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01-08-2014, 06:32 AM   #1096
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QuoteOriginally posted by Digitalis Quote
Excuse me, have you even worked on a continuous basis with the FA31? Tests can reveal many things about a lens. Lens tests are like a bikini on an attractive woman - what they show is interesting, what they hide is vital... tests always completely miss the point of the experience of working with a lens and getting to know a lens. In my opinion as a leicaphile, and an owner of multiple camera systems and some of the best lenses ever made - the FA31 is a truly remarkable lens, I have never made an image with the FA31 where its optical characteristics fell short of what I (or my clients) required . I have seen literally hundreds of shots where a lens from another maker has ruined a shot because of some egregious mechanical/ergonomic/optical blooper.

Sometimes when people criticize a lens I happen to own, I get the feeling they are referring to a completely different lens.
Did you read my post? I said it was a good lens. I wasn't criticizing the lens, I was criticizing a blind test (like DxOMark would do). I think you must've read my post too quickly.

The 31mm is not-quite-welded to my K-5, not that it is relevant.

01-12-2014, 03:37 PM   #1097
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QuoteOriginally posted by wildboar Quote
I tested my Pentax 20-40 against my Tamron 17-50 as soon as the Pentax arrived. The 20-40 won easily for sharpness, especially in the corners and at the edges of the frame. The Tamron had noticeably less distortion at 20mm though. The Pentax is also lighter, smaller, quieter, and sealed. Now we can argue over whether I got a great copy of the Pentax, or a bad copy of the Tamron. ;-)

You must have a ho hum copy of the Tamron, the lens is very sharp only very slight corner softness (extreme corners) across the entire range it's a stunning lens and nothing from the Pentax samples I've seen comes close to it.


Stop it down to f4 and it's stupid sharp across the entire range corners are tack.
It's even good wide open tele end, I would not hesitate to use it wide open at all focal lengths, that's how good a decent copy is
There is some field curvature at the wide end, but I have to say 20mm is a lot less useful than 17mm, that alone rules the Pentax out for me
01-12-2014, 07:08 PM   #1098
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I hope a comparison of the famous Tamron 17-50mm and DA 20-40mm ltd will be of actual beautiful subjects and not just test charts. Let's see photographs of flowers, animals, people, objects in the real world. Where the photographer tries to take a good photo, of the same subject, with both lenses. I think those conditions will reveal the true difference, more than just "blank" shots to demonstrate overall performance.
So, yes, the Tamron is sharp, has a wider range, a constant aperture, and it costs less. But there are more differences still, and I think/hope some might redeem the Pentax lens (other than overall build, WR and QS)
01-13-2014, 05:38 AM   #1099
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QuoteOriginally posted by Mr Spocko Quote
stupid sharp across the entire range corners are tack.
Such a Tamron sounds after my taste Spocky, were you lucky with your first copy, or if not, how many other copies did you have to send back before you got such a sweet one?

01-13-2014, 06:26 AM   #1100
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QuoteOriginally posted by Frater Quote
Such a Tamron sounds after my taste Spocky, were you lucky with your first copy, or if not, how many other copies did you have to send back before you got such a sweet one?

I've used 3
I had to replace one was a bit off, the other 2 were fine though


Like all lenses QC can play a part, so it's not a shock that there is some variation.
But certainly on the good ones f2.8 is great even at 50mm just fine and sharp mostly across to the edges just a very tiny fall off extreme corners, f4 clears that up but for most purposes few would notice unless you take brick wall shots, even then I've never had an issue in real world use. At the wide end of course you would tend to stop down for landscape shots (but watch out for that focal plane distortion) Decentering can be an issue on any lens, but it's quite easy to spot that problem when one side is notably softer than the other, few lenses are absolutely perfect, but you should know if there is something wrong fairly quickly.


In some cases AF issues can be a problem too, hence complaints about xyz lens not sharp at xyz focal length. Simple way to test that is use live view


I'll wait until more review for the Pentax turn up, then we can see what the story is with other samples. But it goes without saying you would expect tighter QC on more expensive lenses
01-13-2014, 06:56 AM   #1101
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I use both the Tamron 17-50 and the DA 20-40.

The Tamron's focus was hit-and-miss with PDAF on the K-x,
so I had to resort to CDAF in live view for critical shots.
Once I got a K-01, the Tamron really came into its own.

Nevertheless, its rendering does not have the richness
that the DA 20-40 is producing.

