Toyo 810M Rail Modification/Bellows Question

[Ari]

I know, I know, but hopefully this one will be helpful to others, and I do have a question at the end.



I've been trying to figure out a way to get more extension out of my Toyo 810M.
The normal configuration allows for 650mm of extension, which is great for 90% of what I need; but I have a lens of 650mm FL, with a FFL of 733mm.
Needless to say, this is somewhat inconvenient when the longest lens is needed.


My front standard returned yesterday from a CLA at Toyo/MAC Group, and before putting all the little screws back on it, I inserted the rail into the bed backwards.
Here is the procedure, quickly:








This is possible, probably even encouraged, but I didn't know about this before. Combine this with a rail extension that would make the Toyo engineers a little nervous, and, lo and behold, I now have 840mm of extension from the same camera.

I intend to modify the screws that sit in the rail so that they can be removed by hand, and possibly replace the two screws with one screw.
Removal of those screws allows the rail to extend further. The rail is still rock-solid at the maxed-out extension, with no hint of movement, wobble or vibration.
The little black bridge that needs to be removed in order to reverse the rail has to be modified for easier removal, as well. It is fixed by three tiny Philips screws.

I will next order a new, longer bellows from Rudy in HK; he has given me a great price on bellows, Toyo frames and installation.

My question is, with 840mm of camera extension, how long should the bellows be made? The bellows need to compress to 3cm (30mm); should a thinner bellows material be used?

Thank you.

[Ari]

Camera with max extension:



So, would an 840mm bellows be the right length to order, or would you suggest something a little longer?

Thanks in advance.

[tgtaylor]

On the MII the standard bellows is listed as 700mm and the longest lens with that bellows is 800mmT. The front standard reverses on the MII allowing for a maximum extension of 820mm allowing for a 1200mm T lens to be used. Toyo makes a 1200mm long bellows which I would use for any lens beyond 650mm. Stretching the bellows out is not good for it and probably leads to corner damage.

Thomas

[Ari]

Thanks, Thomas; the 650mm lens is not one I would use often, so stretching out the bellows would not be a regular occurrence.
I am actually more worried about bellows sag.

The idea of having a 1200mm bellows seems like overkill to me if the camera's maximum extension is only 820mm.
I would think that 20-40 extra centimeters of bellows would be a good length, but I don't know for sure.

[tgtaylor]

On second thought, why not just replace the current front standard with the MII's reversible standard?

The previous owner of my MII was a firm advocate of not stretching-out the bellows and the Toyo long (and bag) bellows came with the purchase. I would agree that 1200mm is probably overkill on the MII O(mu longest lens so far is 610mm), but the 1200mm (+ the normal 700mm) is definitely usable on the 810G if you have the lens and/or shooting 1:1.

Thomas

[Peter De Smidt]

I'd ask the bellows maker if a 1000mm bellows would compress down enough. I agree with Thomas that stretching out a pleated bellows close to it's maximum is not a good idea.

[Ari]

On second thought, why not just replace the current front standard with the MII's reversible standard?

Well, it would cost $1300, unless I can find a front standard from a scrap MII, which might take a long time to find.

[Ari]

The previous owner of my MII was a firm advocate of not stretching-out the bellows and the Toyo long (and bag) bellows came with the purchase. I would agree that 1200mm is probably overkill on the MII O(mu longest lens so far is 610mm), but the 1200mm (+ the normal 700mm) is definitely usable on the 810G if you have the lens and/or shooting 1:1.

Thomas

I'd ask the bellows maker if a 1000mm bellows would compress down enough. I agree with Thomas that stretching out a pleated bellows close to it's maximum is not a good idea.

I'll make sure the new bellows will compress to the required thickness; Rudy has Toyo frames in stock, so I'm sure that he's already aware of the compression requirements. I will stress that point, though.

So, should I go for a 900mm bellows? I don't want to go over 1000mm.
The camera can only extend to 840mm, so how "loose" should the new bellows be?

Thomas, I'm sending you a PM for some more information.

Thank you

[Peter De Smidt]

Does Rudy have any thoughts on the matter?

[Ari]

I haven't asked him, actually; his photo knowledge/experience is an unknown quantity to me. I'm also doubtful that he is in the same location as where the bellows are made.
I think he passes on the specs to someone.
My first thought was to ask Toyo, but that will have to wait until the new year, so I asked here first.

At 650mm extension, the bellows are almost tight on my 810M; that must be factory spec for standard bellows.