicularity, use a gage like an ink pen to measure the distance from one side to the back of the base rail, then adjust the other side so it's the same. Both sides can be locked down independently.

- Leigh

[Oren Grad]

...it wouldn't move back far enough hence me using the rear standard to focus. I'm using a 300mm Fujinon lens with it.

That sounds odd. A 300 is normal for 8x10, and one would expect focusing in most situations to be straightforward with the front standard. Can you explain what you mean by "wouldn't move back far enough"?

[Leigh]

I agree with Oren. There's something seriously wrong here.

I have the double-extension version, and have no trouble focusing a Nikkor W 240/5.6 (FFL 227.3).

The FFL for the Fujinon T 300/8 is 195.3mm, but its image circle of 213mm won't cover 8x10.

The FFL of the Fujinon C 300/8.5 is 282.3.

Per the spec sheet, the minimum bellows extension is 90mm, which should easily cover any reasonable lens.

- Leigh

[welly]

Ok, I can see why I get little movement on the front. There's a stopper nut at the front stopping the front standard from going back too far. Have a look:

109632

So this basically means all my focusing comes from the back. There's no problem focusing but the two focusing nuts on the back are independent and you have to wind both at the same time.

[Leigh]

Mine has that same stop. It prevents the slide from slipping out the back of the camera.

It has never interfered with my focusing of any lens; always moving the standard forward.

What are you shooting?

You realize any optical system has two focal points, one with the lens closer to the subject, the other with the lens closer to the film, yes?

- Leigh

[Maris Rusis]

Hello all,

Question about my Tachihara 8x10, specifically the rear standard. Is there a way of getting both sides of the standard to focus at the same time rather than independently as it appears to work? I'm always concerned that one half of my image is going to be out of focus (slightly). When I'm working under the dark cloth and wanting to focus, it's a little awkward. Or perhaps I need to just figure out using the front standard to focus. But I seem I recall last time I tried, it wouldn't move back far enough hence me using the rear standard to focus. I'm using a 300mm Fujinon lens with it.

Thank you!

welly

The double extension Tachihara 8x10 features independent focussing for the left and right sides of the rear standard. Usually both sides are racked to the same distance as indicated by the scales on the bed of the camera. Super precise focus can be confirmed by tweaking the left and/or right focussing knobs while checking the ground glass. Back swing can be achieved by racking the back different distances on the right and left sides. For most purposes the Tachihara double extension 8x10 focusses by moving the front standard. This is fine where the subject is not close to the lens. For close subjects racking the front standard changes the lens to subject distance and the magnification. Sometimes it is possible to use all the front focus travel and get different size blurry images but no focus at any point. Then back focussing must be done. This is why view cameras well adapted for close work, face portraits for example, need to focus by moving the back of the camera not the front.

[Oren Grad]

There's a stopper nut at the front stopping the front standard from going back too far.

Why do you need to move the front standard far back with a 300? That's the part I'm not yet understanding.

[Leigh]

Why do you need to move the front standard far back with a 300? That's the part I'm not yet understanding.
Same here. I certainly do not do that with mine.

As I mentioned in post #5, we need to know exactly which Fujinon 300mm lens you're using, since different models have different flange focal distances.

Set the lensboard in front of the ground glass by a distance equal to the flange focal distance of your lens.
The camera is then focused at infinity, by definition. If not, there's some serious problem with the lens.

That distance can only increase as you focus on closer subjects.
That is, either front or back can move away from each other.
It will never decrease under any circumstances.

- Leigh

[Keith Fleming]

When I had a double-extension Wista Field (similar to the Tachihara), and using a 300 mm lens, the rear standard (if all the way to the rear) was too far from the front standard for the lens to focus. I always racked the rear standard forward until I achieved rough focus, and then moved it a bit further forward. Then I made sure the two sides of the rear standard were aligned with the same numbers on the side scales. Then I could rack the front standard forward to achieve proper and final focus.

I think I had to use at least a 360mm lens if I were to be able to focus with the rear standard all the way to the rear.

Keith

[Oren Grad]

When I had a double-extension Wista Field (similar to the Tachihara), and using a 300 mm lens, the rear standard (if all the way to the rear) was too far from the front standard for the lens to focus.

Per the listing of the double-extension 8x10 Wista on the B&H website, the camera dimension, and hence the bed dimension, is 12x12". I'm still having a hard time visualizing why it's impossible to focus a 12" lens mounted on a 12" bed, without having to move the rear standard. Do you recall approximately how far you had to move the rear standard forward to achieve infinity focus with a 300 on your Wista?

[Leigh]

I think I had to use at least a 360mm lens if I were to be able to focus with the rear standard all the way to the rear.
And why would you want to do that?

That's not the way the camera is designed to work.

In fact, doing so puts the camera in its least rigid configuration, and should be avoided except in extraordinary circumstances.

- Leigh

[welly]

When I had a double-extension Wista Field (similar to the Tachihara), and using a 300 mm lens, the rear standard (if all the way to the rear) was too far from the front standard for the lens to focus. I always racked the rear standard forward until I achieved rough focus, and then moved it a bit further forward. Then I made sure the two sides of the rear standard were aligned with the same numbers on the side scales. Then I could rack the front standard forward to achieve proper and final focus.


This is what I have to do. I guess it's how this camera works. It's not a big deal, just feels a little inaccurate with the rear standard controls being independent like that.