Camera bed styles ??

[Calamity Jane]

I'm working on the design for my next homemade 4x5 camera and am torn between the "old style" of camera bed (like this one http://img.photobucket.com/albums/v181/calamityjanecanary/anthonycliftonlongfocus8x10a433.jpg) and the style that now seems to be popular on field camers ( http://img.photobucket.com/albums/v181/calamityjanecanary/camera1.jpg )

Although the old style requires a removable "extension" to get good bellows extension and remain fairly portable, it should (from an engineering perspective) be a LOT more rigid at long entensions than the modern type (when both slides are extended).

Has anybody used both styles and would be able to comment on the relative rigidity of each?

(I am interested in the stability of the bed and extensions - the rest of the "mechanics" will be somewhat different than on either of these examples)

The old style is also easier to make and should be easier to maintain smooth movement....

Thanks Group!

[Ole Tjugen]

I have only used the second type you show, and there is no doubt in my mind that it is sufficiently stable. The longest lens I have used on my ca. 1920 German 18x24cm camera is the 23 1/2" front cell of a Rapid Convertible, and the camera/rails are certainly stable enough for that.

Since the camera can also focus lenses down to less than 120mm (shortest I have used), it is a very flexible design.

[Ralph Barker]

I haven't used the older designs with rail extensions, but as I recall, most were essentially just a square frame that attached to the square end of the main extension via knurled screws. As such, they depended on the squareness of the two relatively small end surfaces and the tightness of the screws for rigidity. A small bit of wear on either, and the extension ended up being pretty floppy. My guess is that in practice, many folks used some form of external cross-joint support to add some rigidity.

The newer design has the mechanical advantage of the overlapped tongue and groove, usually combined with a clamping mechanism to hold the bits together once focus has been achieved.

The ideal design might be a combination of the two. The modern T&G design for the basic camera, with an extension that included some form of mechanical overlap for the extension for very long lenses. If combined with interchangeable bellows (bag, normal, and very long), that would result in a very flexible design.

[Ernest Purdum]

I am bothered by extensions because so often the pinions don't ride smoothly over the joint. It's not uncommon for a pinion to jump a tooth resulting in very rapid wear as well as misalignment.



I think either type can have rigidity problems depending on detail design, accuracy of construction and material choice. I don't, though, think that poor rigidity is inherent in either basic design.

[Dan Dozer]

One of my cameras is the first type and there is one issue with it that you might want to consider. This type of camera typically has a front drop down extension bed with the potential of attaching a back drop down extension bed to the back of the camera for longer lenses. This works fine for the long lenses, but I have potential problems with wide angle lenses. When I use my 90 MM Schnieder on my 5 x 7 camera, in order to get the front extension bed out of the field of view, I have to slide the camera way to the front of the front extension bed. The problem is that the tripod mount on the camera bed baseplate is way back behind the camera. This does creat a stability problem at times, and just from a visibility standpoint, the camera and lens are precariously way out over the front of the tripod. It gives the impression that your expensive lens is going to fall off the end of the tripod. If your tripod has a large camera mounting plate, this may not be an issue.

I would recommend that if you build this type of camera with the drop down front bed, you also provide for a tripod mount near the front of the bed for wide angle work.

[Mark Sawyer]

Most of the drop-front cameras are open in the front, so with a wide lens you can just leave it up and attach the rear rail for focusing. Out of the way for even the shortes lens. And many drop-bed cameras have sliding plate on the bottom for the tripod. You can position it under the center of gravity or under one of the rail attachment points for extra rigidity.

Both the designs you're considering are good, though the best advantage of the drop-front for the custom-builder may be that it's simpler to construct without those sliding parts to the bed.

[Jason Greenberg Motamedi]

I have found through use that the "old style" requires some sort of brace to remain rigid, with my Korona came with both support braces and a tripod with a large (~6" x 9") platform as head. I didn't much like it, so I used a majestic head with a 6" x 7" platform. "New Style" cameras, in my experience, don't require these braces or platforms.

[Paul Fitzgerald]

Hi there,

The older style is easier to build, the newer style is lighter to carry. The front extention hinge will keep everything aligned well. If you use 2 thumb screws for the rear extention it will self align. The older style has one advantage, you can use 2 tripod socket threads, one in the base and one in the extention. Agfa/Ansco, Burke & James, Grundlach, ect. all had these, they were not to balance the camera. They used to make tilting heads that screwed into both threads and locked the camera ridgid, the bottom half attached to the tripod.

Just a thought.

[Edward (Halifax,NS)]

I can't answer your question but if you decide on the new style bed Doug Bardell sells plans for double and triple extension 4X5s. I am taking the plunge and ordering the double extension 4X5 plans today. Any suggestions on where to pick up brass hardware or inexpensive bellows? If I Have to pay some of the quotes I have gotten I will be using handmade bellows for a good long time.

[Calamity Jane]

Edward: DANG! I missed that on Doug's site - I'll have to go have a look.

Brass hardware is a BIG problem. I haven't found anybody selling knobs, levers, and such. Fortunately I have a 1.5" bar of brass in the shop cupboard that may become knobs.....

As for bellows, I haven't seen anything "reasonablely" priced since Alletta Photo disappeared (and stuck me with one that leaks light).

I have made one 4x5 bellows recently from Roc-Lon blackout material and aluminum roof flashing and it seemed to turn out well - it's on my homemade enlarger. I have another one partly finished and I am taking pictures as I go. When it's done (in a week or so?) I'll post pictures on my Web site.

I decided to go with the old style bed when I figured out how to do a "bridge" for the extension that would be rigid and would align the front and rear beds so you can run the standard over the joint. I've also inculded two different tripod mounts so I can shift the mounting position when using the extension. The tongue-and-groove type of sliding joint requires a great deal of precission and I don't have a shaper so I figured I'd have better luck with square tracks and a matching carriage.

The new Maple camera is getting close to being done - just finishing up the back. It ought to look real pretty when stained. I plan to install the threaded inserts today so I'll get my first chance to see how rigidly it will lock up (which was my main complaint with camera #1 - a wooden monorail). I'll try to get some pictures up on my Web site next week.

Good luck with your camera building!