[Marc Sabatella]

My understanding is that lenses that are "designed for digital" have better anti reflective coatings on the rear lens element to combat flare reflections off the sensor.

Yes, and of course in practice, it also means "designed to cover an APS-C sensor only" so in theory such a lens can be made smaller than it could otherwise. But these are just a couple of attributes of a lens, and might easily be trumped by other concerns. Eg, the DA18-55 is designed for digital and has these advantages over, say, the FA31, but no one is really claiming the DA18-55 is the better lens overall.

So what I probably should have written is, "I have no trouble believe that being designed-for-digital is a good thing, and that all else equal, it does make difference. But as I often say, all else is rarely equal. So in practice, it is not true that all designed-for-digital are lenses better than all designed-for-film lenses, and in particular, I'm not really claiming Canon's or Nikon's primes are not as good as Pentax's".

All that, again, being a preface for the real point, which is that with the DA15, DA21, DA35, DA40, DFA50, DA*55, DA70, DFA100, DA*200, and DA*300, Pentax has what is as far as I know the most extensive lineup of designed-for-digital primes out there.

[philbaum]

I agree with others who say that Pentax has the best selection of primes for APS.

I think in the range you mentioned, the DA 35 macro F2.8 is the best selection, IMO.

Its a lens that has that 3D appearance in pictures and great resolution. I've walked into restaurants with friends, after taking group ictures on sidewalks and then used it for fun food pictures via close focusing at tables. Don't underestimate the usefulness of a lens that can do close, even macro focusing of subjects, and then can stretch out to infinity. Yes, focusing is a little bit slower than a DA 40, but the speed is a small price to pay for the large focus range.

Others will say that its not a good macro for insects because its too close, but then you're talking about lenses much bigger than the 35 and not nearly as wide on the sidewalks.

If i had to pick a selection of 1 or 2 lenses for a trip, the DA 35 ltd would be in both groups.

[Spock]

"Normal" has nothing to do with aperture, it's simply a description of focal length. A 28mm and 35mm are both considered normal lenses on Pentax APS-C cameras.

Normal lens - Wikipedia, the free encyclopedia

Going by Wikipedia, any lens that can be set to a 'normal' focal length meets the requirement - so both my 18-55 and my 28-105 are 'normal' lenses.

However, old Pentax lens catalogues* I have in front of me are at odds with Wikipedia.

I don't want to type out the standard lens lists from all the catalogues but I will note some examples:

This is how Pentax describes a 'standard' lens in No. 3 (below):

"Standard lenses (F50/1.4, F50/1.7, A501.2, A50/1.4, A50/1.7, A50/2) are the most versatile for all purpose shooting. They approximate the natural viewing perspective of the human eye and their fast maximum apertures make low light shooting easy. Pentax offers a full line up of compact 50mm lenses, from the super-fast f1.2 to the economical f2."

No. 6 (below) lists the following lenses as standard: FA43/1.9, FA50/1.4, FA50/1.7. It lists the FA50/2.8 under 'macro' (along with the FA100/2.8, FA100/3.5 & FA*200/4).

You'll have to take my word for it that this is essentially the case in every catalogue.

* References
1. Asahi Pentax SMC lens catalogue from the 70s
2. Pentax SMC Pentax-A Lenses (1984)
3. Pentax Lenses and Accessories (1988)
4. Pentax 35mm SLR lenses (early 90s)
5. Pentax 35mm SLR Lenses (late 90s)
6. Pentax Lineup Catalog (2004)

Seems like Pentax understands a 'standard' lens differently to Wikipedia.

[Marc Sabatella]

This is how Pentax describes a 'standard' lens in No. 3 (below):

"Standard lenses (F50/1.4, F50/1.7, A501.2, A50/1.4, A50/1.7, A50/2) are the most versatile for all purpose shooting. They approximate the natural viewing perspective of the human eye and their fast maximum apertures make low light shooting easy. Pentax offers a full line up of compact 50mm lenses, from the super-fast f1.2 to the economical f2."

