A great lens or camera can't create you a great picture, but a bad one can lose you one.
For cameras, these two answers, and for EVERYTHINGH in life in general, this:
BUT, THE MOST important thing is not a camera, a lens, or even a photographer.... its a viewer.
Photo means nothing. Its pixels in pixie land or molecules in chemistry, if no one ever LOOKS at it.
Best photo's start with a question...
WHY am I taking this picture?
begging further enquirey:
WHO is going to look at it?
WHY are they going to look at it?
WHAT do they want to see?
Lesson that is very hard to learn as a photographer, is to remember the viewer.
We get interested, in photo's we get enthusiastic about photography, and.... we dissapear up our own anus's a lot of the time worrying about stuff only other photographers will care one iota about!
The rules of classical composition, following them or breaking them; exposure; resolution; clarity, texture, 'mood' colour, over-processing, under processing....
NONE of that will mean a THING unless some-one WANTS to look at the picture in the first place.
And unfortunate 'truth' is, that ultimately, most photo-viewers are not expert photographers; they are your mum, your dad, your family, your freinds..... most of whom, unless you have a very geeky family & circle of freinds... probably don't give two hoots whether the photo is in crisp focus, whether the colour balence has a slight cyan cast to it, or if you have been a bit clumsy with your composition....
What they care about is seeing something that INTERESTS THEM.
NO camera has yet been built that has an automatic 'interest-meter'.
The perfectly composed, perfectly exposed picture of some perfect English Landscape..... is probably PERFECTLY BORING to 99% of people who may ever look at it.
The fuzzy, under exposed, slightly skew and very cluttered happy snap of auntie Mable loosing her bloomers at Bingo..... is forgiven all, by almost all who look at it.... "Look at Mable! Ha-Ha!" because it has some 'relevence' and has some INTEREST to the VIEWER.
Its said time and time again.... and we dont like this fact and start stuttering and saying things like 'Yeah.... But..... if we had a BETTER picture of Auntie Mable?...."
Yeah... be nice, but truth remains; people would still only want to look at it becouse of that interest, and the pleasure they get from looking at it is not going to be hugely increased because the exposure is 'so' much better.
Probably twenty years ago, whilst dissapearing up my own anus; getting all enthusiastic, listening to lots of old wizzened photographers, and thier sage advice..... I had the loan of a Hassablad for a week-end, and went out and tested some of the thoery, taking comparison shots, of stuiff with the medium format, pro grade medium format camera, my own Olympus pro-grade OM4, its ameteur grade, little brother OM10, my old favourite XA2 compact... and a couple of other lesser cameras.
Conclusion:-
1/ I wasted a HECK of a lot of film, on pictures only I would ever look at!
2/ yes the kit can make a difference.
3/ Not THAT much difference.
4/ Where the differences may be found..... lies in the balence!
Between test prints, at normal viewing size of a 5x6 print.... there was bog all discernable difference between ANY of them, from cheapest to most expensive. Enlarged to 10x8 display size.... there was 'some' difference between best and worst. Was it the lens? The camera? The film stock, or even the differences between 35mm format and 120 roll film? VERY hard to say. And it was only when I started taking tiny sectional enlargements of minute details, maybe 2% of the exposed frame, that I started to see any significant differences.
Another reality check. The difference between a good picture, and a bad one is 99% in the INTEREST in the subject and its relevence to the VIEWER.
That leaves only a very small scope for you the photographer to meddle around in looking for improvements from technical dexterity...... and after THAT even less to find infantesimily small gains from infantesimaly small differences in equipment grade, quality or performance.
I have, for a while been scanning my old halide negatives. Its been an interesting review, and I have to confess..... I cannot have asked myself those questions I posed very often! Really, I have so many photo's now, when I look at them I ask "WHY did I take a picture of THAT!" and have no answer!
I have hundreds of reletively competant 'arty' photographs; abstract texture studies; wonderful landscapes... which probably aren't display standard, but, could probably withstand critique of my peers reasonably well..... But, pictures I am actually most proud of.... would probably be utterly rubbished by them!
And I have thousands of them. Mostly obscure parts of old land-rovers or motorbikes... which when my kids or any-one sees them, they gawp at and ask "What on EARTH is that?... Why did you take a photo of it!"
Pretty simple.... I took a photo to illustrate something; how to pull apart a Range-Rover steering link ball-joint and over-haul it; how to balence the carburettors on a motorbike, or how to make a gasket out of a corn-flake box!
These pictures were taken with incredibly cheap, and pretty nasty low price, low resolution, low functionality digi-compacts..... and the results are not astounding, and certainly wouldn't win any prizes.... BUT... they had a 'reason', they had an 'interest' and they have had an audience.
People interested in old land-rovers or motorbikes and fixing them up and keeping them working have wanted to look at them.... and they don't care that technically they are imperfect.... they have interest, and they are 'good enough'.... but most importantly to ME as the photographer, PEOPLE LOOK AT THEM!
If no one looks at them, can be as technically brilliant as can be..... its a useless, meaningless photo.
You can spend thousands upon thousands on some dream photographic outfit, and never take a photo any-one wants to look at.... you can pick up a £10 'toy' and take photo's people will rave about.
IF you remember the VIEWER. and to ask yourself what they want to see, before you press the shutter.
After that... well, nothing is all THAT important, I don't think.