A question about parallax

Negative, russianRF. It's the two R/F windows that need to be far apart. The position of the V/F is of no significance. The Bessa T, for instance, doesn't even have a V/F. You are correct only when R/F and V/F are combined in a single window. This is not true of screw mount Leicas and their copies.
 
Yup -- there's no free lunch when it comes to photography.

With SLRs, it can be a dark viewfinder or viewfinder blackout during longer exposures.

With rangefinders, it's inaccurate framelines (or with many cameras, no framelines at all), parallax and lens hoods blocking the viewfinder. Even vented hoods are only partially successful.

Some viewfinders position themselves so they sit directly above the lens and have tilting mechanisms to adjust for parallax. But in practice, they're a pain in the neck to use, and you often forget to reset it, so some pictures will be framed perfectly and others will be all out of whack.

If nothing else, at least your precisely centered subject (or so you thought) will now be on the right side of the frame and will now conform to the "rule of thirds," making your photo more visually interesting. And when people "ooh" and "ahh" over it, you can say that was the composition you had in mind, without spilling the beans on yourself.
 
payasam said:
Negative, russianRF. It's the two R/F windows that need to be far apart. The position of the V/F is of no significance. The Bessa T, for instance, doesn't even have a V/F. You are correct only when R/F and V/F are combined in a single window. This is not true of screw mount Leicas and their copies.
Click to expand...

EDIT: My screw-mount Leica copy has a combined single window...

I found your post to be exceedingly confusing.

I can't speak for other models of cameras, but my Fed 5 -- a Leica knock-off -- has TWO windows: the rangefinder window and the viewfinder window. TWO. The rangefinder image is sent via mirror to the middle of the viewfinder window, and there you have it.

Maybe I'm just mixed up on terminology, or something, but my camera does *not* have two rangefinder windows.

Also, on all the modern Leicas (M7, MP) there are only two windows: the rangefinder window and the viewfinder window.

I wasn't even aware there were cameras with rangefinding windows separate from the viewfinder.
 
What is a Leica copy and what is not? I meant copies of the II, the first Leica to have a built-in range-finder. The FED 1 and the Zorki 1 are pretty faithful copies of that.
 
Google Leica. Anything up until the IIIg had separate VF and RF windows... and as payasam said, the FED-1 and Zorki-1 are close enough that with just a tiny bit of work they sell as real Leicas all the time.

Calling FED-5 a "Leica knockoff" is kind of a huge stretch! 🙂

>>I wasn't even aware there were cameras with rangefinding windows separate from the viewfinder.
 
Okay ... so BASICALLY what I was saying is true, then. The longer the distance between the rangefinding window and the viewfinding window (or, in older cameras, the second rangefinding window), the more accurate the focus...

Edit: What *is* a Fed 5 then? A totally original Russian design?
 
russianRF said:
Okay ... so BASICALLY what I was saying is true, then. The longer the distance between the rangefinding window and the viewfinding window (or, in older cameras, the second rangefinding window), the more accurate the focus...
Click to expand...

Yes. But again, the FOV change causes as much inaccuracy and can not be changed by getting the finder closer to the lens.
 
Well, I have found all the replies very interesting but still haven't heard a really convincing argument for putting the viewfinder way off to the side. 🙂

I know that just about every manufacturer German, Japanese or any other nationality build their rangefinders like that, but as John Stuart Mill said "The fatal tendency of mankind to leave off thinking about a thing when it is no longer doubtful, is the cause of half their errors."

I mentioned in my original post the positioning of the viewfinder on an SLR: and if it is not heresy to speak of them here, a twin lens reflex also has the viewfinder lens directly above the picture-taking lens. Surely putting them side-by-side so the camera is held horizontally, in both hands, would make for a more stable arrangement, wouldn't you think?
 
Actually, to me, having the viewfinder on the side has a huge advantage for me: my nose is free from pressing into the camera. If you are a left eyed shooter, it is not an advantage, but to me this is great.

If you want a really precise framing, an rangefinder is not the solution. However, for me, its the perfect instrument. There is nothing wrong in not being a rangefinder user! (except that you are missing the best glass in the world! 🙂
 
SimonK said:
Well, I have found all the replies very interesting but still haven't heard a really convincing argument for putting the viewfinder way off to the side. 🙂
Click to expand...

Take a look at this picture:
http://flickr.com/photos/laurenm/179897855/
The Nokton lens blocks 25% of the view. Imagine if the viewfinder was directly above the lens, basically 50% of the scene (the entire bottom half) would be blocked. I'd say that is the biggest reason the viewfinder is placed off to the side.
 
If a range-finder camera is to be small, a corner is the farthest point from the lens. The view from that point, as has been said, is obstructed the least by the lens. Unfortunately this placement makes the problem of parallax more serious.

