[DRabbit]

I'm not sure that would be very practical. If the weather is bad enough to need WR, you are probably not going to be changing lenses. Looking at it that way, a WR zoom makes much more sense.

Huh? Whether I'm going to change lenses or not, it would be nice if the DA primes were weather-sealed for SHOOTING in the rain or snow. I don't understand why changing lenses has anything to do with shooting in bad weather...

I certainly would not object to WR on all lenses including primes, but it does add cost and complexity and you have to look at the cost/benefit.

It would be nice to have the option. If there were WR versions of the 21, 35 and 70, I'd buy them in a flat second, even at an additional cost.

[Dice]

Hmmm... sorry to hear about the soft comers and the fact it's unusable at 20mm wide open. Wide is important to me (and my paid work), so I'll have to look more carefully at samples that are out there.

Can I just say I wish Pentax would put out a line of weather-sealed DA primes?

Hi DRAbbit. I would suggest that you evaluate based on your own set of needs. If you read the user reviews and even some of the professional reviews you will see there appears to be enough weight of information to suggest that the zoom is sharper than the DA 21 wide open (which I can also support) and does not need to be stopped down to produce an acceptable image. For me, the wide end of the lens is only marginally less sharp than the long end. I know that Sandy's copy was unacceptable to him but don't be afraid to PM some of the current users and ask for their input and to see full size images. The comment about soft corners, is so subjective, debatable, may not even be relevant unless you are pixel peeping, or shoot a lot of brick walls. Are the edges and corners less sharp than the center, yes. But you can say this for 99.9% of the lenses out there. Can you create an image where the corners are more than acceptably sharp...absolutely.

In the end, this is a rather unique lens in form, fit and function. There are lots of alternatives, each with there own set of faults/strengths. But it is not cheap, so make sure you do your homework and figure out whether it fits your needs.

[normhead]

I'm completely mystified as to why this lens is where it is... my everyday lens is my 18-135, 20-40 is very limited in range by comparison....

I carry my 21 for when I want professional looking bokeh, and what I call, smoothness...

this is an ordinary snap from a walk in the woods....


The bokeh is just exceptional, this is shot at ƒ5.6

And when you're looking for "smooth" the 21 is unbeatable....











I just find the idea that the 20-40 has better bokeh leaves me saying... ok, I'm open, but show me an example. The example images in the 20-40 thread look to me like zoom bokeh, not prime bokeh..

I can't really see it as a prime replacer.... but for some it could take the place of my 18-135 I guess... not for me, but for some...

[DRabbit]

Good advice Dice, and thanks. I know it can be hit or miss when you're asking for opinions online... someone can be more or less picky than yourself, and charts or brick walls may show imperfections that often aren't visible in real-world shooting. What I'd like to do is try to keep the DA21 even with the purchase of the 20-40, but I'll have to see if I can afford to do that.

Will likely be trying to see that DA*55 next week, so we'll see what I decide by then

Norm, thanks for the samples.
I've considered the 18-135 also, but I did buy it a couple of years ago and just wasn't happy with the focus and sharpness. Of course, that was on the original K5, and I could have had a bad copy, but you can imagine it makes me a little leery.

[normhead]

Good advice Dice, and thanks. I know it can be hit or miss when you're asking for opinions online... someone can be more or less picky than yourself, and charts or brick walls may show imperfections that often aren't visible in real-world shooting. What I'd like to do is try to keep the DA21 even with the purchase of the 20-40, but I'll have to see if I can afford to do that.

Will likely be trying to see that DA*55 next week, so we'll see what I decide by then

Norm, thanks for the samples.
I've considered the 18-135 also, but I did buy it a couple of years ago and just wasn't happy with the focus and sharpness. Of course, that was on the original K5, and I could have had a bad copy, but you can imagine it makes me a little leery.

Ya, that seems to happen with every lens... in fact, my wife doesn't think she gets good images with my 18-135, she just says "I don't seem to be able to get the images you do" and we leave it at that. Same lens. There's guys posting bad images taken with 31 ltds, and according to lens rentals.com it happens with every lens and every manufacturer. But still it is hard to get over a bad copy.

And there's always the possibility that like my wife, the 18-135 doesn't suit your style. She loves her Tammy 17-50 2.8 though.That for me is the big question for me.. is it better than the fixed aperture Tammy?

I went looking for a review, I hope there are a few better than this one..
http://www.lenstip.com/396.4-Lens_review-Pentax_HD_DA_20-40_mm_f_2.8-4.0_ED_...esolution.html

[cbope]

Huh? Whether I'm going to change lenses or not, it would be nice if the DA primes were weather-sealed for SHOOTING in the rain or snow. I don't understand why changing lenses has anything to do with shooting in bad weather...

I don't know how you shoot, but when I am in the field I rarely stick to one focal length for long. If I'm shooting primes, I change often.

It would be nice to have the option. If there were WR versions of the 21, 35 and 70, I'd buy them in a flat second, even at an additional cost.

I don't disagree, but I think the market for weather sealed primes is pretty small. It's a simple business decision, how many more Limiteds would Pentax sell if they were weather sealed? If the increase is very small, as I would expect, then they will never recoup the investment. Just my 2 cents as a product manager who looks at these kinds of decisions on a daily basis. YMMV.

[bdery]

Can I just say I wish Pentax would put out a line of weather-sealed DA primes?

It's much more likely that the FA limiteds will get the WR treatment, I think. the DA were very recently upgraded. but I would inteed love to replace my amazing DA40 with either a WR version or a FA43 WR.

