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03-02-2010, 09:32 AM   #91
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QuoteOriginally posted by jezza323 Quote
im eagerly awaiting initial testing and pricing on the 8-16mm, need to decide if i should delay my impending 10-20 or 12-24 purchase....
Ditto

24X36NOW - I'm feeling a bit intellectually challenged on your point that the 12-24 has the widest angle of view - how can a 8 degree lens have less angle than 12? Could you point me to a webpage that's help me get this?

Cheers

03-02-2010, 11:15 AM   #92
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I can explain it, actually. The 12-24 is a Full Frame lens which means its angle of view covers a bigger diagonal. The 8-16 only covers an APS-C image circle, which limits the angle of view to the much smaller APS-C diagonal. The 8-16 on APS-C is close to, but not quite the angle of view "equivalent" of the 12-24 on Full Frame. The APS-C focal length is about 2/3 of the Full Frame focal length, but has to be to cover a similar angle of view on the smaller sensor.

Have I cleared it up?
03-02-2010, 12:22 PM   #93
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QuoteOriginally posted by 24X36NOW Quote
I can explain it, actually. The 12-24 is a Full Frame lens which means its angle of view covers a bigger diagonal. The 8-16 only covers an APS-C image circle, which limits the angle of view to the much smaller APS-C diagonal. The 8-16 on APS-C is close to, but not quite the angle of view "equivalent" of the 12-24 on Full Frame. The APS-C focal length is about 2/3 of the Full Frame focal length, but has to be to cover a similar angle of view on the smaller sensor.

Have I cleared it up?
Thanks for taking the time - I think so. The 12-24 has that superwide view, but it's the figure when mounted on 35mm. When mounted on dSLR the FoV is still that, but the sensor, being smaller than 35mm film, just actually grabs less of it. So comparing 12-24 and 8-16 on like for like dSLR bodies, the 8-16 actually gives the wider FoV on the negative/sensor as such - I think that's it, or not? What confused me was how a 12mm could have a greater FoV than an 8 mm if on the same body - which it does as a theoretical maximum of course if it's a FF lens but in practise it doesn't mean that on APS-C you'd see more of a FoV than with the 8-16... I think?

03-02-2010, 05:21 PM   #94
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The Sigma 12-24mm has 122 (diag. FOV) on a FF DSLR and the new 8-16mm has 121.2 on a Pentax DSLR. I don't think many will notice the 0.8 difference.

03-02-2010, 05:34 PM   #95
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Nass: You have it right. On an APS-C body, you'd have less angle of view with the Full Frame 12-24, or for that matter any 12mm lens. Focal length is still focal length. But the 12-24 on Full Frame gives you a bit more angle of view than the new 8-16 does on APS-C.

Kudos to Sigma for continuing to make lenses that the stuffed shirts at the camera makers don't dare to. Sigma was the pioneer of wide angle zooms, back when the ultra conservative camera makers insisted it couldn't be done. They've also pushed the envelope with super tele zooms that the camera makers don't offer.

Widest (rectilinear) APS-C zoom lenses from the camera makers are 10mm (Canon and Nikon), 11mm (Sony) and 12mm (Pentax). Sigma gets you down to 8mm with this new lens.

Widest (rectilinear) Full Frame zooms from the camera makers are 14mm (Nikon), 17mm (Canon), and 24mm (Sony) (and Pentax has none). Sigma gets you down to 12mm.

Longest zooms from the camera makers top out at 400mm (Canon, Nikon and Sony) and 300mm (Pentax - APS-C only). Sigma gets you to 800mm. (But only if you shoot Nikon or Canon (or Sigma or 4/3, believe it or not) - sigh)
03-02-2010, 07:47 PM   #96
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QuoteOriginally posted by WMBP Quote
I think zooms should all work the way ordinary wood screws work.


Will
Have you seen Pentaxya's prices lately?

I do agree with you about the direction for both focus and zoom rings. It would be nice to maintain a standard.

Last edited by bogiesbad; 03-02-2010 at 07:54 PM.
03-03-2010, 01:43 AM   #97
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QuoteOriginally posted by 24X36NOW Quote

(...)

Longest zooms from the camera makers top out at 400mm (Canon, Nikon and Sony) and 300mm (Pentax - APS-C only). Sigma gets you to 800mm. (But only if you shoot Nikon or Canon (or Sigma or 4/3, believe it or not) - sigh)
Pentax used to propose K 135-600 mm f/6.7 then F*/FA* 250-600 mm f/5.6. I'm not sure they sold a bunch of either of them...
03-03-2010, 01:48 AM   #98
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Thanks, 24X36NOW, for taking the time

03-03-2010, 11:25 AM   #99
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...wish Sigma would start producing weather resistant lenses...
03-03-2010, 01:25 PM   #100
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QuoteOriginally posted by m8o Quote
...wish Sigma would start producing weather resistant lenses...
+1, and include weather resistant Kmount version of their 300-800mm f5.6 or at least the 800mm f5.6...
03-04-2010, 11:41 AM   #101
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QuoteOriginally posted by m8o Quote
...wish Sigma would start producing weather resistant lenses...
It wouldn't be that big of a thing against Pentas lenses but against the rest of the market, IMO, it would drive Sigma sales very well IMO.
03-04-2010, 12:59 PM   #102
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QuoteOriginally posted by pcarfan Quote
No, rectilinear, and that's why it's so promising to me............built-in hood is very nice but ouch on no filters
If you know the full-frame version (the 12-24mm that is) it had no filter thread either but they allowed gel inserts at the back of the lens. The reason is that the spread in front is so wide that the lens bulges from the barrel, hence it got the nickname "popeye" lens.

I suspect the built-in hood is to protect a bulging element here too. Yes, filters would be useful sometimes but considering the most useful filter (polarizer) would not really work with such a lens due to the angle-of-view, that is not so bad. One would probably also need huge filters to avoid blocking incomming light too with such field-of-view.

- Itai
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03-07-2010, 10:27 AM   #103
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QuoteOriginally posted by Nass Quote
Thanks, 24X36NOW, for taking the time
My pleasure!
03-08-2010, 02:06 AM   #104
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It's pretty clever of them to include an adpator to extend the lens hood for the smaller sensors for some of those lenses. I already do that for my homemade rain cover on my old 70-200.

Though I wish they's bring out the 120-300/f2.8 for Pentax, though I could probably never afford it!
03-08-2010, 07:25 PM   #105
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QuoteOriginally posted by Arpe Quote
It's pretty clever of them to include an adpator to extend the lens hood for the smaller sensors for some of those lenses. I already do that for my homemade rain cover on my old 70-200.

Though I wish they's bring out the 120-300/f2.8 for Pentax, though I could probably never afford it!
I actually don't like that lens, since it triggers one of my pet peeves by switching the position of the zoom and focusing ring. It also zooms in the opposite direction, another annoyance. Finding yourself zooming when you want to focus or focusing when you want to zoom (or zooming out when you want to zoom in, or vice-versa) while in the field is not a good thing.
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