SimonK, if you had lens and finder side by side, in which space and in which direction would a focal plane shutter run and where would the film canister and take-up spool go? Maybe you are thinking of the Tessina.

Does anyone remember the finder arrangement of Kodak's sophisticated disaster, the Ektra?
 
russianRF said:
Maybe I'm just mixed up on terminology, or something, but my camera does *not* have two rangefinder windows.

I wasn't even aware there were cameras with rangefinding windows separate from the viewfinder.
Click to expand...
Actually the FED 5, like ALL rangefinders, has two rangefinder windows. By definition you need two. The FED 5, like many others, combines one of the RF windows into the VF window.

As has been noted, the Leica II, FED 1, Zorki 1 etc have totally separate VF/RF systems, resulting in three windows on the front of the camera.

Overall, where you put the VF will always be a compromise except on an SLR. You aren't looking through the taking lens, so there has to be parallax error. Placing it close means that lenses block your view, placing it further away avoids that but increases the parallax error - take your pick! It's only a major problem for closer work, where an SLR is usually a big advantage anyway.
 
Last edited:
So I'd like to resurrect this topic because there is one particular situation that ought to have a simple answer but somehow has my feeble grey matter stumped all the same.

We all know that as we focus an RF from an object at infinity to one that's close-up the FOV shifts, and we see this as the framelines shift from upper left to lower right. Vice-versa as we go from close-up to infinity. This is commonly called "parallax compensation" which is a bit of a misnomer but a convenient term.

Now consider the situation where the scene consists of looking at a chain-link fence, say at 1m, and at a tree about 20m beyond the fence. You set up your RF on a tripod. As previously mentioned, the framelines will shift depending on where you focus: at the chain-link fence in the foreground, or the tree in the back. However, the camera itself is completely static, so in theory the FOV should not shift at all, correct? What then is the correct FOV? This is what has me stumped.

You can do the same experiment with an SLR and notice that as focus changes, the FOV itself doesn't shift laterally, apart from the phenomenon of the effective focal length changing which is more of a slight "zoom" effect than a lateral shift.

Am I missing something here?

Ming
 
Hmm, interesting experiment indeed. I'd say the only way to know for sure what the true FOV is for your particular camera is to set it up like you say -- with the back open and a piece of ground glass at the film gate.

The whole hassle about moving framelines and parallax adjustment on external finders has always baffled me. They're extra moving parts which inevitably bring inaccuracies with them. I don't trust them things farther than I can throw 'em.

I prefer the TLR shooter's way of dealing with it: On a tripod, you frame your shot in the viewing screen, then crank your tripod up by the exact distance between viewing lens and taking lens, bringing the taking lens in the spot where the viewing lens was when you composed. With some exercise, you learn to do this without the tripod.

A variation on the same idea is to aim for a spot on your subject that's higher than your intended center by that same distance between the lenses. Imagine your viewing and taking lenses each sending out a laser beam. These two beams would stay parallel and hit your subject the same distance apart. The lower laser dot is the center of the image you're taking, the upper the center of your view. On a building a hundred feet away, that difference is negligible. On a person's face 5 feet away, it's not. You aim for the higher of the two dots.

Same idea works with any RF/VF camera, except most often, the two "beams" are offset side-to-side, as well. Compose, then move the camera diagonally to bring the lens where the VF was. Or, aim at a spot on your subject that's a little up and to the left to begin with. Is this practical, precise, fast? No. That's why SLRs are better for close-up work.
 
SimonK said:
It can't be a question of ergonomics; every SLR has the viewfinder in this position and is easy enough to put against your face.
Click to expand...

Huh, this is precisely one of the reasons that RFs attracted me away from SLRs. The centered VF with lack of eye relief in SLRs causes me to rotate my head such that my left eye is no longer aimed at the subject.
 
My 2 cents:
- Centered viewfinder would make the camera much taller to accomodate a large modern viewfinder window. Aesthetics.
- Being right on top of the lens, the larger faster lenses would obstruct a lot of the lower portion of the frame. A really fast 50 or an 85/90 f/2 would really be a problem, and for most systems, those are workhorse lenses.
 
You must log in or register to reply here.

Similar threads

EddieO
Parallax Correction Using Voigtlander 40mm on Leica IIIf
2
Replies
20
Views
1K
aw614
A
G
Canon VT deluxe, parallax pin query
Replies
2
Views
180
gordonrgw
G
L
35mm Auto-parallax finder for Canon L1, 2 &3 and other V series bodies: what's the magnification?
Replies
0
Views
28
Ljós
L
B
Voigtlander 25mm on a Canon 7s
Replies
5
Views
710
Coldkennels
Coldkennels
J
Looking for a square-frame brightline viewfinder. Any 126 cameras out there have a decent finder I can adapt/cannibalize?
2
Replies
20
Views
521
justins7
J
Back
Top Bottom