I'm not sure that would be very practical. If the weather is bad enough to need WR, you are probably not going to be changing lenses. Looking at it that way, a WR zoom makes much more sense.

I don't know how you shoot, but when I am in the field I rarely stick to one focal length for long. If I'm shooting primes, I change often.

When I use a prime, I often stick with it and not change lenses. For instance the K-3 with DA40 makes for a very nice and light package when I move around a lot. The DA21 does the same. Some prefer zooms, some want to change often, some live with one prime mounted and that's it.

[Kozlok]

My biggest issue with zooms is flare resistance. The limited primes walk all over any zoom when the sun's in the frame. For example, I don't think the 20-40 could recreate these shots without a smear of flare across the frame:

[lytrytyr]

The limited primes walk all over any zoom when the sun's in the frame. For example, I don't think the 20-40 could recreate these shots without a smear of flare across the frame.

Think?

Try looking at samples from it, e.g. in the
https://www.pentaxforums.com/forums/122-lens-clubs/247859-da-limited-zoom-clu...ml#post2710857

---------- Post added 03-19-14 at 08:04 PM ----------

Well, corner sharpness with the 20-40 has never impressed me.

Really? 40 lp/mm on the K5 not good enough for you?

---------- Post added 03-19-14 at 08:07 PM ----------

I'm completely mystified as to why this lens is where it is... my everyday lens is my 18-135, 20-40 is very limited in range by comparison.

But your DA 21 is even more limited in its range!

[bdery]

Originally posted by bdery Well, corner sharpness with the 20-40 has never impressed me. Really? 40 lp/mm on the K5 not good enough for you?

Tossing one number in the discussion isn't very helpful. You can of course find one setting where the lens is at its best. The same is true of any lens. Trust me, I'm an optical designer But I'm talking about sample images. I could not see myself replacing my 21 and 40 with the 20-40, even though I would really, really like to do so.


No need to get defensive, unless you designed the lens, of course

[GaryH]

But size is really the biggest factor for me. As you can imagine, as a prime shooter primarily, I like to keep lenses as small and light as possible. Hence why I'm hesitant to give up the 21mm at all.

Here are a couple of shots comparing size. I did not keep the lens but did keep the 16-50 and all of my limiteds. So far, I am happy with it.

[Sandy Hancock]

Can I just say I wish Pentax would put out a line of weather-sealed DA primes?

They already do. Unfortunately it is currently limited to the DA*55, DA*200 and DA*300.
A fast 24, 35 and 85/135 are long overdue....

[DRabbit]

They already do. Unfortunately it is currently limited to the DA*55, DA*200 and DA*300.
A fast 24, 35 and 85/135 are long overdue....

I should have been more specific ... I want the 21, 35, 40 and 70 that I already own to be offered in weather-sealed versions.
And while we're at it, the 31, 43 and 77.

Considering that "weather-sealed" has become the latest-greatest feature on many manufacturers' cameras, and Pentax was somewhat ground-breaking in this arena years ago, I guess I'm not sure why any of their lenses aren't weather sealed. I find it frustrating quite honestly. It's like the new Fuji XT1... how the heck can you release a camera into the market place boasting it's weather-sealed-ness, and not have the kit lens it comes with at least be weather-sealed?

But I digress...

Thanks for all the feedback everyone. I enjoyed the photos comparing the size of the lens. The 20-40mm will clearly be highly redundant in my collection of lenses (considering I own the 21mm, 35, and 40, plus the Sigma 10-20). I think the best solution may be only to buy it if I can afford to keep what I already have too, since I like each of my lenses for the reasons I bought them initially... it's just in the weather-sealing department they are all lacking. Maybe the 18-135 makes more sense as a overall lens to cover my bases in the rain and snow, so I'll really have to give it some serious thought.

I do shoot in the rain and snow quite a bit, and it would be nice to not have to cover my camera with plastic.

[Sandy Hancock]

I should have been more specific ... I want the 21, 35, 40 and 70 that I already own to be offered in weather-sealed versions.
And while we're at it, the 31, 43 and 77

The DA limiteds have just been updated, so that's unlikely to happen anytime soon.
The DA*16-50 should suit your needs well.

[lytrytyr]

Tossing one number in the discussion isn't very helpful.

Au contraire: It negates the claim that the lens cannot deliver corner sharpness.
And ironically, that number is taken from the negatively worded Optyczne/Lenstip review that @normhead linked.

You can of course find one setting where the lens is at its best. The same is true of any lens.

At its best for one particular parameter, at least.

But the issue is, how good is that best?

The A 20/2.8, for example, has soft corners on APS-C at all apertures,
so I do not find that its best in that regard is good enough for critical applications.

Trust me, I'm an optical designer

I am aware of that, which is why I quoted you a specific number,
which might not have meant much to casual users,
rather than saying, for example, that it delivers more than 90%
of the optimal corner sharpness on APS-C available from the FA 31.

But I'm talking about sample images.

Which ones? The ones from the very start of production?

I could not see myself replacing my 21 and 40 with the 20-40, even though I would really, really like to do so.

No need to get defensive, unless you designed the lens, of course.

It is not a question of "getting defensive," but of setting the record straight.

It would be a shame if potential users of this lens were misled by the kind of ill-informed comments that have appeared,
or thought that the early samples are representative of what you would get if you were to purchase the lens now.

I was very skeptical of this lens when I first received it,
precisely because of the experiences of early users like Adam or Sandy Hancock,
so I was very pleasantly surprised when I found it to be better
than my A20/2.8, K24/2.8, and DA 40 XS.
And since it is a zoom, after all, I am not disappointed that it doesn't outperform my DA 35 Ltd.