OK, but there's a difference between a description of four particular standard lenses and a definition of the term in general. Sure, those particular standard lenses happen to be fast. That doesn't mean they are saying this is a necessary feature of *all* standard lenses.

Seems like Pentax understands a 'standard' lens differently to Wikipedia.

Not surprising; it's not like there is really a official arbiter of such things. People use terms like these to mean what it suits them to mean. Like Pentax making reference to "natural viewing perspective of the human eye", which as anyone who has tried following the various threads over the years on this issue knows, is actually a pretty meaningless statement.

[Spock]

OK, but there's a difference between a description of four particular standard lenses and a definition of the term in general.

In that definition, I added the list in brackets. It was a general definition not a description of any four particular standard lenses. But in fact, if you count them, you will see that there were actually six standard lenses on offer in 1988! (Seven if you really want to include the 50/2.8 macro). Compare that to the situation today!.

it's not like there is really a official arbiter of such things. People use terms like these to mean what it suits them to mean.

Yes I agree - and to me a standard lens is how Pentax described them above. Nowadays Pentax do not claim to have any standard lenses on offer for aps-c.

[Douglas_of_Sweden]

And who has significantly more primes that would be normal on APS-C?

Pentax: 31/1.8ltd, 35/2.0, 35/2.8ltd, in total 16 primes, most of them new designs for APS-C/digital

Nikon: 28/2.8, 35/2.0, DX28/1.8, in total 36 primes, but only two developed for APS-C

Canon: 28/2.8, 28/1.8, 35/1.4, 35/2.0, in total 20 primes

Sony: 30/2.8, 35/1.4, 28/2.8, 30/2.8, in total 14 primes, two of them specifically for APS-C

Olympus (4/3rd sensor): 25/2.5, in total 6 primes

Counted from their Swedish home pages. I'm not so familiar to these other systems, so I may have gone somewhat wrong on the numbers, but probably not very much. I can't tell how many of the CaNiSous lenses that are designed for digital, takes too much reading, but it is throughout a very low number that are designed for APS-C, and many of the Nikon and Canon sounds very familiar to lenses they had already on the 90's. I've included Olympus with their 4/3rd lenses despite that it is not directly comparable, but they have made a real effort to design new lenses for their sensor size.

In summary, I don't see any advantage in terms of the choice of APS-C normal lenses except for Canon and Sony who have one f1.4 lens each (think these are for full frame). But Pentax had a 30mm f1.4 on the lens road map before Hoya started to sensor the road map keeping new lenses in the dark. Hopefully it is still on its way, maybe after the 645 is out with some new lenses?
In terms of total number of primes, only CaNikon beat us, but with help of a large number of 90's designs. It would have been nice if Pentax had still had new FA28/2.0 and FA28/2.8 in production or stock, but they can be had on the used market.
In terms of the number of APS-C dedicated primes, Pentax is the clear winner!

[joele]

Pentax: 31/1.8ltd, 35/2.0, 35/2.8ltd, in total 16 primes, most of them new designs for APS-C/digital

Nikon: 28/2.8, 35/2.0, DX35/1.8, in total 36 primes, but only two developed for APS-C

Problem with the Nikon ones for me is their lack of performance on digital cameras.. ones that I owned or tried, 24/2.8, 28/2.8, 35/2 and new dx35/1.8, only the last was in any way impressive.. The 85/1.8 I owned had the worst (most sensitive to) Purple Fringing of any lens on any format I have ever used (in the right conditions it almost glowed)... So even though the 36 primes for nikon may sound high many I tried weren't that impressive..

Ohh I also have owned both the Pentax F*300/4 and Nikon IF ED 300/4 and the Pentax is smaller and FAR better optically (sharper, better colour, more contrast etc)..

One of the main reasons I am back with Pentax, for prime lenses Pentax honestly wins hands down if you factor in whether they are good enough to be worth owning ;-)

As to the OP, I just bought the FA31 ltd along with the K7, I have owned the FA35/2 in the past and it is a great lens, but now out of production, harder to get and just doesn't quite have that special quality of the 31ltd but still very good and very worthwhile if you can't afford the 31ltd (and beats the hell out of the nikon 35/2)..

