I am thinking about getting a digital piano in my apartment for convenience of practicing (and playing fun stuff), so I don't need to go to practice rooms all the time. Though I would like to get a piano that has great touch (Kawai ES8 etc.) I am worried that practicing on the digital piano regularly would do harm to my piano skills. Thus, I wonder if you could share your experience in digital pianos?

The keys of e-pianos today are weighted.

My son is professional pianist. He plays on different grand pianos and keyboards and he never complained about losing skills. I wouldn’t worry about yours especially as you say you play fun stuff.

Mind that also the keys of different pianos haven’t always the same weight and the distance of the hammers to the strings can be manually adjusted. This factor is more important:

I remember when I was about 16 my hands were more stressed on the grand piano at the conservatory and my fingers and muscles became fatigued because the different attack.

tl;dr

1. Yes it spoils the touch


2. I prefer electronic (still!) for other reasons most centrally alternate tunings


3. I believe it also has contributed to spoiling my ears

Yeah its a tough choice !

In more detail

I grew up on an old upright hard steinway and also a schiedmayer boudoir grand.
(And Bach and Beethoven were the only guys that mattered!)
I find the sheer physical exercise of driving wood satisfying at a level that an electronic imitation never matches… but this is not a musical aspect of the discussion.

After some twelve years of having no piano got a Casio celviano with something strange called alternate tunings — Werkmeister Kirnberger Just... and the usual equal.
And found that even standard western composers sound better:

• Bach in Werckmeister See for example
  


• Beethoven in Kirnberger


• And eastern music in just intonation sounds utterly different
  

Over time my ears have become so sensitised to this that when last I went to a classical concert I left half way because I found the current standard (ET) unbearably out of tune.

And yes I am growing older… and deafer… I suspect electronic sounds are at least part responsible

There are several out there which feel remarkably similar to acoustic pianos. Which themselves will vary quite a lot in their touch. It's almost like asking if I play XYZ upright, will it spoil my technique for when I return to ABC grand.

I use several electronics, and Roland FP2 (now 12 yrs old) feels fine still, a little light, but that's my preference.

One big advantage is the facility to use different sounds, which obviously acoustics don't offer.Different tunings can be interesting too.

Find one that you do like the feel of, and use it - a lot. It may take a few minutes to re-adjust to the acoustic after, but that's not detrimental. Get in another car, and the clutch pedal may feel different - it's no big deal. And, being experienced, you'll compensate more easily, won't you?

Not if you were trained to play from the arm and with gravity. The brain has amazing capabilities to adapt to different keyboard actions very quickly but, the proper movement has to be there in the first place.

People who often complain that some pianos are stiffer than others are most likely using the incorrect muscles to play. If you move improperly then sure, the change of action could either harm or hinder.

I play a tracker organ at my church and many other organists and pianists complain about the weight of the keys. I have no problem and zero fatigue playing it because I don't use my flexors to depress the keys, I use my arm weight which makes the fingers feel effortless.

You know this. When you were a kid riding a bike uphill, you probably stood up, adjusted your hips and put all your weight on one leg while the other relaxed. The piano is much the same but you have five legs. Actions feel stiff because we are trying to use two muscles at the same time. Likewise, you can't pedal both pedals at the same time. It is impossible. Sadly, we can execute movements with our hands that belie the laws of physics. Some teachers ignorantly teach to practice more or run silly exercise to build strength and endurance but like riding the bike, you don't need more practice or strength to put all your weight into one pedal. Your brain knows to do this or it doesn't. Once you learn it though, it is there forever. Just like improper movement.

The only negative about a digital piano is that they don't have a tangible point of sound. If you slowly depress an acoustic piano key without making a sound, you will eventually feel a little bump. Push beyond that and it will give way and you will be pressing into the keybed. The secret to acquiring that pearly carrezando tone is learning to play to the point of sound. It is not an issue of practice but knowing how to move properly and accurately.

Once learned, it is there forever and you don't need to practice it anymore. Like riding a bike, but with five legs, and 88 pedals.

I have a very good digital stage piano, a Kawai MP11SE. The action, full length keys, escapement, and graded weighting feel like an acoustic grand piano. In fact none of the acoustic uprights and only a few of the practice grands at my school feel as good. Moreover, none of them are ever in tune as well as my digital piano. It's not even close. The performance Steinway Ds they are only used on stage are another story. But! they are tuned and tweaked on the day of a performance. My MP11SE is always in tune. And, if I want its tuning to have some other temperament, I can change it. If I want A4 to equal 432Hz, 448Hz, 388Hz, etc, I can change it and hundreds of other things in an instant... e.g. the hammer hardness or strike-point.

Leaving aside the action, there is one thing that I don't think any electronic keyboard simulates and that is sympathetic vibration.

If you hold the sustain pedal down on an acoustic instrument and strike a note or chord it will spread to other unplayed strings. For certain pieces this makes a difference to the 'atmosphere' of the sound.

I had a very average digital piano (Yamaha Clavinova CLP910 from around year 2000), weighted keys, and all, and I thought it had a nice touch, but then I bought a real piano, and of course it's much better (specially with a "silent" mode which allows me to play with the headphones)

When I tried to play on that digital piano again (before finally selling it), it really felt like my first non-weighted keyboard from the 1980s: horrible.

Then I tested some digital pianos for a friend who wanted one and came across a Kawai with exact same mechanism as a real piano, and a "new" Yamaha Clavinova. I thought "how long was I away?".

My friend chose the Clavinova, and every now and then I play at their house and I really enjoy the touch just after/before playing my piano at home. And I don't feel a great difference.

The only big difference I see is about the pedal: a real piano pedal lasts like forever, whereas on most digital pianos, the older sustained notes end up fading away more quickly because of the limited polyphony. So on an electronic piano (or on my piano with silent mode on), you can hold the pedal wrongly/too much without making it sound weird, but don't try that stunt on a real piano.

So (apart from the pedal stuff) what you're stating has been true, but now it's no longer the case thanks to constructors trying hard to recreate the real piano experience truthfully and for a reasonable price.

Besides, what really harms performance is not to play at all. So if you have a digital piano available at your place, you'll make big progress, and you'll enjoy playing real pianos more.

Short answer is likely not. As others have mentioned good technique will come from proper alignment of the body, shoulder, arm, wrist, hands, and fingers. If the good form is there you will be able to adjust to any action or touch on different instruments. For example I have a Yamaha studio upright U series which I practice a majority of the time on at home and I'm using to the action. I also have a Roland E-300 which I use with headphones and for effects like strings. The Roland doesn't have weighted keys so I know the actions is going to be quick, but if I concentrate on using my technique I can still produce a the sound I want. Throughout the years I have not suffered with losing my touch for any piano that I play on.