Getting the focus exactly right - TOYO 45CF

<p>I have a problem I could use some help with.</p>

I have a very nice Toyo 45CF. I am going to try some shallow depth of field work so I need to make sure that my ground glass image agrees with my film so my focus is accurate. Currently, it is not.

 

I have the clear cover glass, the "Toyo View" fresnel lens and what appears to be an acrylic ground glass. I have it arranged so that the ground glass is closest to the lens with the clear side towards the lens and the frosted side towards the back. Then the fresnel, with the grooves in contact with the ground glass. The "Toyo View" is in the lower right and reads properly from the back. Then this is covered by the clear glass at the very back. When I focus with this back I discover that at six feet I am focusing about six inches further from the camera with the ground glass than with the film. That is, I focus the camera's ground glass image at six feet but the film shows the camera is focused at a point six inches closer.

 

How is this arrangement supposed to be done so that I can get my subject in focus? Please help.

 

If anyone has specific guidance for this specific camera I would greatly appreciate it.

For starters, The ground , or frosted, side should be towards the lens , not the other way round.

 

Do you have a 4x magnifier (AKA loupe)?

<p>1. any non 35mm slr camera that uses a ground glass or focusing screen the ground side goes toward the lens.<br>

2. a fresnel always goes the ribbed side toward the ground glass. if the camera was designed to have the fresnel between the ground glass and lens then it must be there or the ground glass shimmed to account for the optical distance the fresnel was providing which may not be the physical dimensions of the fresnel.<br>

3. taking things 1 step further. Film Holder specifications state that the surface of the sheet of film should be .197 ± .007 inch below the edge of the film holder. Sheet film varies between .005 to .007 inch. place a piece of scrap film in the film holder then measure from the edge of the film holder to the surface of the film in several places. The measurements should be the same. I usually just check the base of the holder without film as TriX is .007 inch thick and is the thickest film in the industry.</p>

<p>Now with a known good film holder inserted into the back and the darkslide removed lay a straight edge across the back making sure the straight edge is not laying on a bump or ridge that is higher on one side and measure from the straight edge to the film holder base or use a sheet of film in the holder and measure to the surface of the film at several places. all measurements should be the same. now remove the film holder and repeat the measurements to the groundglass at the same places, they should be the same as the base of the film holder or surface of the film whichever you used. I divide the film holder and ground glass into thirds both horizontally and vertically and measure at the center of the 9 resulting spaces. The film holder to ground glass position measurements can be a simple strip of wood securely attached to the straight edge making the check easy and quick. Add or remove shims as necessary to get the gg to match the film holder.</p>

Also I have no idea what that last piece of glass is doing the n your set up. Having used a variety of view cameras* over

the years the set up has always been groundglass (ground side towards the lens) and then if you use a fresnel, Thre

fresnel and that's it.

 

*Sinar P, C, and F; Arca-Swiss F; Linhof Technikardan and Technika; Cambo; and Canham.

A clear piece of glass is probably meant as a cover, allowing the use of markers on it to mark all sorts of things.<br>Glass can be treated with all sorts of solvents to get those marks off again without any harm to it (though even then water soluble ink markers are preferable, because easiest to remove). Do that on plastic (the Toyo's Fresnel), and the marks you make or the mess the attempt to clean them off makes may well turn out to be permanent.

<p>I think you simply have the ground glass backwards... use it the other way around (frosted side to the lens).</p>

<p>Then check for focus accuracy using the GG and a loupe, you don`t need anything else to focus (keep the fresnel aside). You will see the image darkens considerably, but it should not affect focus accuracy.<br /> <br /> If after that, you notice the focus is not perfect, it could be that:</p>

<ol>

<li>The "acrylic" ground glass is not flat. Ground glass sheets use to be made on glass, cheap and effective, but if yours is made on acrylic (not likely), it could be that is bent (quite common with some bright -fresnel&GG- screens). If the ground glass is made on glass (as it should be) just skip this point.</li>

<li>Your camera use a quite old configuration, typical of old press cameras, with the fresnel between the ground glass and the lens. Not likely, too, because your camera is not that old, and you can read "Toyo View" on the fresnel from the back of the camera (in the "old press" configuration, the fresnel side should be in contact with the GG, so the words would be the other way around).</li>

