t6un
Established
BTW, Canon P has 1:1 finder with 35 mm frame.
effective vs actual rf base- does it matter?
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ampguy
Veteran
Right
Right
I think Roger was referring to old Leicas, but I'm not sure.
An Epson RD1 with 1:1 mag finder, even with a 1.25 magnifier, can show 28 lines with your eye up against the cup, but most camera specs try to put the eyepoint > 1cm away to accommodate glasses users, and left eye viewers, etc., along with some minor negative diopter correction.
Right
I think Roger was referring to old Leicas, but I'm not sure.
An Epson RD1 with 1:1 mag finder, even with a 1.25 magnifier, can show 28 lines with your eye up against the cup, but most camera specs try to put the eyepoint > 1cm away to accommodate glasses users, and left eye viewers, etc., along with some minor negative diopter correction.
t6un
Established
...And Canon has Albada brightlines that are not reflected by the main beamsplitter.
28mm becomes 42 equivalent in Epson, so I assume the viewfinder is almost the same as the one in the Bessa R3.
28mm becomes 42 equivalent in Epson, so I assume the viewfinder is almost the same as the one in the Bessa R3.
rxmd
May contain traces of nut
All-time favourite two words: crop factor
Roger Hicks
Veteran
rxmd
May contain traces of nut
Last edited:
Rob-F
Likes Leicas
I see a lot of good answers, here! Here's what I say:
1. No rangefinder can be made with 100% perfect construction. Therefore, a longer base will help to compensate for machining errors, and is to be preferred to a short base that is augmented by extra magnification.
2. Accuracy isn't just about the rangefinder, it's also about the ability of the eye to use that rangefinder. So the rangefinder and the eye should be viewed as a system, rather than treating each separately. Higher magnification makes the rangefinder easier to see; therefore increases the accuracy with the user can obtain accurate focus.
3. Those with high visual acuity will require less magnification. Those with lower acuity need more.
4. Cameras with poorer manufacturing precision need a longer physical base to compensate.
5. Eyes with poorer vision need more magnification.
6. Therefore: a longer base alone does not entirely address the issue.
7. Neither does increased magnification.
8. There must be an optimum balance, or trade-off, entre base length vs. magnification. An inverted, U-shaped curve, where the peak of the curve occurs at the optimum point. To the left of that peak, not enough base length. To the right, not enough magnification.
9. where that peak occurs must vary according to the manufacturer's tolerances, vs. the user's eyesight. It also varies with time of day: how is eye fatigue at a given moment being the dominant factor?
10. In consideration of the above, there is no ideal combination of base length vs. magnification, but one might arrive at the best trade-off via statistical means: average manufacturing accuracy vs. average eyesight.
Thus the best solution must vary from user to user, and from camera to camera. So it is a user vs. camera issue, making it a personal thing with no one-size fits-all answer. Ben Franklin had the right idea: moderation. Enough, but too much, base length, combined with enough (but not too much) magnification.
Final note: Having an 85 pound German Shepherd that gets you up in the middle of the night to go pee, augmented by some really good Scotch, can increase one's participation in the RFF. Thank you and good night.
1. No rangefinder can be made with 100% perfect construction. Therefore, a longer base will help to compensate for machining errors, and is to be preferred to a short base that is augmented by extra magnification.
2. Accuracy isn't just about the rangefinder, it's also about the ability of the eye to use that rangefinder. So the rangefinder and the eye should be viewed as a system, rather than treating each separately. Higher magnification makes the rangefinder easier to see; therefore increases the accuracy with the user can obtain accurate focus.
3. Those with high visual acuity will require less magnification. Those with lower acuity need more.
4. Cameras with poorer manufacturing precision need a longer physical base to compensate.
5. Eyes with poorer vision need more magnification.
6. Therefore: a longer base alone does not entirely address the issue.
7. Neither does increased magnification.
8. There must be an optimum balance, or trade-off, entre base length vs. magnification. An inverted, U-shaped curve, where the peak of the curve occurs at the optimum point. To the left of that peak, not enough base length. To the right, not enough magnification.
9. where that peak occurs must vary according to the manufacturer's tolerances, vs. the user's eyesight. It also varies with time of day: how is eye fatigue at a given moment being the dominant factor?
10. In consideration of the above, there is no ideal combination of base length vs. magnification, but one might arrive at the best trade-off via statistical means: average manufacturing accuracy vs. average eyesight.
Thus the best solution must vary from user to user, and from camera to camera. So it is a user vs. camera issue, making it a personal thing with no one-size fits-all answer. Ben Franklin had the right idea: moderation. Enough, but too much, base length, combined with enough (but not too much) magnification.
Final note: Having an 85 pound German Shepherd that gets you up in the middle of the night to go pee, augmented by some really good Scotch, can increase one's participation in the RFF. Thank you and good night.
Sparrow
Veteran
t6un
Established
There is an "ideal", or at least "special" magnification for a viewfinder: 1:1, life-size. The rangefinder integrated into this viewfinder simply has no choice of magnification, physical baselength will be the only variable.
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