[thibs]

I rather see a distinction being made between Limiteds and DFA* lenses. But, we'll see...

May very well be, but does my point prevent yours ?

[monochrome]

That's not what I meant. An FF 20-40 makes less sense and IMO very weird range as an FF lens. 20-35 would be more in line.
I didn't say it made no sense, though. An APS 20-40 considering current

I once had an M24~35/3.5 which I thought was pretty odd FL. Maybe there is a special camera not yet revealed that this lens attaches to.

[Kunzite]

May very well be, but does my point prevent yours ?

Does it have to?
It appears we both envision barely faster than f/2 DFA Limiteds.

[gazonk]

That's not what I meant. An FF 20-40 makes less sense and IMO very weird range as an FF lens.

Pentax used to have a 40mm/2.8 kit lens and an ultra compact 20mm/4 lens for the M series cameras, so to me 20-40/2.8-4 makes a whole lot of sense. It also covers the old M-series 28 and 35mm lenses - what's not to like?

[lytrytyr]

Pentax used to have a 40mm/2.8 kit lens and an ultra compact 20mm/4 lens for the M series cameras, so to me 20-40/2.8-4 makes a whole lot of sense.

Thanks for reminding us.

Curiously, it's now the 20mm length that gets f/2.8,
and 40mm that gets f/4.

[thibs]

Pentax used to have a 40mm/2.8 kit lens and an ultra compact 20mm/4 lens for the M series cameras, so to me 20-40/2.8-4 makes a whole lot of sense. It also covers the old M-series 28 and 35mm lenses - what's not to like?

That 20-35 or 24-50 would make a lot more sense?
Yeah, Pentax indeed did produce a 24-50, I know

[gazonk]

Thanks for reminding us.

Curiously, it's now the 20mm length that gets f/2.8,
and 40mm that gets f/4.

Are you sure? I mean, with Pentax you never know

[Charles Hueter]

Back in 2008, I talked about a wish list lens idea: a 20-40 f/2.0 I called the ambient party zoom. It would offer a decent wide angle through a mild telephoto field of view and that aperture would provide useful flexibility for low-light shooting. See here for the discussion: Wish lens: 20-40mm f/2.0: Pentax SLR Talk Forum: Digital Photography Review

While I would be disappointed if the aperture on the future lens is f2.8-4.0, if the image quality was great and they utilized the sacrificed aperture costs to incorporate a DC motor and weather sealing, I'd consider getting one. It would be a high-grade kit lens for the space-conscious roaming photographer.

However, I would almost certainly get the Sigma 18-35 f/1.8 first because I shoot frequently in low light and a 28mm equivalent opening up to f/1.8 is too tempting to skip.

[ElJamoquio]

Sounds like the Sigma is very close to your ambient party zoom wishlist.

I wish Pentax would've made it... it would've been slightly smaller I think... but oh well.

[Mr Spocko]

I don't get it. Nice to see a WR limited zoom.
20-40mm f2.8-f4 is a strange focal range to pick for APS-C
20mm isn't wide enough and 40mm isn't that long.

Somebody isn't thinking properly about the lens line up
Just buy a plastic bag and stick it over your Tamron 17-50mm f2.8

[jonny1986]

what lens is this? come on. totally useless.
a 30-60 2,8-4....

pentax is coming out with great body but they need to rethink roadmap.

we need sealed lenses like da* with second generation sdm that is much faster...we need long lenses, zoom or fixed...we need fast prime
like 30 1,4...24 1,8..20 f 2 for example...or try to do 55 1,2 something new ..the apse circle will let pentax produce fast prime still smaller than ff equivalent.
ff is not important but we need these lenses.

[Quicksand]

we need sealed lenses like da* with second generation sdm that is much faster...we need long lenses, zoom or fixed...we need fast prime
like 30 1,4...24 1,8..20 f 2 for example...or try to do 55 1,2 something new ..the apse circle will let pentax produce fast prime still smaller than ff equivalent.
ff is not important but we need these lenses.

Who is this "we"? I don't need those lenses.

And if I did, I could buy the existing 55/1.4, the 31 Ltd., or various Sigma lenses.

[Digitalis]

I say that this could be fullframe indeed, otherwise such a hood makes no sense at all

If this lens was full frame it would have the D-FA designation and it would also need a deeper hood to shield the front element from stray light - have you seen the hood on the DA15 mm f/4? - that is roughly how deep it would have to be.

[Quicksand]

If this lens was full frame it would have the D-FA designation and it would also need a deeper hood to shield the front element from stray light - have you seen the hood on the DA15 mm f/4? - that is roughly how deep it would have to be.

Care to elaborate on your thinking re: the hood?

On a crop sensor, the FOV is narrower, so a deeper hood is justified.

On an FF sensor using the same lens, the wider FOV suggests a smaller, shallower hood.

[Digitalis]

Let me put it this way, using a smaller sensor is not like cutting cylinders* through the lens elements, throwing away the outer perimeter (annulus) of all the glass, and just using "the center of the lens". In fact, the full diameter of the entrance pupil of the lens is always employed, regardless of how tight a sensor crop you take, because the entrance pupil diameter (D) defines the focal ratio (f) in conjunction with the Focal length F (f = F/D). Since cropping doesn't change focal length, and doesn't change the image brightness, it cannot change the entrance pupil size either. So in order to be effective on this lens, the hood should be bigger IMO otherwise even with the hood attached flare will be problematic on both DX and FX format.

* in actuality it is more like a cone going from the annulus of the first element and receding in diameter towards the focal plane. Though this is only a model for when the lens is used at its widest aperture, things change once you start stopping the lens down.