How to pronounce NIKON (tm)?

Nikon [naika:n] in US English, [nIkon] in British English.
Sometimes British-made pronunciation dictionaries fail to include the correct American pronunciation. So, in Longman Pronunciation dictionaries (with includes both RP and General (and Western) American pronunciation) we get only [nIkon].

The same dictionary ignores disguise [diskaiz] pronunciation in American English.

Nikon [naika:n] in US English, [nIkon] in British English.
Sometimes British-made pronunciation dictionaries fail to include the correct American pronunciation. So, in Longman Pronunciation dictionary (which includes both RP and General (and Western) American pronunciation) we get only [nIkon].

The same dictionary ignores disguise [dIskaiz] pronunciation in American English.

Mxsmanic and his tired old "Vowel length is not phonemic in English." again. As I keep saying, this depends on your accent. "In order to avoid confusion, it's best not to refer to it when identifying phonemic vowel sounds." Of course, I disagree. There's no harm in telling your readers whether the vowel is long or short even if the dialect you're transcribing doesn't have phonemic vowel length.

/ni:kA:n/ is probably just my idiolect... most likely from my Japanese knowledge.

Anyway, I agree with Jim on the vowel length matter. I don't see why showing vowel length in phonemic transcription could ever be confusing.

The American pronounciation is "neye-kon"

I myself have ["n@Ika~:n] when speaking English.

>>Mxsmanic and his tired old "Vowel length is not phonemic in English." again. As I keep saying, this depends on your accent. "In order to avoid confusion, it's best not to refer to it when identifying phonemic vowel sounds." Of course, I disagree. There's no harm in telling your readers whether the vowel is long or short even if the dialect you're transcribing doesn't have phonemic vowel length.<<

I disagree with Mxsmanic's statement because in many English dialects outside North American English and even in some North American English dialects, tense vowels are always long phonemically, tenseness may not be fundamental phonemically (in the case of Australian English), and new long often exist (either due to non-rhoticness or other cases of long vowels being innovated).

At the same time, in much of North American Engilsh, the last vestiges of Middle English vowel length have been completely lost altogether, with vowel length being completely allophonic in nature. Consequently, speaking of vowels in English being "long" or "short" when not specifically speaking of phonetics at a technical level is likely to be quite misleading to many North Americans.