A coupled rangefinder moves the rangfinder mirror as you focus the camera, however the focusing works on a particular model it is "coupled" to the rangefinder, while an uncoupled rangefind simply tells you the distance to subject and you must set the lens focus seperatley.
Originally Posted by stradibarrius
Both work fine; they're just different. Which is best depends on how you use the camera and what you like personally. My Ikonta super has a coupled rangefinder, and it works well. But I find that often I use an auxilliary rangefinder and zone focus instead of focusing on each shot.
The uncoupled viewfinder is usually brighter than a rangefinder and viewfinder combined, but many cameras have one sighting hole for the rangefinder only and a second one to compose the shot. If they are seperate the composing finder is usually much brighter than the focusing finder.
If you are really serious about getting into a folder, let me sugest a strategy before you drop any real money in it.
First, get an old beater coupled RF from the big auction site, and don't pay much. Then get another folder, either with an uncoupled rangefinder or no rangefinder (and use an auxilliary rangefinder - my person a preferences since it's not atached to the camera) and try them both out. (Or just use the coupled RF and zone focus like I do.)
Even if these are junk cameras, you can probably get them working well enough to shoot a handful of rolls to try the two techniques. Like I said, neither is better - they are different.
Once you have a better idea which style *YOU* like, then start looking for a keeper camera. My personal favorite folder is a postwar Zeiss Super with a coupled rangefinder I bought from Certo6 with the lens replaced by a prewar uncoated lens so I can make those old style creamy-dreamy low contrast pics on Ilford Pan-F (which is kind of contrasty to begin with). If he's got the parts laying around he'll assemble whatever you'll pay for.
If choosing a camera with a built in RF (not comparing to a camera without any rangefinder)then a coupled RF is better, no question; as mentioned by Sirius Glass, when looking through the RF and adjusting the duel image to become one image, the lens is set to the correct distance (in focus) in the same simple step.
Originally Posted by stradibarrius
With an uncoupled RF you have to read the distance scale on the dial, then tip the camera and read the scale on the lens, then turn the lens to the same distance, then recompose your shot again.
advantage of a coupled RF is; it saves time by eliminating those steps of transferring the distance and composing twice; more consistent and accurate, particularly when aperture is set wide open (portrait for example); more likely to find a camera that has unit focusing lens (not Zeiss Ikonta though), most (may as well say ALL) un-coupled RF folding cameras have front lens cell focusing only.
reasons to have an un-coupled RF camera vary; but most of all, because they are cheaper than their coupled RF siblings (i.e.Isolette III is good bang for your buck); wider range of cameras available; the extra step doesnt bother you and you have saved some money; or if you happen to like the 'zone'* focusing method as someone is more inclined to use on a folding camera with no RF at all, which is basically point and shoot. if you prefer to shoot this way but like to have the option to gain some accuracy on occasion (when using the lens on wider apertures or close distance) then its handy step up to have an on board RF, compared to a camera without any RF, of course if the camera is without then you can carry an auxiliary RF. I can see no reason at all to carry an auxiliary RF if the camera already has one built in (coupled or not), unless its not working or image brightness or clarity is not what it should be (in other words needs fixing), that just defeats the purpose.
*(using the hyperfocal distance scale on the front lens e.g. set aperture between f8-11 and setting distance to either 3m for close subjects or 10m for further away will get most things in focus, same principle as a point and shoot camera, of course you still can use this method on a CRF camera if you wish).
I have bought half a dozen folding roll film cameras on eBay in the last week
One thing I have noticed is that everyone wants the coupled rangefinder versions. There is a massive leap in price from the versions without rangefinders to the ones with RF, especially coupled,, even with the same lens / shutter combinations. (I'm thinking Isolettes and Ikontas, for example).
Obviously, they are the bees knees for convenience - but rather than buy an uncoupled rangefinder version, better I think to buy a rangefinderless model and pick up a seprate rangefinder for the flash shoe. These are very cheap. A really good folder with an excellent lens can be had at about a quarter of the price or less than the equivalent coupled RF version...
I have three cameras I can comment on from hands on experience:
1) Certo Six.
-For best image this is up there with my Hasselblad. Good wide open.
-The thing was repaired by acquiring a new 1/2 silver mirror for the beamsplitter and fixing a few shortcomings that weren't too difficult.
-Has, absolutely, the best lens in my group.
-Unusual focus mechanism, has parallax correction.
-Cannot be closed with shutter cocked.
-Frame spacing just OK. -
-Quite hard to find and expensive when you do.
2)Super Ikonta 532/16 with coated Opton Tessar.
-This is my favorite folder, perhaps my favorite camera overall.
-Lens softer than the Certo Six. (front cell focusing)
-Easy to use
-Frame spacing just OK.
-Not too expensive when all things considered, and relatively easy to find.
3) Super Ikonta IV
-More compact than the Certo or Super Ikonta 532/16
-Front cell focus lens. Sharpness no better than 532/16, not as good as Certo Six.
-Focus a little easier than my other two cameras.
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Steven's suggestion that if you are not going to get a coupled RF then why get any RF at all just get a shoe mount RF??? Opinions please. I do have two fixed lens, coupled RF's, A Konica Auto S2 and a Minolta Hi-Matic 7s. The Konica is currently having a CLA performed on it and I hope to get it back next week. I think a RF would be a great camera to use for IR photography. I love the Med. format...I have an RB67 that is super. So that leads me to my interest in medium format RF's. Plus I have always loved old stuff that really works well! I don't like old or new stuff that is temperamental and undependable.
Maybe we should fill you in on some of the drawbacks of older folders and possible solutions. In no particular order:
Originally Posted by stradibarrius
1. The bellows may have to be replaced. Some brands tend to need this more than others.
2. After all these decades, the shutter may need a CLA to be accurate.
3. There is more limited depth of field with longer focal length lenses used in medium format cameras to cover errors in rangefinder focusing, particularly with close subjects. It helps to back off, distance-wise, and to stop down.
4. With repeated use the front standard may get sloppy and out of parallel with the film plane.
5. Some users report film flatness problems with folders, especially 6x9's. Supposedly it helps not to wind the film until one is ready to take the picture, so that there is more tension on the film. This also helps avoid the problem of sucking the film forward when unfolding the camera.
6. Rangefinders seem to get dimmer with age. I don't have much success with using them indoors in dimmer light.
7. Some people report that using the self-timer screws up an older shutter. I believe that I might have created such a problem by accidentally setting off the self-timer on my Ercona II. External self-timers are available and are probably safer.
8. The springs holding the rear pressure plate in place may get less springy with age, again contributing to film flatness problems. Some people report that gently pulling on the pressure plate helps firm up the tension. I wouldn't do this unless you think that you are having a problem.
I hope that there is something there that might prove useful to you. I love my folders, but they do have their weaknesses.
Thanks Charles, that is all very useful info!