Another advantage of the DA 20-40 is its rapid availability for grab shots, with the hood.
On the Tamron, I've had to shoot with the hood in the reversed carrying position
if I've needed to use it in a hurry. (At least the reversed hood doesn't interfere with the focus ring.)
01-13-2014, 07:09 AM   #1102
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The rendering is fine on the Tamron it's neither poor nor amazing. If you want amazing then just buy the Tamron 90mm f2.8 one of the bokeh kings and well respected
You will certainly have the ability to take better portraits with the 90mm at f2.8 than you will at 40mm f4.


And sealing the deal you can buy both for about the same cost of the Pentax 20-40mm lens, and you get a 1:1 macro too, bit of a no brainer really
20mm just isn't wide enough and I'm really surprised Pentax picked such a range


AF performance should be looked at on a body to body basis, I had a K-x and it was ok for focus, but it has very large AF points making critical focus somewhat harder at times
01-13-2014, 07:13 AM   #1103
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QuoteOriginally posted by Mr Spocko Quote
20mm just isn't wide enough and I'm really surprised Pentax picked such a range
The field of view of an FA 31 in its native format.

01-13-2014, 08:16 AM   #1104
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20 mm is great... but odd for a lower limit, not even as wide as a 28mm zoom.

I think Pentax started with a package size and asked what they could do in that package rather than starting with a list of requirements and trading off package size.

If it's not the lens for you, don't worry about it, and don't purchase it.
01-13-2014, 08:37 AM   #1105
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I think being blunt it's not the lens for most people, not just me
I suspect many users will have migrated from the 18-55m kit lens, probably to a 16-50mm f2.8, either the Tamron/Sigma 17-50mm f2.8 or even the Sigma 17-70mm f2.8-f4
In most cases I can't see a place in the bag for a 20-40mm it seemingly came out of nowhere, and nobody was asking for it. Hence my comments on being a strange choice from Pentax


I'm not entirely convinced limited zooms are wanted by most Pentax users.
01-13-2014, 08:42 AM   #1106
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QuoteOriginally posted by Mr Spocko Quote
I'm not entirely convinced limited zooms are wanted by most Pentax users.
maybe not by most, but i want one!
01-13-2014, 08:46 AM   #1107
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QuoteOriginally posted by ElJamoquio Quote
20 mm is great... but odd for a lower limit, not even as wide as a 28mm zoom.
There used to be a time when the kitlens was a 35-70 zoom. A 23-46 zoom would give the same FoV on APS-C. Given that, the 20-40 is actually considerably wider, albeit a bit short at the long end.

Wim
01-13-2014, 09:10 AM   #1108
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QuoteOriginally posted by Mr Spocko Quote
The rendering is fine on the Tamron it's neither poor nor amazing. If you want amazing then just buy the Tamron 90mm f2.8 one of the bokeh kings and well respected
You will certainly have the ability to take better portraits with the 90mm at f2.8 than you will at 40mm f4.
If the Tamron 90 rendering was in their zoom then we'd have something to talk about. But it doesn't and the 90 isn't exactly wide nor normal and for me is a little long for most portraiture.
QuoteOriginally posted by Mr Spocko Quote
I think being blunt it's not the lens for most people, not just me
I suspect many users will have migrated from the 18-55m kit lens, probably to a 16-50mm f2.8, either the Tamron/Sigma 17-50mm f2.8 or even the Sigma 17-70mm f2.8-f4
In most cases I can't see a place in the bag for a 20-40mm it seemingly came out of nowhere, and nobody was asking for it. Hence my comments on being a strange choice from Pentax


I'm not entirely convinced limited zooms are wanted by most Pentax users.
I was one who waited a long while.....since 2007... for the lens. I had the 16-50 for a while but never fell in love with it. So I bought the ltd. primes and loved them...but I got tired of always switching between lenses and wanted weather/dust protection. Perhaps it is my mixed style of photography. Not that it matters. Now that it is here, I'm happy as a clam.
01-13-2014, 09:22 AM   #1109
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QuoteOriginally posted by Ishpuini Quote
There used to be a time when the kitlens was a 35-70 zoom. A 23-46 zoom would give the same FoV on APS-C. Given that, the 20-40 is actually considerably wider, albeit a bit short at the long end.

Wim
And there was a time when zoom lenses meant you didn't care at all about image quality.



I'd rather have a 20-40 than a 23-46, for sure. This isn't really a lens for me but that's OK, some (most?) lenses should NOT be for me.
01-13-2014, 11:04 AM   #1110
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QuoteOriginally posted by Mr Spocko Quote
I'm really surprised Pentax picked such a range
Yes, 10-500/2 would be the ideal lens!
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