Convertible Schneider-Kreusnach on a Graflex?

[pbromaghin]

I'm interested in a Schneider-Kreuznach 150mm f/5.6 / 265mm f/12 Symmar Technika Lens for my Pacemaker Speed Graphic. Will it have enough bellows extension at subject distance closer than infinity for the 265mm lens?

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[Ian Grant]

Yes, you will have enough bellows extension. However the rear cell is not that sharp on its own, best use is for portraits.

Ian

 

[Dan Fromm]

Yes, you will have enough bellows extension. However the rear cell is not that sharp on its own, best use is for portraits.

Ian

Sorry to disagree, Ian. The 4x5 Pacemaker Speed Graphics maximum extension is 323.9 mm. According to Schneider, the 150/265 convertible Symmar's rear cell requires 325 mm extension at infinity.

 

[Ian Grant]

Sorry to disagree, Ian. The 4x5 Pacemaker Speed Graphics maximum extension is 323.9 mm. According to Schneider, the 150/265 convertible Symmar's rear cell requires 325 mm extension at infinity.

You are right Dan, I was forgetting the position of the rear cell relative to the front standard,

Ian

 

[Pioneer]

As I recall the bellows extension on my Crown Graphic was barely enough to handle my SK Symmar 135/235mm convertible but the 150 would not work. YMMV

 

[pbromaghin]

Well, scratch that idea. Just what non-convertible lens focal length would be the longest I could use?

 

[Dan Fromm]

Well, scratch that idea. Just what non-convertible lens focal length would be the longest I could use?

See post #3 above. To focus to infinity, a lens' flange to film distance can't be longer than the camera's maximum extension. The relationship between flange-to-film distance and focal length depends on the lens' design type and mechanical design.

Practically speaking, the flange-to-film distance of most non-telephoto lenses mounted in shutter used in LF photography is approximately the lens' focal length.

FWIW, the longest standard issue lens for 4x5 Speed Graphics was a 15"/5.6 Wollensak telephoto.

 

[pbromaghin]

See post #3 above. To focus to infinity, a lens' flange to film distance can't be longer than the camera's maximum extension. The relationship between flange-to-film distance and focal length depends on the lens' design type and mechanical design.

Practically speaking, the flange-to-film distance of most non-telephoto lenses mounted in shutter used in LF photography is approximately the lens' focal length.

FWIW, the longest standard issue lens for 4x5 Speed Graphics was a 15"/5.6 Wollensak telephoto.

Your post #3 was why I asked this question - this particular 265mm needing 325mm of extension. That's a 60mm more extension than focal length.

Now your 15" Wollensak example is 55mm the other way. I take this to mean that I have to be very careful in choosing.

 

[Dan Fromm]

Your post #3 was why I asked this question - this particular 265mm needing 325mm of extension. That's a 60mm more extension than focal length.

Now your 15" Wollensak example is 55mm the other way. I take this to mean that I have to be very careful in choosing.

Re the convertible Symmar's rear cell, don't ask me, ask Schneider.

Re the 15" Wolly, it is a telephoto lens. A teles' back focus is shorter than its focal length. If you want to use a lens longer than around 10"/250 mm on a 4x5 Speed, look for a tele and make sure that the lens flange-focal distance is usefully short.

Re usefully short, I have a 12"/4 TTH tele in barrel made for for AGI F134, F139 and Vinten F95 cameras. The rear of its barrel is threaded internally. I attached it to a 2x3 Pacemaker Graphic board with an adapter that goes through the board and screws into the back of the barrel. The board is clamped between the adapter and the rear of the barrel. It makes infinity on my 2x3 Pacemaker Speed Graphic with the camera's front standard on the inner bed rails.

You don't have to be very careful, you have to be better educated.

 

[pbromaghin]

You don't have to be very careful, you have to be better educated.

Right. Large format is almost completely new to me so I'm pretty far at the wrong end of the learning curve. Thank you for your help.

 

[Chuck1]

Extended lenboards(tophats) might work for you.

