Toyo Field 45AII and lens focus

I am new to large format and just recently acquired a Toyo Field 45AII field camera and have a question about focusing and the lens reference scale on the bed yoke. According to the manual, the white scale on the lens yoke gives the distance from the front of the lensboard to the film plane when the back is not extended. When the back is extended then the red scale is used.
So I have a 150mm lens mounted. I set the lens at the 150 mark (back not extended), locked it in place and I focused using the front rollers that move the bed forward/backward. Locking it at the 150 mark for a 150 mm lens was indicated on a YouTube video I watched about setting up the Toyo field camera.
For my first photos using the camera, I did a lot of simple still life setups and the odd portrait with my wife standing in. I had no difficulty getting the subject focused the way I wanted.
Recently I moved outside with the camera and the lens locked at the 150 mark on the reference scale - and I found that I could only focus up to a point, and that anything beyond say 15-20 feet could not be brought into focus. So I released the lock on the lens (the lock that holds it in place on the bed yoke) and then moved the lens back towards the camera back (film plane) and I was now able to focus on farther objects.
So I guess I am a little confused as to the utilization of the scale and whether I should be able to get focus with the lens locked on the scale that reflects its focal length. Or is it normal to free up the lens so that it can be moved closer to the back in order to focus?
Any insight, suggestions, references to look up would be most appreciated.

What you wrote seemed a little strange so I downloaded the manual from https://www.butkus.org/chinon/toyo-view/toyo-view.htm. Have you set the infinity stops correctly? Use the infinity stops to position the standard, not the scale.

Dan Fromm said:

What you wrote seemed a little strange so I downloaded the manual from https://www.butkus.org/chinon/toyo-view/toyo-view.htm. Have you set the infinity stops correctly? Use the infinity stops to position the standard, not the scale.

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Thanks for such a quick reply Dan.
The camera has the infinity stops already installed. I bought i used and the person selling it says that it is all set up for the 150 mm. I saw the statement about the infinity stops in the manual, but wasn't sure about the exact way to check for their placement. So if I understand correctly you are saying that I should not lock the lens at the 150 mark on the reference scale but should use the infinity stops instead?

Ottawa_Mario said:

Thanks for such a quick reply Dan.
The camera has the infinity stops already installed. I bought i used and the person selling it says that it is all set up for the 150 mm. I saw the statement about the infinity stops in the manual, but wasn't sure about the exact way to check for their placement. So if I understand correctly you are saying that I should not lock the lens at the 150 mark on the reference scale but should use the infinity stops instead?

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Yes, exactly, that's what they're for.

Dan Fromm said:

Yes, exactly, that's what they're for.

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OK. I guess that YouTube video on setting up the Toyo needs an edit as it specifically mentioned the 150 mark. But since I focus using the ground glass I read in another thread on this forum that some people don't use the infinity stops, especially if they are using multiple lenses. They "estimate the initial position" for the lens in use and then fine tune position and focus using the image on the ground glass. Which is a little bit like what I ended up doing in order to see a focused image. I will have to check which of the 3 infinity stop pairs that are mounted on the yoke works for the 150 lens.
Thanks again for your help. Much appreciated.

Think of it as any boxed camera and lens attached where lens will have it infinity marker at one end of helical run and shortest distance at the other. If you don't have FS set at infinity marker (bed retracted fully) then you will lose either shortest distance achievable limited by bellows draw, or will not be able to focus at infinity if FS is moved fwd of the infinity stop (with bed retracted). For closest focusing achievable move FS to front end of the bed as this is governed by bellows length, so to get bellows go as long as camera limits allow, FS needs to be front end (with bed retracted). Of course in this setting infinity focus is not possible.

Witold said:

Think of it as any boxed camera and lens attached where lens will have it infinity marker at one end of helical run and shortest distance at the other. If you don't have FS set at infinity marker (bed retracted fully) then you will lose either shortest distance achievable limited by bellows draw, or will not be able to focus at infinity if FS is moved fwd of the infinity stop (with bed retracted). For closest focusing achievable move FS to front end of the bed as this is governed by bellows length, so to get bellows go as long as camera limits allow, FS needs to be front end (with bed retracted). Of course in this setting infinity focus is not possible.

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Thanks - that's some of what I was finding by locking in the lens at the 150 reference mark on the scale - I could close focus on objects that were near - as in a still life set) but could not focus to infinity when I was outside. So the infinity stop that is closest to the camera back seems to be about right for infinity focus, which I will test out when I get outside again in a day or two. Much appreciated that you responded. I have lots to learn. But am having lots of fun.

