What's a Sinar auto shutter and a DB mounted lens?

[Dave Benfer]

I guess the subject line said it all, Sinar users or LF experts, a little help p lease, just out of curiosity. Dave

[Per Volquartz]

A Sinar shutter (mechanical or electronic) fits on a Sinar (any Sinar) behind the front lens panel/bearer. Sinar DB mount lenses (or DBM mount) have no shutter. Instead they all share the one Sinar shutter.

Advantages: DB mount lenses stop down to f.45 from behind the camera. DBM mount lenses stop down to f.90 using a manual override. If you use DB mount lenses with a Sinar Shutter you never have to set anything in front of the lens; everything can be set from the back of the camera. This does enable you to work fast (and in some cases safer: like when hanging over the edge of the Grand Canyon f. inst.) The Sinar shutter makes you work a bit like using a single lens reflex camera. The shutter stays open until you insert a film holder. Through a connection cable the shutter then closes and selects the proper f. stop. Remove the film holder and the shutter opens again, ready for the next shot. Also, the shutter is self tensioning.

Disadvantages: Sinar DB and DBM mount lenses are a bit heavier than if they had their own Copal or Compur shutter. Also, BEWARE of older Sinar mechanical shutters. They may cause vibration.

[Dave Benfer]

Sounds like the ideal method, like a high tech packard shutter. Can a Sinar shutter be modified to work in other cameras? Are their diferent sizes? Is the release cable routed thru the lens board?

[Bjorn Nilsson]

The Sinar system has a detachable bellows which connects to the front standart. This front standart has the same measures for all the different types and sizes of cameras that Sinar makes. The shutter goes in between the back of the front standart and the bellows. The (dedicated) release cable is connected to the side of the shutter. The shutter is a dedicated Sinar accessory, but I think that it will also fit Horseman monorail cameras. They are only made in one size, i.e. to fit the back of the Sinar front standart. It is possible someone mechanically inclined can modify the shutter (or preferably the front standart) to fit other brands. Now, the Sinar shutter is quite useable without a DB lens mounting. I.e. it is very useable for barrel mounted lenses, in which case you have to set the aperture as per usual. You just have to see to that the back of the lens doesn't protude more than 18.5 mm behind the lens board (on a Sinar camera). If the back of the lens is more than 80 mm in diameter it shouldn't protude behind the lens board at all. The Sinar shutter together with DB mounted lenses are very good with Sinar cameras, especially in a studio on a sturdy tripod/column stand. But it is also quite useable in the field, if you don't mind the little extra weight and bulk. You get the advantage of having ONE shutter, without having to worry about or compensating for differenties of your exsisting shutters. And, at least here in Sweden, DB mounted lenses can be found quite cheap.

[Kevin J. Kolosky]

Just to add to your information, the older ones have a wide aperture of 5.6 while the newer ones have a wide aperture of 4. Per is correct. they do vibrate.

[Dick Roadnight]

Another disadvantage is that mine/they have a maximum speed of 1/60th of a second, which makes it hard to eliminate or control ambient light with falsh.

I think that, with lenses that pertrude behind the lensboard, you can use them on the rear standard - for flash use anyway.

I am planning to use mine with my Hasselblad - see Medium format Digest/K.I.S.S TTL + Studio flash

[Jerry Flynn]

Since 4X5 Horseman bellows fit Sinar standards and vice versa, I suppose a Sinar Auto Aperture shutter wuld fit a Horseman camera without modification. Never tried it, though.

[Jerry Flynn]

One other thing. If used with the Sinar meter system, the electronic shutter provides automatic exposure capability with flash and/or ambient light. I.e. it feeds the readings into the shutter.

[Frank Petronio]

I have an older Norma era Auto Aperature shutter that is missing the dedicated cable release -- any body have a source? It needs to push a 1.25 inch throw (approx 3 cm). thanks, f@frankpetronio.com