 

[Dan Fromm]

Right. Large format is almost completely new to me so I'm pretty far at the wrong end of the learning curve. Thank you for your help.

photrio.com is more popular than largeformatphotography.info but the LF site is richer in LF resouces than photrio. Go there and root around. Also look in the forums (largeformatphotography.info/forum). The forums' search engine isn't very good, I use google advanced search when I want to find something there. If you don't know what you're looking for, though that won't be very helpful.

The has another resource that's somewhat harder to find. The first post in this https://www.largeformatphotography.i...mainly)-lenses discussion has a link to an annotated list of links of interest to LF photographers. Look for info there.

The list of links includes links to highly recommended books on LF photography. Reading a good book is a much better way to learn a lot quickly than asking questions on a bulletin board like photrio or the LF forum.

 

[abruzzi]

When deciding what focal lengths you can use--yes a 325mm bellows can focus a 300mm lens to infinity, but since focusing closer involves moving the lens further away for the fil, you only have 25mm to focus closer, so what does the 25mm get you? The formula is:

S = 1/(1/F - 1/P)

S is the subject distnace
F is the focal length of the lens
P is the distance from the lens to the film

so

S = 1/(1/300-1/325)
S=3900mm
S=3.9 meters

So with 25mm of additional bellows a 300mm lens can be focused to 3.9meters at the closest.

 

[pbromaghin]

I don't know how many photography books I possess or have read. 30?

On large format I have;

Large Format Camera Practice by Joseph Foldes. As a lifelong autodidact, I started by teaching myself to ride a bike and how to swim, and this is quite simply the best "how to" book I have ever read on any subject. The text exactly matches the illustrations and the illustrations exactly match the text. Not one extra word, nor one word missing. In my career as a software developer, I used it as a guide to my technical/business writing and communication. I may have foolishly lent this to another student in my darkroom class and not had it returned. The most important book in my library.

Graphic Graflex Photography by Morgan and Lester. A snoozefest of galactic proportions. It probably has some good information, but I fell asleep before I came across any of it. Gawd, how did they justify writing the checks to these guys? Where was Foldes when they needed him?

View Camera Technique by Leslie Stroebel. Covers the same territory as the above, but in much more detail than Foldes, and in a readable form. I've read parts of it, but I just brought it up from the basement tonight and hope to read it cover to cover.

 

[reddesert]

Some context for the convertible Symmar.

The base Symmar is a close-to-symmetric lens design. When you "convert" one of these lenses to the longer focal length, you remove one of the cells, leaving a very asymmetric lens. This asymmetric lens may have a principal plane outside the lens body. The principal plane to film distance is the lens focal length. In normal lenses, the principal plane is typically somewhere in the middle, so the flange to focal plane distance is roughly the same as the focal length (+/- 5-10 mm or so).

To make it worse, Schneider always recommended that you use the rear cell only when converting. So the bellows has to be racked out even further. Thus, the converted Symmar requires an unusually long bellows draw and doesn't play nice with a short camera.

On a camera with around 300mm of bellows, if you use a typical 250mm lens (non-telephoto), you have maximum extension past infinity of 50mm. This is enough for some margin of usability, for ex using the optical formula
1/focal length = 1/(image_dist) + 1/(subject_dist)
1/250 = 1/300 + 1/1500
you would be able to reach a subject distance of 1500mm (1.5 meters) and a magnification of 1/5, which is perhaps enough for a head-and-shoulders portrait on 4x5.

You will find that using a camera at its absolute maximum bellows extension is inflexible and somewhat annoying. So 250mm is about as long as usable on a camera with ~300mm extension, such as a Graphic or Tachihara-type 4x5 wood field.

 

[BrianShaw]

...

Graphic Graflex Photography by Morgan and Lester. A snoozefest of galactic proportions. It probably has some good information, but I fell asleep before I came across any of it. Gawd, how did they justify writing the checks to these guys?

...

Good grief... heresy, of the highest order.

 

[Mal Paso]

My old 210 Symmar converted to about 370 and took close to 500mm to focus.

My Fujinon 400 Tele works fine on my Wista with 300mm of bellows.