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View Full Version : Are the cams for Linhof MT and Tech V normally flat or are they slightly bent?



byuddy
2-Aug-2012, 12:33
I have a couple of 90mm rangefinder cams for MT or Tech V. One is slightly bent at about 5 degrees. The other is perfectly flat. Which one is correct? Maybe it doesn't matter if there is a slight bend. I presume a cam can be bent if the bed is dropped with a cam in place.

Bob Salomon
2-Aug-2012, 14:30
They are flat. They get bent when you leave the cam in place and drop the bed. But neither cam will work properly unless the lens serial number matches the serial number on the cam. And if the cam has two serial numbers it is for a 4 and not the later models.

byuddy
2-Aug-2012, 15:52
The cam that is flat has a number on each side, one number is the same as the one on my Angulon 90/6.8 and the other number (76790) is stamped on the opposite side. It looks just like the slightly bent cam. Does a Tech IV cam have the same grooves as the Tech V and Master cams?

Both cams have grooves in the portion that slips into the camera's rangefinder clamp. They slip fairly easily into my Tech V. The slightly bent cam appears to have been ground a bit on the long, top side. The flat cam appears not to have been ground. I have not tried to see if the Angulon and its cam syncs with the rangefinder in my Tech V.

Thank you, Bob, for the speedy response.

Bob Salomon
2-Aug-2012, 18:16
The IV cam fits the later models but the cam will only focus correctly with the camera whose serial number is on the bottom of the cam and the lens whose serial number is on the top. In other words, neither of your cams will focus properly, over the full focusing range, on your camera with any 90mm. Cams are not recylable to later cameras or other lenses of the same focal length.

You can usually tell when someone tried to do so because they then try to re-adjust the position of the infinity stops and leave a pattern of small indentations on the rails where the stops were moved from as the screws in the infinity stops have points that bite into the rails.

byuddy
5-Aug-2012, 18:59
OK ... I see I have a Linhof select 90mm Angulon and the matching cam, but it's for a Tech IV. The Tech IV cam looks just like a cam for a Tech V and Master, but it is stamped with the camera serial number. That's the clue. I bought the lens, cam, and recessed lens board on eBay for a pretty decent price so I guess I'm not really out much ... the lens and the board are OK.

byuddy
7-Aug-2012, 03:42
Hmmm ... I wonder if using the word "eBay" attracts spam.

Bill, 70's military B&W
13-Aug-2012, 19:49
I just bought on e-bay a Technika IV #67738, Bob if you would please date that one for me. From what I've been reading it should be 1960ish.
If I am understanding this cam stuff right, when I buy another lens, I should buy one that comes with a cam that is already machined for that lens.
Also the cam is only important if I want to use the range finder. Using GG I can just buy a lens holder and a lens and use a loupe.
Any help would be appreciated, I just paid for my IV today, I'm looking forward to it's arrival.
Another question, does the IV use standard 4x5 film holders?
Bill

David A. Goldfarb
13-Aug-2012, 21:18
The IV uses normal filmholders, but cams for the IV need to be matched both to the camera and to the lens, so buying a lens with a cam matched to the lens and not the body isn't sufficient. The V and MT have a zeroed groundglass, so cams are interchangeable between V and MT bodies. That said, if you're going to have a new lens cammed, it's worth sending in to Marflex to have the rangefinder and groundglass calibration checked and lenses shimmed to share infinity stops where possible, so not having a zeroed groundglass isn't a huge disadvantage. Having a zeroed groundglass, though , means that if you were particularly extravagant, you could have two or more Tech V or MT bodies and interchange lenses and cams between them.

If you focus on the groundglass a cam is unnecessary.

About the bend in the cam--there should be a slight upward bend where the foot meets the working part of the cam. If you hold the foot down on a flat surface the cam will be bent upward. If it isn't then it won't track properly when you focus past the end of the cam and try to bring the focus back. If the cam is bent in the other direction, then that is the situation in which the cam has been bent downward by dropping the bed with a cam in place.

Bob Salomon
14-Aug-2012, 01:56
I just bought on e-bay a Technika IV #67738, Bob if you would please date that one for me. From what I've been reading it should be 1960ish.

1959/60

If I am understanding this cam stuff right, when I buy another lens, I should buy one that comes with a cam that is already machined for that lens.
Also the cam is only important if I want to use the range finder. Using GG I can just buy a lens holder and a lens and use a loupe.

If you want to use the rangefinder with a new lens the camera and all your lenses will have to be sent in for camming with a IV.

Any help would be appreciated, I just paid for my IV today, I'm looking forward to it's arrival.
Another question, does the IV use standard 4x5 film holders?

Yes
Bill

byuddy
14-Aug-2012, 04:42
About the bend in the cam--there should be a slight upward bend where the foot meets the working part of the cam. If you hold the foot down on a flat surface the cam will be bent upward. If it isn't then it won't track properly when you focus past the end of the cam and try to bring the focus back. If the cam is bent in the other direction, then that is the situation in which the cam has been bent downward by dropping the bed with a cam in place.