<li>Your film holder is way off. Not likely, unless you were using a great piece of junk, old wooden one or so. Just compare it with the others; if they are modern and measure about the same, I`d think they are good.</li>

</ol>

<p>The protective glass should be removed when focusing.</p>

<p>Thank you all for your advice.<br>

Yes,I have a 6x Schneider loupe that I use to aid my focusing.<br>

The reason I asked for assistance with regard to this particular camera is that the advice I am receiving (above) ignores this camera's particular design. There is a "well" of sorts in the back below what are two "rails" for the placement of a cover glass. The clear glass is a cover glass. The "well" below it is exactly thick enough to hold the GG and the fresnel. The cover glass protects the softer plastic of the fresnel (I believe) and is the only one of the three components that fits exactly on the rails. The other two components are smaller/shorter along the 5" dimension.<br>

I have an 8x10 Kodak All Metal Commercial View, a Plaubel Peco III 5x7, a Crown Graphic, and over the years I have owned several other view cameras. Never a problem. They are designed for JUST a plain GG and they work fine that way.<br>

This arrangement in the Toyo 45CF is somewhat unique. It seems to be designed to incorporate the fresnel but since I bought it used I am uncertain exactly how to incorporate it. It came with the camera. I'll flip the GG and try that. Any other feedback from someone who knows this (or similar) cameras please add to these fine efforts from you colleagues.<br>

Thanks.</p>

<p>Hmmm, let me think aloud... :)<br /> It may be that there is simply enough space to attach the fresnel behind the GG. It is the "easiest" configuration (I use it this way on my Sinar). Frosted side of the GG towards the lens, then the fresnel with the relief side towards the lens. You place the loupe on the soft side of the fresnel.<br /> This way, it doesn`t matter at all if the fresnel is attached or not , the GG is always on the right place (to hold the GG you may need some shims). Anyway, you should check it, specially if you suspect it is not factory adjusted.</p>

<p>If your camera use the "old press camera configuration" (like older Technikas), the fresnel should be placed between the ground glass and the lens, the fresnel relief in contact with the frosted side of the GG (frosted side always towards the lens). This configuration ask to be factory adjusted, even shimmed, or at least, I`d think original parts should be used for accuracy. The only advantage I see on this configuration is that the fresnel weak surface is protected by the GG.</p>

<p>Given that your camera is not that old, I`d think it should have a straight seat for the GG, and it should be the one closer to the lens. If there is enough room for a fresnel behind, is another topic.</p>

<p>Just some ideas; I also use different cameras, but sadly, neither of them is a Toyo...</p>

<p>I have just found an image of the rear standard of the 45CF <a href="http://www.bhphotovideo.com/c/product/257305-REG/Toyo_View_180_106_4x5_45CF_Field_Camera.html">(link to B&H)</a>. Is this your camera? As far as I can see, the GG holder is not that complex, there is a clear seat (bright, machined area) where the GG should rest... that`s all. <br /> You can attach the fresnel over the GG if you like (as mentioned), or not, or simply (hand) hold it against the GG for a brighter view... after composing, leave it over the bag and focus directly on the GG.<br /> (BTW, it looks to be a nice camera! :).</p>

<p>Thank you very much, Jose. Oddly enough, the GG that came with this camera is too small (short) to actually fit from one polished and machined rail to the other (it's a side-to-side arrangement). I'd like to use the fresnel but of course it is not necessary, just an amenity for composition. It enables me, with my bifocals, to get a nice bright view of my frame with my eyes about 18 inches away. I can forgo that if I have to.<br>

I'll cut myself a piece of GG, place the frosted side on the rails and shim as necessary. Anybody want to buy a Toyo View fresnel, retail value over $100? (just kidding)<br>

If one day someone reads this post who has bought the fresnel from Toyo and successfully installed it into this particular, specific camera, Toyo 45CF, do not hesitate to share. <br>

I have also sent them (Toyo product support) this question and perhaps they will respond with a good solution since they make and sell the camera and the fresnel.<br>