[audiobomber]

Going by Wikipedia, any lens that can be set to a 'normal' focal length meets the requirement - so both my 18-55 and my 28-105 are 'normal' lenses.

Your zooms aren't nornal lenses but when set to 28-35mm, they provide a normal perspective. If you had a zoom that went from 28-35mm, it would be a normal zoom. You won't see anything about aperture in any of these definitions of nornal:
define: normal lens - Google Search

However, old Pentax lens catalogues* I have in front of me are at odds with Wikipedia.

"Standard" and "nornal" don't necessarily mean the same thing. The terms are often interchanged, because cameras were usually sold with a nornal lens attached. In the Pentax manual, they're using "standard" to mean the "normal" lenses they provided in 35mm camera kits.

standard lens: Usually the lens provided with a camera as standard equipment; in still cameras, the standard lens is one whose focal length is about equal to the length of the diagonal of the negative area normally provided by the camera; the normal field of view of a standard lens is about 53°. standard lens: Definition from Answers.com

Note that again there is no reference to aperture in the above definition.

No. 6 (below) lists the following lenses as standard: FA43/1.9, FA50/1.4, FA50/1.7. It lists the FA50/2.8 under 'macro' (along with the FA100/2.8, FA100/3.5 & FA*200/4).

This is a good example of the divergence in meaning of normal and standard. The FA 50/2.8 is a normal lens, but not supplied as standard by Pentax.

[stanleyk]

I have the DA 35mm and the Sigma 28. Both are really good lenses. I am planning on purchasing the 31mm shortly. However, it is very expensive compared to the 35 and the 28.

I have a friend who has the Sigma 30. It's also very good. If you can afford the 31mm that would probably be my choice.

If you don't mind manual focus (and in some cases stop down metering), then all of the written above is true with older Pentax lenses. I almost exclusively manual focus and have no problem with stop down metering, so I use a lot of them. I have found the lens reviews on this site to be very informative.

[konraDarnok]

28mm FA is a really nice lens if you can get one used. It's replaced my FA 50mm as a standard lens. Pitty it's not faster however.

[Wheatfield]

Not surprising; it's not like there is really a official arbiter of such things. People use terms like these to mean what it suits them to mean. Like Pentax making reference to "natural viewing perspective of the human eye", which as anyone who has tried following the various threads over the years on this issue knows, is actually a pretty meaningless statement.

All the manufacturers have used that definition in the past. I'm pretty sure that at some point, some time, someone did some tests to figure out what a person's field of view tended to be so as to make lenses of a focal length that approximated it.
I realize that times have changed and people now resist trying to define things in absolute terms, but that doesn't negate that on 35mm, a ~50mm lens is a normal, or that something around 30mm would be a normal on the APS-C format.
At some point, in order to be able to communicate with each other, we need to be able to pin concepts down with language. The trend away from doing that takes away from the ability to communicate succinctly.

[Wheatfield]

My understanding is that lenses that are "designed for digital" have better anti reflective coatings on the rear lens element to combat flare reflections off the sensor.

Yes, and of course in practice, it also means "designed to cover an APS-C sensor only"

I believe Nikon and Canon both have "designed for digital" full frame lenses, though I could be wrong.
In Pentax's world, the smaller image circle is, of course, part of their digital lens design.

[Douglas_of_Sweden]

Problem with the Nikon ones for me is their lack of performance on digital cameras.. ones that I owned or tried, 24/2.8, 28/2.8, 35/2 and new dx35/1.8, only the last was in any way impressive.. The 85/1.8 I owned had the worst (most sensitive to) Purple Fringing of any lens on any format I have ever used (in the right conditions it almost glowed)... So even though the 36 primes for nikon may sound high many I tried weren't that impressive..

Ohh I also have owned both the Pentax F*300/4 and Nikon IF ED 300/4 and the Pentax is smaller and FAR better optically (sharper, better colour, more contrast etc)..