That's helpful ... I presume the side of the cam facing up must be the side with the grooves. One of my cams (for a 90mm lens) is perfectly flat. It came with a 90mm Angulon with a matching number. The working edge of the cam appears untouched, i.e. never filed or ground. Do you suppose it could have been bent downward so as to be straight?

David A. Goldfarb
14-Aug-2012, 05:23
Yes, the side with the grooves is the top. With a wide lens, it wouldn't be so unusual to drop the bed, particularly for verticals, or if you wanted a little extra front fall, so I suspect a 90mm cam is more prone to getting bent out of shape than cams for longer lenses. If the cam has a matching number to the lens, it's been ground to match the lens. It's done to a very fine tolerance, so the working edge should appear polished.

Bob Salomon
14-Aug-2012, 07:06
That's helpful ... I presume the side of the cam facing up must be the side with the grooves. One of my cams (for a 90mm lens) is perfectly flat. It came with a 90mm Angulon with a matching number. The working edge of the cam appears untouched, i.e. never filed or ground. Do you suppose it could have been bent downward so as to be straight?

All Linhof cams are flat. They get bent when the bed is dropped with the cam in its holder. On page 14 of the Master Technika Classic/2000 instruction book, in bold red type, it states

"ATTENTION: Remove rangefinder coupling cam before lowering the dropbed into the wide angle position."

Those that follow these instructions do not have bent cams for any focal length lens.

E. von Hoegh
14-Aug-2012, 07:19
All Linhof cams are flat. They get bent when the bed is dropped with the cam in its holder. On page 14 of the Master Technika Classic/2000 instruction book, in bold red type, it states

"ATTENTION: Remove rangefinder coupling cam before lowering the dropbed into the wide angle position."

Those that follow these instructions do not have bent cams for any focal length lens.

It says that for the ST IV, too. My 50+ year old cams are not bent.

byuddy
14-Aug-2012, 07:32
So if my cams are bent, should I whack them with a hammer (carefully, of course) ... to make them flat? I would avoid extending the working edge so as to not change the focusing curvature. It's interesting to note that nearly all the photos I see of Linhof cams show bent cams ... always the same direction.

E. von Hoegh
14-Aug-2012, 07:35
So if my cams are bent, should I whack them with a hammer (carefully, of course) ... to make them flat? I would avoid extending the working edge so as to not change the focusing curvature. It's interesting to note that nearly all the photos I see of Linhof cams show bent cams ... always the same direction.

Sure. Hammer them. (sarcasm)

Clamp them in a vise between two blocks of flat wood to straighten them. This isn't blacksmithing.

E. von Hoegh
14-Aug-2012, 07:44
It's interesting to note that nearly all the photos I see of Linhof cams show bent cams ... always the same direction.

This just shows how few take the time to read, understand, and follow directions.

David A. Goldfarb
14-Aug-2012, 11:02
If the cams are bent upward as I describe (see photo attached), that couldn't happen by dropping the bed with the cam in place. Without the bend at the joint of the foot with the cam, the cam won't sit flat in the camera bed, because the hinge of the cam shoe is slightly higher than the plane where the cam sits in the bed. All my cams (75, 90, 135, 150, 210, 360) have been checked by Marflex or have come originally from Marflex exactly like this, and I don't think Martin would let anything out of the shop, if it weren't right.

Dropping the bed with the cam in place would cause it to be bent downward or to be straightened, not to be bent upward as in the attached photo. I would suspect a straight cam has either been straightened improperly, or has been bent as a result of dropping the bed with a cam in place. I would not recommend straightening a cam that has the correct upward bend at the joint of the foot and the cam.

As to why Bob and I aren't in agreement about this, I'm not sure, but I suspect some sort of miscommunication.

byuddy
14-Aug-2012, 12:03
78760

Here are 3 cams from an eBay seller who sounds like he knows what he's talking about. And here is what I think is going on ... Bob says cams are flat ... OK, they are flat ... it's the cam shoe that is bent from the cam. Geesh, I just finished flattening all my cams! haha

David A. Goldfarb
14-Aug-2012, 12:13
Just to keep the terminology straight--the foot is that two-pronged piece with the grooves on the cam, and it slides into the shoe on the camera.

Bob Salomon
14-Aug-2012, 12:56
78760

Here are 3 cams from an eBay seller who sounds like he knows what he's talking about. And here is what I think is going on ... Bob says cams are flat ... OK, they are flat ... it's the cam shoe that is bent from the cam. Geesh, I just finished flattening all my cams! haha

A seller that really knows what he is doing would also know that these cams are scrap metal once the lens they were cut for is no longer with the cam.

byuddy
14-Aug-2012, 15:48
A seller that really knows what he is doing would also know that these cams are scrap metal once the lens they were cut for is no longer with the cam. That's not what the seller is doing. He's selling a Master and three cammed lenses ... a bit pricey, though.

http://www.ebay.com/itm/Linhof-Master-Technika-package-4x5-9x12-best-large-format-camera-in-the-world-/170890022011?pt=UK_Film_Cameras&hash=item27c9d6cc7b#ht_3526wt_1091