[Richard Day]

For me, primes fall into two specific catagories that I find really useful.

1. Macros, because the image quality is probably the finest you can achieve and they have a definitive function that no zoom can equal. I love my FA 50 macro and will probably buy a 100 macro in the future, I can't afford or find a FA*200 macro!

2. Long telephotos, because very long zooms tend to have much poorer performance and are usually so much larger and heavier. The FA*/DA*300 plus a decent TC is an excellent and very workable combo.

Otherwise, I find that the DA 16-45 (or 16-50) and either the 50-135 or hopefully the 60-250, fulfill almost all my needs. I would like to add a DA 12-24, I think I would find it the perfect street lens.

I've worked with fast primes for many years and have owned the FA*24 and FA 35 f2.0 and have used the 3 DA Limited pancakes and the FA 31 and 77 for considerable periods. I don't miss any of them one bit.

I switch focal lengths considerably and find working with primes and the mental complication of determining which lens will I use for each shot very restrictive. I hear all the comments about a prime will make you think more about your compositions etc., but I don't buy into that thinking! The nearest I got to liking a particular FL was with the FA* 24, but even then I often reverted back to my 16-45.

Another reason is that I hate carrying around a lot of kit and owning excessive hardware, I prefer minimalism.

[dantuyhoa]

FA50/1.4 for me !

"Cheap" enough to get . Low light use . Nice bokeh .

[Noisychip]

Thanks to everybody for voting, what an awesome lot of opinions!

Seems like 28-31mm is the favourite and 50 is second. That's not quite what I expected, though very interesting

Next would be a poll where to get the money for the FA31 Ltd from ...

Please keep on voting!

[KungPOW]

For my DSLR, a 28-31 is the ideal general purpose length. (I dream of the 31 LTD, one day...)

For my SLR, a 50-55 is the length of choice.

If I had only one lens for both cameras, it would be the 43 LTD.

[georgweb]

Good god,
this again reminded me of all the manual lenses I've got.
I voted for 50mm on my K100D, just perfect for me.
Take the SMC Takumar 1.4/50, currently clinging to the cam since 3 days?
Or the M42-conversion Summicron R 2/50?
One sleeper for me is the Mamiya Sekor SX 1.4/55, special lens like the Summicron.
Of all the nice Pentax lenses I have not got, I'd be tempted the utmost by the 77Ltd.

Ah well, give it up for the Takumar, nothing it can't do!
With the Tak comes the Panagor Tele Macronet 3x converter - you said only one lens :-)
Georg
PS: Forgot about a very close second choice: the CZJ Flektogon 2.4/35. Does macro, landscape, portrait, anything. Better colors than the Tak!

[reeftool]

I got by for several years with my SP 1000 and 55mm f2. I couldn't afford anything more at the time. I still have it.

[thePiRaTE!!]

Best range for a prime is 1000mm because a zoom would be much bigger and you couldn't carry it.

[benjikan]

31mm Limited.

Ben

[ericc]

FA 31 Ltd. as well.

[Voe]

For me having to choose only one prime is like someone asking me "If you could own only one pair of shoes what type of shoes would it be (formal shoes, sports shoes, winter boots, thongs etc.)" My point is that with primes you are not supposed to have only one. No matter how good you are you still need at least two different focal lenghts.
But if you ask me what is my most used focal lenght I would say it is the 50mm. But I can't imagine having only 50s.

For me having only one prime kills all the purpose of shooting with primes.

[expatCanuck]

I'm not entirely sure I fully grok the question ... but a 35mm macro (on a DSLR) would suffice.

Here's a recent 35mm image: boy and dog
(K200D, DA 18-55 AL II, f4.5, 1/10 sec, ISO 400 )

I lived for years with two Nikkors, a 55mm f2.8 macro and a 28mm f3.5, both on my Nikon FE (all of which I still have -- and they still produce splendid images).

I'd be hard pressed to say which one I used more.

Cheers,

- Richard
Old Without Money

[regken]

You didn't list it but it is far and away my favorite. Close to a normal view and you can zoom with your feet.

[NickC]

DA 35mm Macro. Loving this lens, great focal length (normal), close focus, great IQ, feels good.

Probably be the 43mm on a film body, but it's too long for DSLR. Doesn't focus close enough either.

Nick

[thePiRaTE!!]

For me having to choose only one prime is like someone asking me "If you could own only one pair of shoes what type of shoes would it be (formal shoes, sports shoes, winter boots, thongs etc.)" My point is that with primes you are not supposed to have only one. No matter how good you are you still need at least two different focal lenghts.
But if you ask me what is my most used focal lenght I would say it is the 50mm. But I can't imagine having only 50s.

For me having only one prime kills all the purpose of shooting with primes.

Actually, this is well put. My sentiments exactly. I just couldn't contain my sarcastic humor on my original answer, hehe. And like others FA 31 was my first. Not the most interesting, but perhaps the most useful.

[GaryM]

I thought my One True Prime would be the DA35 Macro, but I keep getting the most 'keepers' from my DA21, so that would have to be the one I'd keep. It's the most underated Limited, IMO.