Originally posted by StreetShooter
While we're on the topic, can someone knowledgeable tell me the differences (including advantages and disadvantages) of rangefinders vs split-focus screens?
I understand the 1 series and 6 series of Canon EOS cameras allow you the option of changing your focus screen to a split focus screen. Is this right, and if so, what would you see when using autofocus?
Hi
i can try, in non technical terms, cos i have no idea of the
exact science behind the rangefinding system as well. EOS 1 series, and the 3, does allow user changeable focusing screen to the split image type. However, you will lose evaluative metering mode.
In the SLR viewing system, when u rack your focus to infinity and u point your camera at something near to you, u're not going to be able to make out a lot of wat u're pointing at. The viewfinder and the manual focusing aid cannot be separated. When you use the split image focusing, you have to turn the focusing ring until the 2 split images at the centre of the focusing screen line up exactly, at which point u're in focus. The image is split into 2 halves, top and bottom. Once you line top to bottom half. u're done. My SeaGull SLR works that way ;p
I used to clamour for such a focusing screen to be installable in the D30 cos i could never for the life of me manual focus the D30 correctly. Everytime i think it's in focus, it turned out not. I've tried the diopter controls to no avail.
Personally i think a split image screen is better than no manual focusing guide / visual manual focusing, but there are pple who think otherwise, of course. This is a personal preference thing.
Then we have the rangefinder. The rangefinder is a mechanism that can work separately from the viewfinder, its main purpose being to help you find the range to target (subject). It requires you to position 2 coincident images together to focus. Think of it as this: watever u see in front of you is now split into 2 images, one on the left, the other on the right. So you see your subject on the left and right. You need to turn the focus ring until the 2 subjects become one, at which point u're in focus.
Older Leica screw mount cameras have their rangefinders separate from the viewfinders. You look through one window to do the rangefinding business, then look at another window / viewfinder to frame up your image. Some recent Voigtlander cameras have no viewfinders as well, and only have rangefinders. For viewfinding, you use separate hotshoe mounted viewfinders.
Lest we think this is weird, we should know that HCB uses a Vidom viewfinder exclusively mounted on the hotshoe of his Leica. The Vidom goes from 35mm to 135mm, with parallax correction built in. In fact, he scale focus a lot (focus using distance scale on the lens) and i doubt he spends a lot of time with his rangefinder window.
For M mount Leicas, the rangefinder is embedded conveniently in the viewfinder. So are
most other recent rangefinder cameras from other brands.
OK, so wat are the advantages and disadvantages of both?
Personally, i think it is much easier to focus using a rangefinder than a split screen SLR. With the SLR, it is not precise - you always want to line up the split images exactly, if not your focus will be off. For faces of portraits in low light, non linear subjects, or scenes with multiple horizontal lines, u're going to have a hard time lining up those images. For a start, there's no clear vertical lines as a frame of reference for lining up the top-bottom split images.
For the rangefinder, you can easily see the 2 coincident images and can line them up together even in low light (as long as the rangefinder window is bright). You do not have to depend on "lining up the lines". You line up facial features, subject textures etc. It's either in focus, or out of focus. It becomes a binary operation - as long as the images merge into one, u're in focus. If not, u're out. No more adjusting until the lines match etc. it's faster, and easier, and more accurate.
Furthermore, even if u wish to do split image focusing with the rangefinder, it is still possible. At the edge of the rangefinder box in a Leica M camera, for example, there actually exists a split image mode. inside the rangefinder box it's coincident image; at the edge, you can see lines lining up. It's a bit hard to describe in text until u see it for yourself. For subjects with lots of vertical lines (eg tall buildings) it is possible to utilise this mode to line up focus faster.
The last advantage is, because you don't focus using the entire viewfinder like the SLR, you can see very clearly wat's going on in the viewfinder as opposed to the SLR. For SLRs, while focusing, you do not have a direct clear view of the scene. Most rangefinder cameras also have much brighter viewfinders and rangefinder boxes than SLRs, making direct viewing much more effective.
The success of the rangefinder also depends on implementation. On the Leica M and Bessa R series rangefinders, rangefinders are big, bright, clearly defined and works very well even in extremely low light. Their viewfinders are also brighter than most other cameras (more so than the 1v with a fast lens), making focusing and seeing much easier. And the best thing is, you get to see outside of the framelines for the focal length u're using - u can see subjects moving into and out of the frame. (well this is more of an advantage of rangefinder cameras over SLRs....nothing to do with focusing....)
Of course some pple still prefer the split image mode. And well, some prefer AF ;p
The rangefinder is not without problems though. The rangefinder is more accurate than the SLR systems for shorter focal lengths, especially wide angles. However, when it comes to long lens work, the SLR is still king. This is because of the SLR's through the lens operation - the SLR brings the subject closer to you when u view it through the lens, letting u see the exact magnification of the image and focus using this enlarged image. For the rangefinder, the size of the subject remains the same. You still focus by lining up coincident images, only this time your subject becomes smaller due to distance, and accuracy of lining up suffers, unless you have a high magnification viewfinder. Even then, there are limits. Hence for focal lengths 135mm and above, the SLR rules the roost.
The SLR also has the great advantage of letting you see wat the lens see - you see every perspective distortion effect, effect of filters, magnification, DOF effects etc. You also get almost perfect framing, and u get 100% framing accuracy with SLRs with 100% viewfinders. With rangefinder cameras, you have to go by experience.......and experience does take time to gather.....
the other problem is poorly implemented rangefinders in certain cameras, which do negate some of the advantages. For example, not bright enough viewfinders / rangefinders, low magnification viewfinders leading to lower rangefinding accuracy, some cameras have fragile rangefinding systems tat can be easily knocked out of alignment due to hard knocks on the cameras.
Of course a Lecia M will never have these problems :devil:
(last statement meant to be fun, and pls take it as such
)