JacquesBalthazar
Leading Member
It is generally admitted across internet forums that the focusing screens of modern DSLRs are not suited for manual focusing of fast lenses. This is said to be due to the inability of those screens to discriminate focus changes at apertures larger than f2.8, and to a perceived lack of precision of the electronic rangefinder (the "green dot").
It is also generally admitted that proper manual focus of fast lenses would require old fashioned ground glass focusing screens, such as the ones used in film SLRs of the golden age.
The conversation invariably then goes on to lament the fact that current Nikon DSLRs, Df included, do not provide for interchangeable focusing screens, and that the only solution is to use third party modified screens that can be found on line.
Also invariably, the promoters of such solutions go on saying that it is quite easy to change screens (check YouTube for instructions) and that the whole manual focus experience then becomes reliable, straightforward, robust, etc.
Well, I have just gone through the process, and would like to share a word of warning for anyone tempted to do same. Not saying my exprience is the universal truth, but it is my experience...:
1. Changing the screen is not that easy. It can be very fiddly, till you get used to the manipulation.
2. The screens are dust suckers. As you fiddle around, dust specks settle both on the focusing screen and on the glass panel within the body. Those specks are invisible when you manipulate the contraption but are horribly intrusive when you check the viewfinder.
3. Getting rid of those dust specks implies to re-do the whole process, try and clean the screens (not that easy) and try again. This paradoxically encourages additional specks. Much worse than cleaning a sensor.
4. All those manipulations end up causing mishaps, such as touching the screen with a sweaty finger. That leaves smudge traces that are impossible to clean up, and are also very intrusive when you look through the viewfinder.
5. When you think you are done, you are not done at all, unless you are very lucky. You need to test the calibration of the screen, and are likely to realise that you back focus if you rely on what you see . Which means you need to add one or two shims (again go through the whole fiddly process).
Finally, when you are calibrated and you test your camera with your favourite f1.4 or f2 wide angle or standard lens, you are reminded that the focusing aids of those screens (split image, microprisms, ground glass itself, etc) are in fact NOT that reliable at all.
You are reminded as to how imprecise they can be, and you remember your first photo classes decades ago when wise teachers explained that, up to 75mm or thereabouts, well calibrated rangefinders were much more precise than the SLR focusing aids. You remember why people preferred Leica for fast focusing at wide-to-normal focal lengths, and why AF was such a blessing when it was invented.
You then pathetically realise that the "green dot" of your Df works way better than the darn split image gimmick, and that you just traded a perfectly bright viewfinder for a messy smudge of a screen.
As I said, some might have a different experience, but I hope this word of warning might be useful to others.
It is also generally admitted that proper manual focus of fast lenses would require old fashioned ground glass focusing screens, such as the ones used in film SLRs of the golden age.
The conversation invariably then goes on to lament the fact that current Nikon DSLRs, Df included, do not provide for interchangeable focusing screens, and that the only solution is to use third party modified screens that can be found on line.
Also invariably, the promoters of such solutions go on saying that it is quite easy to change screens (check YouTube for instructions) and that the whole manual focus experience then becomes reliable, straightforward, robust, etc.
Well, I have just gone through the process, and would like to share a word of warning for anyone tempted to do same. Not saying my exprience is the universal truth, but it is my experience...:
1. Changing the screen is not that easy. It can be very fiddly, till you get used to the manipulation.
2. The screens are dust suckers. As you fiddle around, dust specks settle both on the focusing screen and on the glass panel within the body. Those specks are invisible when you manipulate the contraption but are horribly intrusive when you check the viewfinder.
3. Getting rid of those dust specks implies to re-do the whole process, try and clean the screens (not that easy) and try again. This paradoxically encourages additional specks. Much worse than cleaning a sensor.
4. All those manipulations end up causing mishaps, such as touching the screen with a sweaty finger. That leaves smudge traces that are impossible to clean up, and are also very intrusive when you look through the viewfinder.
5. When you think you are done, you are not done at all, unless you are very lucky. You need to test the calibration of the screen, and are likely to realise that you back focus if you rely on what you see . Which means you need to add one or two shims (again go through the whole fiddly process).
Finally, when you are calibrated and you test your camera with your favourite f1.4 or f2 wide angle or standard lens, you are reminded that the focusing aids of those screens (split image, microprisms, ground glass itself, etc) are in fact NOT that reliable at all.
You are reminded as to how imprecise they can be, and you remember your first photo classes decades ago when wise teachers explained that, up to 75mm or thereabouts, well calibrated rangefinders were much more precise than the SLR focusing aids. You remember why people preferred Leica for fast focusing at wide-to-normal focal lengths, and why AF was such a blessing when it was invented.
You then pathetically realise that the "green dot" of your Df works way better than the darn split image gimmick, and that you just traded a perfectly bright viewfinder for a messy smudge of a screen.
As I said, some might have a different experience, but I hope this word of warning might be useful to others.
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