One of the main reasons I am back with Pentax, for prime lenses Pentax honestly wins hands down if you factor in whether they are good enough to be worth owning ;-)

As to the OP, I just bought the FA31 ltd along with the K7, I have owned the FA35/2 in the past and it is a great lens, but now out of production, harder to get and just doesn't quite have that special quality of the 31ltd but still very good and very worthwhile if you can't afford the 31ltd (and beats the hell out of the nikon 35/2)..

Well, I basically wanted to show that the OPs statement "...I've noticed Pentax does not have a huge offer of Prime lens..." was
not motivated. Pentax have the largest number of APS-C primes, and even if we count all formats, only Nikon have a significantly larger number of primes, but these are largely older film age designs, where you have to judge from lens to lens what optical problems it may have on digital. As for normal lenses for the APS-C format (28-35mm), they all have 3-4 options, and the only thing Pentax lack is the f1.4 lenses of Canon and Sony, which probably is comming in the future (the 30/1.4 that was on the old lens road map), and then it will be a dedicated APS-C design.
It is interresting to hear you who have tried both Pentax and Nikon lenses say that the Pentax generally does better on digital. Pentax have been critisized for cancelling most of their FA lens designs, but this was obviously part of their plan to make a complete APSC/digital lens program, and had they kept more of the old FA lenses in production, I'm sure there had been plenty of threads here complaining on their various problems on digital.

[Marc Sabatella]

I'm pretty sure that at some point, some time, someone did some tests to figure out what a person's field of view tended to be so as to make lenses of a focal length that approximated it.

No need to rely on a test done in the past. Anyone can do this test right now. Look straight ahead, fixating on a particular object in front you. Make a mental note of the further object you can see on either side. Now put some lenses on your camera and see which gives you that field of view. For me, on my APS-C camera, my 18-55 doesn't go wide enough to encompass what I can see. So unless I'm just a freak of nature, or human evolution has resulted in the field of view doubling over the last century, the idea that the field of view of a 50mm lens (on FF; 33mm on APS-C) represents human field of view is just ludicrous.

At best, it's some sort of subjective wet-finger estimate of the field of view we might be able to perceive an "acceptable" amount of detail in. But it's also possible to do tests showing that the real peak of visual acuity is found only within the field of view of around a 100mm lens on APS-C. Choosing 50mm as somehow best representing the "natural viewing perspective of the human eye" is just plain arbitrary.

I realize that times have changed and people now resist trying to define things in absolute terms, but that doesn't negate that on 35mm, a ~50mm lens is a normal

Depending on how you define "normal", sure. But any definition of "normal" that results in 50mm being chosen can have little or nothing to do with the human field of vision, and can only tangentially relates to what can be called "natural viewing perspective" (that term has relevance only with respect to making prints of a "typical" size and then viewing them at a "typical" distance.

I'm not saying statements like that weren't commonly tossed around. I'm saying when you actually examine the matter, they turn out to not be very meaningful. Never were then, but people bought into them without giving it much thought. It would have been just as possible to debunk these notions 50 years as it is now; it's just that no one bothered to then (or if they did, they've been long forgotten). Just as for decades anyone who wrote about photography, would tell you that perspective was affected by focal length, and that different lenses therefore had inherently different perspectives, and that a 35mm lens on APS-C therefore somehow has a different perspective than a 50mm lens on FF. The fact that many people believed this doesn't make it true.

Anyhow, I really could care less how anyone wants to use the term "normal" or "standard". I'm just pointing out that there really is no universally agreed upon One True Defintion.

[brosen]

Thanks for the great feedback. I am undecided between:

- Pentax SMC DA* 55mm f/1.4
- Pros: fast, WR, top quality, light, Pentax
- Cons: narrow angle, price (expensive)

- Sigma 30mm f/1.4 EX DC HSM
- Pros: fast, price (cheap), wide angle
- Cons: heavy, no WR, no Pentax, quality

I am very much inclined to Sigma, mainly for the "Wide Angle", but from the other side I really like the WR option and quality of the Pentax lens.

What do you think ?, any recommendation ?, I am not sure about Sigma Lens quality and Pentax compatibility ?, thanks again