domromer said:
Thought I'd chime in with my first post. I've been lurking for a few days. I'm in the middle of a film rennisance of sorts. I started scanning old 35mm slides a few weeks ago and realized even after I scan the slides they still look better than the pics straight from my D80. So about a month ago I got my hands on a Rolleicord and have put a few rolls through that and borrowed an olymus xa off a friend. Still working on the fist roll in the XA. My wifes doesn't understand it at all. She can't belive I've got 2k worth of gdigtal gear sitting at home but I'm runnin around taking pics with a P&S and a 50 year old tlr!
Other than the smaller size and quiet shutter, what are some benefits of a range finder over an slr? Also can someone explain how focus works on a rangefinder? My xa has a funny little translucent focusing screen and I can't figure out where it comes from.
There used to be a nice website on how the technologies of rangefinders and SLRs work that I used to refer people to, but it's gone now. let's see how well I can recap from memory:
An SLR uses a sort of periscope arrangement (a mirror and a second mirror or a prism) that allows you to look through the photo-taking lens. This has advantages and disadvantages.
Advantages:
1. Works much better with telephoto lenses.
2. Through the lens viewing allows the use of graduated neutral density filters and polarizers. You have
got to be able to see through the lens to use these particular filters properly.
3. Exposure compensation for colored lens filters is automatic.
4. TTL viewing allows the use of zoom lenses.
Disadvantages:
1. One of the disadvantages is that space has to be made for the mirror behind the lens to swing up out of the way when the shutter release is pressed. This means that the viewfinder blacks out for the duration of the exposure.
2. Another disadvantage is that When the mirror reaches the top of its swing, it strikes a foam bumper, creating vibrations. This can cause motion blur at certain shutter speeds.
3. Yet another disadvantage is that, because of the space an SLR needs for swinging a mirror around, the lens has to be placed farther from the film plane; while this has no effect on telephotos lenses, it has a slight negative impact on normal lenses and a profound negative impact on wide angle lenses. It requires lenses of a special type, called retrofocus lenses. Retrofocus lenses have extra elements designed to overcome this, but more elements means more opportunities for distortion.
4. An SLR's retrofocus lenses always have one aperture that is sharpest. This will usually be somewhere between f/11 and f/8, depending on the lens.
5. An SLR is focused by turning the focus ring until the image looks sharp. Well, there is a range of adjustment where the range looks sharp, so it isn't very precise. Since someone is bound to bring up the split image focusing screen at this point, let's cover that too. a split image focusing screen takes a small sample from each edge of the lens, and it displays them in the center of the image in the viewfinder. Lining the two images up to form one image focuses the camera. If this sounds awfully familiar to a lot of you it is because it is, in effect, making an SLR into a rangefinder (a sort of second rate rangefinder, but a rangefinder nevertheless).
Now about rangefinders. There are several kinds. (A) There are electronic rangefinders, wherein a beam of light is emitted from the front of the camera. The light bounces off of the subject and the camera either times how long the beam takes to bounce back or measures the doppler shift of the light's wavelength. This is how most autofocus compact cameras work. (B) Another type, mostly used for forensics, uses a pair of lasers to project a pair of dots onto the target. Focusing the camera moves the two dots closer together or farther apart. When the two dots merge, the subject is in focus. (C) The most common type though, the one most everyone here has, is the coincident rangefinder. Pretty much all the rest of what I am going to write will be about coincident rangefinders.
A coincident rangefinder uses two mirrors in the viewfinder, like an SLR. However, these are arranged not to look through the taking lens, but to show you TWO images in the viewfinder. Focusing the camera moves the two images farther apart or closer together. When the two images are merged, the camera is in focus. Instead of using an SLRs subjective judgement of when an image looks sharpest, this is far more objective and much more precise. It works better than an SLRs split image viewfinder too, because the focusing method is based on triangulation, and the farther apart the base pair is, the more accurate it will be.
Advantages:
1. A rangefinder's focusing method is much easier to use in dim light.
2. More precise focusing.
3. Wide angle and normal lenses are superb, much better than
any wide angle or normal lens on an SLR.
4. Rangefinder lenses don't have just one good sharp aperture. There is very little, if any, difference between the sharpness of the subject in photos taken at different apertures.
Disaadvantages:
1. Rangefinders don't work well at all with telephoto lenses, and in fact, I've never seen a lens for a rangefinder longer than 135mm.
2. They don't have TTL viewing, and so you can't use polarizer filters -- and getting the line of demarcation on a graduated neutral density filter lined up on the horizon would be more trouble than it was worth.
3. Most of the fixed lens rangefinders you will find here have -- well, fixed lenses.
4. No mirror swinging around means no mirror-induced vibrations. This means handheld use with a rangefinder is possible with shutter speeds far slower than would be possible with an SLR.
Conculsion:
As you may have noticed, if you were paying attention through all of this, each system's strong points match with the other's weak points to an almost eerie extent. Ideally, a photographer should take advantage of
both systems, as they compliment one another nearly perfectly.