Think of infinity stops as "quick stops" for easy setup in general field photography where focusing at infinity is usually in play. These are not critical to have as when you find out infinity focus is not possible, then FS is too far ahead of film plane and needs to be moved back. And when FS is not correctly set up for infinity position, then you will just lose some closer focusing ability, which again can be simply adjusted on the fly by moving FS on rail more forward.

When closest focusing as in macro is required, then stops must be out of the way to get the longest bellows draw possible (if that is needed of course).

Witold said:

Think of infinity stops as "quick stops" for easy setup in general field photography where focusing at infinity is usually in play. These are not critical to have as when you find out infinity focus is not possible, then FS is too far ahead of film plane and needs to be moved back. And when FS is not correctly set up for infinity position, then you will just lose some closer focusing ability, which again can be simply adjusted on the fly by moving FS on rail more forward.

When closest focusing as in macro is required, then stops must be out of the way to get the longest bellows draw possible (if that is needed of course).

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Thanks. I think I am understanding what I'm being told. Now just need to get back out and try some more photos. And make the FS positioning more intuitive, i.e. burn that concept into my old brain with more repetition.
Cheers every one of you that responded.
I think I am going to like this forum .

The focal length of a normal lens is the distance from the focal point of the optical assembly to the film plane / ground glass. That focal point may shift a bit depending on the design of the lens assembly, usually represented by the focal flange distance. Using a Schneider Symar-S 150mm f/5.6 as an example, depending on the shutter, the FFD is anywhere from 141mm to 143.5mm-- so if you set any of those lenses to 150mm, you've exceeded the distance for focusing at infinity.

The manual has a section on setting the infinity stops correctly for your lens.

I use the reference scale on the focus bed only as a starting point when focussing, often locking the lens a bit short of it's actual focus length. Then i use the ground glass to focus more precise, moving the bed forward as fat as necessary. I often use a bit of back tilt in combination with front shift, which makes the infinity stops of this camera more or less useless anyway. And when making close-ups i lock the front panel at a posiition where i think i will be able to achieve focus. It takes a bit of experience, but after a while it becomes second nature.

grat said:

The focal length of a normal lens is the distance from the focal point of the optical assembly to the film plane / ground glass. That focal point may shift a bit depending on the design of the lens assembly, usually represented by the focal flange distance. Using a Schneider Symar-S 150mm f/5.6 as an example, depending on the shutter, the FFD is anywhere from 141mm to 143.5mm-- so if you set any of those lenses to 150mm, you've exceeded the distance for focusing at infinity.

The manual has a section on setting the infinity stops correctly for your lens.

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I looked over the manual regarding the position of the infinity stops and I will check their current position at some point today. There are 3 sets of infinity stops already installed on the yoke. The person I bought it from did tell me that it was all set up and ready to use. So I expect that one of the sets is probably already in place for the lens. It's supposed to clear a bit in the afternoon so I will probably venture out at that point and experiment.

Huub said:

I use the reference scale on the focus bed only as a starting point when focussing, often locking the lens a bit short of it's actual focus length. Then i use the ground glass to focus more precise, moving the bed forward as fat as necessary. I often use a bit of back tilt in combination with front shift, which makes the infinity stops of this camera more or less useless anyway. And when making close-ups i lock the front panel at a posiition where i think i will be able to achieve focus. It takes a bit of experience, but after a while it becomes second nature.

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That makes sense to me since I did wonder about how locking down the lens while doing movements would work. In the little bit of experimentation that I did with front lift and tilt I found that I had to "unlock" the lens from the position I had it in and move it in order to get anything in focus. Hope that makes sense. Anyway - I think that once I get more practice in with the camera then I will have the idea more ingrained and a focus process that will seem intuitive.

Thank you both for responding.

oh! and welcome to the group.

I too got started large format recently after picking up a Toyo 45AII. I don't even bother using the scale or infinity stops. I just move the lens bed forward while looking through viewing hood, once it comes into relative focus I back it up a bit and lock it into place. After that I use the focus knobs to bring it into general focus and then critical focus.

cowanw said:

oh! and welcome to the group.

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Thanks

kevinjp said:

I too got started large format recently after picking up a Toyo 45AII. I don't even bother using the scale or infinity stops. I just move the lens bed forward while looking through viewing hood, once it comes into relative focus I back it up a bit and lock it into place. After that I use the focus knobs to bring it into general focus and then critical focus.

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Good to find another Toyo 45AII user, or at least someone else that has used the same setup. I'm thinking that your method is generally what others have been saying as well. So.... guess that's what I'll be doing from here on in. Thanks for taking the time to comment - very much appreciated.