-Peter</p>

<p>Oh, for the sake of Ellis Vener,<br>

Calumet 4x5 and 8x10 (ugly and clunky), Kodak Clinical 5x7 and Kodak Commercial 8x10 (elegant classics), Crown Graphic (x3 the standard) , Busch Pressman Model D, Technica III, Wista Field (Cherrywood), Ritterick 5x7, Plaubel Peco III 5x7. More than one of these has employed a fresnel lens and more than one of those had a clear cover glass because the fresnel is soft (scratches) and not stain-proof. The Crown Graphic has a glass over the fresnel but it's the GG. In all cases, the glass protects it from scratches and stains. </p>

<p>Peter, what are you going to use for the ground glass? A piece of acid etched glass used on picture frames? I may need to know that in the future.</p>

<p>Follow up:<br>

I sent this same inquiry to MAC - the company that imports and distributes the Toyo 45CF (BTW it is the only camera I use which is currently in production!)<strong> Here</strong> is their response:<br>

Peter:<br>

The problem is the Fresnel; it is only for the AII and AX cameras. Its width is the likely cause of the focusing error.<br>

-------------<br>

So, I will use a regular GG. I cut one last night from an old salvage 5x7" piece I had on hand. I had bought a glass cutter, a simple one, on eBay for 5 <strong>bucks. </strong> I shimmed the glass with three thin strips of sheet film between it and the rails it mounts upon because a test shot yesterday showed it needed this little bit of extra distance. Or so I think. I shot a test sheet of film and and I'll let you know.<br>

This is an interesting little puzzle to solve. I am checking GG vs film using the ruler tilted away from the camera at about 6 feet away, lit with studio strobe. I do like solving these little puzzles and that's how I first convinced myself to open up a shutter to try to clean the old lube off myself. It worked.<br>

I am not much for solving these things with complex mathematical formulas and I have enough experience to know that "perfect" is a mirage. Good enough really can be good enough. Empirical trial-and-error is a way I have learned a great dealof what I know. Tuning up my tools is not as creative as actually being out (or in) shooting film but it is satisfying to be self reliant. Also, some problems I can solve for myself are extra satisfying because I can use the saved money for film or maybe another lens.<br>

If you'd like to see my work, go to: www.Lerman.net<br>

Thanks again, everyone. If someone reads this thread in the future and has achieved good focus reliability (registration) with the Toyo 45CF and a fresnel PLEASE let me know. My old eyes to appreciate a brighter image.</p>

<p>Maybe I`m an ignorant or a bit rude, but I don`t get it.<br /> I don`t know how the fresnel could be the problem here. How the width of a fresnel can cause focusing problems? Maybe they are refering to the thickness.</p>

<p>The fresnel is a lens, so I understand it could affect when focusing over it... specially if they are placed in front of the GG, but... are the GG of the AII and AX much different than the one on the CF...? Are they placed in front of the GG... ?(?!?!) Well, they must be right.</p>

<p>Anyway, you can use almost any fresnel over any groundglass, if finally you focus directly over the GG. If you`re decided to discard yours, maybe you can modify it to be used as a detachable one, Sinar style. Use it to compose, remove it to focus. If you`re a bit handy, maybe you can build somekind of magnetic clips or so to make this task faster and easier.</p>

<p>I am going to keep working on getting the fresnel into the camera without shifting focus during composition and focus time. I'll figure it out. <br>

For now I finally got the GG and the film to agree right on the money! I put the GG on the 'rails' it was meant to mount upon and shimmed it on each side with a strip cut from a piece of FP4+ 4x5. Perfect thickness shim! It works. (I think)</p>

<p>Jose, if the camera's back is not made to have a fresnel in front of the ground glass then putting a fresnel in front of the GG will move the GG backwards so that it will no longer be in register with the film holder.</p>

<p>Peter, some cameras have the fresnel mounted permanently behind the GG. I don't see why you think you have to put it in front.</p>

<p>FWIW, the focusing panels in Pacemaker Speed Graphics came in two types. In both the GG sits on bosses in the casting. One focusing panel casting, to be used with GG and no fresnel, has high bosses. The other, to be used with GG and a fresnel mounted in front of the GG, has the bosses milled down. Both types have the same casting number and this has got some users into trouble.</p>